Spring does not look to jump right toward summer but have winter hang-over.

WSBRADIO.COM

Temps slightly cooler than normal rest of March and first half of April.

Near normal temps 2nd half of April and May: averaging out Near normal to slightly cool for the 3-month season.

Spring rain above normal thru mid-April then normal to drier than normal Mid-April to Mid-May: working out near average to above-average for the 3-month period.

MAY has the best chance to be warmer than normal.

Tornado season near normal to slightly less than normal: 10 twisters in the state for the spring, 19 on the year. Average is 21. (This should be considered EXPERIMENTAL as I know of nobody who has tried to predict tornado season in advance and I have never tried it before)

Factors that MAY help limit severe weather: lack of lasting warm air temps and cooler than normal Gulf of Mexico water.

In summary, it looks like we only ease out of the wet cool pattern that started with the floods of Autumn, and we do so in fits and starts rather than a quick flip to permanently warm and dry.

Hurricane season more active than normal:

15 named storms
6 hurricanes
4 major

Preliminary analog years: 1958, 1963, 1964, 1966, 1969, 1973, 1977, 1978, 1995, 1998, 2003, and 2005.

El Nino forecast from dynamical and statistical computer models show the downward trend.

Columbia University's IRI

El Niño events typically die out in the spring, and most of the El Niño computer forecast models are predicting an end to El Niño by summer. Note that the last time we had a strong El Niño event--the record El Niño of 1997 - 1998--the event ended very abruptly in May, and a La Niña event developed by the 1998 hurricane season. This resulted in a very active 1998 hurricane season (14 named storms, 10 hurricanes, and 3 major hurricanes, including Category 5 Hurricane Mitch). The recent weakening of El Niño is a likely sign that there will not be El Niño conditions for the coming hurricane season. Only once since 1950 has an El Niño event lasted through two full hurricane seasons, and we do not expect that will occur this time, either. Given that since 1995, the Atlantic has been in an active hurricane period, except for in El Niño years, a more active than normal hurricane season is likely in 2010.

Sea Surface Temperatures (SSTs) in the Atlantic's Main Development Region for hurricanes were at their highest February level on record last month, according to an analysis of historical SST data from the UK Hadley Center. SST data goes back to 1850, though there is much missing data before 1910 and during WWI and WWII. The region between 10°N and 20°N, between the coast of Africa and Central America, is called the Main Development Region (MDR) because virtually all African waves originate in this region. These African waves account for 85% of all Atlantic major hurricanes and 60% of all named storms. When SSTs in the MDR are much above average during hurricane season, a very active season typically results (if there is no El Niño event present.)

SSTs in the Main Development Region (10°N to 20°N and 20°W to 85°W) were an eye-opening 1.02°C above average during February. This easily beats the previous record of 0.83°C set in 1998. SSTs in the Main Development Region are already warmer than they were during June of last year, which is pretty remarkable, considering February is usually the coldest month of the year for SSTs in the North Atlantic. The 1.02°C anomaly is the 6th highest monthly SST anomaly for the MDR on record. The only other months with higher anomalies all occurred during 2005 (April, May, June, July, and September 2005 had anomalies of 1.06°C - 1.23°C).

Don't blame El Niño for the high Atlantic SSTs. El Niño is a warming of the Pacific waters near the Equator, and has no direct impact on Atlantic SSTs. Instead, blame the Arctic Oscillation (AO) or its close cousin, the North Atlantic Oscillation (NAO). The AO and NAO are climate patterns in the North Atlantic Ocean related to fluctuations in the difference of sea-level pressure between the Icelandic Low and the Azores-Bermuda High. They are some of the oldest known climate oscillations; seafaring Scandinavians described the pattern several centuries ago. Through east-west oscillation motions of the Icelandic Low and the Azores-Bermuda High, the AO/NAO controls the strength and direction of westerly winds and storm tracks across the North Atlantic. A large difference in the pressure between Iceland and the Azores (positive NAO) leads to increased westerly winds and mild and wet winters in Europe. Positive NAO conditions also cause the Icelandic Low to draw a stronger south-westerly flow of air over eastern North America, preventing Arctic air from plunging southward. In contrast, if the difference in sea-level pressure between Iceland and the Azores is small (negative NAO), westerly winds are suppressed, allowing Arctic air to spill southwards into eastern North America more readily. The winter of 2009 - 2010 has seen the most negative AO and NAO patterns since record keeping began in 1950, which caused a very cold winter in Florida and surrounding states. A negative AO/NAO implies a very weak Azores-Bermuda High, which reduces the trade winds circulating around the High. During December - February, trade winds between Africa and the Lesser Antilles Islands in the hurricane Main Development Region were 1 - 2 m/s (2.2 - 4.5 mph) below average. Slower trade winds mean less mixing of the surface waters with cooler waters down deep, plus less evaporational cooling of the surface water. As a result, the ocean has heated up significantly, relative to normal, over the winter. This heating is superimposed on the very warm global SSTs we've been seeing over the past decade, leading to the current record warmth. Global and Northern Hemisphere SSTs were the 2nd warmest on record in both December and January.

According to Dr. Phil Klotzbach of the University of Colorado, February temperatures in the MDR are not strongly correlated with active hurricane seasons. The mathematical correlation between hurricane season Accumulated Cyclone Energy (ACE) and February SSTs is only 0.26, which is considered weak. Past hurricane seasons that had high February SST anomalies include 1998 (0.83°C anomaly), 2007 (0.71°C anomaly), and 1958 (0.68°C anomaly). These three years averaged 13 named storms, 8 hurricanes, and 3 intense hurricanes, which is considerably higher than the average of 10, 6, and 2. The big question is, how long will the strong negative AO/NAO conditions keep the Azores-Bermuda High weak? Well, the AO has risen to near-neutral values over the past week, and the latest 2-week forecast from the GFS model show that the AO and NAO will not be as strongly negative during March. This should allow the Azores-Bermuda High to strengthen some this month and increase the trade winds over the MDR. However, we may still set a record for warmest-ever March SSTs in the Main Development Region. Longer term, the crystal ball is very fuzzy, as our ability to predict the weather months in advance is poor. The long-range NOAA CFS model is predicting SSTs in the Atlantic MDR will be about 0.70°C above average during the peak months of hurricane season, making it one of the top five warmest years on record--but not as warm as the unbelievable Hurricane Season of 2005, which averaged 0.95°C above normal during August - October. When will El Niño fade? El Niño is currently holding steady at moderate intensity, and it'lll continue through at least mid-April. It is possible El Niño will linger long enough into the summer that it will create increased wind shear that will suppress this year's hurricane season.

The set of dynamical and statistical model forecasts issued during late January and early February 2010 are in unanimous agreement about maintaining El Nino conditions through at least April. There is some disagreement about the timing and rate of dissipation, and even more disagreement about what ENSO condition to expect for the northern summer 2010 and beyond. The median time of predicted SST falling below 0.5 C is during the AMJ or MJJ season. At the time of preparing this, the SST observations in the NINO3.4 region indicate moderate El Nino conditions, with an area-averaged weekly anomaly of 1.2 C. Current forecasts and observations indicate a probability of about 93% for maintaining El Nino conditions  into April, and still just over 80% for the Mar-May period.

For the upcoming hurricane season there are a number of factors pointing to a more active season than last year, and more active than the long-term average. The rapidly weakening El Niño, warmer ocean temperatures in the typical Atlantic tropical breeding grounds compared to last year, weakening trade winds which reduce the amount of dry air injected into the tropics from Africa, higher humidity levels which provide additional upward motion in the air and fuel tropical storm development energy.

A number of past years set-up compare to the upcoming season, including 1952, 1958, 1964, 1966, 1995, 1998, 2003, 2005, and 2007.

This leads me to this PRELIMINARY 2010 HURRICANE SEASON OUTLOOK for the Atlantic-Carribean:

15 Named storms

6 Hurricanes

4 Major hurricanes

An Above-normal risk of U.S. landfall, threat of at least 2 major hits.

In a typical season, there are about 11 named storms, of which two to three impacts the coast of the United States. The Atlantic hurricane season officially begins on June 1 and continues through November 30. These dates were selected because 97 percent of hurricane activity occurs during this six-month period.

Snow was seen much more often in Atlanta this winter.

ninaspace.typepad.com/my_weblog/adam_roberts/

While winter's back appears broken Old Man Winter has probably not gone to Florida or Arizona to stay until next year just yet, even if odds of snow are slim especially South of the Perimeter/Mountains.

The 30-DAY OUTLOOK for Georgia is for temperatures to be below-normal on average with precipitation above-normal on average. The 60-90 DAY OUTLOOK is for near-normal conditions on average. March is often a volatile month of extremes and is known as "bowling ball" season for the cut-off lows that look like bowling balls on the upper-air charts. They are known for bringing surprises if they pass over your area. Be sure to click on the link at the bottom to see the national maps of the winter that was 2009-10.

Just no way the current limitations of weather forecasting can pin point such sharp changes in snow.

NWSFO Peachtree City, GA

Just not possible given the current state of the art of weather forecasting to nail down such a tight gradient between a little, a lot and none. Not only did small horizontal distances make a big difference, small differences in elevation made huge differences, proving what we talked about was right--how it was just a thousand feet and a few degrees that would separate Atlanta from mostly wet or mostly white. Reports have come in that the top of Kennesaw and Sweat Mountains in Cobb County had 5-6 inches of snow just some extra 400-600 feet higher. Atlanta has a top 5 snowy winter, from the National Weather Service Peachtree City:

Snow in Georgia
March 2, 2010

An upper level disturbance traversing the western portion of the United States February 28 and March 1, 2010 helped to develop a surface low along the Texas coast on March 1. This surface low pressure system tracked along the Gulf coast and advected moisture ahead of the system into Georgia from both the Gulf of Mexico and the Atlantic Ocean. By Tuesday, March 2, the surface low moved across southern Georgia and the Florida panhandle and by that afternoon, had moved into the Atlantic Ocean along the Carolina coast. This system brought both rain and snow to the state. Precipitation started as rain and began moving into western Georgia just before midnight on March 2. During the morning hours on March 2 the precipitation continued moving across the state and changed to snow across north Georgia. The snow proceeded to change back to rain during the afternoon and ended across eastern Georgia late in the evening. Snowfall amounts averaged from 2 to 4 inches across north Georgia. However, higher values were reported across northeast Georgia with reports of 9.0 inches in Union county.

* Preliminary snowfall totals across north & central Georgia...

For the 2009-10 season, all four climate stations rank in the top 10 for highest snowfall amounts. The 1.1 inches of snow reported in Atlanta on March 2, 2010 brings the current snowfall total to 5.3 inches for the season. This ranks number five for the highest seasonal (July 1 to June 30) snowfall totals in Atlanta. Athens received 5.0 inches of snow this year, ranking number ten for highest snowfall totals for the area. Macon tied 1939-40 and 1976-77 for the fifth highest snowfall this season with 3.0 inches received this season to date. Two inches of snow has fallen in Columbus this season, tying with the 1978-79 and 1981-82 seasons for third highest snowfall.

The Outlook for March is for a winter lull for a week or more, but Old Man Winter may be on break but not on summer vacation until April. MARCH OUTLOOK: is for precipitation to be normal to above-normal with temperatures cooler than normal on average.

Costly winter for cities and states like Atlanta, Georgia

Stock photo

Cities and states across the country are having budget woes worsened by Old Man Winter. Atlanta has had 3 snow/ice systems of note this season compared to many winters that go with nary a flake.

After being swamped with snow just a few weeks ago, the Northeast got clobbered by the storm dubbed the "Snowicane,"  caused powerful winds, immobilizing snow, whiteouts, horizontal rain and flooding and beach erosion. Now yet another wind rain and snow making is hitting the region from the Carolina's Northward today. Chicago is having a rare 52 inch plus winter 94% above-normal! Not only does this kind of extreme weather cause hazardous driving conditions, it also cost millions of dollars in snow removal costs and other damages.

In New York, for example, it costs the city an estimated $1 million per inch to plow the snow. And Planalytics, a Pennsylvania based firm that specializes in business-related weather forecasting, estimates the wintry messes in February topped $100 million a day during the worst weather when you add up overtime expenses, reduced productivity and lost sales. Many cities across the country have used up their snow-removal budgets and then some. Atlanta has had 5 inches of snow compared to the 30-year average of 2 inches. Georgia DOT is having to dig into road maintenance funds to cover salting and sanding operations with 4-8 inches having fallen in the North Georgia Mountains with yesterdays storm, and 1-4 inches fell from the Airport to the North Suburbs. Officially at Hartsfield Airport 5.3 inches of snow has fallen this season and the state Department of Transportation has spent almost 5 million dollars fighting snow and ice this winter. That is about a million per inch.

But while some companies are flaking out when it snows, some stocks in particular are poised to cash in big-time because of this winter's extreme weather and may cash-in on the clean-up and repair. Old man winter's stock is sure up this year, maybe some others will follow.

Atlanta based Home Depot (HD) has about 2,300 retail stores in the U.S., and is likely to be the first destination for homeowners looking to fix burst pipes, mend fallen gutters or tend to other havoc inflicted by Old Man Winter.

HD made a splash recently with a fantastic Q4 earnings report. A 1.2% jump in same-store sales for the period helped the company trounce Wall Street estimates of 17 cents per share with actual profits of 24 cents per share. Do-it-yourself repairs in the wake of the winter storms are sure to pad Home Depot's bottom line for the current quarter.

As one of North America's largest roofing materials distributors, Beacon Roofing Supply (BECN) operates 175 branches throughout the U.S. and Canada. Besides roofing products, the company also manufactures related materials, such as siding, windows and waterproofing systems -- products that are sure to be in high demand after the current round of winter weather.

In its fiscal first-quarter earnings report released in February, BECN did show signs of tough times with a 20% decline in sales year-over-year. However, residential roofing sales were up against strong comparisons to the previous year where Hurricane Ike literally drove sales through the roof in Texas. This shows how weather patterns can affect Beacon Roofing's results, so the stock should cash in after the storms of February.

Compass Minerals (CMP) is a leading chemical company that specializes in fertilizers and salts. While it's clearly not time to be watering the garden, Kansas-based CMP is seeing brisk business from its deicing and salt products thanks to the wintry weather.

Compass has grown its earnings per share dramatically across the last few quarters and is looking to share more of those profits with shareholders. On Feb. 8, CMP raised its quarterly dividend by 10% 39 cents per share, payable March 15 to shareholders of record as of March 1. This stock is going strong right now and should see continued success from the winter weather.

Ford (F) may not sound like a winter-weather stock, but the company makes internal combustion engines for far more than just Mustangs and F-150s. The fact is that Ford remains one of the largest engine suppliers for top privately held generator companies like Generac and Kohler.

Ford is a great stock to buy right now for a number of reasons -- it's gobbling up market share from bankrupt GM and Chrysler and is benefiting from uncertainty over Toyota (TM) vehicles in the wake of the recent recalls. The generator angle provides just one more reason to like Ford stock right now.

Area in question for snow threat.

NWS/HPC/NOAA

First some thoughts from the NWS:

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1009 PM CST SUN FEB 28 2010

ALZ011>015-017>038-011400-
BIBB-BLOUNT-CALHOUN-CHAMBERS-CHEROKEE-CHILTON-CLAY-CLEBURNE-COOSA-
ETOWAH-FAYETTE-GREENE-HALE-JEFFERSON-LAMAR-MARION-PERRY-PICKENS-
RANDOLPH-SHELBY-ST CLAIR-SUMTER-TALLADEGA-TALLAPOOSA-TUSCALOOSA-
WALKER-WINSTON-
1009 PM CST SUN FEB 28 2010

...WINTER PRECIPITATION POSSIBLE MONDAY NIGHT INTO TUESDAY...

A STRENGTHENING LOW PRESSURE SYSTEM WILL CROSS THE NORTHERN GULF
OF MEXICO MONDAY AND MOVE INTO NORTHERN FLORIDA BY TUESDAY AFTERNOON.
AHEAD OF THIS SYSTEM...MOISTURE WILL SPREAD INTO CENTRAL ALABAMA
MONDAY AFTERNOON RESULTING IN WIDESPREAD RAINFALL. COLDER AIR WILL
FILTER INTO THE AREA MONDAY NIGHT FROM THE NORTHWEST...RESULTING
IN THE POSSIBILITY OF WINTER WEATHER.

AT THIS TIME...RAIN IS EXPECTED TO MIX WITH OR TRANSITION TO SNOW
STARTING EARLY TUESDAY MORNING...AND THEN CONTINUE THROUGH THE
DAY ON TUESDAY...EVENTUALLY ENDING FROM WEST TO EAST TUESDAY
AFTERNOON. THE BEST CHANCE FOR SNOW IS ALONG AND NORTH OF A LINE FROM
EUTAW...TO CLANTON...TO ROANOKE.

THE CURRENT FORECAST IS FOR ONE INCH OR LESS OF SNOW IN THESE AREAS.
HOWEVER...THIS FORECAST IS BASED ON TEMPERATURES STAYING JUST WARM
ENOUGH SO THAT MOST OF THE SNOW THAT DOES FALL WILL QUICKLY MELT.
HOWEVER...IT WOULD TAKE A TEMPERATURE DROP OF JUST 2 OR 3 DEGREES TO
CAUSE THESE AMOUNTS TO INCREASE SIGNIFICANTLY.

EVEN AT THIS RELATIVELY LATE JUNCTURE...THERE IS STILL CONSIDERABLE
UNCERTAINTY IN THE FORECAST. MINOR CHANGES IN THE STORM TRACK AND
INTENSITY COULD HAVE A CORRESPONDING MAJOR IMPACT ON THE POSSIBILITY
OF WINTER PRECIPITATION. THE RAIN/SNOW TRANSITION LINE AND
ACCUMULATION POTENTIAL WILL LIKELY NEED TO BE REFINED WITH FUTURE
FORECASTS. CENTRAL ALABAMA SHOULD STAY TUNED FOR UPDATES ON THIS
DEVELOPING WINTER WEATHER SITUATION.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
353 AM EST MON MAR 1 2010

GAZ001>009-011>016-019>025-027-030>035-041>045-012100-
DADE-WALKER-CATOOSA-WHITFIELD-MURRAY-FANNIN-GILMER-UNION-TOWNS-
CHATTOOGA-GORDON-PICKENS-DAWSON-LUMPKIN-WHITE-FLOYD-BARTOW-
CHEROKEE-FORSYTH-HALL-BANKS-JACKSON-MADISON-POLK-PAULDING-COBB-
NORTH FULTON-GWINNETT-BARROW-HARALSON-CARROLL-DOUGLAS-
SOUTH FULTON-DEKALB-
353 AM EST MON MAR 1 2010

...WINTRY PRECIPITATION EXPECTED ACROSS MOST OF NORTH GEORGIA
TONIGHT THROUGH TUESDAY NIGHT...

A STORM SYSTEM DEVELOPING OVER TEXAS WILL MOVE EAST ACROSS THE
NORTHERN GULF OF MEXICO TODAY. THIS LOW PRESSURE SYSTEM WILL BEGIN
TO SPREAD PRECIPITATION ACROSS THE SOUTHEAST TONIGHT.

AT THIS TIME...IT APPEARS THAT PRECIPITATION WILL BEGIN AS RAIN
ACROSS MOST OF THE AREA...POSSIBLY MIXING WITH SNOW IN THE MOUNTAINS
AT THE ONSET.

TEMPERATURES ON TUESDAY WILL WARM INTO THE UPPER 30S ACROSS MOST
OF NORTH GEORGIA...THOUGH THE MOUNTAINS WILL LIKELY REMAIN IN THE
LOW TO MID 30S. THE MOST PRECIPITATION WILL FALL IN CENTRAL
GEORGIA IN THE FORM OF ALL RAIN. ACROSS NORTH GEORGIA...
PRECIPITATION ON TUESDAY IS EXPECTED TO BE A MIX OF SNOW AND
RAIN...THOUGH BECAUSE OF THE WARM SURFACE TEMPERATURES THE SNOW
SHOULD MELT AS IT REACHES THE GROUND ON TUESDAY. THE HIGHER
ELEVATIONS OF THE MOUNTAINS...HOWEVER...WILL LIKELY SEE ALL SNOW
AND SOME ACCUMULATIONS DURING THE DAY.

TEMPERATURES WILL DROP TO NEAR OR JUST BELOW FREEZING ACROSS MOST
OF NORTH GEORGIA TUESDAY NIGHT...ALLOWING ANY MIXTURE TO CHANGE
OVER TO ALL SNOW WITH POSSIBLY SOME BRIEF LIGHT ACCUMULATIONS...
MAINLY NORTH OF THE INTERSTATES 20 AND 85 CORRIDORS...BEFORE THE
SYSTEM EXITS.

ANY SNOW THAT MANAGES TO STICK WILL GENERALLY AMOUNT TO LESS THAN
A HALF INCH ACROSS MOST OF NORTH GEORGIA...MAINLY NORTH OF A LINE
FROM CARROLLTON TO ATLANTA TO JEFFERSON. IN THE MOUNTAINS...
ESPECIALLY AT HIGHER ELEVATIONS ABOVE 1500 FEET...AN INCH OR TWO
MAY BE POSSIBLE.

THERE IS STILL SOME UNCERTAINTY WITH THIS SYSTEM. SMALL
ADJUSTMENTS IN THE STORM TRACK MAY MAKE SIGNIFICANT CHANGES IN
TEMPERATURES...AND THUS IN THE POTENTIAL SNOWFALL ACCUMULATIONS.
RESIDENTS OF NORTH GEORGIA ARE URGED TO MONITOR FURTHER UPDATES.

Meteorologist Coleman at Huntsville NASA Center:

this is one of the most difficult forecasts we've seen in a while. An
upper-level system will move out of Texas today and help develop a low
pressure area in the northern Gulf. This low will be in the Florida
panhandle by midnight tonight, and likely strengthen as it moves
northeast. And, temperatures at 850 mb (the "critical level", near
4-5,000 feet, that typically is the rain/snow line) are below freezing.
As an old friend said, "a storm to be proud of." But, despite the
almost perfect dynamic setup for snow, there are some obstacles that
could limit, or even prevent, significant accumulation of snow in
Alabama.

All 5 of the models we often look at, the GFS, NAM, Canadian, European, and UKMET show an area of precipitation moving across central and south Alabama tonight and tomorrow. One thing that makes the forecast difficult is precipitation amount. There will be large differences in precipitation totals over short distances from north-to-south with this storm...one spot along I-65 will get 0.5″ of liquid equivalent precipitation, while another spot 50 miles up the road could get almost nothing. The GFS says BHM will get about 6″ of snow, and the NAM says we will get none. The exact track of a low is hard to pin down even this close to the event, and yet with this one it is very important.

The other challenge is the low-level temperature field. It will be cold enough aloft at Birmingham, Tuscaloosa, and Anniston for the precipitation to fall as snow, at least aloft. However, the models indicate that temperatures will climb to near 50 today, and the melting of the falling snow (causes cooling) will not be enough to overcome the warm temperatures we build up today. The heavier the precipitation, the colder.

The bottom line is that confidence in the forecast is still low for an event only 24 hours away. However, rain is already moving across Texas, and high clouds are moving into Alabama this morning. The key thing may be amount of sunshine and warming today. If it stays below 45, snow becomes more likely. It appears to me that it will be difficult for there to be no precipitation in BHM, or even in Cullman, with a system of this strength. So, rain will likely begin tonight, and slowly mix with and change over to snow by Tuesday morning. If the sun comes out for several hours and it gets warm today, it will look pretty falling, but melt quickly and probably not even accumulate, except maybe in higher elevations. If it stays cold today, there could be a band between Birmingham and Clanton where up to 3″ of snow falls.

NWS South Carolina:

AS THIS POTENTIAL WINTER STORM APPROACHES...CONFIDENCE IN HEAVY SNOW
ONLY MARGINALLY INCREASED WITH THE LATEST MODEL SUITE. THE 00Z GFS
IS STILL THE MOST BULLISH ON COLD AIR AND QPF...PAINTING WARNING
CRITERIA SNOW ACROSS THE ENTIRE THE FA. MEANWHILE...THE
NAM/ECMWF/SREF ARE ALL MUCH DRIER AND A BIT WARMER (DUE TO SLIGHTLY
SLOWER STORM EVOLUTION...AND HENCE LESS DYNAMICAL COOLING THAN THE
GFS. THE 00Z GEM HAS COME IN CLOSE TO THE GFS ON QPF/SNOW AMTS (AND
IS EVEN A LITTLE FASTER ON PRECIP ONSET AHD OF THE SYS. ALSO...THE
CIPS ANALOG OF 25 MAR 1983...WHICH PRODUCED A SWATH OF 6-12" OF SNOW
ALONG THE I-85 CORRIDOR ONLY SEEMS TO BE STANDING OUT MORE WITH EACH
GFS RUN. SO WITH THIS ALL TAKEN INTO ACCOUNT...FEEL THAT THERE IS
ABOUT A 50% CHC OF WARNING CRITERIA SNOW IN A SWATH SOMEWHERE IN THE
FA ON TUESDAY. SO WILL ISSUE A WINTER STORM WATCH FOR ALL COUNTIES
SOUTH OF I-40. BASED ON THE CURRENT STORM TRACK...A GFS RA/SN LINE
ALONG SRN FRINGE OF THE FA...AND HPC QPF (WITH 10:1 SLR)...THE
CURRENT FCST IS FOR 2-4" SNOW ACCUM FROM THE SW NC MTNS...ALONG THE
I-85 CORRIDOR OF THE UPSTATE...TO THE CHARLOTTE METRO AREA. THIS IS
BY NO MEANS SET IN STONE. IN FACT...THERE IS STILL A CHC THAT THE
NAM COULD BE CLOSER TO REALITY...AND A WARM SFC LAYER BASICALLY
PRECLUDES ANY SNOW ACCUM AT ALL.

MY THOUGHTS (as heard on the radio the past 48 hours):

So there you have it, a piece of cake! ;) 

As a side note history tells us snow can fall with surface temps as high as 41 proof that it's how "deep" the above 32 air is that matters in the end, deep = rain shallow = snow.

We have to watch this one closely and not let our guard down yet. While more rain or melted snow is favored by me now as the safer forecast, it has potential to be a big snow maker, so it should not be dismissed out of hand. Only a couple degrees C  and about 40 miles in storm track separate ATL from a cold rain with some melting snow, and a significant wet snow storm Tuesday. So obviously a lot can change at the last minute. This is probably as close a call as last March 1st and an infamous Atlanta storm back in March of 1983. In fact, IF the computers were showing the lowest 1-2,000 feet of atmosphere just 2 degrees or so cooler I'd be forecasting 1-4 inches for much of the metro. So with only 2 degrees or so between a cold wet day and potential trouble this could go down to the wire. How fast precip falls and just small changes in track will mean a world of difference in the end.

Right now the upper and middle atmosphere (remember our top-down approach homework quiz last week) are projected to be cold enough for all snow. But the models show the boundary layer surface to 1,000 feet or so to be just warm enough to melt a lot of it, producing a rain mix or changeover. If the storm gets strong enough to generate heavy precip fall rates and strong energy lifting dynamics overhead, it would drag down the colder air aloft bringing moderate to heavy snow to much of the area. It looks like a very fine line between the mostly  rain look we have in the forecast now OR more snow. A line I'll be tracking on the radio all day and tomorrow.

As of now it looks like mostly rain for most of Atlanta with some nuisance snow late tonight and tomorrow. But separating us from very wet or very white is just those two three degrees and thousand feet or so. The plain hard truth is our computer models and data net just dont have fine enough details to confidently resolve that fine a line. So while more rain than snow is the call at this writing, it could just as easily go the other way! And we may not know until the event is taking place having to nowcast the rain/snow line and amounts as we go or give a last second all clear.  This is quite unlike our mid-Feb snow when I was very confident there would be snow, the forecast challenge was only the amount of snow. This time moisture is no question, its the vertical temperature profile that's in question.

MODEL OUTPUT ONLY NOT A FORECAST:

The recent average of the best numerical variants is a liquid equivalent of 0.60 so a good soaking if its all rain. IF that was ALL snow using the standard 10:1 conversion ratio it would be 6 inches of snow.

The mean of the last 10 model runs or so, note these include a range from zero snow to an outrageous 11:

Again these are averages of snow IF all snow

ECMWF 3.5

GFS 3.5

JMA 3

REGEM/GGEM 4.65

NOGAPS 4.5

NAM/DEGEX 5.1

The slightest change can alter everything, a million things need to go right for snow just one wrong for no.  Usually when you need a system to "create" its own cold air-- it fails to happen, but when it does happen, it makes for lollipop isolated dumpings of wet flakes.

Since anything I can write hear I will say on the radio tune-in to News Talk 750 WSB AM or click listen live or 5-day forecast at wsbradio.com for the latest update.

Energy jumps from Desert Southwest and Southern Plains to cause Gulf cyclogenesis.

NWS/NCEP/HPC

As you will see if you look at the slide show maps at examiner.com/Atlanta, just using two of the 28 or so models there is still wide disparity between the various equations output.  I am giving PRELIMINARY demarcation of where snow accumulation is most likely as it looks right now but future data will no doubt change. At least some snowflakes will probably be seen in most if not all of the Atlanta metro area mixed with or starting as rain. However, as of this writing the highest odds for 1-3 inches accumulation mainly on grassy areas etc. appears to be along and North of a Line from around Calhoun GA to Athens. Keep in mind that this is a guidepost line, not a line drawn in the sand. There is no magic wall in the sky :) and in the real world the "line" is really a transition zone that is often 15-30 miles either side of the line estimate.

The big questions remain the same with the system. Will the two jet stream energy bundles phase together and if so where and how soon? Where will the cyclone track what will its path be? How much moisture will be drawn into the system? Will the surface or near-surface temps ever cool enough to allow snow flakes in the clouds to make it to the ground before melting?  If you take the composite average of all the main models over the past few days they average out for a good part of Atlanta or at least the North and East suburbs as 3 inches IF it all falls as snow-- which seems iffy at this point. Rain and melting would seem likely to reduce whatever amount of snowflakes fall. In order to get snow we need a thousand things to go right, to be missed only one to go wrong.

Inevitably the weather keeps changing and so therefore must forecasts. I don't know if I'll have time to post anymore so remember to click on 5-day forecast at wsbradio.com or click LISTEN LIVE at wsbradio.com OR turn your radio on. It's radio-active. :)

Preliminary map for Tuesday Morning, slightly slower and further South than yesterdays expectation

HPC/NOAA/NWS

VALID 12Z MON MAR 01 2010 - 12Z THU MAR 04 2010

GFS3 out to lunch on next week weather threat in Gulf Coast states to VA, but way too soon to tell who will gets snow vs. rain, and how much of each will fall or where Tuesday-Wednesday. Storm could be a swing and a miss and North Georgia gets little or nothing at all, OR significant snow is either North of Georgia or SOUTH of Atlanta.

Here is some model output for the system next week for Atlanta liquid equivalent as of this writing:

Euro ENS 0.50-0.75
Euro OP .25-.50

JMA .10-.25

DEGEX 0.0

NOGAPS .25-.50

CMC .10-.25

GFS 0.0

UKMET shows storm no QPF available

USED THE 00Z/25 ECMWF TO UPDATE THE PRELIMINARY FRONTS AND
PRESSURES FOR DAYS 3-6 ACROSS THE NATION...WITH A MODEST
INCORPORATION OF THE ECENS MEAN DAY 7 TO MITIGATE THE UNCERTAINTY
IN SYNOPTIC DETAILS INHERENT TO THAT TIME RANGE. FOR THE SOUTH
AND EAST...THE MAJOR CONCERN IS THE WAVE THE MODELS TRACK ACROSS
THE GULF OF MEXICO...AND THEN OVER THE ATLANTIC OCEAN. THIS
WINTER SEASON HAS SEEN WAVE AFTER WAVE CROSS THE GULF OR DEEP
SOUTH...AND THEN TURN EITHER SUBTLY OR SHARPLY UP THE EASTERN
SEABOARD. IN MOST CASES...THE GLOBAL NUMERICAL MODELS HAVE BEEN
SHY ABOUT LIFTING THESE SYSTEMS FAR ENOUGH NORTH SEVERAL DAYS
OUT...WITH AN INEVITABLE CREEP NORTHWARD TOWARD CAPE HATTERAS WITH
TIME. THE SNOWFALL OVER MUCH OF THE SOUTHEAST A COUPLE WEEKS AGO
IS AN EXAMPLE OF SUCH A CASE...WITH MUCH OF THE GUIDANCE NOT
GIVING THE REGION ITS DUE UNTIL A MERE 36 HOURS FROM IMPACT. TOOK
THE CUE FOR THIS FORECAST...AND USED THE DETERMINISTIC
ECMWF...WHICH TRACKED CLOSEST TO THE COAST DAY 6. THIS MODEL HAS
THE SUPPORT OF THE GEM GLOBAL...AS WELL AS THE ENSEMBLE GUIDANCE
FROM BOTH THE EUROPEAN AND CANADIAN CENTERS. THE GFS AND ITS
ATTENDANT ENSEMBLE PACKAGE LOOKED FLAT BASED ON THE EXPERIENCE OF
THIS SEASON. THE WEST COAST WILL CONTINUE TO BE AT THE SPLITTING
POINT OF WAVES COMING IN FROM THE PACIFIC...WITH A COUPLE INTENSE
COLD MARITIME POLAR VORTICES SLATED FOR THE NORTHWEST DURING THE
SECOND HALF OF THE PERIOD. THE MIDDLE OF THE NATION WILL BE UNDER
THE INFLUENCE OF A CONTINUAL FEED OF CONTINENTAL POLAR AIR...THIS
REGIONS LOT IN LIFE IN THE TENACIOUS BLOCKING REGIME OF THE WINTER
OF 09-10.

THERE IS MUCH LESS AGREEMENT ON THE POTENTIAL FOR HEAVY SNOW IN THE LOWER MISSISSIPPI AND LOWER TENNESSEE VALLEYS FOR MONDAY INTO TUESDAY. THE PAST SEVERAL CYCLES OF THE GFS HAVE TAKEN THE FORECAST STORM FROM THE SOUTHERN PLAINS INTO THE CENTRAL/SOUTHERN GULF OF MEXICO WITH A DRIER FORECAST FOR THIS REGION. TODAY'S 00Z AND 12Z CMC AND ECWMF OPERATIONAL RUNS FOLLOW A TRACK CLOSER TO THE NORTHERN GULF AND BRING PRECIPITATION INTO THESE AREAS. HOWEVER, TODAY'S OPERATIONAL ECMWF THERMAL PROFILES WOULD SUPPORT A MIX OF RAIN/SNOW, WITH CMC'S MORE SUPPORTIVE OF AN ACCUMULATING SNOWFALL. GIVEN THE INCREASED UNCERTAINTY, THE AREA OF HEAVY SNOW ACROSS THESE REGIONS WAS REMOVED, BUT THIS AREA WILL NEED TO BE VERY CAREFULLY MONITORED WITH THE LATEST MODEL RUNS. IN THE LEAST, IF THE ECMWF AND/OR CMC SOLUTIONS ARE CORRECT, SLICK ROADS DUE TO A RAIN/SNOW MIX OR ACCUMULATING SNOWS WOULD BE EXPECTED ACROSS THESE AREAS.

THERE IS A POTENTIAL THREAT OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF CENTRAL AND SOUTHERN FLORIDA ALONG AND AHEAD OF THE SURFACE COLD FRONT ASSOCIATED WITH THIS SYSTEM.
 

Preliminary weather map for next Tuesday Morning.

HPC/NOAA/NWS

PRELIMINARY EXTENDED FORECAST DISCUSSION

VALID 12Z SUN FEB 28 2010 - 12Z WED MAR 03 2010

...SIGNIFICANT WINTER WEATHER THREAT FOR THE SW/SRN/SE US AND POSSIBLY MID-ATLC NEXT WEEK...
Greatest threat TN NC and VA Northward but may have to shift threat south.

THE MODELS CONTINUE TO ADVERTISE A RETROGRADING POSITIVE MID-UPPER
LEVEL HEIGHT ANOMALY FROM EASTERN INTO W-CENTRAL CANADA. THIS
SHOULD ALLOW AN AMBIENT CLOSED NORTHEAST VORTEX TO EXIT STAGE
RIGHT OVER THE WEEKEND...YET TRAP SOME MID-LEVEL ENERGY BACK
ACROSS THE MIDWEST NEXT WEEK. REPERCUSSIONS ARE MANY FOR ITS
INTERACTION WITH A NEARLY CLOSED CYCLONE ALOFT/STRONG SHORTWAVE
WHICH SPLITS OUT OF THE EASTERN PACIFIC TROUGH IN A POTENT SRN
STREAM TO NEAR 4 CORNERS BY SUN. THIS ENERGETIC FLOW/SYSTEM THEN
PROGRESSES BODILY/STEADILY EASTWARD OVER THE SOUTHERN TIER OF THE
COUNTRY...WITH QUESTION MARKS WITH RESPECT TO WHETHER OR NOT
DIGGING MIDWEST NRN STREAM ENERGY IS STRONG ENOUGH TO LURE THE
SOUTHERN SYSTEM NORTHWARD OR MERGE WITH IT...AND IF SO HOW FAR
NORTH THE COMBINED SYSTEM COULD MOVE. WITH A TWO DAY TREND
SOMEWHAT TO THE SOUTH NOTED AMONGST THE MULTI-MODEL ENSEMBLE
MEMBERS...FELT THE BEST COURSE OF ACTION WAS TO GO IN THE MIDDLE
OF THE ENSEMBLE CLUSTERING RATHER THAN THE NORTHERN SIDE
CONSIDERING CONTINUITY. THIS SOLUTION ADVERTISES A SNOWSTORM
THREAT ACROSS THE SRN ROCKY STATES SUN OUT ACROSS THE SRN THEN
SERN US/LOWER MID-ATLANTIC MONDAY INTO WEDNESDAY NEXT WEEK AS A
DECENT CLUSTER OF ECMWF ENSEMBLE MEMBERS CLOSE OFF A VORTEX AT 500
HPA WITH HEIGHTS BELOW 5400 METERS INTO THE SOUTH. HOWEVER...A
CLUSTER OF GEFS/CANADIAN MEMBERS ARE LOCATED MORE NORTHWARD OVER
THE MID-ATLANTIC STATES. NEEDLESS TO SAY...SOME UNCERTAINTY
REMAINS CONCERNING THESE IMPORTANT SMALLER SCALE DETAILS AND
INTERACTIONS OF THIS FORECAST. THE UPDATED PRELIM HPC SURFACE
FRONTS/PRESSURE AND 500 MB PROGS MAINTAIN CLOSE HPC CONTINUITY AS
PRIMARILY DERIVED FROM 50-50 BLEND OF SIMILAR 00 UTC
GFS/ECMWF...ALBEIT ADJUSTED SLIGHTLY CLOSER TO THE SE US COAST
INTO NEXT MIDWEEK BASED ON POTENTIAL BEST SHOWN BY ECMWF ENSEMBLE
CLUSTERING. DESPITE UNCERTAINTIES WITH EMBEDDED SYSTEM
DETAILS...LARGER SCALE FLOW DEPICTION FROM THE MODELS AND
ENSEMBLES ARE ACTUALLY QUITE SIMILAR...WITH BELOW NORMAL FORECAST
SPREAD LEADING TO ABOVE AVERAGE FORECASTER CONFIDENCE. THIS
INCLUDES AMPLIFIED NRN STREAM FLOW POTENTIAL...LEAD SRN STREAM
ENERGY OUT FROM SW US THROUGH THE US SRN TIER/GULF OF MEX...AND
SUBSEQUENT RELOADING OF AMPLIFIED ERN PACIFIC TROUGH ENERGY AND
ASSOCIATED RENEWED US W COAST ORGANIZED PCPN POTENTIAL AGAIN BY
DAYS 6/7. ACCORDINGLY...THE MAIN WEATHER SYSTEMS HAVE A HIGHER
THAN NORMAL CHANCE OF DEVELOPING IN A VEIN SIMILAR TO
GUIDANCE...EVEN THOUGH THE FOCUS FOR SIGNIFICANT SENSIBLE WEATHER
IS MORE UNCERTAIN.

It's a very fine line between rain, snow or sleet. Margin of error can be 1% or less. Skew-T BHM

National Weather Service Birmingham, AL

The Difference Between Rain and Freezing Rain

Weather Review - January 29, 2010 from the Birmingham, Alabama National Weather Service Office.
This could just as well apply and does to Atlanta, Georgia or any city in America.

See the slide show for graphics the first one is the Birmingham LAPS Sounding at Noon on Friday, January 29, 2010. The second is the Sounding for the same time for Marion County Alabama.

Many times during the winter months, central Alabama finds itself on the edge of disaster. There are many times when our counties are less than 100 miles away from having large amounts of winter precipitation, whether that is ice pellets, snow or even worse...freezing rain. Friday morning was no different. Portions of NW Alabama, including the Muscle Shoals area, received freezing rain accumulations Friday morning and afternoon of Jan 29th. The freezing rain was seen as far south as Winston and Marion Counties. The question is, why did these two counties see the freezing rain and the Birmingham area did not? We will attempt to illustrate why the Birmingham area was spared Friday.

The two graphs displayed here are known as Skew-T graphs or Thermodynamic diagrams. If you are having trouble  seeing them visit the examiner.com/Atlanta page for bigger version in slide show. They are a depiction of what the atmospheric conditions are over a given location. Skew-T graphs are created from the release of a weather balloon with an attached instrument called a radiosonde. After release, the radiosonde sends a signal back to our office that gives us four parameters: environmental temperature, dew point, atmospheric pressure and wind speed and direction. These two graphs are actually computer generated in order to help us maintain a current picture of what's going on in central Alabama. The two green lines on each graph reflect the environmental or air temperature (green line furthest to the right) and the dew point temperature (furthest green line to the left). These two lines can tell meteorologists many things, such as, the closer they are together, the more moisture that is present in that layer of the atmosphere. The solid horizontal lines (white) are pressure levels in the atmosphere. The solid lines running from bottom left to top right indicated temperature in degrees celsius.

So what are these two Skew-Ts telling us about Friday's weather? In the winter months, forecasters use the Skew-T and a method called "The Top-Down Approach" in order to determine what type of precipitation is going to reach the ground. The first graph is a Skew-T over Birmingham and the second is over northern Marion County, both at noon Friday. In this method, a forecaster examines three different layers of the atmosphere.

For simplification, we have highlighted the three most important temperature lines:
The first layer to analyze is the one above -12 degrees celsius. If the atmoshpere is saturated (the green lines close together) above -12 degrees celsius, then it is ripe for the growth of snow crystals. Atmospheric saturation has occured above -12 degrees celsius, so we already have snow forming.

The next layer to analyze is the one just above the surface. If there is a warm layer of air just off the surface and the temperature in this layer is warmer than 4 degrees celsius, precipitation will usually fall in the form of rain. In the case of the atmosphere in Birmingham, the temperature in the warm layer is approximately 6 degrees celsius. This means it's too warm to get anything but rain.

In Marion County, the warm layer temperature is slightly cooler than 4 degrees celsius. This is warm enough for the snow crystals to melt, so at this point, the snow crystal has turned into a rain droplet, but depending on what's going on at the surface...there may still be time for some type of winter precipitation to occur.

Finally, we must examine the layer closest to the surface. If the temperature at the surface at or below freezing, as was the case in northern Marion County Friday, rain droplets will freeze upon contact with the ground. This is why freezing rain was seen in northern portions of the county. With temperatures at 31 to 32 degrees, the rain droplets froze upon contact with the ground (or the trees or the power lines).

In summary, over both areas, the upper atmosphere was ripe for snow crystal growth, but over Birmingham, there was a warm enough layer just above the surface to melt those snow crystals, allowing only rain to reach the ground. In Marion County, the layer above the surface was warm enough to melt the snow crystals, and with the temperature right at or just below freezing at the surface, when the precipitation reached the ground , it was cold enough to freeze on contact. But if the forecast for the surface temp was off by just a degree or two (well within the normal and expected margin of error) there could have been just rain for everyone or freezing rain, or if a tad colder ANYWHERE in the atmosphere then sleet.

Notice just how close a call it was! The lines just barely need to move for a different outcome. Research has shown that there is a margin of error of 1% or less in rain/snow/ice forecasts. This is why weather forecasting is such a difficult job. How would you like to have a margin of error of 1% or less in your job or personal life?

Another problem arises with these Skew-T diagrams that come from the weather balloon releases. The balloons are only released twice a day around sunrise and sunset. It then takes a couple hours before the results arrive. Then about 6 hours for the data to process in computers in time steps forward.

Any changes in the atmosphere between those times is unknown! On top of that, the balloons are released at only some 90 or so spots across the country. 90 tiny points. What the atmosphere is doing inbetween those points (most of the country) is unknown. There are zero balloons released over the oceans, none! The earth is more water than land so most of the atmosphere does not get a thorough measurement for forecasters to use!  This is a major handicap to say the least. Meteorologists must make due with a tiny fraction of data compared to the whole.

And the balloons are not released over every major city nor across a whole city. In Georgia for example the closest Skew-T diagram generated from balloon release is way down in Peachtree City well South of the city and nothing for downtown, the North Suburbs, Athens or the Mountains!  So all those unknowns must be extrapolated, estimated, approximated in time and space going forward in the future to make a forecast. Its as if the weatherman is blindfolded with one hand and leg tied behind them then asked to hit a bullseye with a bow and arrow from 1000 paces in a strong wind.  Its a small wonder forecasts are sometimes wrong, its amazing that against all odds they're often right.

Now that you've had instruction go ahead and try your hand at it for the next storm here or anywhere in the country. Have fun, enjoy.

The Euro if right implies another rare snow for parts of Dixie before the month ends.

ECMWF

You may recall that I posted back on February 3rd about correlations between moon phases and major weather pattern changes and/or big ticket storm systems. These seem to occur a few days either side of the New Moon and the Full Moon. That pattern has worked out well so far this winter with that Feb 3 post warning about the big ticket event of Feb 12th. The last New Moon Feb 14th saw an historic Southern Snow near it on the 12th and 15-16th cold blast and snow flurries. The next Full Moon is February 28th and the next New Moon is March 15th. Lets see if it works again.

Early modeling says yes and I've already been talking about it for many weeks now. As of this writing it looks like it will be a swing and a miss for Atlanta with any real snow being TN and NC north to New England. However, the Euro says don't take any part of Georgia off the table for this yet. Now this is just one operational run of the model and not a forecast, but if it verifies it implies a snow threat from I-40 to I-10.

It also means don't get used to long dry spells and don't expect warm air to lock in anytime soon as February will end cold. Perhaps that "New Moon" phase of March 15th will be a pattern shift toward spring at last, or will it just be another storm?

This weekend the split flow pattern continues with a zonal flow across the South allowing temps to moderate as a new storm series begins to hit the West Coast in CA. As we head toward next weekend that upper low heads East through Texas and may end up phasing along the East Coast as a Nor-Easter after sparking low pressure in the Southeastern USA. It will be preceded and followed by more polar air.

See slide show here for more at examiner.com

North American Ensemble Forecast System shows more cold to come.

Environment Canada

Although some relaxation in the winter chill is on the way for the Southland, I see no permanent wholesale reversal in the long cold winter pattern prevalent for much of the United States anytime soon. And certainly not before late February and probably not until sometime in March at the earliest.

Note the brief appearance of a semi-zonal (west-east) jet stream flow across the lower half of America-- or at least less amplified-- does not last.  In the longer range the stormy active pattern reloads to some extent according to the European model and most others. The NAEFS sure shows the high probability of below-normal temps in the medium range. The stratospheric warming above the North Pole which began in late January signaled to us the negative AO would return and strengthen. This supports more cold air and based on past SSW events, the pattern we've been in should last another 2 weeks.

For the other maps Click here for slide show.

MID MS VALLEY TO OH/TN VALLEYS...

A VERY DYNAMIC UPPER VORTEX MAKING ITS WAY SOUTHEAST INTO THE
REGION THIS MORNING FROM SD WILL MAKE ITS WAY INTO THE LOWER OH
VALLEY BEFORE TURNING EASTERLY.  GIVEN HIGH SNOW TO WATER
RATIOS...THERE IS A POSSIBILITY OF 4 INCH AMOUNTS ACROSS
NORTHEASTERN MO IN A REGION OF MID LEVEL FRONTOGENESIS ALONG THE
TRACK OF THE LOW.  INCREASED PROBABILITIES OF 4 AND 8 INCH AMOUNTS
ARE INDICIATED ALONG THE OH RIVER GIVEN THE TENDANCY FOR HIGHER
PCPN IN AREAS WHERE THE LOW PIVOTS AND MAKES ITS TUIRN. THE 13/18Z
AND 14/00Z RUNS WERE CONSISTENT IN SENDING THE MESSAGE OF A
NORTHWARD SHIFT TO THE TRACK OF THE LOW...BUT THE 14/06Z NAM
BACKED AWAY FROM THAT IDEA ALONG AND SHIFTED THE PRECIP MAX BACK
SOUTH OF THE OH RIVER.  THE HPC MANUAL GRAPHICS WERE NOT ALTERED
SIGNIFICANTLY BY THE 06Z NAM STILL SHOWED SUFFICENT MESOSCALE
FORCING IN THE FORM OF FGEN IN AREAS COVERED BY THE PROBABILITY
MAPS...PLUS THE FACT THAT THE 00Z NAM HAD A LOT OF SUPPORT FROM
THE OPERATIONAL SUITE AND ENSEMBLES.  

AS A SURFACE COLD FRONT ASSOCIATED WITH THE LOW PRESSURE SYSTEM
SWEEPS TO THE SOUTH AND EAST...COLD ADVECTION LOWERED LOW LEVEL
TEMPS/THICKNESSES SHOULD ALLOW FOR PCPN TO FALL IN THE FORM OF
SNOW AND PERHAPS SOME SLEET ACROSS THE TN VALLEY AND INTO PARTS OF
AL/GA FROM SUNDAY NIGHT INTO EARLY MONDAY MORNING.  THERE SOULD BE
ENOUGH PCPN TO WARRANT A LOW END MDT RISK EXTENDING INTO NORTHERN
GA/AL WITH A SLGT RISK EXTNENDING SOUTHWARD BEHIND THE FRONT.
THE PROBABILITY OF SIGNIFICANT ICING IS LESS THAN 10 PERCENT.