Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 282254 AAA
AFDHUN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
454 PM CST SAT FEB 28 2015

.UPDATE...
FOR 00Z TAFS

&&

.DISCUSSION...
/ISSUED 345 PM CST SAT FEB 28 2015/
WARMER CONDITIONS NOTED ACROSS THE TENNESSEE VALLEY HAS HELPED TO
MELT MORE OF THE SNOW THAT OCCURRED DURING THE PAST MID WEEK. ONLY
A FEW PATCHES OF SNOW REMAINED AS OF THIS WRITING...AS HIGH
TEMPERATURES WARM INTO THE 50S UNDER PARTLY SUNNY TO SUNNY SKIES.
BROAD SURFACE HIGH PRESSURE MOVING OFF OF THE MID ATLANTIC WAS
BRINGING AN EASTERLY FLOW OVER THE REGION. A SYSTEM THAT BROUGHT
WINTRY WEATHER OVER THE SOUTHERN GREAT PLAINS YESTERDAY CONTINUED
TO SHIFT TO THE NE...WITH THE CLOSEST PRECIP FROM IT MAINLY FROM TX
TO EASTERN MO.

A PREDOMINATELY ZONAL FLOW OVER THE CONUS CONTINUED...WITH AN UPPER
LOW FORMING OVER THE WESTERN GREAT BASIN. A MOIST/STORMY FLOW UNDER
THIS LOW WAS SENDING A SERIES OF DISTURBANCES ACROSS THE CENTRAL
CONUS. TO OUR SE...CONVECTION WAS IN PROGRESS OVER FLORIDA.
MOISTURE INDIRECTLY ASSOCIATED WITH THIS CONVECTION WILL CREEP TO
THE NW... BRINGING MORE CLOUDS AND RAIN CHANCES LATER TONIGHT.

THE ABOVE NOTED MOISTURE SHOULD CONTINUE SURGING TO THE NW TONIGHT
FROM THE SE...AS A STRONGER BOUNDARY LEVEL WIND PICKS UP. THIS
MOISTURE COULD RESULT IN LIGHT RAIN AND/OR DRIZZLE FOR OUR FAR
EASTERN AREAS LATE TONIGHT. MORE SUPPORT FROM A PASSING UPPER
SYSTEM WILL BRING A CHANCE OF RAIN TO THE VALLEY TO BEGIN A NEW
WORK WEEK SUNDAY. A COLD FRONT APPROACHING WILL BRING LIKELY RAIN
CHANCES SUN NIGHT. RAIN CHANCE WILL CONTINUE FOR THE FIRST HALF OF
THE WEEK...AS A GENERALLY UNSETTLED PATTERN CONTINUES. DURING THIS
PERIOD...WINDS WILL BECOME EASTERLY...THEN SOUTHERLY ON TUE. THIS
WILL BRING A SHORT PERIOD OF WARM CONDITIONS TO THE VALLEY. IN
FACT...HIGHS ON TUE SHOULD WARM INTO THE 60S...THE FIRST TIME SINCE
VALENTINES DAY.

THIS WARMTH WILL ALSO BRING MORE MOISTURE TO THE AREA..RESULTING IN
INCREASING INSTABILITY. THIS WILL RESULT IN THUNDERSTORM ACTIVITY
FOR TUE/WED TIME FRAME. MODEL SOUNDINGS DO SHOW DECENT SHEAR...
WITH MARGINALLY UNSTABLE CONDITIONS...WHICH COULD RESULT IN SOME
OF THE STORMS CAPABLE OF PRODUCING STRONG TO MARGINALLY SEVERE WIND
GUSTS. LOCALLY HEAVY RAINS COULD ALSO BE REALIZED...AS PRECIP WATER
AMOUNTS RISE BETWEEN 1 - 1.5 INCHES.

AS HAS BEEN THE CASE MUCH THE PAST COUPLE OF WEEKS...ANOTHER COLD
CHANGE IS EXPECTED FOR THE MID WEEK AND BEYOND...AS A STRONG COLD
FRONT NEARS FROM THE NW. TIMING BETWEEN MEDIUM RANGE MODELS
VARIES...WITH THE GFS/CANADIAN THE FASTER AND ECMWF SLOWER. LEANED
TO THE SLOWER SOLUTION...KEEPING DEFINITE RAIN CHANCES IN WED/WED
NITE. HOWEVER...MUCH COLDER AIR FILTERING IN BEHIND THE FRONT WILL
RESULT IN A PRECIP PHASE CHANGE-OVER...TO THE WINTRY VARIETY...
AGAIN! THE GFS WAS THE MOST PESSIMISTIC...WITH ITS SOUNDINGS
SUGGESTING A FREEZING RAIN POTENTIAL WED AFTERNOON/EVENING...
BECOMING ALL SNOW LATE WED NIGHT AND THU MORNING. THE EC BEING
SLOWER TO BRING IN THE COLDER AIR WOULD BRING A SHORTER DURATION OF
FREEZING PRECIP...BUT DOES END THE PRECIP EPISODE AS SNOW LIKE THE
GFS DOES. TOO FAR OUT GIVEN TIMING DIFFERENCES...AND HOW WARM THE
GROUND WILL BE BEFOREHAND...REGARDING ACCUMULATIONS (IF ANY). IN
EITHER CASE...A COLDER LATTER HALF OF NEXT WEEK...WITH HIGHS ONLY
IN THE 30S TO NEAR 40 ON THU...WARMING INTO THE 40S FRI...AND 50S
BY NEXT SAT. DRY WEATHER OTHERWISE IS EXPECTED THIS PERIOD.

RSB

&&

.AVIATION...
FOR 00Z TAFS... VFR CONDS ARE EXPECTED THRU ~09-11Z WITH A MID LEVEL
CLOUD DECK OVERHEAD. S-SELY FLOW WILL ADVECT MOISTURE AND LOW CLOUDS
INTO THE REGION LATE TONIGHT AND EARLY SUNDAY MORNING WITH IFR CONDS
DUE TO LOW CLOUDS AND -DZ AT KHSV EXPECTED BY 09Z. LOW CLOUDS AND
MVFR ARE EXPECTED AT KMSL BY 11Z FOLLOWED BY A REDUCTION TO IFR BY
16Z. THESE CONDITIONS MAY IMPROVE BRIEFLY SUNDAY AFTERNOON. HOWEVER,
CONFIDENCE IS TOO LOW TO INCLUDE IN THIS UPDATE AS AN UPPER LEVEL
DISTURBANCE ARRIVES WITH THE POSSIBILITY OF -RA DEVELOPING WHICH MAY
KEEP THE FLIGHT CATEGORY IFR OR MVFR.

AK

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&

$$

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE
AT WEATHER.GOV/HUNTSVILLE.



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