Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 012300 AAA
AFDHUN

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HUNTSVILLE AL
500 PM CST SUN MAR 1 2015

.UPDATE...
FOR 00Z TAFS

&&

.DISCUSSION...
/ISSUED 423 PM CST SUN MAR 1 2015/

MODERATE ISENTROPIC LIFT AND A SATURATED COLUMN UP TO AROUND 700 MB
WILL CONTINUE MUCH OF THE NIGHT. THIS WILL KEEP RAIN SHOWERS IN THE
FORECAST THROUGH THE OVERNIGHT PERIOD...BEFORE BETTER ISENTROPIC
LIFT PUSHES SOUTH OF THE TENNESSEE RIVER AFTER DAYBREAK BEHIND A
DEPARTING COLD FRONT MOVING INTO CENTRAL ALABAMA. RAIN SHOWERS WILL
REMAIN LIKELY MAINLY SOUTH OF THE TENNESSEE RIVER MONDAY MORNING.
THIS COLD FRONT WILL ADVECT MUCH DRIER AND COOLER AIR INTO NORTHERN
ALABAMA ON MONDAY. IN FACT LOCATIONS NORTH OF THE TENNESSEE RIVER
AND IN SOUTHERN MIDDLE TENNESSEE MAY SEE SOME SUNSHINE BREAK THROUGH
CLOUD COVER MONDAY AFTERNOON. HOWEVER...CLOUDS AND COLD AIR
ADVECTION WILL KEEP HIGHS IN THE 40 TO 45 DEGREE RANGE IN MOST
LOCATIONS.

THIS FRONT WILL REMAIN OVER CENTRAL ALABAMA BEFORE DECENT SOUTHWESTERLY
FLOW DEVELOPS MONDAY NIGHT INTO TUESDAY MORNING AND BRINGS INCREASED
LIFT AND ABUNDANT LOW LEVEL MOISTURE BACK INTO THE TENNESSEE VALLEY.
THIS WILL AGAIN BRING LIGHT RAIN SHOWERS INTO NORTHERN ALABAMA AND
SOUTHERN MIDDLE TENNESSEE MONDAY NIGHT. MODELS CONTINUE TO INDICATE
SOME DRY AIR ALOFT BECOMING ENTRAINED ABOVE 700 MB MONDAY NIGHT INTO
TUESDAY. THIS SHOULD PROVIDE A THERMODYNAMIC SETUP COMBINED WITH
A SHORT WAVE TO PRODUCE SOME SCATTERED ELEVATED THUNDERSTORMS ON
TUESDAY. THIS WILL ALL BE OCCURRING AHEAD OF A DEVELOPING AREA OF
LOW PRESSURE OVER THE KANSAS AND NEBRASKA AREA. AT THIS TIME...THE
MAIN THREAT WITH THESE STORMS WOULD BE STRONG TO MARGINALLY SEVERE
WIND GUSTS AND HEAVIER DOWNPOURS.

TUESDAY NIGHT INTO WEDNESDAY MORNING...A STRONG SOUTHERLY WIND FIELD
(90 KT 500 MB WINDS/40-50 KT 850MB) DEVELOPS AHEAD OF A INTENSIFYING
TRAILING COLD FRONT STRETCHING FROM NEAR NASHVILLE TO MEMPHIS.
THIS WILL BRING MUCH WARMER TEMPERATURES TO THE REGION...ESPECIALLY
ON WEDNESDAY. LUCKILY LOW LEVEL SOUNDING PROFILES ARE CAPPED BY A
STRONG INVERSION AHEAD OF THE FRONT OVER THE TENNESSEE VALLEY. STRONG
LIFT AHEAD OF THIS FRONT WILL ALLOW AT LEAST ELEVATED THUNDERSTORMS
TO DEVELOP. THESE MAY BECOME SURFACE BASED BRIEFLY SOUTH OF THE
TENNESSEE RIVER ON LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. SHEAR
WILL BE QUITE HIGH, SO A TYPICAL HIGH SHEAR/LOW CAPE SCENARIO
EXPECTED. STRONG TO MARGINALLY DAMAGING WINDS ARE THE MAIN THREATS
EXPECTED...WITH AN ISOLATED CHANCE OF A BRIEF TORNADO.

MODELS CONTINUE TO SHOW VERY COLD AIR ADVECTED BEHIND THIS
FRONT ASSOCIATED WITH A 1040 HIGH PUSHING SOUTHEAST FROM THE UPPER
MIDWEST. HOWEVER...THEY DIFFER BY 6 HOURS...WITH ECMWF BEING THE
SLOWEST WITH THE ARRIVAL OF NEAR FREEZING TEMPERATURES INTO NORTHERN
ALABAMA. TRENDED HOURLY TEMPERATURES AND PRECIPITATION TIMING TO THE
ECMWF. THIS DELAYED FREEZING RAIN ONSET INTO THE EVENING
HOURS...EXCEPT IN SOUTHERN MIDDLE TENNESSEE...WHERE IT COULD START AS
EARLY AS 4 PM.

MODELS CONTINUE TO SHOW VERY STRONG COLD AIR ADVECTION CONTINUING
THROUGH MIDNIGHT...AS THE FREEZING RAIN WILL CHANGE TO A MIXTURE OF
SLEET AND FREEZING RAIN...AND THEN TO SNOW BETWEEN MIDNIGHT AND
DAYBREAK ON THURSDAY. SNOW SHOWERS ARE EXPECTED TO CONTINUE THROUGH
NOON BEFORE TAPERING OFF FROM WEST TO EAST.

FREEZING RAIN AND SLEET ACCUMULATION BETWEEN 0.1 AND 0.25 INCHES
LOOKS REASONABLE...ENDING WITH AN ACCUMULATION OF 1 TO 3 INCHES OF
SNOW. TIMING IS STILL UNCERTAIN WITH THE WINTRY PRECIPITATION DURING
THE MIDDLE OF THE WEEK...BUT CONFIDENCE CONTINUES TO REMAIN HIGH THAT
A WINTRY PRECIPITATION EVENT WILL OCCUR.

LUCKILY A DRY WEATHER PATTERN EMERGES TOWARD THE END OF THE WEEK.

KTW

&&

.AVIATION...
FOR 00Z TAFS... IFR CONDITIONS ARE EXPECTED THRU THE PERIOD WITH CIGS
REMAINING AOB 010AGL. AREAS OF -RA/DZ WILL PERSIST DURING THIS TIME
AS AN UPPER LEVEL DISTURBANCE AND COLD FRONT TRACK THRU THE REGION
TONIGHT INTO EARLY MONDAY. THE FRONT WILL SHIFT SELY FLOW TO THE N-NE
BY ~08Z AT KMSL AND ~10Z AT KHSV.

AK

&&

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

$$

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



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