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000
FXUS64 KHUN 092355
AFDHUN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
655 PM CDT SUN MAR 9 2014

.UPDATE...
FOR 00Z TAFS

&&

.DISCUSSION...
/ISSUED 218 PM CDT SUN MAR 9 2014/
THE 19Z SURFACE ANALYSIS INDICATED THAT THE WEAK COLD FRONT HAD MADE
IT SOUTHWARD INTO CENTRAL ALABAMA...WHICH WAS ALSO INDICATED BY THE
CLOUD COVER IN THE LATEST FEW IR/VISIBLE SATELLITE IMAGES AND
DEWPOINT ANALYSIS. THE COLD FRONT SHOULD CONTINUE TO WASH OUT ACROSS
CENTRAL ALABAMA BY 00Z TONIGHT. SOME LOW TO MID LEVEL CLOUDS ARE
EXPECTED TO SHIFT EAST-NORTHEASTWARD ACROSS THE REGION THIS EVENING
AND WILL CONTINUE WITH A PARTLY CLOUDY FORECAST ACROSS THE AREA
TONIGHT. HAVE ONLY MADE SOME MINOR ADJUSTMENTS TO TEMPS TONIGHT.

A WEAK AREA OF HIGH PRESSURE WILL REMAIN ACROSS THE AREA THROUGH 12Z
TUESDAY IN A ZONAL MID TO UPPER LEVEL FLOW ACROSS THE SOUTHEAST. A
WEAK UPPER LEVEL LOW IS PROGGED BY THE MODELS TO ROTATE NORTHEAST OUT
OF THE SOUTHERN BAJA COAST BY TONIGHT...AND THEN INTO SOUTH TEXAS BY
12Z TUESDAY. THIS UPPER LEVEL SYSTEM WILL BE THE FOCUS OF OUR
INCREASING CHANCE OF SHOWERS/SCATTERED STORMS BY TUESDAY NIGHT. THIS
SOUTHERN STREAM SYSTEM IS EXPECTED TO SHIFT EAST-NORTHEAST THROUGH
THE NORTHERN GULF THROUGH 00Z WEDNESDAY...WITH INCREASED LOW THROUGH
MID LEVEL MOISTURE STREAMING NORTHEAST INTO THE FORECAST AREA. HAVE
INCREASED PRECIP CHANCES INTO THE LIKELY CATEGORY FOR TUESDAY NIGHT.
HAVE KEPT IN A CHANCE OF STORMS BETWEEN THE 06Z-12Z WEDNESDAY TIME
FRAME AS THERE IS THE POSSIBILITY OF SOME ELEVATED CONVECTION IN THE
EXPECTED NORTHEAST MOVING AREA OF SHOWERS. LIFTED INDICES DO FALL TO
AROUND ZERO AND THE OTHER STABILITY INDICES ARE FAVORABLE FOR A FEW
STORMS.

DURING THE SAME TIME PERIOD BETWEEN 00Z AND 18Z WEDNESDAY...A
TRAILING COLD FRONT IS PROGGED BY THE ECMWF AND GFS MODELS TO
PROGRESSIVELY MOVE SOUTHEAST OUT OF THE LOWER OHIO VALLEY INTO AND
THROUGH THE FORECAST AREA. THE MODELS ARE SIMILAR IN DEVELOPING A DRY
SLOT AND ENDING THE PRECIP BY WEDNESDAY AFTERNOON. HAVE MADE SOME
CHANGES INVOLVING TIMING FOR WEDNESDAY...TO AT LEAST LESSEN THE
PRECIP CHANCES AFTER 18Z. HAVE GONE WITH A COMPROMISE BETWEEN THE GFS
AND ECMWF MODELS FROM MONDAY THROUGH THE EXTENDED FORECAST PERIODS.

A LARGE AREA OF HIGH PRESSURE WILL SHIFT SOUTHEAST INTO THE TENNESSEE
VALLEY REGION ON WEDNESDAY...WITH MUCH COLDER TEMPS AND NEARLY STEADY
TO SLOWLY FALLING TEMPS EXPECTED THROUGH THE DAY. THE FORECAST HAS A
DECENT HANDLE INVOLVING THIS SCENARIO AND ONLY MINOR TEMP CHANGES
WERE MADE. THE BACK SIDE OF THE RIDGE AXIS IS EXPECTED TO MOVE EAST
OF THE FORECAST AREA BY AROUND 00Z FRIDAY. THIS WILL RESULT IN A
WARMING TREND INTO THE WEEKEND WITH NEAR NORMAL TEMPS EXPECTED.

A MID TO UPPER LEVEL ZONAL FLOW IS EXPECTED BY SATURDAY TO GIVE WAY
TO MORE OF A NORTHWEST FLOW...AS AN UPPER TROUGH MOVES SOUTHEAST
THROUGH THE GREAT LAKES REGION. A COLD FRONT WILL DROP SOUTHEAST
THROUGH THE UPPER PLAINS STATES INTO THE LOWER OHIO VALLEY BY 00Z
SUNDAY. A SURFACE LOW IS EXPECTED TO FORM ALONG THE COLD FRONT AND
THEN SLIDE EASTWARD THROUGH THE FORECAST AREA BETWEEN 18Z SUNDAY TO
00Z MONDAY. HAVE AT LEAST ADDED IN A CHANCE POP FOR THE FORECAST
AREA ON SUNDAY.

TT

&&

.AVIATION...
FOR 00Z TAFS...RECENT SATELLITE IMAGERY AND SFC OBS SUGGEST THAT A
THICKER DECK OF AC/AS CLOUDS BTWN 4-6 KFT CONTINUES TO OVERSPREAD
REGION FROM THE WEST THIS EVENING. THUS...BKN050 WILL BE INDICATED AS
INITIAL PREVAILING CIG AT BOTH MSL/HSV. CIGS WILL LOWER TO ARND 3500
FT BY MID-EVENING AS A WEAK UPPER-AIR DISTURBANCE DRIFTS SWD OVER THE
TN VALLEY...AND SHOULD REMAIN AT THIS LEVEL THRU 10/14Z. WITH A LGT
WEST FLOW EXPECTED OVERNIGHT...CONDS WILL ALSO BE FAVORABLE FOR A
PERIOD OF REDUCED VSBY IN HZ BTWN 10-14Z. STRONGER MIXING AFTER 14Z
WILL ALLOW STRATUS TO SCATTER...WITH A SW FLOW OF 10G18 KTS
CONTINUING THRU END OF TAF PERIOD.

70/DD

&&

.HUN WATCHES/WARNINGS/ADVISORIES...

AL...NONE.

TN...NONE.

&&

$$

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AT WEATHER.GOV/HUNTSVILLE.