Area Forecast Discussion
Issued by NWS Birmingham, AL

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000
FXUS64 KBMX 222346
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
546 PM CST SAT NOV 22 2014

.UPDATE...
FOR 00Z AVIATION.

&&

.DISCUSSION...

AN IMPRESSIVE SHORTWAVE WILL MOVE THROUGH THE MISSISSIPPI VALLEY
REGION TOMORROW AND TOWARDS THE GREAT LAKES. ISENTROPIC ASCENT
AHEAD OF THE SYSTEM IS BRINGING MIDLEVEL MOISTURE TO THE AREA
WITH A GRADUAL INCREASE IN RAIN BEGINNING LATER THIS AFTERNOON
AND ESPECIALLY INTO THE EVENING. AT THE SURFACE TEMPERATURES HAVE
WARMED WELL INTO THE 60S AND ALSO SOME LOWER 70S OUT THERE THIS
AFTERNOON. WINDS CONTINUE TO BE EAST TO SOUTHEAST AS A WEDGE
AFFECT REMAINS IN PLACE WITH A SURFACE HIGH CENTERED OVER EASTERN
NORTH CAROLINA.

THE SEVERE THREAT ON SUNDAY REMAINS A BIT UNCERTAIN AS SURFACE AND
LOWER LEVEL MOISTURE RETURN IS IN QUESTION. WINDS ACROSS THE
CENTRAL GULF COAST THIS AFTERNOON REMAIN EASTERLY WITH DEWPOINTS
IN THE MIDDLE 50S. AS THE SHORTWAVE LIFTS INTO THE MID MISSISSIPPI
VALLEY REGION...STRONG MIDLEVEL WINDS WILL BEGIN TO TRANSPORT
HIGHER MOISTURE NORTHWARD AND TRY TO LIFT A WARM FRONT UP FROM THE
COAST OVERNIGHT AND SUNDAY MORNING. MODERATE TO HEAVY RAIN
NORTHWARD OF THE SURFACE FRONT ALONG WITH THE LINGERING WEDGE
AFFECT...SHOULD HELP SLOW/LIMIT THE NORTHWARD PROGRESSION OF THE
FRONT AND LIMIT ANY SIGNIFICANT SEVERE THREAT TO OUR FAR SOUTHERN
COUNTIES...PERHAPS ALONG THE HIGHWAY 80 CORRIDOR.
HOWEVER...BECAUSE THIS IS SUCH AN ENERGETIC SYSTEM...ITS
DIFFICULT TO COMPLETELY RULE OUT SOME POTENTIAL FOR A FURTHER
NORTHWARD PROGRESSION AND WILL LEAVE THE CURRENT WORDING IN THE
HWO AS IS.

AS FAR AS THE GENERAL SCENARIO GOES...LOOK FOR A SQUALL LINE TO
APPROACH FROM THE WEST IN THE MID MORNING HOURS AND THEN PROGRESS
THROUGH THE CWA. THE CHANCE FOR SEVERE WEATHER WILL BE NEAR AND
SOUTH OF THE MAIN WARM FRONT. THERE ARE SOME POTENTIAL MESO-SCALE
FEATURES PLAYING A ROLE AS WELL INCLUDING A POSSIBLE SECONDARY
SURFACE LOW DEVELOPING OVER MISSISSIPPI DURING THE DAY SUNDAY.
REGARDLESS...IT WILL ALL HINGE ON INSTABILITY...AS THERE IS MORE
THAN ENOUGH SHEAR...AND THAT WILL BE THE THING TO WATCH OVERNIGHT
AND TOMORROW. THIS IS MOST LIKELY A QUICK HITTING SYSTEM WITH RAIN
CHANCES DROPPING VERY RAPIDLY AS THE SQUALL LINE PUSHES PAST.

MIDWEEK...ANOTHER LOW LATITUDE SHORTWAVE WILL PASS OVERHEAD WITH
THE CHANCE FOR A FEW SHOWERS ACROSS OUR SOUTHEASTERN COUNTIES ON
WEDNESDAY. THANKSGIVING AND GOING INTO THE REMAINDER OF THE
HOLIDAY WEEKEND LOOK MOSTLY DRY...ALTHOUGH THERE IS A WEAK FEATURE
THAT MIGHT TRY TO SQUEEZE OUT A FEW SPRINKLES FRIDAY EVENING OR
SATURDAY.

FOR TEMPERATURES...ANOTHER WARM DAY TOMORROW WITH HIGHS AND LOWS
DROPPING ON MONDAY AS HIGH PRESSURE BUILDS IN. READINGS FROM
TUESDAY THROUGH THE HOLIDAY WEEKEND LOOK BELOW AVERAGE WITH HIGHS
MAINLY IN THE 50S AND LOWS IN THE 30S.

88

&&

.AVIATION...
00Z TAF DISCUSSION.

CEILINGS ARE BEGINNING TO LOWER ACROSS THE SOUTH AND WILL CONTINUE
TO DO SO OVER THE REST OF THE AREA BY 02 TO 03Z. REALLY LOOKS LIKE
THIS FIRST WAVE WILL ONLY SLIGHTLY IMPACT TCL...BHM AND EET. WITH
THE LITTLE BIT QUICKER CLEARING MODELS ARE NOW HINTING AT A PERIOD
IN WHICH IFR CEILINGS WILL BE POSSIBLE ALONG WITH THE CHANCE AT
THUNDERSTORMS. VCTS MAY HAVE WORKED BETTER FOR THIS SET BUT
ALREADY HAD IN TSRA SO LEFT IT IN FOR PLANNING PURPOSES AND WILL
MAKE THOSE MINOR ADJUSTMENTS WITH THE NEXT SET OF TAFS.

SUNDAY MORNING...SHOWERS AND THUNDERSTORMS WILL BECOME MORE
WIDESPREAD AHEAD OF A DYNAMIC STORM SYSTEM AND CONDITIONS ARE
EXPECTED TO DETERIORATE. THERE REMAINS LOW CONFIDENCE IN THE
FORECAST AT THE END OF THIS PERIOD DUE TO UNCERTAINTY IN THE
EVOLUTION AND TIMING OF CONVECTION.

16

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$







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