Area Forecast Discussion
Issued by NWS Birmingham, AL

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000
FXUS64 KBMX 210601
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1201 AM CST SUN DEC 21 2014

.UPDATE...
FOR 06Z AVIATION.

&&

.DISCUSSION...

A SURFACE FRONT REMAINS NEAR THE GULF COASTAL INTERFACE THE NEXT
FEW DAYS. SEVERAL IMPULSES RIDE THROUGH THE SOUTHWESTERLY FLOW
ALOFT WITH A FEW WAVES DEVELOPING ALONG THE FRONT.

IN CENTRAL ALABAMA...CLOUDS COVERED MUCH OF THE SOUTHEASTERN HALF
OF THE AREA WITH HINTS AT MOVING SOUTHEASTWARD OVERNIGHT. BUT
AFTER SUNSET...THE CLOUDS HAVE ALMOST COMPLETELY HALTED AND
EVENTUALLY EXPECT THESE CLOUDS TO INCH BACK NORTHWARD IN RESPONSE
TO THE UPPER IMPULSES AND DEVELOPING ISENTROPIC LIFT. THIS CLOUD
GRADIENT WILL LEAD TO A RATHER LARGE TEMP GRADIENT OVERNIGHT. THE
CLEAR AREAS NORTHWEST SHOULD REACH THE UPPER 20S WHILE AREAS
SOUTHEAST REMAIN NEARLY STATIONARY WITH LOWS NEAR 50. THE
PROBLEMATIC AREA WILL BE RIGHT AT THE CLOUD NO CLOUD INTERFACE. IF
THE CLOUDS SLIDE SOUTHWARD SLIGHTLY...TEMPS WILL FALL ALONG THE
I-20 CORRIDOR...THEN STEADY OUT. GENERALLY WENT WITH THE IDEA THAT
THE CLOUDS MOVE VERY LITTLE BEFORE EVEN LOWER CLOUDS
REDEVELOP/MOVE NORTHWARD LATER TONIGHT. ADJUSTED TEMPS AND CLOUDS
FOR THESE TRENDS. WENT AHEAD AND MENTIONED SOME PATCHY FOG
AREAWIDE OVERNIGHT. DO NOT THINK THERE WILL BE MAJOR RESTRICTIONS
IN VISIBILITIES BUT FOG NONETHELESS FOR DIFFERING REASONS. HIGHER
LOW LEVEL MOISTURE SOUTH WILL HAVE TO BE MONITORED BECAUSE IF
TEMPS DO INDEED FALL A FEW DEGREES IT WILL BE CLOSE TO THE NON
MIXED CROSSOVER TEMP. NORTH...COOLER BUT NEAR SATURATED GROUND
CONDITIONS MAY CAUSE SOME FOG. UPDATES ALREADY OUT.

75


&&

.AVIATION...
06Z TAF DISCUSSION.

IT IS GOING TO BE TOUGH DEALING WITH THE CLOUDS OVER THE NEXT 24
HOURS. CONDITIONS AT 06Z RANGED FROM CLEAR AT TCL...TO IFR AT TOI.
IN BETWEEN THE TWO EXTREMES...THERE WAS A DECK OF 3500 FT CLOUDS
WITH PATCHES OF MVFR LEVEL MIXED IN. THE FORECAST WENT WITH THE
GENERAL IDEA THAT THE CLOUDS WOULD SPREAD BACK AND BECOME LOWER
NORTH AND WESTWARD THROUGH THE OVERNIGHT HOURS. THE LATEST
COMPUTER MODEL MOISTURE PROFILES SUGGEST THAT CONDITIONS RIGHT NOW ARE
THE BEST THEY ARE GOING TO BE OVER THE NEXT 24 HOURS...AND THERE
WILL LIKELY BE LITTLE TO NO BREAKS IN THE CLOUDS (ONCE THE CLOUDS
RETURN TO BHM AND TCL).

/61/

&&

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

&&

$$





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