Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 201207 AAA
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
607 AM CST SAT DEC 20 2014

.UPDATE...
FOR 12Z AVIATION.

.DISCUSSION...

AN UPPER LEVEL SHORTWAVE TROUGH IS MOVING EAST ACROSS LOWER
MISSISSIPPI AND TENNESSEE VALLEY REGION THIS MORNING. AT THE SFC
THE RAIN IS QUICKLY SHIFTING EAST IN GA WITH DRIER AIR ALOFT
MOVING IN FROM THE WEST. THERE IS ALSO A WEAK SFC LOW IN THE
CENTRAL GULF JUST OFF THE LA COAST. THE BEST CHANCE OF RAIN THIS
MORNING WILL BE SOUTH OF I-85 WITH RAIN COMING TO AN THIS
AFTERNOON.

ANOTHER UPPER SHORTWAVE WILL CROSS THE PLAINS ON SUNDAY AND ALLOW
THE CURRENT SFC LOW IN THE GULF TO EJECT NORTHEASTWARD ALONG THE
ATLANTIC COAST. THIS WILL BRING ANOTHER CHANCE OF RAIN TO CENTRAL
ALABAMA...PRIMARILY IN THE EAST...SUNDAY AND SUNDAY NIGHT. SHOWERS
COULD LINGER INTO MONDAY WITH SOUTHEASTERLY FLOW AND CONTINUED LOW
LEVEL MOISTURE THANKS TO A WEDGE IN PLACE ALONG THE ATLANTIC
SEABOARD DOWN INTO EASTERN AL.

THE SYSTEM OF INTEREST WILL IMPACT THE FORECAST AREA ON TUESDAY INTO
WEDNESDAY AS A TROUGH DEEPENS ACROSS THE PLAINS STATES. MODELS STILL
SHOW A SFC LOW DEVELOPING ACROSS EASTERN TX LATE MONDAY BUT THE
TRACK OF THIS LOW HAS SHIFTED MORE TO THE NORTH VS EAST AS THE
SYSTEM OCCLUDES. WITH THE SFC LOW PASSING JUST TO OUR NORTH AND WEST
THIS WOULD GENERALLY PUT CENTRAL ALABAMA IN A FAVORABLE SPOT FOR
SEVERE WEATHER POTENTIAL. ALTHOUGH THERE IS SUFFICIENT SHEAR AND LOW
60 DEW POINTS ARE PROGGED TO SURGE NORTHWARD INTO SOUTHERN PORTIONS
OF THE CWA...THERE ARE SOME POTENTIAL LIMITING FACTORS. CURRENT
MODEL GUIDANCE INDICATES ONGOING SHOWER ACTIVITY AND OVERCAST SKIES
ACROSS THE FORECAST AREA TUESDAY MORNING...AND THERE IS ALSO
INDICATIONS OF A LARGE CLUSTER OF RAIN/STORMS THAT DEVELOPS IN THE
NORTHERN GULF. TAKING THIS IN CONSIDERATION IT`S UNCERTAIN HAS TO
HOW MUCH INSTABILITY WILL BE REALIZED ACROSS OUR AREA. DUE TO LOW
CONFIDENCE HAVE DECIDED TO LEAVE OUT ANY MENTION OF SEVERE IN THE
HWO AT THIS TIME. HOWEVER WILL CONTINUE TO MONITOR TRENDS CLOSELY.

THE SFC COLD FRONT WILL SHIFT EAST OF AL WEDNESDAY MORNING BUT
ISO/SCT SHOWERS WILL REMAIN POSSIBLE IN THE NORTH/EAST WEDNESDAY
MORNING DUE TO SOME WRAP AROUND MOISTURE. IT WILL BE A BIT WINDY ON
WEDNESDAY WITH WESTERLY WINDS OF 15 MPH AND GUSTS UP TO 25 MPH.
TEMPS COOL DOWN BRIEFLY IN THE WAKE OF THE FRONT BUT QUICKLY
REBOUND BY THE END OF THE WORK WEEK AS SFC SOUTHERLY FLOW RETURNS
AHEAD OF THE NEXT SYSTEM.

19

&&

.AVIATION...
12Z TAF DISCUSSION.

MVFR TO OCCASSIONALLY IFR CEILINGS AND VSBYS PREVAIL ACROSS MUCH OF
THE AREA EARLY THIS MORNING ALTHOUGH MOST OF THE RAIN HAS PUSHED TO
ALONG AND SOUTHEAST OF THE I-85 CORRIDOR.  THE RAIN SHOULD CONTINUE
TO MOVE EASTWARD AND BE MOSTLY OUT OF THE AREA BY AFTERNOON.
CEILINGS WILL IMPROVE TO VFR IN NORTHWEST SECTIONS BY MID MORNING AS
INDICATED BY SOME CLEARING OCCURRING TO THE WEST IN MISSISSIPPI...
BUT WILL BE SLOWER TO IMPROVE IN OUR SOUTHEASTERN SECTIONS.
HOWEVER...EXPECT ALL TAF SITES TO BECOME VFR BY AFTERNOON...AND
REMAIN VFR FOR MUCH OF THE REMAINDER OF THE PERIOD...ALTHOUGH MODEL
SOUNDINGS INDICATE THAT CEILINGS AND VISIBILITIES COULD BEGIN
LOWERING BACK TO AT LEAST MVFR CONDITIONS AFTER 06Z...ESPECIALLY IN
THE SOUTHEASTERN SECTIONS AT TOI AND MGM. A LIGHT NORTH TO NORTHEAST
WIND FLOW LESS THAN 7 KNOTS SHOULD PREVAIL THROUGHOUT THE PERIOD.

41

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     51  36  53  44  55 /  20  10  10  40  30
ANNISTON    52  39  55  47  56 /  20  10  10  50  30
BIRMINGHAM  53  40  57  47  60 /  20  10  10  40  30
TUSCALOOSA  55  39  57  47  60 /  10  10  10  30  30
CALERA      53  41  56  47  59 /  20  10  10  40  30
AUBURN      54  46  55  48  59 /  50  10  30  60  40
MONTGOMERY  56  45  58  49  63 /  40  10  20  50  30
TROY        56  46  57  50  65 /  60  20  40  50  30

&&

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

&&

$$











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