Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 131128
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
528 AM CST SAT FEB 13 2016

.UPDATE...
AVIATION DISCUSSION.

&&

.DISCUSSION...

SHORT TERM (TODAY AND TONIGHT)...

STRONG SURFACE HIGH PRESSURE WILL CROSS THE OHIO RIVER VALLEY
TODAY AND MID APPALACHIANS TONIGHT. LOW LEVEL COLD ADVECTION
WILL KEEP HIGH TEMPS THIS AFTERNOON IN THE MID 30S TO LOWER 40S
ACROSS THE NORTH...AND MID 40S TO LOWER 50S IN THE SOUTH. LOW
LEVEL WINDS DIMINISH AND ADVECTION BECOMES NEUTRAL THIS EVENING...
AND AS WINDS BECOME SOUTHERLY TO WESTERLY LATE TONIGHT...WEAK WARM
ADVECTION RETURNS. WITH LIGHT WINDS AND MOSTLY CLEAR SKIES...LOWS
TONIGHT WILL FALL INTO THE LOW TO MID 20S.

14

LONG TERM (SUNDAY THROUGH FRIDAY)...

HEIGHT FALLS WILL OCCUR SUNDAY INTO MONDAY AS A TROUGH TAKES SHAPE
TO OUR WEST...LEADING TO A TRANSITION TO SOUTHERLY FLOW. SURFACE
HIGH PRESSURE DOWNSTREAM NEAR THE EAST COAST WILL LOSE SUPPORT AS
ITS ASSOCIATED UPPER-LEVEL CONFLUENCE ZONE RAPIDLY MOVES EAST. A
RESIDUAL THERMAL GRADIENT AND UPPER-LEVEL TROUGH WILL SUPPORT THE
DEVELOPMENT OF A WARM FRONT SUNDAY NIGHT NEAR THE TN/AL BORDER...
AND PRECIPITATION THROUGH SUNDAY AFTERNOON AND EVENING SHOULD
LARGELY REMAIN NORTH OF OUR AREA. THE APPROACHING TROUGH IS
EXPECTED SHARPEN ON MONDAY WITH SURFACE CYCLOGENESIS TAKING PLACE
TO OUR WEST. AFTER 12Z MONDAY THINGS ARE LOOKING VERY WET WITH A
DEVELOPING LOW-LEVEL JET AND SYNOPTIC-SCALE LIFT EXPECTED TO
OVERSPREAD THE AREA. MODELS ARE SUGGESTING THE SURFACE LOW WILL
DEEPEN AND TRACK NEAR THE I-20 CORRIDOR. COLD 300-500MB TEMPS
INDICATE THE POTENTIAL FOR THUNDER AS A WARM SECTOR TRIES TO MOVE
INTO THE SOUTHERN HALF OF THE FORECAST AREA. THE EFFECTS OF
WIDESPREAD LIFT AND PRECIPITATION WILL PROBABLY LIMIT THE
NORTHWARD PROGRESSION OF A MODIFIED AIRMASS OVER THE GULF...BUT A
NON-ZERO SEVERE THREAT COULD TAKE SHAPE ACROSS SOUTH ALABAMA. IF
DEWPOINTS CAN RISE INTO THE UPPER 50S ACROSS THE SOUTHERN PART OF
THE CWA...INSTABILITY WOULD BE SUFFICIENT FOR A LIMITED RISK FOR
DAMAGING WINDS OR BRIEF TORNADOES. CONFIDENCE IS TOO LOW TO
INCLUDE THIS IN THE HWO AT THIS TIME.

WIDESPREAD RAIN SHOULD CLEAR OUT MONDAY NIGHT. A CLIPPER COULD
BRING A FEW SHOWERS TO THE NORTH ON TUESDAY EVENING...BUT OVERALL
THE RETURN OF NORTHWESTERLY FLOW SHOULD YIELD DRY CONDITIONS
THROUGH THE END OF THE WEEK. HEIGHT RISES WILL LEAD TO RELATIVELY
WARM CONDITIONS FOR THURSDAY AND FRIDAY.

87/GRANTHAM

&&

.AVIATION...
12Z TAF DISCUSSION.

VFR CONDITIONS WILL REMAIN IN PLACE OVER THE FORECAST PERIOD.
GUSTY NORTHERLY WINDS WILL BE POSSIBLE...PREVAILING AT 10-12 KNOTS
WITH A FEW GUSTS TO 18 KNOTS...PRIMARILY THIS AFTERNOON.

14

&&

.FIRE WEATHER...

A COLDER AND DRIER AIRMASS WILL MOVE INTO THE REGION TODAY WITH
DEW POINTS IN THE SINGLE DIGITS AND RH VALUES DROPPING INTO THE 20
TO 30 PERCENT RANGE. 20 FT WINDS SHOULD REMAIN UNDER 15 MPH AND
MOIST GROUND CONDITIONS WILL LIMIT FIRE WEATHER CONCERNS. RAIN
WILL ENTER THE PICTURE LATE SUNDAY INTO MONDAY AS A STORM SYSTEM
DEVELOPS.

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     38  22  47  38  52 /   0   0  20  60 100
ANNISTON    40  24  49  39  53 /   0   0  10  40 100
BIRMINGHAM  41  24  50  42  56 /   0   0  10  60 100
TUSCALOOSA  45  24  53  43  59 /   0   0  10  60 100
CALERA      43  26  52  43  58 /   0   0  10  50 100
AUBURN      47  27  51  40  58 /   0   0   0  20  80
MONTGOMERY  52  27  56  40  64 /   0   0   0  20  90
TROY        51  27  56  40  64 /   0   0   0  20  80

&&

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

&&

$$


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