Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 041129
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
529 AM CST WED MAR 4 2015

.UPDATED...
AVIATION DISCUSSION.

&&

.DISCUSSION...

FORECAST REMAINS LARGELY INTACT EARLY THIS MORNING. SURFACE
ANALYSIS REVEALS THE COLD FRONT STRETCHES ROUGHLY LITTLE ROCK TO
BOWLING GREEN...WITH A FEW WIND SHIFTS TO THE NORTHWEST NOTED IN
NORTHWEST TN THE LAST COUPLE HOURS INDICATING ADVANCEMENT OF THE
FRONT. HERE IN CENTRAL ALABAMA...CONDITIONS REMAINED MILD
OVERNIGHT. STEADY WINDS HAVE KEPT FOG FROM BECOMING A MAJOR ISSUE.

MODELS CONTINUE TO PAINT A WET AND (FOR SOME FOLKS) ICY PICTURE
OVER THE NEXT 24 TO 36 HOURS. AHEAD OF THE FRONT...TEMPERATURES
WILL REMAIN MILD TO WARM. THE FRONT SHOULD REACH OUR NORTHWEST
COUNTIES BETWEEN 21Z AND 00Z...AND REACH I-85 BY 12Z THURSDAY.
THERE`S AN INITIAL TEMP DROP ASSOCIATED WITH THE FRONTAL
PASSAGE...BUT TEMPS WILL CONTINUE TO STEADILY FALL WELL INTO THE
DAY THURSDAY. USING A BLEND OF RAW MODEL TEMP DATA...WE`VE GOT THE
FREEZING LINE REACHING MARION COUNTY ABOUT 10Z THURSDAY
MORNING...AND ADVANCING AS FAR SOUTH/EAST AS I-59 BY 18Z. MODELS
CONTINUE TO SHOW MOISTURE WELL INTO THE COLD POST-FRONTAL AIR...
AND A MIX OF RAIN...FREEZING RAIN...AND SLEET APPEARS LIKELY
DURING THAT 10Z-18Z TIME FRAME. ONLY CHANGE TO THE WINTER STORM
WATCH AREA WILL BE TO ADD BLOUNT COUNTY.

THE MODEL DATA WOULD SUGGEST THAT QPF SHOULD BE FAIRLY LOW. BUT
LOOKING AT FORECAST SOUNDINGS...I DID NOTICE THAT IF ONE WERE TO
LIFT A PARCEL FROM AROUND 800 MB -- OR AT THE WARMEST PART OF THE
WARM NOSE -- THERE IS A LITTLE BIT OF INSTABILITY/CAPE. SO THERE
IS A CHANCE THAT THERE COULD BE SOME ENHANCED UPDRAFTS WITH
HEAVIER PRECIPITATION WITHIN THE OVERALL LIGHTER RAIN PATTERN. IF
ONE OF THOSE CONVECTIVE CELLS WERE TO OCCUR WITHIN THE COLDEST
(SUB-FREEZING) LOCATIONS...THERE COULD END UP BEING MORE
SIGNIFICANT ICING THAN CURRENTLY EXPECTED IN A SMALL AREA.

THE PRECIPITATION SHOULD ULTIMATELY MOVE OUT OF THE AREA...IF NOT
BY DARK THURSDAY THEN NOT LONG AFTERWARD. VERY COLD CONDITIONS ARE
EXPECTED THURSDAY NIGHT...WITH LOWS AS LOW AS THE UPPER TEENS.
MODELS CONTINUE TO HAVE BIG TIME PROBLEMS WITH THE PATTERN AFTER
THAT...AND FORECAST CONFIDENCE DROPS OFF A CLIFF.

/61/

&&

.AVIATION...
12Z TAF DISCUSSION.

LOW CIGS AND FOG CONTINUE THIS MORNING...AS LOW LEVEL MOISTURE
ACROSS THE AREA REMAINS HIGH. EXPECT SOME IMPROVEMENT THROUGH THE
MORNING...BUT IFR TO MFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH
THE DAY. SOUTH TO SOUTHWESTERLY WINDS WILL INCREASE THIS AFTERNOON
AND  RAIN SHOWERS AHEAD OF AN APPROACHING COLD FRONT WILL AFFECT
NORTHERN TERMINALS. WINDS WILL DECREASE SLIGHTLY THIS EVENING AND
SHIFT TO THE NORTHWEST TO NORTH. EXPECT A RETURN OF LIFR TO IFR
CONDITIONS TONIGHT WITH RAIN REMAINING ACROSS THE NORTH.

14

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     70  36  37  22  45 /  40  90  80  10  10
ANNISTON    71  40  42  23  46 /  30  80  80  10  10
BIRMINGHAM  72  34  36  22  45 /  40  90  80  10  10
TUSCALOOSA  76  35  37  23  46 /  40  90  80  10  10
CALERA      73  37  39  23  47 /  30  80  80  10  10
AUBURN      73  60  62  31  49 /  20  50  70  20  10
MONTGOMERY  76  51  56  29  51 /  20  50  70  20  10
TROY        76  61  64  32  50 /  20  40  70  30  10

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH THURSDAY AFTERNOON
FOR THE FOLLOWING COUNTIES: BLOUNT...FAYETTE...LAMAR...MARION...
WALKER...WINSTON.

&&

$$








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