Area Forecast Discussion
Issued by NWS Birmingham, AL

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KBMX 021755
AFDBMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BIRMINGHAM AL
1155 AM CST MON MAR 2 2015

.UPDATE...
FOR 18Z AVIATION.

&&

.DISCUSSION...

FOG IS BEING REPORTED JUST ABOUT EVERYWHERE ACROSS CENTRAL ALABAMA
EARLY THIS MORNING...ALTHOUGH THERE DOES NOT SEEM TO BE A
DISCERNIBLE PATTERN TO THE VISIBILITY VALUES (WHICH RANGE FROM 1/4
TO 5 MILES). THERE`S BOUND TO BE PLENTY OF DENSE STUFF OUT
THERE..AND WE`VE GONE AHEAD AND ISSUED A DENSE FOG ADVISORY UNTIL
9 AM THIS MORNING.

SURFACE ANALYSIS THIS MORNING SHOWED A COLD FRONT DRAPED ACROSS
THE NORTHWEST CORNER OF THE STATE...DROPPING DOWN INTO
SOUTHWESTERN MS. THE FRONT IS FORECAST TO GET INTO THE SOUTH HALF
OF ALABAMA TODAY...TURN AROUND (AND NOT DROWN)...AND PUSH BACK
NORTH AS A WARM FRONT TONIGHT AND TUESDAY. LOW/MID LEVEL FLOW
(ABOVE THE BOUNDARY LAYER) WILL BE OUT OF THE SOUTHWEST...TAPPING
GULF MOISTURE AND OVERRUNNING THE SURFACE FRONT. THIS WILL PRODUCE
PLENTY OF CLOUDS AND AREAS OF RAIN THROUGH THE DAY TODAY AND INTO
TONIGHT. THE FOCUS OF THE WET WEATHER PUSHES NORTH WITH THE FRONT
ON TUESDAY.

AN ELONGATED UPPER LEVEL TROUGH WILL SWING ACROSS THE EASTERN HALF
OF THE COUNTRY WEDNESDAY AND WEDNESDAY NIGHT. MODELS CONTINUE TO
DEPICT ANOTHER STRONG (ARCTIC) SURFACE COLD FRONT BEING FORCED
SOUTHWARD INTO OUR REGION BY THE UPPER TROUGH. CONDITION AHEAD OF
THE FRONT WILL ACTUALLY BECOME QUITE MILD. BUT THE FRONT WILL
USHER IN ANOTHER VERY COLD AIR MASS LATE WEDNESDAY INTO WEDNESDAY
NIGHT.

WHILE THE MODELS AGREE ON THE GENERAL IDEA OF A STRONG COLD FRONT
PASSAGE MID-WEEK...THERE ARE STILL SOME DIFFERENCES ON TIMING OF
THE FRONT. 00Z AND 00Z RUNS OF THE GFS WILL NOTICEABLE FASTER THAN
THE 00Z AND 06Z NAM AND THE 00Z ECMWF. THE FORECAST WAS LOOSELY
BASED ON THE SLOWER MODELS...DELAYING THE ARRIVAL OF THE FRONT
IN OUR NORTHWEST COUNTIES UNTIL WEDNESDAY AFTERNOON (ABOUT 4-6
HOURS SLOWER THAN THE GFS).

THE MODELS DO SHOW PLENTY OF MOISTURE ON THE COLD SIDE OF THE
SURFACE FRONT. WHILE VERY COLD IN COMPARISON TO THE AIR MASS AHEAD
OF IT...THE INBOUND COLD AIRMASS LOOKS TO BE QUITE SHALLOW. MODEL
SOUNDINGS CONTINUE TO SHOW THE POTENTIAL FOR WINTRY WEATHER FOR
SEVERAL HOURS AFTER FRONTAL PASSAGE. THE STRENGTH OF THE WARM NOSE
AND THE DEPTH/MAGNITUDE OF THE LOW LEVEL COLD LAYER SUGGEST THAT
WE WOULD BE DEALING PRIMARILY WITH A FREEZING RAIN AND SLEET
SITUATION. ANY SNOW GETTING INTO OUR COUNTIES WOULD BE RIGHT AS
THE PRECIPITATION WAS ENDING...AND LIMITED TO THE NORTHWESTERN
COUNTIES.

WE ARE NOW WITHIN 2 1/2 DAYS OF THE START OF THE POTENTIAL WINTRY
WEATHER. CONFIDENCE OF GETTING SOMETHING WINTRY CONTINUES TO
CREEP UP. NOT SURE IF THE AMOUNT OF FREEZING RAIN OR SLEET
CURRENTLY FORECAST WOULD QUALIFY FOR A WINTER STORM WARNING BASED
ON CRITERIA ALONE. BUT THE FACT THAT THE EVENT WOULD BE OCCURRING
BEFORE AND DURING WHAT WOULD BE THE MORNING RUSH HOUR...AND
TEMPERATURES WOULD BE FALLING AS THE PRECIPITATION FELL...MAY
EVENTUALLY MAKE US CONSIDER A WATCH/WARNING BASED ON THE
SIGNIFICANT IMPACTS ASSOCIATED WITH THE TIME OF DAY. STAY TUNED.

/61/

&&

.AVIATION...
18Z TAF DISCUSSION.

PESSIMISTIC FORECAST THROUGH THE END OF THE TAF PERIOD. SEE NO
REASON TO BRING CIGS ABOVE IFR WITH LIGHT BOUNDARY-LAYER WINDS AND
ABUNDANT MOISTURE IN PLACE. POSSIBLILITY FOR LIFR CIGS/VIS NEAR
AIRPORT MINUMUMS SHOULD INCREASE OVERNIGHT. LIGHT RAIN SHOWERS MAY
AFFECT THE NORTHERN TAF SITES PERIODICALLY.

87/GRANTHAM

&&

.PRELIMINARY POINT TEMPS/POPS...
GADSDEN     52  46  67  60  66 /  80  60  50  40  60
ANNISTON    55  50  69  61  67 /  70  60  40  30  60
BIRMINGHAM  53  50  72  62  66 /  80  60  40  30  60
TUSCALOOSA  58  51  73  62  70 /  70  50  30  30  60
CALERA      56  53  73  61  69 /  70  50  30  30  60
AUBURN      63  56  73  61  71 /  40  40  20  10  40
MONTGOMERY  63  57  76  61  74 /  40  40  20  10  40
TROY        65  58  76  61  74 /  30  30  20  10  40

&&

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

&&

$$

61/87




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.