431  
FXUS64 KMOB 080000  
AFDMOB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOBILE AL  
600 PM CST SUN FEB 7 2016  
   
DISCUSSION
 
UPDATED FOR LATEST AVIATION DISCUSSION BELOW.  
 

 
   
AVIATION
 
 
00Z ISSUANCE...A VFR FORECAST CONTINUES THROUGH THE NEXT 24 HOURS.  
CLEAR SKIES AND LIGHT WEST TO SOUTHWEST WINDS CAN BE EXPECTED  
TONIGHT. A COLD FRONT WILL MOVE ACROSS THE REGION MONDAY  
MORNING...AND WEST TO NORTHWEST WINDS WILL INCREASE TO 15-20 KNOTS  
WITH A FEW GUSTS AROUND 30 KNOTS EXPECTED BY MONDAY AFTERNOON.  
SCATTERED LOWER CLOUD DECKS AROUND 4-5 KFT AGL ARE POSSIBLE  
MONDAY. /21  
 

 
   
PREV DISCUSSION
 
/ISSUED 426 PM CST SUN FEB 7 2016/  
 
NEAR TERM /NOW THROUGH MONDAY/...FORECAST AREA IS POSITIONED  
BETWEEN TWO WEATHER SYSTEMS. THE FIRST BEING A LOW PRESSURE SYSTEM  
OFF THE COASTAL CAROLINA'S...LIFTING NORTH NORTHEAST AND THE SECOND  
BEING A STRONG COLD FRONT SURGING SOUTHEAST ACROSS THE  
CENTRAL/SOUTHERN PLAINS. THERE IS A STRONG PUSH BEHIND THE PLAINS  
FRONT WITH SURFACE OBSERVATIONS SHOWING VERY STRONG NORTHWEST FLOW  
FROM NEBRASKA...NORTHWARD ACROSS THE DAKOTAS...WHERE FORECASTERS  
NOTE GUSTS RANGING FROM 35 TO 45 KNOTS. A FEW LOCALES IN THESE  
STATES ARE SHOWING BETWEEN 50 AND 55 KNOTS AND THIS HAS BEEN THE  
CASE FOR SEVERAL HOURS. A VERY STRONG SYSTEM INDEED. GIVEN THE  
TRENDS SEEN UPSTREAM AND LATEST FORECAST LOW LEVEL WIND PROFILES IN  
FORECAST SOUNDING DATA...FORECASTERS HAVE ISSUED A WIND ADVISORY FOR  
MONDAY AFTERNOON AREA-WIDE. WILL MAINTAIN THIS ADVISORY INTO MONDAY  
NIGHT ALONG THE IMMEDIATE COAST AS THE STRONG THERMAL GRADIENT/COLD  
ADVECTION PATTERN BETWEEN THE LAND/SEA INTERFACE KEEPS WINDS HIGHER  
THERE. WINDS WILL BE THE MAIN IMPACT FOR MONDAY.  
 
THE ENSEMBLES ARE TIGHTLY CLUSTERED WITH AN ANOMALOUSLY LOW BASE TO  
THE LONGWAVE TROF SETTING UP FROM ACROSS THE NORTHERN FLORIDA  
PENINSULA TO THE SOUTHERN HALF OF MISSISSIPPI MONDAY AFTERNOON.  
HEIGHTS ALOFT LOWER THROUGH THE DAY...SOME 3 TO 4 STANDARD  
DEVIATIONS BELOW THE MEAN FROM GEORGIA TO MISSISSIPPI BY THE CLOSE  
OF MONDAY AFTERNOON. GIVEN THE LOWERING 1000-850 MILLIBAR THICKNESS  
VALUES MONDAY AFTERNOON...A NON-DIURNAL TEMPERATURE CURVE IS  
ANTICIPATED...PROGRESSIVELY LOWERING THROUGH THE AFTERNOON IN THE  
WAKE OF THE FRONTAL PASSAGE. AN INCREASE IN CLOUDS IS FORECAST FROM  
NORTH TO SOUTH DURING THE DAY MONDAY...BUT THE DEPTH OF THE MOISTURE  
ALOFT IS SHALLOW DENOTED BY CROSS-SECTION ANALYSES. THUS...ALTHOUGH  
UPPER LEVEL STORM/DYNAMICS IS AN ANOMALY FOR THIS TIME OF YEAR...NOT  
ANTICIPATING ANY MEASURABLE RAIN GIVEN THE SHALLOW RH STRATA ALOFT.  
/10  
 
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...CONTINUED WINDY  
ALONG THE ESPECIALLY ALONG THE COAST AS GFS AND ECMWF DEPICT THE  
TROPOSPHERIC FOLD STILL OVER THE AREA COURTESY OF THE POTENT UPPER  
LEVEL TROUGH PROPAGATING OVER THE AREA. WINDS THOUGH MAY TAPER BACK  
TO BREEZY IN OUR MORE PROTECTED INLAND WITH A MIXTURE OF SPOTTY WINDY  
CONDITIONS IN MORE EXPOSED AREAS AND EVEN LIGHT WINDS MIXED IN WHERE  
ENOUGH COOLING CAN OCCUR IN SHELTERED AREAS TO SET UP A SHALLOW  
INVERSION. BUT IN GENERAL COLD AIR ADVECTION (CAA) CONTINUES  
OVERNIGHT KEEPING LOWER AIRMASS WELL MIXED AND ALLOWING HIGHER WINDS  
ALOFT TO MIX DOWN TO THE SURFACE. GFS HAS TEMPERATURES AT THE 850 MB  
LEVEL BOTTOMING OUT AT BETWEEN -8 TO -10C ACROSS THE AREA. OVERNIGHT  
LOWS THOUGH WON'T PLUMMET TOO FAR DUE TO THE EFFICIENT  
MIXING...GENERALLY MID 20S TO NEAR 30 NORTHWEST OF THE I-65 CORRIDOR  
AND NEAR 30 TO MID 30S SOUTHEAST.  
 
WINDS WILL GRADUALLY DIMINISH TUESDAY AS THE UPPER LEVEL DISTURBANCE  
DEPARTS THE AREA. DAYTIME HIGHS WILL PROBABLY TOP OFF IN THE 40S AND  
PERHAPS LOW 50S CLOSER TO THE COAST. DRY...COOL WEATHER PERSISTS THEN  
THROUGH WEDNESDAY NIGHT AS REGION REMAINS UNDER THE INFLUENCE OF THE  
UPPER LEVEL LONGWAVE TROUGH...A REINFORCING SHOT OF COOLER AIR IS  
PROGGED TO PUSH THROUGH WEDNESDAY. THE ECMWF AND GFS DIVERGE  
SIGNIFICANTLY ON THE IMPACTS TO SENSIBLE WEATHER E.G., GFS FORECASTS  
OVERNIGHT LOWS IN SOME LOCATIONS AS MUCH AS 6 TO 11 DEGREES COLDER  
THAN THE ECMWF. THE CAA DOESN'T APPEAR THAT STRONG AT THIS TIME BUT  
RADIATIONAL COOLING AND LIGHT WINDS WEDNESDAY NIGHT SHOULD PROVIDE  
EFFICIENT COOLING SO TRENDED TEMPERATURES A LITTLE COOLER THAN THE  
LAST FORECAST PACKAGE BUT NOT AS COOL AS THE GFS. /08  
 
LONG TERM /THURSDAY THROUGH SUNDAY/...BY THURSDAY HEIGHTS START TO  
RISE ALOFT AS THE SHORTWAVE TROUGH EJECTS TO THE NORTHEAST...FLOW  
ALOFT GENERALLY BECOMES ZONAL BUT WE REMAIN MORE UNDER THE INFLUENCE  
OF THE LONGWAVE TROUGH MORE THAN THE UPSTREAM RIDGE. ANOTHER COLD  
FRONT APPROACHES THE AREA FRIDAY NIGHT. FAIRLY STRONG UPPER LEVEL  
SHORTWAVE IN ADVANCE OF THE FRIDAY NIGHT FRONT COULD RESULT IN A  
SLIGHT CHANCE OF RAIN THEN...BUT MORE LIKE A SPRINKLE. TEMPERATURE  
SHOULD WARM INTO THE 60S FRIDAY...UPPER 50S AND LOW 60S SATURDAY AND  
MAINLY 50S ON SUNDAY. WHILE LOWS WILL TREND UPWARD FROM THE MID 30S  
TO LOW 40S FRIDAY MORNING TO 40S TO LOW 50S SATURDAY MORNING AND THEN  
DOWNWARD INTO THE 30S AND LOW 40S ON SUNDAY MORNING. /08  
 
MARINE...HAZARDOUS CONDITIONS FOR SMALL MARINE CRAFT TO DEVELOP  
MONDAY AND CONTINUE INTO TUESDAY. A STRONG COLD FRONTAL PASSAGE  
MONDAY MORNING IS LIKELY TO BRING GALE CONDITIONS AND HIGH SEAS IN  
ITS WAKE MONDAY AFTERNOON...CONTINUING INTO EARLY TUESDAY. GALE  
WATCHES HAVE BEEN UPGRADED TO WARNINGS ON THIS PACKAGE. DUE TO THE  
STRONG NORTHWEST FETCH...SEAS WILL BE HIGHEST MONDAY NIGHT INTO  
TUESDAY. SEAS BUILDING TO 5 TO 8 FEET NEAR SHORE BY MONDAY AFTERNOON  
THEN 7 TO 10 FEET MONDAY NIGHT. WELL OFFSHORE...SEAS BUILD TO 8 TO  
10 FEET BY MONDAY AFTERNOON AND 10 TO 13 FEET MONDAY NIGHT.  
/10  
 

 
   
MOB WATCHES/WARNINGS/ADVISORIES
 
 
AL...WIND ADVISORY FROM NOON TO 6 PM CST MONDAY FOR ALZ051>060-  
261>264.  
 
WIND ADVISORY FROM NOON MONDAY TO 6 AM CST TUESDAY FOR ALZ265-  
266.  
 
FL...WIND ADVISORY FROM NOON TO 6 PM CST MONDAY FOR FLZ201-203-205.  
 
WIND ADVISORY FROM NOON MONDAY TO 6 AM CST TUESDAY FOR FLZ202-  
204-206.  
 
MS...WIND ADVISORY FROM NOON TO 6 PM CST MONDAY FOR MSZ067-075-076-  
078-079.  
 
GM...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST MONDAY  
FOR GMZ650-655-670-675.  
 
SMALL CRAFT ADVISORY FROM 1 PM TUESDAY TO 6 AM CST WEDNESDAY FOR  
GMZ630>635-650-655-670-675.  
 
GALE WARNING FROM NOON MONDAY TO 1 PM CST TUESDAY FOR GMZ630>635-  
650-655-670-675.  
 
SMALL CRAFT ADVISORY FROM 6 AM TO NOON CST MONDAY FOR GMZ630>635.  
 

 
 

 
 
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