049  
FXUS64 KMOB 181634 AAB  
AFDMOB  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE MOBILE AL  
1034 AM CST WED JAN 18 2017  
   
DISCUSSION
 
SEE UPDATED INFORMATION FOR LAND AND MARINE AREAS BELOW.  
 

 
   
UPDATE
 
UPDATED TO REMOVE THE DENSE FOG ADVISORY FROM THE FORECAST.  
SOME PATCHY FOG CONTINUES NEAR THE COAST, HOWEVER VISIBILITIES HAVE  
RISEN ABOVE CRITERIA. THE REMAINDER OF THE FORECAST REMAINS ON  
TRACK. /13  
 

 
   
MARINE
 
EXTENDED THE DENSE FOG ADVISORY FOR THE MARINE AREA THROUGH  
NOON AS VISIBILITIES REMAIN BELOW 1 MILE. /13  
 

 
   
PREV DISCUSSION
 
/ISSUED 653 AM CST WED JAN 18 2017/  
 
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.  
 
AVIATION...  
18/12Z ISSUANCE...FOG AND LOW CEILINGS AT LIFR OR LOWER AT MANY  
LOCATIONS EARLY THIS MORNING IMPROVING BY MID MORNING. SIMILAR  
CONDITIONS EXPECTED AGAIN TONIGHT. CEILINGS INCREASING TO MVFR  
(POSSIBLY IFR AT TIMES) MOST LOCATIONS LATE THIS MORNING THROUGH  
EARLY EVENING. SURFACE WINDS ARE EXPECTED TO BE OUT OF THE SOUTH OR  
SOUTHEAST AT 5 TO 10 MPH OR LESS THROUGH NEXT 12-24 HOURS. 12/DS  
 
PREV DISCUSSION... /ISSUED 508 AM CST WED JAN 18 2017/  
 
NEAR TERM /NOW THROUGH WEDNESDAY NIGHT/...SURFACE HIGH PRESSURE  
WILL BEGIN TO WEAKEN ACROSS THE SOUTHEAST TODAY AS A WEAK TROF  
DEVELOPS OVER THE INTERIOR PORTIONS OF THE FORECAST AREA AND A MORE  
ORGANIZED FRONTAL SYSTEM DEVELOPS ACROSS EASTERN TEXAS AND WESTERN  
LOUISIANA. ALOFT A HIGH PRESSURE RIDGE AXIS REMAINS ORIENTED JUST  
EAST OF THE FORECAST AREA WITH WEAK UPPER LEVEL IMPULSES RIDING THE  
SOUTHWESTERLY FLOW ALOFT. THE CONTINUED ONSHORE LOW LEVEL FLOW WILL  
TO SUPPLY A MOIST AIRMASS OVER THE REGION WITH PWATS IN THE 1.2 TO  
1.4 INCH RANGE THROUGH TONIGHT. THE WEAK IMPULSES ALOFT, COMBINED  
WITH MAX HEATING THIS AFTERNOON COULD RESULT IN ISOLATED SHOWERS OR  
THUNDERSTORMS TODAY AND THIS EVENING, BUT RAIN CHANCES ARE EXPECTED  
TO BE 20 PERCENT OR LESS. THE MOIST ONSHORE FLOW AND COOLER NEAR  
SHORE MARINE WATERS WILL CONTINUE TO RESULT IN FOG POTENTIAL AS WELL,  
ESPECIALLY EARLY THIS MORNING (WERE A DENSE FOG ADVISORY IS IN EFFECT  
ALL ZONES THROUGH 8AM) AND AGAIN TONIGHT. OTHERWISE WILL CONTINUE TO  
SEE TEMPERATURES THAT ARE WELL ABOVE CLIMATIC NORMALS, WITH DAYTIME  
HIGHS AGAIN APPROACHING OR BREAKING RECORD LEVELS. HIGHS TODAY IN THE  
MID TO UPPER 70S MOST LOCATIONS, LOWS TONIGHT GENERALLY IN THE LOW TO  
MID 60S. 12/DS  
 
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...DEEP MID TO UPPER  
TROF/LOW OVER THE CENTRAL PLAINS STATES EARLY THU MORNING WILL SHIFT  
NORTH NORTHEAST OVER THE GREAT LAKES REGION THROUGH FRI EVENING  
BECOMING REINFORCED FRI NIGHT INTO SAT AS ANOTHER DEEP TROF MOVES  
QUICKLY OVER THE WESTERN CONUS AND CENTRAL PLAINS STATES LATE FRI  
NIGHT. TO THE SOUTH AHEAD OF THE LOW SEVERAL MID LEVEL IMPULSES WILL  
TRACK EAST NORTHEAST OVER THE LOWER MS RIVER AND CENTRAL GULF STATES  
PROVIDING INCREASED LIFT OR FORCING FURTHER EAST GENERALLY THU AND  
EARLY THU NIGHT...LEADING TO BETTER COVERAGE OF SHOWERS AND  
THUNDERSTORMS THU AND EARLY THU NIGHT. A 30 TO 40 KNOT H8 JET IS  
NOTED WITH THIS PATTERN MOSTLY THU AFTERNOON AND THU NIGHT COMBINED  
WITH THE RRQ OF AN DEPARTING UPPER JET MOVING NORTH...ALL LOCATED  
OVER THE LOWER TO MID MS RIVER AND CENTRAL GULF STATES. WITH THIS  
PATTERN BULK SHEAR VALUES REACH 50 KNOTS OR SLIGHTLY HIGHER ACROSS  
THE REGION LATE THU AFTERNOON AND THU NIGHT COMBINED WITH MUCAPES OF  
400 TO 600 J/KG ALL SUGGESTING A FEW STRONG TO POSSIBLE SEVERE  
THUNDERSTORMS WILL BE LIKELY THU AFTERNOON AND THU NIGHT WITH THE  
MAIN THREAT BEING DAMAGING STRAIGHT LINE WINDS AND LARGE HAIL.  
CURRENT THINKING FROM SPC CONTINUES TO PLACE THE REGION IN A  
MARGINAL RISK FOR SEVERE THUNDERSTORM DEVELOPMENT OCCURRING OVER  
LOWER PARTS OF AL AND MS INCLUDING THE WESTERN FL PANHANDLE MOSTLY  
THU AFTERNOON AND THU EVENING. HIGHS THU WILL CLIMB TO THE MID TO  
UPPER 70S ON THU FOLLOWED BY LOWS IN THE MID TO UPPER 50S WELL INLAND  
AND THE LOWER TO MIDDLE 60S CLOSER TO THE COAST. BY FRI THE BETTER  
LIFT OR FORCING LIFTS OFF TO THE NORTHEAST LEADING TO PARTY SUNNY TO  
MOSTLY CLOUDY SKIES ON FRI WITH LITTLE CHANCE IN HIGH AND LOW TEMPS  
THROUGH FRI NIGHT.  
 
LONG TERM /SATURDAY THROUGH TUESDAY/...MOST OF THE MODEL GUIDANCE  
CONTINUES TO DEPICT A RATHER WET PATTERN ON SAT AS NEXT DEEP TROF TO  
THE WEST SHIFTS EAST OVER THE CENTRAL PART OF THE COUNTRY AND DIGS  
SOUTH OVER TX AND THE WESTERN GULF. BY SAT AFTERNOON ANOTHER STRONG  
MID LEVEL IMPULSE EJECTS NE FROM THE LOWER MS RIVER TO THE NORTH  
CENTRAL GULF COAST HELPING TO PROVIDE ANOTHER ROUND OF THUNDERSTORMS  
OCCURING MOST OF THE DAY ON SAT CONTINUING THROUGH SAT EVENING. WITH  
0-6KM BULK SHEAR VALUES CLIMBING TO 50 TO 60 KTS COMBINED WITH  
SLIGHTLY HIGHER INSTABILITY...SFC BASE CAPES UP TO 900 J/KG...THE  
THREAT FOR STRONG TO SEVERE THUNDERSTORM DEVELOPMENT WILL RESURFACE  
SAT AND SAT EVENING CONTINUING THROUGH EARLY SUN MORNING. BY SUN THE  
MAIN UPPER TROF AXIS SHIFTS EAST OF THE FORECAST AREA LEADING TO SOME  
LIGHT RESIDUAL SHOWERS SUN INTO EARLY MON THEN CLEARING FROM WEST TO  
EAST ON MON. TEMPS WILL BE COOLER SUN AND MON WITH HIGHS IN THE  
UPPER 60S TO LOWER 70S SUN AND THE UPPER 50S TO LOWER 60S ON MON.  
LOWS SUN NIGHT WILL RANGE FROM THE MID 40S INLAND AND THE LOWER 50S  
CLOSER TO THE COAST. FOR TUE SKIES WILL BE MOSTLY SUNNY WITH NEAR  
SEASONAL TEMPS RANGING FROM THE LOWER TO MIDDLE 60S FOR MOST AREAS.  
32/EE  
 
MARINE...DENSE FOG WILL CONTINUE OVER THE NEAR SHORE GULF WATERS  
AND AREA BAYS THIS MORNING AND AFTER DISSIPATING SOMEWHAT DURING THE  
DAY REDEVELOP TONIGHT. A HIGH PRESSURE RIDGE OVER THE MARINE AREA  
WILL BEGIN TO BREAK DOWN TODAY AS A COLD FRONT DEVELOPS TO THE WEST.  
THIS COLD FRONT WILL APPROACH THE COASTAL WATERS TONIGHT AND MOVE  
EAST ACROSS THE WATERS ON THURSDAY. THE FRONT WILL STALL ACROSS THE  
AREA ON FRIDAY, AND THEN A STRONGER COLD FRONT WILL APPROACH FROM  
THE WEST ON SATURDAY AND MAKE A PASSAGE ACROSS THE MARINE AREA LATE  
SATURDAY NIGHT INTO SUNDAY. THESE FRONTS WILL BRING AN INCREASED  
COVERAGE OF SHOWERS AND THUNDERSTORMS TO THE COASTAL WATERS LATE  
WEEK AND THROUGH THE WEEKEND. A LIGHT TO MODERATE ONSHORE FLOW WILL  
GRADUALLY INCREASE THROUGH LATE WEEK, BECOMING STRONG ON SATURDAY AS  
THE SECOND FRONT APPROACHES AND THEN INCREASES FURTHER AND SHIFTS  
MORE WESTERLY ON SUNDAY. RESULTANT BUILDING SEAS LATE WEEK THROUGH  
THE WEEKEND, AND SMALL CRAFT ADVISORIES WILL LIKELY BE REQUIRED.  
12/DS  
 

 
   
MOB WATCHES/WARNINGS/ADVISORIES
 
 
AL...NONE.  
FL...NONE.  
MS...NONE.  
GM...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR GMZ630>635.  
 

 
 

 
 
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