762  
FXUS64 KMOB 032117  
AFDMOB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOBILE AL  
317 PM CST SAT DEC 3 2016  
   
NEAR TERM /NOW THROUGH SUNDAY/
 
NEXT MAIN UPPER TROF DIGGING  
SOUTH OVER THE SW CONUS AND CALIFORNIA BAJA WILL BEGIN TO SHIFT  
EASTWARD LATE TONIGHT AND DURING THE DAY ON SUN RESULTING IN A  
PERSISTENT MEAN FLOW ALOFT AT AROUND 50 KTS FROM THE SOUTHWEST  
TONIGHT AND DURING THE DAY ON SUN. AT THE SURFACE A STRONG RIDGE OF  
HIGH PRESSURE CENTERED NEAR MID ATLANTIC AND TN/OH RIVER VALLEYS  
STRETCHING SOUTHWARD TOWARDS THE NORTHERN GULF STATES...WHICH  
CONTINUES TO LEAD TO A DRY COOL WEDGE OF STABLE AIR OVER MUCH OF THE  
DEEP SOUTH ALONG THE NORTHERN GULF...WILL BEGIN TO SLOWLY RETREAT  
NORTHWARD EARLY SUN AND CONTINUE THROUGH SUN AFTERNOON IN RESPONSE TO  
THE DEEP UPPER TROUGH TO THE WEST SHIFTING EASTWARD. WITH THIS  
PATTERN EXPECT A CONTINUED STRATUS DECK AT AROUND 10 KFT TO CONTINUE  
THROUGH EARLY THIS EVENING THEN LOWERING OVERNIGHT AND EARLY SUNDAY  
AS THE DEPTH OF THE COOLER/STABLE AIR BEGINS TO DECREASE. WITH THIS  
CLOUD BASES LOWER TO AROUND 1.5 KFT BY EARLY SUN MORNING RESULTING IN  
A LOW STATUS DECK SLOWING ERODING GENERALLY FROM SOUTH TO NORTH  
DURING THE DAY ON SUN. WITH THE BETTER LAYER LIFTED NOTED LIGHT RAIN  
AND FOG WILL ALSO BE POSSIBLE BY EARLY SUN BECOMING BETTER DEVELOPED  
THROUGH SUN AFTERNOON. ALTHOUGH WE ARE NOT SEEING MUCH IN THE WAY OF  
WIDESPREAD GLACIATED CONVECTION WITH THIS PATTERN THROUGH SUN WILL  
CONTINUE TO MENTION A SLIGHT CHANCE TO CHANCE THUNDERSTORMS ALSO  
WHICH WILL BE EMBEDDED MAINLY IN THE HEAVIER RAIN.  
 
AS FOR TEMPS WILL CONTINUE TO LEAN TOWARDS THE COOLER MAV GUIDANCE  
THROUGH SUN AFTERNOON DUE TO THE COOL WEDGE SLOWLY ERODING THROUGH  
THE NEXT 24 HOURS. LOWS TONIGHT WILL RANGE FROM THE UPPER 40S TO  
LOWER 50S OVER NORTHERN SECTIONS OF THE FORECAST AREA AND THE MIDDLE  
TO UPPER 50S OVER MIDDLE AND COASTAL SECTIONS. HIGHS SUN WILL  
EVENTUALLY CLIMB TO THE LOWER TO MIDDLE 70S GENERALLY FROM I-10 AND  
SOUTHWARD AND HE MIDDLE 60S LOWER TO LOWER 70S FURTHER NORTH. 32/EE  
   
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/
 
A CUT OFF UPPER  
LOW OVER NORTHERN MEXICO WEAKENS TO AN OPEN WAVE AND EJECTS ACROSS  
THE SOUTHEAST STATES MONDAY NIGHT INTO TUESDAY AFTERNOON. AN  
ASSOCIATED SURFACE LOW MEANWHILE MOVES FROM NEAR THE TEXAS COAST TO  
THE LOWER MISSISSIPPI RIVER VALLEY MONDAY EVENING, THEN TO NEAR THE  
OHIO RIVER VALLEY TUESDAY MORNING. A SURFACE FRONTAL BOUNDARY WILL BE  
ORIENTED ALONG THE NORTHERN GULF COAST EARLY SUNDAY EVENING,  
INCLUDING BEING SLIGHTLY INLAND OVER THE COASTAL COUNTIES OF THE  
FORECAST AREA DUE TO A SURFACE WAVE ON THE BOUNDARY WHICH EXITS TO  
THE EAST. A SURFACE RIDGE OVER THE SOUTHEAST STATES WILL BE AN  
IMPEDIMENT TO THE FRONTAL BOUNDARY MAKING MUCH NORTHERN MOVEMENT INTO  
THE FORECAST AREA WITH THE APPROACH OF THE SURFACE LOW AT LEAST  
THROUGH MONDAY, AFTER WHICH THE FRONTAL BOUNDARY PUSHES NORTHWARD  
THROUGH THE FORECAST AREA MONDAY NIGHT. WITH THE FRONTAL BOUNDARY  
POSITIONED NEAR THE COAST SUNDAY NIGHT INTO MONDAY, THIS SETS UP AN  
EXTENDED PERIOD OF ISENTROPIC LIFT (OVERRUNNING FLOW) OVER MUCH OF  
THE FORECAST AREA UNTIL THE FRONT PUSHES NORTHWARD MONDAY NIGHT  
OPENING THE REMAINDER OF THE AREA TO A WARM SECTOR. THIS PERIOD OF  
EXTENDED PRECIPITATION NORTH OF THE FRONTAL BOUNDARY WILL HAVE  
IMPORTANT IMPACTS ON THE FORECAST, ESPECIALLY SHEAR AND INSTABILITY.  
NUMERICAL VISIBILITY GUIDANCE IS INDICATING FOG AT LEAST OVER THE  
SOUTHERN PORTION OF THE AREA SUNDAY NIGHT WHICH LINGERS NEAR THE  
COAST MONDAY MORNING, AND HAVE ADDED THIS TO THE FORECAST. TABULAR  
GUIDANCE ALSO INDICATES FOG COULD AFFECT ESSENTIALLY THE ENTIRE  
AREA AND THE MENTION OF FOG MAY NEED TO BE EXPANDED, ALTHOUGH  
VISIBILITIES OVERALL LOOK TO REMAIN ABOVE DENSE FOG ADVISORY  
CRITERIA.  
 
ASSESSING INSTABILITY, MLCAPES WILL RANGE FROM 200 J/KG AND LESS  
OVER MOST OF THE FORECAST AREA THROUGH MONDAY, TRANSITIONING TO  
VALUES NEAR 1000 J/KG WELL OFFSHORE. ALONG THE COAST, VALUES NEAR 500  
J/KG WILL BE POSSIBLE. VALUES NEAR 500 J/KG WILL SPREAD FURTHER  
INLAND MONDAY NIGHT, BUT LIKELY MAKE IT TO AT BEST MIDWAY THROUGH THE  
AREA, WHILE VALUES NEAR 200 J/KG PERSIST WELL INLAND. A NEGATIVE  
ITEM IS THAT THE CONDITIONAL PROBABILITIES FOR THUNDER ONLY GET TO  
35% NEAR THE COAST MONDAY AFTERNOON, THEN WILL BE AROUND 40% MONDAY  
NIGHT BEFORE FALLING OFF INTO THE SINGLE DIGITS.  
 
ASSESSING THE SHEAR PROFILE, DESPITE THE FRONTAL BOUNDARY PUSHING  
NORTHWARD THROUGH THE AREA, MODEL SOUNDINGS SHOW THAT THE LOWER  
LEVELS OF THE ATMOSPHERE, SUCH AS BELOW 900-950 MB, ARE AT BEST  
ISOTHERMAL. THIS IN TURN INDICATES THAT CONVECTION WILL BE ELEVATED  
AND NOT HAVE ACCESS TO THE BEST VEERING WIND PROFILE. THAT MEANS THAT  
SHOULD THESE SOUNDINGS BE CORRECT (THIS IS A VERY IMPORTANT CAVEAT), THE  
SHEAR AVAILABLE TO CONVECTION WILL BE MUCH LESS. 0-3 KM HELICITY  
VALUES ARE INDICATED TO BE AROUND 200 M2/S2, BUT VALUES WHERE THE  
CONVECTION WILL BE BASED (ABOVE THE LOW LEVEL VEERING), IF THE  
CURRENT SOUNDINGS ARE CORRECT DEPICTING THE ISOTHERMAL LAYER, THEN  
THESE VALUES WILL BE LOWER - POSSIBLY AS LOW AS NEAR 50 M2/S2.  
 
THE ONLY EXCEPTION TO THIS IS AT THE IMMEDIATE COAST WHERE THE  
ISOTHERMAL LAYER IS VERY SHALLOW, AS THIS TRANSITIONS TO A SURFACE  
BASED ENVIRONMENT OVER THE NORTHERN GULF. THIS INDICATES THAT THE  
BEST POTENTIAL FOR SURFACE BASED CONVECTION WHICH WOULD HAVE ACCESS  
TO THE HIGHER SHEAR VALUES WILL BE AT THE IMMEDIATE COAST. TIMING  
WISE, THIS LOOKS TO BE GENERALLY DURING MONDAY AFTERNOON, BUT COULD  
BEGIN LATE MONDAY MORNING AND ALSO STRETCH INTO MONDAY EVENING. THE  
ANTICIPATED EVOLUTION OF SURFACE BASED CONVECTION MOVING NORTHWARD  
FROM THE NORTHERN GULF INTO THE IMMEDIATE COASTAL AREAS LOOKS GOOD,  
SO AT THIS POINT THE ONLY POTENTIAL FOR SURFACE BASED CONVECTION IS  
AT THE IMMEDIATE COAST, AFTER WHICH CONVECTION BECOMES INCREASINGLY  
ELEVATED.  
 
DESPITE THIS ASSESSMENT AND TAKING INTO CONSIDERATION THAT LATER DATA  
MAY INDICATE A MORE FAVORABLE ENVIRONMENT - ESPECIALLY IF THE LOW  
LEVEL SOUNDING DATA PROVES INCORRECT - WILL STAY WITH THE CURRENT  
HAZARDOUS WEATHER OUTLOOK WHICH HAS MENTION OF SOME SEVERE STORMS  
POSSIBLE ACROSS THE ENTIRE AREA MONDAY INTO MONDAY NIGHT. THAT SAID,  
CURRENTLY THIS POTENTIAL APPEARS TO BE CONFINED TO NEAR THE COAST.  
 
HAVE GONE WITH LIKELY POPS ACROSS THE AREA SUNDAY NIGHT FOLLOWED BY  
CATEGORICAL POPS ON MONDAY AS THE ISENTROPIC LIFT STRENGTHENS NORTH  
OF THE FRONTAL BOUNDARY. HIGH POPS CONTINUE FOR MONDAY EVENING, THEN  
TAPER OFF LATE MONDAY NIGHT TO DRY/SLIGHT CHANCE POPS ON TUESDAY AS  
THE UPPER TROF PASSES THE AREA WITH SUBSIDENCE FOLLOWING IN THE WAKE  
OF THE UPPER SYSTEM. LOWS SUNDAY NIGHT RANGE FROM THE LOWER/MID 50S  
WELL INLAND TO THE LOWER 60S AT THE COAST WITH A BIT WARMER VALUES  
FOR MONDAY NIGHT. TUESDAY NIGHT WILL BE COOLER AS DRY HIGH PRESSURE  
BUILDS INTO THE REGION, AND RANGE FROM THE MID 40S INLAND TO THE  
LOWER 50S AT THE COAST. HIGHS ON MONDAY RANGE FROM THE MID 60S WELL  
INLAND TO THE LOWER 70S AT THE COAST, THEN FOR TUESDAY HIGHS WILL  
RANGE FROM THE MID 60S INLAND TO THE UPPER 60S CLOSER TO THE COAST.  
/29  
   
LONG TERM /WEDNESDAY THROUGH SATURDAY/
 
AN EVOLVING LONGWAVE TROF  
AT THE BEGINNING OF THE PERIOD OVER THE WESTERN AND CENTRAL STATES  
CONTINUES EASTWARD ACROSS THE EASTERN STATES THROUGH FRIDAY, AND INTO  
THE WESTERN ATLANTIC ON SATURDAY. AN ASSOCIATED SURFACE LOW WAY TO  
THE NORTH BRINGS A REINFORCING COLD FRONT THROUGH THE FORECAST AREA  
WEDNESDAY NIGHT (WITH NO RETURN FLOW AHEAD OF THE FRONT), AND USHERS  
WHAT COULD BE THE COLDEST AIR OF THE SEASON INTO THE REGION. WILL  
HAVE SLIGHT CHANCE POPS FOR WEDNESDAY NIGHT AND THURSDAY AS LAYER  
LIFTING PRODUCES ISOLATED TO SCATTERED PATCHES OF RAIN, BUT OTHERWISE  
DRY CONDITIONS ARE EXPECTED.  
 
HIGHS ON WEDNESDAY WILL RANGE FROM THE LOWER 60S WELL INLAND TO THE  
MID/UPPER 60S NEAR THE COAST, THEN TREND MUCH COOLER THROUGH FRIDAY  
TO RANGE FROM THE LOWER 40S INLAND WITH UPPER 40S NEAR THE COAST.  
SATURDAY WILL SEE SOME RECOVERY WITH HIGHS NEAR 50. LOWS WEDNESDAY  
NIGHT RANGE FROM THE LOWER 40S WELL INLAND TO THE LOWER 50S AT THE  
COAST, THEN VERY COLD NIGHTS ARE EXPECTED FOR THURSDAY NIGHT AND  
FRIDAY NIGHT WITH LOWS RANGING FROM MID 20S INLAND TO THE LOWER 30S  
AT THE COAST. /29  
 

 
   
MARINE
 
A STRONG EASTERLY WIND FLOW WILL CONTINUE OVER THE NORTHERN  
GULF THROUGH TONIGHT AHEAD OF DEEP TROF APPROACHING FROM THE WEST  
COMBINED WITH STRONG HIGH PRESSURE TO THE NORTH AND EAST. A MODERATE  
TO STRONG SOUTHERLY FLOW WILL EVENTUALLY DEVELOP DURING THE DAY ON  
SUN AND CONTINUE THROUGH MON NIGHT AS WARMER AIR CONTINUES TO SHIFT  
NORTHWARD AHEAD OF THE MAIN UPPER SYSTEM TO THE WEST REACHING THE  
NORTHERN GULF AND INLAND COAST LATER IN THE DAY. AS A RESULT A SMALL  
CRAFT ADVISORY WILL CONTINUE OVER THE OPEN GULF WATERS THROUGH SUN  
AFTERNOON AND THE LOWER END OF MOBILE BAY AND MS SOUND THROUGH THIS  
AFTERNOON. RAIN CHANCES ALSO INCREASED SUN THROUGH MON WITH A FEW  
STRONG THUNDERSTORMS POSSIBLE BY LATE MON AND MON NIGHT. A COLD FRONT  
MOVES EAST OF THE MARINE AREA IN THE WAKE OF THIS SYSTEM BY TUE NIGHT  
INCREASING LATE IN THE WEEK AS A STRONGER SURGE OF COLDER AIR MOVES  
SOUTH OVER MUCH OF THE NORTHERN GULF. 32/EE  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
MOBILE 55 73 60 69 / 50 80 60 80  
PENSACOLA 58 72 64 73 / 40 70 70 80  
DESTIN 61 74 67 75 / 30 60 70 80  
EVERGREEN 53 70 59 69 / 40 70 70 80  
WAYNESBORO 51 63 53 67 / 60 80 70 90  
CAMDEN 50 64 55 65 / 60 80 70 90  
CRESTVIEW 53 73 63 73 / 30 70 70 80  
 

 
   
MOB WATCHES/WARNINGS/ADVISORIES
 
 
AL...HIGH RIP CURRENT RISK THROUGH SUNDAY AFTERNOON FOR ALZ265-266.  
 
FL...HIGH RIP CURRENT RISK THROUGH SUNDAY AFTERNOON FOR FLZ202-204-  
206.  
 
MS...NONE.  
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST SUNDAY FOR GMZ650-655-670-  
675.  
 
SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ631-632.  
 

 
 

 
 
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