719 
FXUS64 KMOB 281657 AAA
AFDMOB

AREA FORECAST DISCUSSION...MESOSCALE AND AVIATION UPDATE
NATIONAL WEATHER SERVICE MOBILE AL
1159 AM CDT FRI MAR 28 2014


.MESOSCALE UPDATE...CURRENT PERIOD BEING DEFINED BY ISENTROPIC 
UPGLIDE SHOWERS NORTH OF A COMBINATION OUTFLOW/SQUALL LINE. THE 
EASTERN EDGE HAS MOVED OUT OF THE FA...WITH SOUTHERN EXTENTS 
APPROACHING SOUTHERN EDGES OF THE MARINE FA. AM EXPECTING THIS MORE 
STABLE PRECIP TO LAST WELL INTO MID AFTERNOON...BRINGING ANOTHER 
HALF OF AN INCH TO INCH OF RAIN TO THE FA. RADAR ESTIMATES SHOW A 
BAND OF 4"+ OVER NORTHERN PERRY AND GREENE TO CHOCTAW AND WILCOX 
COUNTIES...AND ALSO ALONG THE AL/FL GULF COAST. A FFW IS BEING 
CONSIDERED...ESPECIALLY WITH ANOTHER ROUND OF RAIN EXPECTED LATER 
TONIGHT INTO SATURDAY.

/16

&&

.AVIATION...
(18Z ISSUANCE)...IFR OR LOWER CIGS IN A BAND OF THUNDERSTORMS HAS 
MOVED EAST AND SOUTH OF THE FA...WITH MVFR TO VFR CIGS BEING 
REPORTED AT FORECAST POINTS. AM EXPECTING THE HIGHER CIGS TO LAST 
INTO TONIGHT...WITH ANOTHER LINE OF TSRA MOVING OVER THE FA IN THE 
LATTER PART OF THE FORECAST BRINGING DROPS IN CIGS/VISBYS TO IFR OR 
LOWER LEVELS.

/16

&&


.SHORT TERM (TODAY AND TONIGHT)...THE COMBINATION OF INCREASED UPPER 
LEVEL DIVERGENCE...LOW LEVEL WARM AIR ADVECTION...AND ELEVATED 
INSTABILITY...HAS RESULTED IN A LARGE COVERAGE OF SHOWERS AND 
THUNDERSTORMS EARLY THIS MORNING. IN ADDITION...A LARGE AREA OF 
CONVECTION IS ALSO NOTED OVER CENTRAL AL SOUTHWEST INTO SOUTHWEST 
MS. SEVERAL RUNS OF THE HRRR AND THE 00Z NSSL WRF SHOW THIS 
CONVECTION ORGANIZING INTO A COMPLEX OF STORMS THAT MOVES SOUTHEAST 
THROUGH OUR AREA LATER THIS MORNING HOURS. IN FACT...THESE HI-RES 
MODELS ARE INDICATING ENOUGH OF A COLD POOL DEVELOPING TO RESULT IN 
BOWING STRUCTURES ALONG THE LEADING EDGE OF THE COMPLEX. WHILE 
REGIONAL RADAR DOES NOT YET SHOW THIS CONSOLIDATION...THE GLOBAL 
MODELS INDICATE THE BEST UPPER LEVEL DIVERGENCE (INITIALIZED WHERE 
THE CONVECTION IS) WILL SHIFT SOUTH AND EAST AS THE MORNING 
PROGRESSES. THEREFORE...WE WILL MAINTAIN CATEGORICAL RAIN CHANCES 
(80-90%) FROM AFTER SUNRISE THROUGH MIDDAY. WHILE THE BOWING 
STRUCTURES DO INDICATE THE POTENTIAL FOR STRONG WINDS...MLCAPES OF 
LESS THAN 500 J/KG COMBINED WITH DECREASING DEEP LAYER WIND PROFILES 
AS THE PARENT SHORTWAVE OVER THE MIDWEST QUICKLY MOVES TO THE 
NORTHEAST...SUGGESTS THE SEVERE THREAT WILL REMAIN ISOLATED AT BEST. 
THE PERSISTENT W-SW MID TO UPPER FLOW CONTINUES TO BRING IN STEEPER 
MID LEVEL LAPSE RATES (6.5-7.0 C/KM) FROM THE MEXICAN PLATEAU. THESE 
LAPSE RATES HAVE RESULTED IN PERIODS OF FREQUENT LIGHTNING AND A FEW 
SMALL HAIL SIGNATURES ON RADAR. SMALL HAIL WILL REMAIN POSSIBLE 
THROUGH THE MORNING ON AN ISOLATED BASIS.

THE FORECAST FOR THIS AFTERNOON AND EVENING HINGES ON THE EVOLUTION 
OF THE CONVECTION THIS MORNING. BASED ON THE ANTICIPATION OF A 
COMPLEX OF STORMS MOVING SE THROUGH THE AREA THIS MORNING...A LARGE 
STRATIFORM SHIELD OF RAIN COULD AFFECT THE SOUTHERN AND EASTERN 
PORTIONS OF THE AREA THIS AFTERNOON...WITH CONDITIONS DRYING OUT 
FROM NW-SE THROUGH THE LATE AFTERNOON EARLY EVENING. WE COULD SEE A 
LULL IN PRECIP THROUGH THIS TIME FRAME AS WE WAIT FOR THE COLD FRONT 
AND NEXT STRONG SHORTWAVE TO MOVE IN FROM THE WEST. 

DEEP LAYER FORCING IS FORECAST TO INCREASE LATE THIS EVENING OVER 
INLAND SE MS AND SPREAD EASTWARD AFTER MIDNIGHT. GUIDANCE SHOWS MID 
LEVEL LAPSE RATES STEEPENING FURTHER...ON THE ORDER OF 7.0-8.0 C/KM. 
MLCAPES POTENTIALLY APPROACH 1000 J/KG TOMORROW NIGHT...HOWEVER THE 
AMOUNT OF SFC BASED INSTABILITY WILL BE DEPENDENT ON EARLIER 
CONVECTION. IN EITHER CASE...A GOOD DEGREE OF ELEVATED INSTABILITY 
WILL BE PRESENT. THEREFORE...THE COMPLEX OF STORMS THAT MOVES 
THROUGH LATE TONIGHT/EARLY SATURDAY MORNING WILL CARRY THE 
POTENTIAL OF LARGE HAIL. AN ISOLATED OCCURRENCE OF DAMAGING WINDS IS 
ALSO POSSIBLE...BUT AGAIN WILL DEPEND ON THE AMOUNT OF SFC BASED 
INSTABILITY. PRECIPITABLE WATERS AROUND 1.5 INCHES COMBINED WITH 
PERIODS OF DEEP CONVECTION WILL CERTAINLY PRODUCE LOCALLY HEAVY 
RAINFALL. GIVEN THE UNCERTAINTIES IN CONVECTIVE EVOLUTION 
TODAY...CONFIDENCE IS TOO LOW TO ISSUE ANY SORT OF FLOOD WATCH. 
MINOR FLOODING IN URBAN AND LOW LYING AREAS IS POSSIBLE ALONG WITH 
ISOLATED INSTANCES OF FLASH FLOODING. 

WENT LOWER THAN MAV GUIDANCE FOR HIGHS TODAY BASED ON THE ABUNDANT 
PRECIP AND CLOUDS. ON THE FLIP SIDE...WENT SLIGHTLY WARMER FOR LOWS. 

WILL MAINTAIN THE HIGH RIP CURRENT RISK AND HIGH SURF ADVISORY 
THROUGH THIS EVENING AS SURF HEIGHTS OF 4 TO 5 FEET WILL CONTINUE TO 
AFFECT THE BEACHES. 34/JFB

.SHORT TERM (SATURDAY THROUGH SUNDAY)...SURFACE HIGH MOVING INTO THE 
WESTERN ATLANTIC OCEAN CONTINUES TO BRING A MODERATE TO STRONG 
ONSHORE FLOW DUE TO A SURFACE LOW DEEPENING AND MOVING RAPIDLY FROM 
EAST TEXAS TO THE CENTRAL OHIO/TENNESSEE VALLEY BY 12Z SATURDAY. A 
COLD FRONT WHICH WILL BE ASSOCIATED WITH THAT DEEPENING LOW WILL 
STRENGTHEN WHILE PASSING THROUGH OUR REGION SATURDAY MORNING. THESE 
FEATURES WILL ACT AS A CONVEYOR BELT BRINGING WATER VAPOR FROM THE 
CENTRAL GULF. WINDS ALOFT WILL GENERALLY BE SOUTHWEST ACROSS THE 
FORECAST AREA. AS AN UPPER TROUGH MOVES THROUGH OUR REGION FROM THE 
PLAINS...IT WILL DEEPEN TO AN EXTREMELY DEEP TROUGH THAT SHOWS A 
PROPENSITY TO CLOSE OFF IN THE GFS OUTPUT...AND AS COMPUTED BY THE 
EURO...IT ACTUALLY DOES CLOSE OFF BY LATE SATURDAY NIGHT AS IT 
CROSSES THE PIEDMONT REGION. THAT WOULD BRING A MORE CERTAIN 
PROSPECT OF A CLEAN SWEEP OF CLOUD COVER AND RAIN CHANCES BY 
SATURDAY AFTERNOON.

EXPECTING BAND OF CONVECTION TO PASS EAST OF THE REGION CLOSE TO OR 
BY SUNRISE OR SHORTLY THEREAFTER. BOTH THE EURO AND GFS SHOW THE 850 
MB TROUGH PASSING OUR REGION SO ANY POST-FRONTAL STRATIFORM RAIN 
WOULD END  WITH CLEARING SKIES AROUND NOON OR SHORTLY THEREAFTER. 
MODEL SOUNDINGS SHOW INSTABILITY ELEVATED MOSTLY INLAND. WET BULB 
ZEROES WILL PLUMMET FROM AROUND 10000 FEET AROUND SUNRISE TO ABOUT 
8000 FEET OVER THE WEST FLORIDA PANHANDLE AND SOUTHERN PORTIONS OF 
SOUTH CENTRAL ALABAMA. AT THE SAME TIME THE MODELS COMPUTE LI 
INCREASING FROM -4 TO 0 BETWEEN 12 AND 18Z OVER THE SAME REGION. 
THIS MEANS A HAIL THREAT FOR OUR REGION IS LINGERING AS A NARROW 
WINDOW AS THE MOIST STATIC ENERGY DECREASES AND WET BULB ZERO 
DECREASES ALONG WITH THE CONVECTION WITH THE PASSING LINE. SO ALONG 
THE SOUTHEAST PORTION OF THE REGION AND POINTS SOUTH...SURFACE BASED 
SEVERE CONVECTION IS UNCERTAIN...BUT AGAIN IN THE PRESENCE OF 
COUNTERACTING TERMS IN THE EQUATION AND THEIR RESPECTIVE TIMING...WE 
CANNOT BE THAT CERTAIN IN THE CLOSING STAGES OF THIS EVENT. THE RISK 
OF LOCALIZED FLOODING WILL HAVE ENDED BY SATURDAY MORNING.

AFTER THE RAIN MOVES OUT SATURDAY...A COOL NORTH TO NORTHWEST WIND 
WILL SWEEP IN BUT IT IS NOT ASSOCIATED WITH A DEEP TRAJECTORY FROM 
ALBERTA. THE TRAJECTORY WOULD BE ORIGINATING MORE FROM THE PLAINS SO 
WE WOULD SEE LOWS DROPPING INTO UPPER 30S TO LOWER 40S SATURDAY AND 
SUNDAY NIGHTS. A RELATIVELY CLEAR DAY WOULD ENSUE ON SATURDAY WITH 
HIGHS IN THE LOWER AND MID 70S...AND HIGHS IN THE LOWER 70S SUNDAY. 
77/BD

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)...THE OCCLUDING 
BAROCLINIC SYSTEM OVER THE EASTERN UNITED STATES WILL MOVE OFFSHORE 
AND DEEPEN OVER THE WESTERN ATLANTIC SUNDAY NIGHT. WHILE ANOTHER 
TROUGH DEEPENS OVER THE WESTERN GREAT PLAINS AS A RIDGE BUILDS OVER 
OUR REGION AND THE EASTERN UNITED STATES. MONDAY EVENING...THE 
SURFACE RIDGE WILL HAVE MOVED SUFFICIENTLY EAST OF OUR AREA TO OPEN 
THE GULF UP. AS THE PLAINS SYSTEM GETS DEFLECTED NORTHEAST OVER THE 
GREAT LAKES TUESDAY. THE SURFACE RIDGE WILL MOVE JUST OFF THE GEORGIA
COAST BECOMING QUASISTATIONARY AND MAINTAINING ELEVATED RH THROUGH 
MIDWEEK KEEPING TEMPS ABOVE SEASONAL. AS THE WEEK PROGRESSES...ZONAL 
POTENTIAL ENERGY GETS A CHANCE TO BUILD UP AND CONVERT TO EDDY 
KINETIC ENERGY FORMING ANOTHER TROUGH OVER THE PLAINS AROUND EARLY 
THURSDAY. EVIDENCE OF A WEAK COLD FRONT MOVING TOWARDS THE FA IS 
SHOWN IN THE GFS CALCULATIONS. THIS FRONT IS PROJECTED TO CROSS THE 
REGION LATE THURSDAY INTO FRIDAY. THE GFS COMPUTES THE FRONT 
SWEEPING THROUGH OUR REGION...UNLIKE THE 12Z RUN WHICH STALLED IT 
AND DEVELOPED AN OFFSHORE SURFACE LOW. THE NEW OUTPUT PUTS THE GFS 
MORE IN LINE WITH THE ECMWF AND INCREASING OUR CONFIDENCE IN RAIN 
CHANCES THURSDAY. GUIDANCE IS IN PRETTY CLOSE PHASE UNTIL THEN...BUT 
DISPERSES FURTHER OUT INTO THE EXTENDED PERIODS. 77/BD

&&

.MARINE...A MODERATE TO STRONG ONSHORE FLOW PERSISTS THIS MORNING. 
WINDS HAVE GENERALLY BEEN BELOW ADVISORY LEVELS AND MORE IN THE 
15-20 KT RANGE. THEREFORE...HAVE DROPPED THE ADVISORY FOR INSHORE 
BAYS/SOUNDS. WILL MAINTAIN THE SMALL CRAFT ADVISORY FOR THE AL/NW FL 
GULF WATERS THROUGH MIDDAY AS SEAS UP TO 7 FT WILL PERSIST. 
SIGNIFICANT WAVE HEIGHTS TO RANGE FROM 5-6 FT THIS AFTERNOON INTO 
TONIGHT. A COLD FRONT WILL MOVE THROUGH THE AREA SATURDAY MORNING 
WITH A MODERATE TO STRONG OFFSHORE FLOW DEVELOPING SATURDAY 
AFTERNOON AND NIGHT. A SMALL CRAFT ADVISORY MAY BECOME NECESSARY FOR 
THIS TIME FRAME. WINDS DIMINISH SUN-MON AS A SFC HIGH MOVES OVER THE 
REGION. A MORE PREDOMINATE LIGHT TO MODERATE ONSHORE FLOW DEVELOPS 
BY TUESDAY AS THE SFC HIGH MOVES EAST. 

PERIODS OF SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH TONIGHT. 
GUSTY WINDS...FREQUENT LIGHTNING...AND TORRENTIAL DOWNPOURS CAN BE 
EXPECTED THE STRONGER STORMS. THERE IS A POTENTIAL FOR A FEW STORMS 
TO PRODUCE LARGE HAIL LATE TONIGHT. 34/JFB

&&

.PRELIMINARY POINT TEMPS/POPS...
MOBILE      73  63  75  44  70 /  90  80  30  00  00 
PENSACOLA   71  64  76  48  69 /  90  80  40  05  00 
DESTIN      68  66  75  50  68 /  90  70  50  05  00 
EVERGREEN   72  62  73  41  71 /  90  80  40  00  00 
WAYNESBORO  77  61  72  38  72 /  90  80  20  00  00 
CAMDEN      74  60  71  42  70 /  90  80  40  00  00 
CRESTVIEW   71  63  76  41  73 /  90  70  50  05  00 

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...HIGH RIP CURRENT RISK UNTIL MIDNIGHT SATURDAY FOR THE FOLLOWING 
     ZONES: LOWER BALDWIN...LOWER MOBILE... 

     HIGH SURF ADVISORY UNTIL MIDNIGHT SATURDAY FOR THE FOLLOWING 
     ZONES: LOWER BALDWIN...LOWER MOBILE... 

FL...HIGH RIP CURRENT RISK UNTIL MIDNIGHT SATURDAY FOR THE FOLLOWING 
     ZONES: COASTAL ESCAMBIA...COASTAL OKALOOSA...COASTAL SANTA 
     ROSA... 

     HIGH SURF ADVISORY UNTIL MIDNIGHT SATURDAY FOR THE FOLLOWING 
     ZONES: COASTAL ESCAMBIA...COASTAL OKALOOSA...COASTAL SANTA 
     ROSA... 

MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM FRIDAY FOR THE FOLLOWING ZONES: 
     COASTAL WATERS FROM DESTIN TO PENSACOLA FL OUT 20 NM...
     COASTAL WATERS FROM PENSACOLA FL TO PASCAGOULA MS OUT 20 
     NM...WATERS FROM DESTIN TO PENSACOLA FL FROM 20 TO 60 NM...
     WATERS FROM PENSACOLA FL TO PASCAGOULA MS FROM 20 TO 60 
     NM... 

&&

$$