327  
FXUS64 KMOB 230257 AAB  
AFDMOB  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE MOBILE AL  
957 PM CDT SUN OCT 22 2017  
   
DISCUSSION
 
SEE UPDATED INFORMATION FOR LAND AREAS BELOW.  
 

 
   
UPDATE
 
THE RAIN HAS COME TO AN END OVER THE WESTERN HALF OF THE  
AREA WHILE MODERATE TO OCCASIONALLY HEAVY RAIN PERSISTS OVER THE  
FAR EASTERN ZONES LATE THIS EVENING. THE BACK EDGE OF THE RAIN  
WILL GRADUALLY ADVANCE EAST OVERNIGHT AND MOSTLY DRY CONDITIONS  
ARE EXPECTED FOR ALL AREAS BY JUST AFTER DAYBREAK, WITH JUST  
SMALL CHANCES LINGERING IN THE FAR EAST ZONES FOR MONDAY  
MORNING. UPDATED FORECAST TO REFLECT THIS SLIGHTLY QUICKER TIMING.  
 
THE COLD FRONT IS CURRENTLY MOVING ACROSS CENTRAL MS AND  
SOUTHEAST LOUISIANA. IT WILL MOVE THROUGH THE REGION OVERNIGHT AND  
WILL CLEAR THE FAR EASTERN ZONES BY MID MONDAY MORNING. COOLER  
DRIER AIR WILL FILTER INTO THE AREA BEHIND THE FRONT WITH LOWS IN  
THE WESTERN HALF OF THE AREA DROPPING INTO THE MID TO UPPER 50S BY  
DAYBREAK.  
 
ALSO INCREASED WINDS OVER THE MOST OF THE MARINE AREA TO EXERCISE  
CAUTION LEVELS (15-20KT) IN THE WAKE OF THE FRONT, WHICH IS IN  
BETTER AGREEMENT WITH THE HIGH RES GUIDANCE AND MAKES SENSE GIVEN  
WHAT WE TYPICALLY SEE IN THE WAKE OF THIS STRENGTH OF FRONTAL  
PASSAGE. 34/JFB  
 

 
   
PREV DISCUSSION
 
/ISSUED 659 PM CDT SUN OCT 22 2017/  
 
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.  
 
AVIATION...  
00Z ISSUANCE...  
LIFR CEILINGS AND IFR VISIBILITIES ASSOCIATED WITH THE ONGOING  
CONVECTION WILL CONTINUE INTO THE LATE EVENING. THE LINE OF  
THUNDERSTORMS IS EXPECTED TO MOVE EASTWARD THROUGH THE EVENING.  
MVFR CONDITIONS AFTER MIDNIGHT THOUGH LOW CEILINGS REMAIN OVER  
THE AREA UNTIL MORNING. AFTER WHICH WINDS WILL SHIFT OUT OF THE  
NORTHWEST WITH VFR CONDITIONS THROUGH THE REST OF THE PERIOD.  
DJ/17  
 
PREV DISCUSSION... /ISSUED 351 PM CDT SUN OCT 22 2017/  
 
NEAR TERM /NOW THROUGH MONDAY/...SHARP LONG-WAVE UPPER LEVEL  
TROUGH AXIS EXITING THE PLAINS THIS EVENING IS PROGGED TO MAKE  
STEADY EASTWARD PROGRESS TO THE LOWER MS RIVER DELTA LATE TONIGHT  
THEN PIVOTS OVER THE HEART OF THE FORECAST AREA BY DAYBREAK  
MONDAY. AHEAD OF THE EASTWARD MOVING TROUGH AXIS THIS EVENING,  
THE LOCAL AREA REMAINS ON THE FAVORED SIDE FOR ENHANCED DEEP  
LAYER ASCENT WITHIN AN ANOMALOUSLY HIGH MOIST ENVIRONMENT  
(PWAT'S) ~ 2.00 INCHES. RADAR IS QUITE ACTIVE WITH WIDESPREAD  
SHOWERS/STORMS STREAMING NORTHWARD OFF THE GULF. EFFICIENT WARM  
RAIN PROCESSES TODAY HAVE RESULTED IN HEAVY RAINFALL RATES AND  
EXCESSIVE STORM TOTALS MAINLY OVER THE COASTAL ZONES WHERE AREA  
MESONET SITES AND NWS SURFACE OBSERVING EQUIPMENT HAVE REPORTED  
UPWARDS OF 2 TO 4 INCHES WITH A FEW SITES REPORTING 5+ INCHES.  
THUS, WITH THE FRONT STILL TO THE WEST AND ADDITIONAL RAINS  
DEVELOPING UPSTREAM TO EXPAND INTO THE AREA TONIGHT, COULD HAVE  
SOME ISOLATED FLASH FLOODING PROBLEMS AND WILL INCREASE THE LOCAL  
FLOOD THREAT LEVEL TO ELEVATED OVER THE COASTAL ZONES THIS  
EVENING. THERE REMAINS SOME POTENTIAL FOR A FEW TORNADOES THIS  
EVENING GENERALLY EAST OF THE CONVECTIVE BAND AS WELL. STAY  
WEATHER AWARE TONIGHT.  
 
AS BEST DYNAMICS SHIFT EAST, CATEGORICAL CHANCES (80 TO 100%) OF  
SHOWERS AND STORMS THIS EVENING OVER MUCH OF THE AREA SHIFTS EAST  
TO THE EASTERN HALF OF THE AREA BY MIDNIGHT AND INTO THE PRE-DAWN  
HOURS MONDAY. RAIN CHANCES PROGGED TO SLOWLY TAPER OFF OVER THE  
WESTERN ZONES THROUGH THE COURSE OF THE NIGHT. ATTENDANT FRONTAL  
PASSAGE OCCURS MONDAY MORNING, BRINGING AN END TO THE RAIN.  
OVERNIGHT LOWS DROPPING OFF INTO THE MID TO UPPER 50S OVER THE  
NORTHWEST ZONES BY DAYBREAK WHILE MID TO UPPER 60S ELSEWHERE.  
DAYTIME HIGHS MONDAY IN LOWER TO MID 70S INTERIOR TO MID TO UPPER  
70S COAST. /10  
 
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...A REINFORCING  
FRONTAL BOUNDARY SWEEPS SOUTHWARD OVER THE DEEP SOUTH MONDAY  
NIGHT, BRINGING LOWERING DEEP LAYER THICKNESS VALUES, DEEP LAYER  
DRY AIR AND LOWERING TEMPERATURES WHICH LAST INTO THE MIDDLE OF  
THE WEEK. TO BEGIN THE SHORT TERM, MUCH COOLER CONDITIONS TO START  
THE MORNING COMMUTE TO WORK OR SCHOOL TUESDAY MORNING WITH  
TEMPERATURES IN THE LOWER TO MID 50S INTERIOR, 56 TO 62 COAST.  
DAYTIME HIGHS ON TUESDAY IN THE LOWER TO MID 70S WHICH IS A FEW  
DEGREES BELOW CLIMATIC NORMALS. THE COOLEST PERIOD IS TUESDAY  
NIGHT AND WEDNESDAY WHERE LOWS WILL LIKELY DIP DOWN INTO THE 40S  
FOR MUCH OF THE AREA. THE EXCEPTION BEING RIGHT ALONG THE BEACHES  
WHERE NUMBERS IN THE LOWER TO MID 50S FORECAST. WEDNESDAY'S HIGHS  
IN THE MID TO UPPER 60S FOR MOST LOCATIONS. /10  
 
LONG TERM /THURSDAY THROUGH SUNDAY/...A MODERATION IN HIGHS AND  
LOWS ANTICIPATED TO CLOSE OUT THE WEEK AS SURFACE HIGH PRESSURE  
LIFTS UP ACROSS THE SOUTHEAST. HIGHS THURSDAY AND FRIDAY TREND  
BACK INTO THE 70S. LOWS FRIDAY AND SATURDAY MORNINGS IN THE LOWER  
TO MID 50S INTERIOR TO LOWER TO MID 60S COAST.  
 
NEXT COLD FRONT APPEARS TO DIVE INTO THE DEEP SOUTH BY FRIDAY AND  
PUSHES THRU SATURDAY, BRINGING A RETURN TO A SMALL CHANCE OF  
SHOWERS AND STORMS THROUGH SATURDAY NIGHT. OF NOTE: THERE IS A  
HIGH DEGREE OF DISAGREEMENT IN THE WEATHER MODELS WITH THE TIMING  
OF NEXT WEEKEND'S FRONTAL PASSAGE WHICH WILL DICTATE TEMPERATURE  
FORECASTS GOING INTO SATURDAY OR SUNDAY. FOR NOW, THE BLENDED  
GUIDANCE SUGGESTS HIGHS WILL LOWER BACK INTO THE LOWER TO MID 60S  
BY SUNDAY WITH MORNING LOWS LOWERING INTO THE MID TO UPPER 40S  
INTERIOR. /10  
 
MARINE...AN UNSETTLED PATTERN CONTINUES TONIGHT AHEAD OF A COLD  
FRONT APPROACHING FROM THE WEST. WINDS, WAVES AND SEAS WILL BE  
LOCALLY HIGHER IN AND NEAR SHOWERS AND STORMS TONIGHT. VISIBILITY  
LIKELY TO BE REDUCED TO LESS THAN A MILE AS WELL, WITH THE PASSAGE  
OF HEAVY RAIN. FRONTAL PASSAGE IS FORECAST MONDAY MORNING, BRINGING  
A WIND SHIFT AND AN END TO SHOWERS AND STORMS IN ITS WAKE. A LIGHT,  
TO AT TIMES MODERATE NORTHWEST FLOW CONTINUES INTO THE MIDDLE OF  
THE WEEK BEFORE TURNING MORE ONSHORE BY LATE WEEK WITH HIGH PRESSURE  
LIFTING UP INTO THE SOUTHEAST. /10  
 

 
   
MOB WATCHES/WARNINGS/ADVISORIES
 
 
AL...HIGH RIP CURRENT RISK UNTIL 1 AM CDT MONDAY FOR ALZ265-266.  
 
FL...HIGH RIP CURRENT RISK UNTIL 1 AM CDT MONDAY FOR FLZ202-204-206.  
 
MS...NONE.  
GM...NONE.  

 
 

 
 
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