397  
FXUS64 KMOB 210500  
AFDMOB  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MOBILE AL  
1200 AM CDT SAT SEP 21 2019  
   
DISCUSSION
 
UPDATED FOR LATEST AVIATION DISCUSSION BELOW.  
 

 
   
AVIATION
 
 
06Z ISSUANCE...VFR CONDITIONS PREVAIL THROUGH THE FORECAST PERIOD.  
GENERALLY LIGHT EASTERLY WINDS TONIGHT BECOME BREEZY AND SHIFT TO  
SOUTHEASTERLY DURING THE DAY SATURDAY. /49  
 

 
   
PREV DISCUSSION
 
/ISSUED 855 PM CDT FRI SEP 20 2019/  
 
DISCUSSION...SEE UPDATED INFORMATION FOR LAND AREAS BELOW.  
 
UPDATE...MADE A FEW MINOR TWEAKS TO THE CURRENT FORECAST PACKAGE  
TO CAPTURE CURRENT TRENDS AND DROPPED OVERNIGHT LOWS A DEGREE OR  
TWO AT A FEW LOCATIONS. ALSO, KEPT SLIGHT CHANCE OF POPS OVER THE  
MARINE AREA. /08  
 
PREV DISCUSSION... /ISSUED 401 PM CDT FRI SEP 20 2019/  
 
NEAR TERM /NOW THROUGH SATURDAY/...THE BACKDOOR COLD FRONT THAT  
MOVED WEST ACROSS THE AREA YESTERDAY IS NOW OFF TO THE WEST AND  
BECOMING SOMEWHAT DIFFUSE. IT IS HARD TO FIND THE BOUNDARY IN THE  
WIND OBSERVATIONS, BUT NOTICEABLE IN A DEWPOINT GRADIENT ORIENTED  
MORE OR LESS ALONG THE MISSISSIPPI RIVER (60S TO THE EAST AND 70S  
TO THE WEST). SURFACE HIGH PRESSURE RIDGING IN FROM THE EAST WILL  
BE THE DOMINANT FEATURE CONTROLLING THE WEATHER FOR OUR AREA IN  
THE NEAR TERM PERIOD. VERY DRY LOW LEVELS ACCOMPANY THE RIDGING,  
WITH SLIGHTLY MORE MID LAYER MOISTURE, AS VERIFIED BY MID AND LOW  
LEVEL WATER VAPORY IMAGERY CHANNELS. WITH THIS PATTERN IN PLACE,  
THE NEAR TERM LOOKS TO BE PRIMARILY RAIN FREE, EXCEPT FOR MAYBE A  
COASTAL SHOWER OR TWO LATE TONIGHT INTO EARLY SATURDAY MORNING.  
MUCH MORE COMFORTABLE CONDITIONS EXPECTED, WITH LOWS TONIGHT  
FALLING INTO THE MID TO UPPER 60S ACROSS ALL INTERIOR LOCATIONS  
(GENERALLY ALONG AND NORTH OF I-10) WITH LOWER 70S SOUTH OF I-10  
AND A FEW MID TO UPPER 70S POSSIBLE ALONG THE IMMEDIATE COAST.  
EVEN THOSE WARMER TEMPS NEAR THE COAST WILL FEEL NICE THOUGH, AS  
DEWPOINTS WILL BE DOWN IN THE 60S. FOR SATURDAY, A MOSTLY SUNNY  
AND SOMEWHAT "MILD" DAY COMPARED TO RECENT DAYS, WITH HIGHS NEAR  
THE NORMAL UPPER 80S ACROSS THE ENTIRE AREA. DEWPOINTS  
TEMPERATURES WILL BE REMAINING IN THE 60S ON SATURDAY AS WELL, SO  
IT WILL AGAIN FEEL RATHER NICE ON SATURDAY, MUCH LIKE TODAY. 12/DS  
 
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...AN UPPER  
LEVEL SHORTWAVE SYSTEM MOVING EAST OVER THE NORTHERN CONUS ROTATES  
THE UPPER RIDGE STRETCHING NORTH ALONG THE EASTERN SEABOARD  
CLOCKWISE TO OVER THE OPEN ATLANTIC, WHILST SHIFTING THE BASE OF  
THE UPPER RIDGE (LOCATED OVER THE SOUTHEAST) A BIT WESTWARD,  
WEAKENING IT A BIT IN THE PROCESS. A SURFACE RIDGE STRETCHING  
SOUTHWEST OVER THE SOUTHEAST CONTINUES TO MOVE DRIER AIR WEST  
OVER THE SOUTHEAST. FOR HIGH TEMPERATURES, THE DRIER AIRMASS WILL  
HELP TO COUNTER-BALANCE A DECREASE IN SUBSIDENCE FROM THE UPPER  
RIDGE AND BRING DAYTIME HIGH TEMPERATURES 5-8 DEGREES ABOVE  
SEASONAL NORMS FOR SUNDAY AND MONDAY. HIGH TEMPERATURES IN THE  
UPPER 80S TO AROUND EXPECTED SUNDAY FOR THE FORECAST AREA, AROUND  
90 TO LOW 90S FOR MONDAY. THE DRY AIRMASS WILL HELP TO AID  
RADIATION COOLING OVERNIGHT, AND BRING OVERNIGHT LOW TEMPERATURES  
A FEW DEGREES ABOVE SEASONAL NORMS SATURDAY THROUGH MONDAY NIGHTS.  
LOW TEMPERATURES IN THE MID 60S WELL INLAND TO LOW 70S ALONG THE  
COAST ARE EXPECTED THROUGH THE PERIOD.  
/16  
 
LONG TERM /TUESDAY THROUGH FRIDAY/...GUIDANCE IS ADVERTISING A  
SECOND UPPER LEVEL SHORTWAVE SYSTEM MOVING INLAND OVER THE  
PACIFIC NORTHWEST SUNDAY INTO SUNDAY NIGHT, BEFORE MOVING THE  
SYSTEM SOUTH-SOUTHEAST TO OVER THE DESERT SOUTHWEST, WHERE IT  
MEANDERS AROUND THROUGH MID WEEK. ADDITIONAL UPPER LEVEL SHORTWAVE  
SYSTEMS MOVE INLAND OVER THE PACIFIC NORTHWEST, AND IN COMBINATION  
WITH THE UPPER SYSTEM OVER THE DESERT SOUTHWEST, DIGS AN UPPER  
TROUGH OVER THE WESTERN CONUS WHILST AN UPPER LEVEL RIDGE BUILDS  
NORTH ALONG THE EASTERN SEABOARD. THE SURFACE RIDGE STRETCHING  
SOUTHWEST OVER THE SOUTHEAST SHIFTS SOUTH TO OVER THE NORTHERN  
GULF COAST, BRINGING A MORE DIRECT SOUTHEAST TO SOUTH FLOW OFF  
THE GULF OF MEXICO TO THE REGION, AND WITH THE INCREASE IN GULF  
MOISTURE, RAIN SHOWERS AND THUNDERSTORMS WILL RETURN TO THE  
FORECAST AREA, THOUGH SUBSIDENCE WILL HELP TO LIMIT COVERAGE.  
SUBSIDENCE FROM THE UPPER RIDGE WILL BRING HIGH TEMPERATURES 5 TO  
10 DEGREES ABOVE SEASONAL NORMALS THROUGH THE LONG TERM. THE  
INCREASED MOISTURE LEVELS COUNTERBALANCING OVERNIGHT RADIATIONAL  
COOLING WILL ALSO WORK WITH THE UPPER LEVEL SUBSIDENCE TO BRING  
OVERNIGHT LOW TEMPERATURES AROUND 5 DEGREES ABOVE SEASONAL  
NORMALS.  
/16  
 
MARINE...A MODERATE TO OCCASIONALLY STRONG EASTERLY FLOW IS  
EXPECTED TO CONTINUE OVER THE COASTAL WATERS THROUGH MOST OF  
SATURDAY AND POTENTIALLY INTO SUNDAY AS A STRONG HIGH PRESSURE RIDGE  
BUILDS TO THE NORTH OF THE MARINE AREA. A SMALL CRAFT ADVISORY IS IN  
EFFECT FOR ALL GULF ZONES AS WELL AS SOUTHERN MOBILE BAY AND THE  
MISSISSIPPI SOUND THROUGH MIDDAY SATURDAY AND MAY BE EXTENDED LATER  
INTO THE WEEKEND. SMALL CRAFT SHOULD EXERCISE CAUTION OVER THE  
REMAINDER OF THE MARINE AREA, PRIMARILY FOR WIND GUSTS. 12/DS  
 

 
   
MOB WATCHES/WARNINGS/ADVISORIES
 
 
AL...HIGH RIP CURRENT RISK THROUGH SUNDAY EVENING FOR ALZ265-266.  
 
FL...HIGH RIP CURRENT RISK THROUGH SUNDAY EVENING FOR FLZ202-204-206.  
 
MS...NONE.  
GM...SMALL CRAFT ADVISORY UNTIL 1 PM CDT SATURDAY FOR GMZ631-632-650-  
655-670-675.  
 

 
 

 
 
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