213  
FXUS64 KMOB 211758 AAB  
AFDMOB  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE MOBILE AL  
1158 AM CST SUN JAN 21 2018  
   
DISCUSSION
 
UPDATED FOR LATEST AVIATION DISCUSSION BELOW.  
 

 
   
AVIATION
 
 
18Z ISSUANCE...VFR CONDITIONS WILL PREVAIL ALONG THE NORTH CENTRAL  
GULF COAST REGION THIS AFTERNOON AND THROUGH MUCH OF THE EVENING  
WITH ONLY HIGH LEVEL CLOUDS INCREASING THROUGH THE PERIOD.  
INCREASING LOW LEVEL MOISTURE WILL MOVE NORTH FROM THE GULF OF  
MEXICO AND OVER THE TAF SITES BEGINNING LATE THIS EVENING, WITH  
CEILINGS EXPECTED TO BE IN THE IFR CATEGORY (~700 FEET).  
VISIBILITIES WILL ALSO BE REDUCED OVERNIGHT DUE TO DEVELOPING FOG,  
POSSIBLY REACHING THE LIFR TO IFR CATEGORIES (1/2SM TO 1SM) LATE  
TONIGHT INTO MONDAY MORNING. SOUTHEAST WINDS 7 TO 12 KNOTS THIS  
AFTERNOON WILL LOWER TO BETWEEN 5 TO 7 KNOTS OVERNIGHT. EXPECT  
LIGHT RAIN TO MOVE INTO THE MOBILE METRO AREA AFTER MID MORNING  
MONDAY, SO ADDED A PROB30 GROUP FOR NOW. /22  
 

 
   
PREV DISCUSSION
 
/ISSUED 547 AM CST SUN JAN 21 2018/  
 
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.  
 
AVIATION...  
21/12Z ISSUANCE...GENERAL VFR CONDITIONS THROUGH THIS EVENING  
(AROUND 22/03Z), WHEN IFR TO LIFR CIGS (LOW STATUS) AND  
VISIBILITIES (FOG) DEVELOP. SURFACE WINDS BECOMING SOUTHEAST  
AROUND 10 KNOTS TODAY AND CONTINUING THROUGH TONIGHT. 12/DS  
 
PREV DISCUSSION... /ISSUED 426 AM CST SUN JAN 21 2018/  
 
NEAR TERM /NOW THROUGH SUNDAY NIGHT/...THE UPPER SHORTWAVE NOTED  
YESTERDAY HAS NOW MOVED EAST OF THE FORECAST AREA, NOW OVER NORTHERN  
FLORIDA, AND WILL MOVE OFF THE ATLANTIC COAST TODAY. AS THE UPPER  
LOW MOVES OFF TO THE EAST, UPPER RIDGING WILL DRIFT EAST ACROSS THE  
FORECAST AREA TODAY. TONIGHT, THE UPPER RIDGING IS EXPECTED TO MOVE  
QUICKLY OFF TO THE EAST OF THE FORECAST AREA AS DEEP LOW PRESSURE  
AND TROUGHING DEVELOPS OVER THE PLAINS STATES. SURFACE HIGH PRESSURE  
LOCATED ALONG THE SOUTHEAST ATLANTIC COAST EARLY THIS MORNING WILL  
MOVE OUT OVER THE ATLANTIC THROUGH TONIGHT, WHILE A COLD FRONT  
ASSOCIATED WITH THE DEVELOPING PLAINS SYSTEM APPROACHES FROM THE  
WEST. THIS COLD FRONT WILL BE APPROACHING THE MISSISSIPPI RIVER BY  
DAYBREAK MONDAY, WITH PERHAPS A FEW SHOWERS MOVING INTO OUR FAR  
WESTERN COUNTIES VERY LATE TONIGHT AS THE FRONT APPROACHES AND UPPER  
RIDGING WEAKENS. PERSISTENT LOW LEVEL SOUTHEASTERLY FLOW TODAY AND  
TONIGHT WILL BRING INCREASING MOISTURE INTO THE REGION, AND THIS  
ONSHORE FLOW COMBINED WITH THE COOL NEAR SHORE MARINE WATERS WILL  
LIKELY RESULT IN SOME FOG ACROSS THE AREA TONIGHT, ESPECIALLY OVER  
THE SOUTHERN LOCATIONS NEAR THE COAST. HIGH TEMPERATURES TODAY  
FINALLY RETURN TO THE LOWER 70S FOR MOST LOCATIONS, EXCEPT ALONG THE  
IMMEDIATE COASTAL AREAS WHERE THE ONSHORE FLOW WILL KEEP HIGHS IN  
THE MID TO UPPER 60S. WARMER TONIGHT TOO, WITH LOWS RANGING FROM THE  
UPPER 40S OVER NORTHEASTERN COUNTIES TO THE LOW TO MID 50S  
ELSEWHERE. A FEW UPPER 50S POSSIBLE ALONG THE IMMEDIATE COAST.  
12/DS  
 
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...MONDAY THROUGH MONDAY  
NIGHT, A CLOSED UPPER SYSTEM MOVES FROM OVER THE CENTRAL PLAINS  
EAST-NORTHEAST OVER THE MID/UPPER MISSISSIPPI RIVER VALLEY BEFORE  
GETTING A MORE NORTHEAST PUSH DUE TO A BUILDING UPPER RIDGE OVER  
THE WESTERN ATLANTIC. THIS SYSTEM PUSHES A SURFACE FRONT ACROSS  
SOUTHEAST MISSISSIPPI LATE MONDAY AFTERNOON, THEN EAST OF CENTRAL  
ALABAMA AND THE WESTERN FLORIDA PANHANDLE SHORTLY AFTER MIDNIGHT  
MONDAY NIGHT. SHRA/TSRA PRETTY MUCH A GIVEN AHEAD OF THE FRONT  
MONDAY AFTERNOON INTO THE EVENING HOURS. BIGGEST QUESTION IS THE  
CHANCE OF ANY SEVERE. GUIDANCE REMAINS ON THE MARGINAL SIDE FOR  
ANY STRONG TO SEVERE (TOPPING OUT AROUND 500 J/KG). 0-3KM SHEAR IS  
ENOUGH (200-300 M^2/S^2 IN THE AFTERNOON) FOR SOME ROTATORS.  
MID/UPPER LEVEL SUPPORT HAS SHIFTED NORTH A BIT, NORTH OF THE  
FORECAST AREA IN OUR CASE. SPC CONTINUES TO ADVERTISE A MARGINAL  
RISK OF SEVERE WEATHER WITH DAMAGING WINDS THE PRIMARY THREAT AND  
SEE NO REASON TO ALTER THIS AT THIS POINT, WITH LESS OVERLAP OF  
SURFACE AND UPPER INGREDIENTS THAN YESTERDAY. TEMPS ABOVE SEASONAL  
EXPECTED MONDAY. WITH COOLER AIR MOVING OVER THE AREA BEHIND THE  
FRONT, MONDAY NIGHT'S LOWS WILL SEE A GRADIENT OF AROUND SEASONAL  
LOWS WEST TO ABOVE EAST.  
 
TUESDAY THROUGH TUESDAY NIGHT WILL SEE A RETURN OF NEAR SEASONAL  
TEMPS AS COOLER/DRIER AIR OVERSPREADS THE ENTIRE FORECAST AREA.  
 
/16  
 
LONG TERM /WEDNESDAY THROUGH SATURDAY/...SHORTWAVE ENERGY MOVES  
OVER THE PLAINS MID WEEK INTO THE WEEKEND, PUSHING SURFACE HIGH  
PRESSURE FROM THE PLAINS TO OFF THE MID ATLANTIC COAST. THIS  
BRINGS BACK SOUTHERLY FLOW OFF THE GULF BY FRIDAY. MOISTURE  
LEVELS INCREASE INTO THE WEEKEND UNTIL ANOTHER FRONT MOVES ACROSS  
THE AREA SATURDAY NIGHT. RAIN RETURNS FRIDAY NIGHT, WITH A BETTER  
CHANCE OF RAIN SATURDAY. TEMPS MODERATE SLOWLY UPWARDS FROM AROUND  
SEASONAL MID WEEK TO ABOVE SEASONAL WITH THE RETURN OF SOUTHERLY  
FLOW END OF THE WEEK.  
 
/16  
 
MARINE...FOR THE MOST PART, NO HAZARDS IN THE NEAR TERM EXCEPT FOR  
WINDS NEARING EXERCISE CAUTION LEVELS FOR THE OFFSHORE GULF ZONES  
THIS AFTERNOON. A COLD FRONT APPROACHES THE MARINE AREA FROM THE  
WEST TONIGHT AND EARLY MONDAY BRINGING AN INCREASED CHANCE OF  
SHOWERS AND EMBEDDED STORMS, AS WELL AS AN CONTINUED INCREASE IN  
SEAS ASSOCIATED WITH THE INCREASED ONSHORE FLOW. THE FRONT IS  
EXPECTED TO MOVE EAST ACROSS THE MARINE AREA MONDAY NIGHT. SHOWERS  
AND STORMS ENDING WITH THE FRONTAL PASSAGE AND A MODERATE TO STRONG  
OFFSHORE FLOW IS EXPECTED IN THE WAKE OF THE FRONT TUESDAY THROUGH  
LATE WEEK. WINDS AND SEAS PRIMARILY IN THE EXERCISE CAUTION CATEGORY  
( 15 TO 20 KNOTS AND UP TO 6 FEET)THROUGH MOST OF THE WEEK FOR THE  
OFFSHORE GULF WATERS, BUT POSSIBLY REACHING SMALL CRAFT ADVISORY  
LEVELS (20 KNOTS PLUS) BY WEEKS END AS A REINFORCING SURGE OF  
OFFSHORE FLOW DEVELOPS. 12/DS  
 

 
   
MOB WATCHES/WARNINGS/ADVISORIES
 
 
AL...NONE.  
FL...NONE.  
MS...NONE.  
GM...NONE.  

 
 

 
 
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