957 FXUS64 KBMX 311950 AFDBHM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BIRMINGHAM, AL 245 PM CDT FRI MAY 31 2002 FORECAST QUANDARIES...POPS...TEMPS. CURRENT REGIONAL SFC OBS AND SATELLITE DATA SHOWING DEVELOPMENT OF SCT CU FIELDS...WITH RADAR MOSAIC IMAGERY SHOWING SHWRS NEAR I-59- AL/GA LINE. LATEST MSAS/HAND SFC ANALYZES DEPICTING SFC RIDGE APEX NEAR MSL...TEMPS MID 80S...DEWPOINTS MID 60S...WITH VRBL WIND CONDITIONS. UPPER AIR ANALYZES SHOWING UPPER LEVEL LOW OFF CNTRL LA COAST...WITH RIDGING BUILDING IN FROM FOUR CORNERS HIGH PRESSURE SYSTEM. 12Z FRI REGIONAL MODEL INITIALIZATIONS AND PROGGED EVOLUTIONS THRU 12Z MON IN GOOD GENERAL AGREEMENT...ESPECIALLY IN LOWER LEVELS. HOWEVER...AS POINTED OUT BY LATEST MODEL DIAGNOSTIC DISCUSSION...MODELS DIFFER ON 500MB CLOSED LOW PLACEMENT THRU PERIOD. NCEP PREFERS A BLENDED MODEL SOLUTION...WITH AVN PLACEMENT MOST CONSISTENT. LIKE THE RUN-TO RUN CONSISTENCY OF THE AVN MYSELF. THUS...WILL LEAN TOWARD A BLENDED MODEL SOLUTION WITH ANY DISCREPANCIES SETTLED BY LEANING TOWARD AVN. UPPER LEVEL LOW EXPECTED BY ALL MODELS TO RETROGRADE SWD E OF BRO BY SAT MORNING...WITH UPPER LEVEL RIDGE INFLUENCE FROM NM CONTINUING TO BUILD INTO STATE....ESPECIALLY N. RIDGE AXIS WILL SHIFT INTO CNTRL U.S. ...AND INTO SE U.S. BY 12 MON. LOW WILL EITHER REMAIN QUASI-STATIONARY OR MOVE SLIGHTLY E INTO CNTRL GULF BY 12Z MON. ALTHOUGH RIDGING DYNAMICS DEVELOPING...POSITION OF LOW WILL STILL PROVIDE A SWLY MOISTURE FETCH ACROSS A LEAST CNTRL AND S ZONES THRU MON MORNING. SFC RIDGING PATTERN WILL ALSO CONTINUE TO PERSIST THRU THIS TIME PERIOD. THUS...CONTINUE TO BELIEVE PTCLDY SKIES MOST APPROPRIATE SKY CONDITION. LOOK FOR BEST SCT CU FIELD DEVELOPMENT TO BE DIURNALLY BASED. DO NOT BELIEVE IT WILL BE AS WIDESPREAD AS LAST NIGHT...HOWEVER WILL MENTION PATCHY FOG LATE ALL AREAS TONIGHT. MAIN FORECAST QUANDARY CENTERS AROUND POPS. WITH ISOLATED CONVECTION PRESENTLY ACROSS NE ZONES...WILL USE EVENING WORDING IN ZONES. WILL ALSO INTRODUCE ISOLATED POPS E ZONES NEAR GA BORDER...AS CONVECTION DEVELOPING ACROSS W CNTRL GA. OTHER LOCATIONS WILL LEAVE DRY. WITH PW/S ACROSS REGION THRU MON AOB 1.4 INCHES...AND MULTIPLE INSTABILITY INDICES...ALONG WITH CAPES AOB 3000 J/KG DURING THE AFTERNOON HOURS ON SAT AND SUN... CAN NOT RULE OUT ISOLATED CONVECTION...DESPITE RIDGING INFLUENCES. SPC EVEN PLACING AL IN GENERAL TS CRITERIA FOR SAT. WILL CONTINUE ISOLATED AFTERNOON AND EARLY EVENING SHWRS/TSTMS WORDING ALL ZONES... EXCEPT S ZONES WHERE PROXIMITY TO RICHER MOISTURE POOL MAY RESULT IN SCT SHWR/TSTM ACTIVITY. REST OF WEEK...NEXT FRONTAL PASSAGE WILL OCCUR ON THU...WITH HIGH PRESSURE BUILDING OUT OF THE CNTRL U.S AND INTO THE E U.S. BY FRI EVENING. THIS WILL PROVIDE FOR DRY CONDITIONS ACROSS CWA ON FRI. FROM MON MORNING THRU THU...WILL CONTINUE WITH PTCLDY SKY CONDITION WORDING AND SCT AFTERNOON/EVENING SHWRS/TSTMS. UPPER LEVEL LOW WILL CONTINUE MOVING SLOWLY NEWD...AND INTO S ATLANTIC BY 00Z FRI...WITH UPPER LEVEL RIDGE DEVELOPMENT THAT WOULD HAMPER CONVECTIVE DEVELOPMENT NOT ANTICIPATED UNTIL FRI. TEMPS...WILL GO WITH A MESH FORECAST OF NGM AND AVN MOS VALUES AND SURROUNDING ZONES FORECASTS. MOS ADVERTISING ACROSS CNTRL AND S ZONES ON SUN TEMPS IN LOWER 90S. WARMUP DEPENDENT ON LOW POSITION...AND AT THIS TIME WILL BE A LITTLE CONSERVATIVE AND CUT BACK NUMBERS. THANKS FOR COORDINATION TLH ...PRELIMINARY NUMBERS... HSV 65 88 67 89 / 20 20 0 20 BHM 66 89 68 90 / 0 20 0 20 MGM 67 90 69 91 / 0 20 0 30 .BHM...NONE. 89 JBW