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Displaying AFOS PIL: AFDDMX Received: 2011-12-15 11:44 UTC
177 FXUS63 KDMX 151144 AAA AFDDMX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 544 AM CST THU DEC 15 2011 ...UPDATED AVIATION DISCUSSION... .SHORT TERM /TODAY/... MAIN FORECAST CONCERN TODAY WAS WITH STRATUS DECK REMAINING ACROSS CENTRAL IOWA THROUGH MUCH OF THE DAY. CURRENT SATELLITE TRENDS SHOWS LOW STRATUS DECK EXTENDING INTO THE DAKOTAS AND SOUTHERN CANADA...AND PROJECTED OVER CENTRAL AND WESTERN IOWA. NAM/RUC WERE THE BEST WITH HANDLING TIMING OF STRATUS DECK DEPARTING BY MID AFTERNOON WITH THE GFS AROUND MIDDAY. LEANED TOWARD THE NAM/RUC SOLUTIONS AND BUMPED SKY COVER UP THROUGH 21Z. BUT WOULD NOT BE SURPRISED IF STRATUS DECK HOLDS IN PLACE THROUGH 00Z. THINKING SOME MIXING MAY HELP DISSIPATE AND THIN OUT THE CLOUD DECK...BUT WITH THE STRONG CAA AND 925MB AOA 80 PERCENT THROUGH THIS AFTERNOON...FELT CONFIDENT ENOUGH TO LEAVE CLOUDS ACROSS MUCH OF THE FORECAST AREA TODAY. WINDS WILL REMAIN BELOW ADVISORY CRITERIA...ESPECIALLY SINCE THE STRATUS DECK HOLDING TIGHT THROUGH THE AFTERNOON TO KEEP BACK THE DEEP MIXING. WITH MAINLY THE PRESSURE GRADIENT TODAY...HAVE A FEW GUSTS TO 30 KNOTS IN NORTHERN IOWA THIS AFTERNOON. OTHERWISE...GENERALLY AROUND 20-25KTS THROUGHOUT THE FORECAST AREA. .LONG TERM /TONIGHT THROUGH WEDNESDAY/... CONCERNS IN THIS PERIOD ARE TEMPS INITIALLY...THE EVOLUTION OF THE SYSTEM EARLY NEXT WEEK...AND THE WEAK SYSTEM LATE FRIDAY TO A LESSER EXTENT. EXPECT THE STRATUS TO BE GONE BY TONIGHT WITH SURFACE RIDGE SETTLING INTO MO VALLEY. EXAMINATION OF BUFR SOUNDINGS SUGGESTS GUIDANCE TEMPS MAY BE TOO COOL TONIGHT...ESPECIALLY IN THE NORTH...POSSIBLY TOO INFLUENCED BY CLIMO SNOW COVER SO HAVE GONE AT OR JUST ABOVE WARMEST MOS. NRN STREAM REFLECTION OF POTENT OR/NRN CA SHORT WAVE PASSES THROUGH CANADIAN PROVINCES TODAY AND TONIGHT REACHING NRN PLAINS FRI. GFS FORCING AND MOISTURE REMAINS MOST AGGRESSIVE...BUT EVEN THAT HAS A NEAR SURFACE DRY LAYER WHICH MAY DIMINISH POTENTIAL. HAVE CONTINUED SLIGHT CHANCES NE AND ADDED A BUFFER OF FLURRIES FOR THIS BRIEF PRECIP WINDOW. DRY NW FLOW FOR THE WEEKEND WITH ATTENTION TURNING TO NEXT SWRN CUTOFF LOW EJECTING. GFS HAS HAD BETTER RUN TO RUN CONTINUITY WITH THE SYSTEM...AND 00Z ECMWF HAS NOW TRENDED IN THAT DIRECTION WHICH EMPHASIZES SLOWER MORE SLY SOLUTION. HAVE REDUCED POPS SOMEWHAT SUN NIGHT AND MON...BUT AM HESITANT TO MAKE ADDITIONAL CHANGES UNTIL FASTER/MORE NLY GEM/UKMET SOLUTIONS TREND AND ECMWF HAS AT LEAST TWO RUNS THAT ARE NOT FLIP FLOPPING. IF CURRENT 00Z ECMWF/GFS SOLUTIONS MAINTAIN...AFTERNOON PACKAGE MAY NEED TO PLACE FURTHER EMPHASIS ON SLOWER/DRIER SOLUTION. && .AVIATION...15/12Z MVFR STRATUS DECK WILL PERSIST THROUGH THE LATE AFTERNOON HOURS BEFORE BREAKING UP FROM WEST TO EAST. MAY SEE MVFR STRATUS CONTINUE INTO THIS EVENING ACROSS NORTHEAST IOWA...MAINLY AFFECTING MCW AND ALO AND POSSIBLY OTM. NAM/RUC HAVE 925MB RH THINNING OUT PAST 21Z THIS AFTERNOON...WITH OTHER MODELS DISSIPATING THE STRATUS DECK EARLIER...LOW CONFIDENCE WITH MENTION OF ANY MVFR CIGS PAST 00Z FRIDAY. OTHER CONCERN IS WITH WINDS. TIGHT PRESSURE GRADIENT WILL KEEP WINDS VERY GUSTY THROUGHOUT THE DAY BEFORE RELAXING EARLY THIS EVENING. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...PODRAZIK LONG TERM...SMALL AVIATION...PODRAZIK