FXUS63 KDMX 261138
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
538 AM CST THU NOV 26 2009
.SHORT TERM /TODAY/...
PRIMARY CONCERN WILL BE CLEARING TRENDS WITH BACK EDGE OF LOW CLOUDS
ESSENTIALLY ALONG THE MO RIVER AT THE MOMENT. LIGHT RAIN/LIGHT SNOW
MIX IS STILL IN PROGRESS ACROSS SERN FORECAST AREA...BUT EXPECT THIS
TO EXIT AREA BEFORE FORECAST BECOMES VALID AT 12Z. NAM IS NOT
HANDLING LOW CLOUD PROGRESSION WELL AT ALL WITH GFS LOW LEVEL RH
MORE REALISTIC RIGHT NOW. BACK EDGE IS CLOSE TO 80 PERCENT AND GFS
BRINGS THIS LINE TO JUST EAST OF I35 BY 12Z AND WILL BE
FOLLOWED...WHICH IS ALSO SUPPORTED BY EXTRAPOLATION OF BACK EDGE
ACROSS ND/MN. NAM/GFS SOUNDINGS IN CLOSE AGREEMENT SUGGESTING HIGHS
NEAR NAM MOS. LOW LEVELS CURRENTLY MIXED...AND SHOULD REMAIN SO
THROUGHOUT THE DAY KEEPING WIND GUSTS INTO THE 20S.
.LONG TERM /TONIGHT THROUGH MONDAY/...
THE MAIN FORECAST ISSUE IN THE LONG TERM IS THE SYSTEM FOR LATE
SUNDAY AND MONDAY. UNTIL THEN...UPPER RIDGING WILL BUILD INTO THE
FORECAST AREA WITH MOSTLY CLEAR SKIES AND GRADUALLY WARMING TEMPS
THROUGH SATURDAY. FOR THE WEEKEND...THE MODELS ARE STILL SHOWING A
BROAD LONG WAVE TROUGH SWEEPING ACROSS THE CWA LATE SUNDAY THROUGH
MID DAY MONDAY. THE GFS HAS COME MORE IN LINE WITH THE 00Z EURO AND
THE CANADIAN. IT NO LONGER DEEPENS A CLOSED LOW OVER IA AND DROPS
IT SOUTHEAST RATHER IT CONTINUES WITH THE IDEA OF A SPLIT FLOW
REGIME. MOISTURE REALLY DOES NOT IMPACT THE SYSTEM UNTIL IT PUSHES
EAST OF THE CWA. THUS I HAVE JUST SLIGHT CHANCE POPS FOR SUNDAY
NIGHT ACROSS THE SOUTHEAST THOUGH AS THINGS BECOME BETTER DEFINED IN
THE NEXT COUPLE DAYS THE FORECAST WILL BE TWEAKED FOR TIMING AND
MORE LIKELY...POPS. TEMPS WILL COOL DOWN FOR SUNDAY AND MONDAY AS
THIS SYSTEM PASSES. TEMPERATURES WILL REMAIN NEAR SEASONAL NORMALS
NEXT WEEK BUT OUTSIDE OF THIS FORECAST PACKAGE...THE MODELS ARE
HINTING AT A BIG COOL DOWN LATER NEXT WEEK.
&&
.AVIATION...
26/12Z...WIDESPREAD MVFR CIGS STILL EXIST THIS MORNING...MAINLY
ALONG AND WEST OF MO RIVER VALLEY...WITH BACK EDGE STILL INTO ERN
SD/WRN MN. UNFORTUNATELY CIGS ARE STRADDLING 2KFT AMENDMENT
CRITERIA MAKING FORECAST SOMEWHAT PROBLEMATIC. WILL AVOID TEMPOS
AND JUST GO WITH MOST LIKELY CONDITIONS TO START. WINDS WILL BE
GUSTY...22KTS OR MORE...AT ALL SITES EXCEPT FOD THROUGH MUCH OF THE
DAY. SKIES SHOULD BECOME CLEAR FROM NW-SE 18Z-21Z FOLLOWED BY
DIMINISHING WINDS EARLY THIS EVENING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/AVIATION...BSS
LONG TERM...FAB