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FXUS63 KARX 092029
AFDARX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
229 PM CST MON NOV 9 2009
SHORT TERM
THROUGH WEDNESDAY NIGHT
ONLY CONCERNS ARE WITH CLOUDS AND TEMPERATURES.
SURFACE ANALYSIS THIS AFTERNOON SHOWS HIGH PRESSURE CENTERED FROM
WESTERN MINNESOTA INTO CENTRAL NEBRASKA.
A QUIET WEATHER PATTERN WILL FOUND ACROSS THE AREA THROUGH THE
PERIOD. A SHORT WAVE TROUGH OVER SOUTHERN SASKATCHEWAN THIS
AFTERNOON WILL TURN SOUTHEAST AND CROSS THE NORTHERN GREAT LAKES
TONIGHT. OTHER THAN THE POSSIBILITY OF A FEW CLOUDS...THIS WAVE
LOOKS LIKE IT WILL HAVE MINIMAL IMPACT ON THE AREA. ONCE THE WAVE
PASSES BY UPPER LEVEL RIDGING WILL BUILD OVER THE REGION FOR
TUESDAY THROUGH TUESDAY NIGHT WITH THE FLOW THEN BECOMING
SOUTHWEST THROUGH THE REMAINDER OF THE PERIOD.
AT THE SURFACE...THE AREA OF HIGH PRESSURE WILL DRIFT EAST INTO
THE GREAT LAKES AND BE THE DOMINANT FEATURE THROUGH WEDNESDAY. AS
THE UPPER LEVEL FLOW TURNS TO THE SOUTHWEST...A COLD FRONT IS
EXPECTED TO MOVE ACROSS THE ROCKIES INTO THE HIGH PLAINS FOR
WEDNESDAY NIGHT. THE 09.12Z GFS IS SUGGESTING IN THE DEVELOPING
WARM AIR ADVECTION ZONE AHEAD OF THE COLD FRONT THAT THERE COULD
BE ENOUGH MOISTURE RETURN ON THE LOW LEVEL JET TO ALLOW SATURATION
TO OCCUR AND SOME LIGHT RAIN TO DEVELOP AHEAD OF THE FRONT. FOR
NOW...ALL THESE SIGNALS REMAIN WEST OF THE FORECAST AREA SO HAVE
MAINTAINED A DRY FORECAST.
LONG TERM
THURSDAY THROUGH MONDAY
CONSISTENCY BETWEEN THE MEDIUM RANGE MODELS IN NOT REAL GOOD TODAY
LEADING TO LITTLE CHANGE BEING MADE UNTIL THE DIFFERENCES CAN BE
RESOLVED. MODELS START OUT VERY SIMILAR WITH RIDGING ACROSS THE
EASTERN CONUS AND A LONG WAVE TROUGH OVER THE WESTERN CONUS. THIS
LEAVES THE MIDDLE PART OF THE COUNTRY IN A SOUTHWEST FLOW ALOFT. THE
DIFFERENCES DEVELOP IN HOW FAST THE TROUGH WILL WORK EAST ACROSS THE
COUNTRY. THE 09.00Z OPERATIONAL RUN OF THE GFS AND THE GFS ENSEMBLE
MEANS TAKE THE TROUGH ACROSS THE COUNTRY MUCH FASTER THAN THE 09.00Z
ECMWF WHICH REMAINS MORE AMPLIFIED AND SLOWER WITH ITS PROGRESSION.
BY THE END OF THE PERIOD...THE GFS HAS THE TROUGH ALONG THE EAST
COAST WITH A ZONAL FLOW OVER THE UPPER MIDWEST WHILE THE ECMWF STILL
HAS THE TROUGH OVER THE REGION. WITH SUCH BIG DIFFERENCES...OPTED
FOR CONTINUITY AT THE SURFACE WHICH BRINGS THE FRONT WITH THE TROUGH
INTO THE AREA STARTING FRIDAY AND THEN EAST OF THE AREA BY SATURDAY
NIGHT. TEMPERATURES AT THIS POINT LOOK TO BE WARM ENOUGH TO KEEP THE
PRECIPITATION ALL LIQUID.
AVIATION
HIGH PRESSURE WILL DOMINATE THE WEATHER...RESULTING IN VFR
CONDITIONS THROUGH THE ENTIRE TAF PERIOD.
ARX WATCHES/WARNINGS/ADVISORIES
WI...NONE.
MN...NONE.
IA...NONE.
SHORT/LONG TERM...04
AVIATION...RABERDING
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