[LeArc] Forecast Discussion : MLI@ 12/4/02 2:42:29 AM

[learc@mailman.qth.net]

The following weather message is provided by McDonough County E.S.D.A.


FXUS63 KDVN 040855
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
255 AM CST WED DEC 4 2002

NEXT S/W TO MOVE THROUGH REGION WAS JUST MOVING INTO THE NORTHERN
PLAINS AROUND 06Z.  REGIONAL RADAR COMPOSITE SHOWING A LARGE SWATH
OF LIGHT -SN AHEAD OF THE S/W FROM CENTRAL MN W THROUGH THE
SOUTHERN HALF OF SD.  SURFACE REPORTS FROM THIS AREA SHOW THAT PCPN
WAS MOSTLY --SN WITH VSBYS AT A FEW LOCATIONS IN SRN SD DROPPING
BETWEEN 1 AND 2SM.  TO OUR SOUTH...SOUTHERN STREAM SYSTEM PROVIDING
MORE ACTIVE WX AS IT MOVES INTO THE SOUTHERN PLAINS.  LARGE SWATH OF
MIXED PCPN EAST OF THE SYSTEM THROUGH THE LOWER MS VALLEY.  NORTHERN
FRINGE OF THE PCPN STILL SOUTH OF THE MO RIVER IN SRN MO.  MODELS
INITILIAZED WELL WEDNESDAY EVENING WITH RESPECT TO THE NRN PLAINS
S/W  AND SRN STREAM SYSTEM.  HOWEVER...THE GFS WAS HANDLING THE
STRENGTH OF THE SURFACE HIGH/COLD AIR OVER SOUTHERN ALBERTA/MT
BETTER THAN THE ETA.  THE ETA WAS TOO WEAK WITH PRESSURES NEAR THE
CENTER OF THE HIGH AND WAS ALSO TOO WARM AT H850.  MODEL PROGS
THROUGH THE END OF THE WEEK WERE SIMILAR WITH NO SIGNIFICANT
DIFFERENCES NOTED IN THE BROAD SCALE FEATURES.

FOCUS FOR THIS MORNINGS ISSUANCE WILL BE THE NRN PLAINS S/W AND
ASSOCIATED POPS AS IT MOVES THROUGH THE REGION BY EARLY THURSDAY.
BOTH GFS/ETA SHOW LIFT WITH NRN PLAINS SYSTEM DIMINISHING WITH
TIME. MODELS ALSO KEEP LOW LEVELS ACROSS SOUTHERN SECTIONS OF
CWA DRY THROUGH THIS AFTERNOON. IT STILL LOOKS LIKE BEST THREAT OF
MEASURABLE PCPN WILL BE ACROSS THE NORTHERN THIRD OF CWA FROM LATE
THIS MORNING UNTIL ABOUT MID AFTERNOON.  30 POPS ARE ALREADY IN
PLACE AND DON'T SEE ANY REASON TO DIFFER.  THE DRY LOW LEVELS AND
WEAKENING MID LEVEL DYNAMICS STILL SUPPORT FLURRIES AT BEST THIS
AFTERNOON/EVENING ACROSS THE SOUTH.  MID/HIGH CLOUDS WILL LIMIT
SUN/WARMING TODAY.  THE MAV LOOKS A LITTLE TOO COOL SO WILL USE A
MET/FWC BLEND.  ONLY SIGNIFICANT ADJUSTMENT TO TEMPS TODAY IS IN
THE NORTHEAST. 1 TO 2 INCHES OF SNOW COVER FROM THE DBQ AREA EAST
SHOULD LIMIT WARMING SO OPTED TO GO A LITTLE BELOW THE COOLER MAV
NUMBERS. SURFACE HIGH OVER THE NRN PLAINS PROGGED TO DROP SOUTH...
STAY WEST OF CWA.  THIS WILL PUT REGION IN WESTERLY FLOW THROUGH
THE END OF THE WEEK.  A COUPLE OF IMPULSES ROTATING THROUGH REGION
WILL NOT HAVE ANY MOISTURE TO WORK WITH.  HAVE REMOVED MENTION OF
FLURRIES IN THE NORTH FOR THURSDAY.  WITH WESTERLY FLOW AND SOME SUN
THROUGH FRIDAY...WILL LEAN TOWARD WARMER MET NUMBERS...ESPECIALLY
FOR HIGHS.  THE EXCEPTION WILL BE THE NORTHEAST WHERE COOLER MAV
NUMBERS LOOK GOOD DUE TO SNOW COVER.

LOOKS LIKE MOISTURE OVER THE REGION WILL STILL BE LACKING AS NEXT
COLD FRONT MOVES THROUGH THE REGION EARLY IN THE WEEKEND. THE GFS IS
GENERATING SOME LIGHT PCPN OVER THE EASTERN CWA BY 18Z SATURDAY.
WILL REMOVE MENTION OF PCPN FOR FRIDAY NIGHT AND CONTINUE CHANCE POPS
FOR SATURDAY. WILL STILL GO WITH R/S MIX.

IA...NONE.
IL...NONE.
MO...NONE.

DLF