[LeArc] Forecast Discussion : MLI@ 12/1/02 8:32:48 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 011445
AFDMLI

AREA FORECAST DISCUSSION...RETRANSMITTED
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
300 AM CST SUN DEC 1 2002

UPPER AIR PATTERN DOMINATED BY VORTEX OVER HUDSON BAY AND STRONG
RIDGING FROM THE PACIFIC NW INTO BRITISH COLUMBIA.  IN BETWEEN...
STRONG NW FLOW REMAINS IN PLACE OVER THE MID/UPPER MS VALLEY.  AT
THE SURFACE AT 06Z...RIDGE IN PLACE FROM ERN OK THROUGH CENTRAL IA.
RETURN FLOW WAS SETTING UP OVER THE NORTHERN PLAINS AHEAD OF WEAK
LOW PRESSURE MOVING INTO NRN ND.

MAIN CONCERNS THIS FORECAST WILL BE EXTENT OF WARM UP TODAY THEN...
SNOW/RAIN THREAT AND AMOUNTS FOR MONDAY.  MODELS APPEAR TO HAVE
INITIALIZED WELL SUNDAY EVENING WITH NO SIGNIFICANT DISCREPANCIES
NOTED.  MODELS ARE SIMILAR IN HANDLING BROADSCALE FEATURES THROUGH
TUESDAY.  HOWEVER...THERE ARE SOME TIMING DIFFERENCES WITH RESPECT
TO THE S/W ENERGY MOVING THROUGH REGION MONDAY.  WILL GENERALLY
FOLLOW BLEND OF AVN/UKMET WITH EXCEPTION OF TODAY'S THERMAL FIELDS
WHICH THE ETA IS THE PREFERRED MODEL.

STRONG WAA SETS UP OVER CWA BY MID MORNING WITH 850 TMPS AT KDVN
INCREASING FROM -16 AT 01/00Z TO AROUND 3C AT 01/21Z. CWA SHOULD SEE
GOOD MIXING THIS AFTERNOON AS  SW SURFACE WINDS INCREASE IN TO THE 15
TO 25 MPH RANGE.  THE MET HAS BEEN THE WAY TO GO FOR THESE WAA
EVENTS LATELY.  HOWEVER...06Z MESOETA APPEARS TO BE BACKING OFF
SOME ON THE 2M TEMPS.  WILL USE A BLEND OF MET/MAV FOR WEST AND
SOUTH AND TREND TOWARD THE MAV NUMBERS IN THE NE WHERE MID CLOUDS
WILL HAMPER WARMUP.  NEXT SURGE OF COLD AIR MOVES SOUTH THROUGH CWA
BETWEEN LATE THIS EVENING AND EARLY MONDAY MORNING. POST FRONTAL
CLOUDS AND MAYBE SOME FLURRIES WILL ACCOMPANY THE COLD AIR. S/W WAVE
ENERGY MOVING FROM NRN BRITISH COLUMBIA INTO THE MID MS VALLEY SUNDAY
NIGHT AND MONDAY WILL BRING THE POTENTIAL FOR SOME LIGHT SNOWFALL TO
THE REGION. 01/00Z RUNS HAVE BACKED OFF SOME ON THE QPF FOR THE
CWA...BUT IT STILL LOOKS LIKE NORTHERN CWA COULD SEE SOME MINOR
ACCUMULATIONS. WILL CONTINUE TO LIKELY POPS NORTH MONDAY TO AVOID
FLIP FLOPPING...BUT WILL BACK OFF SOME ON THE ACCUMULATION. WILL
MAINTAIN CHANCE POPS SOUTH WITH PCPN BEGINNING AS -RN THEN CHANGING
TO -SN.

POTENTIAL SNOW COVER NORTH AND NELY LOW LEVEL FLOW AND LAKE EFFECT
CLOUDS CAUSING SOME UNCERTAINTY ABOUT HOW MIN FOR TUESDAY MORNING.
FOR NOW WILL GO CLOSE TO COLDER MAV NUMBER NW AND USE MET/MAV BLEND
EAST AND SOUTH.  TEMP RECOVERY TUESDAY WILL BE LIMITED BY CLOUDS
AND NERLY FLOW...THUS WILL ALLOW FOR ONLY A 10 DEGREE RECOVERY.  S/W
ENERGY DROPPING SOUTH THROUGH NRN PLAINS WEDNESDAY SUGGESTING SOME
SN TO OUR WAS WITH AVN SUGGESTING IT COULD BRUSH WRN CWA.  WILL
HOLD OFF FOR NOW ON INTRODUCING PCPN...BUT WILL INCREASE CLOUD
COVER.  NO OTHER CHANGES PLANNED FOR EXTENDED AT THIS TIME.


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

DLF