[LeArc] Forecast Discussion : MLI@ 11/11/02 3:30:19 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 110940
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
340 AM CST MON NOV 11 2002

H5 TROF MOVING THROUGH EASTERN IA EARLY THIS MORNING AND IS
DEPICTED NICELY ON THE WATER VAPOR IMAGERY.  88D LOOP SHOWS PCPN
NORTH AND WEST OF THE VORT...WORKING ITS WAY SLOWLY SE.  COLDER
AIR WAS WRAPPING AROUND SYSTEM INTO SOUTHEAST IOWA. COLD AIR SURGE
ACROSS WESTERN CWA WAS KEEPING PCPN MAINLY LIGHT SNOW OVER CENTRAL
AND NORTHEAST IOWA...WHILE RAIN OR A RAIN/SNOW MIX WAS OCCURING
INTO SOUTHERN WISCONSIN.

PCPN TYPE/AMOUNT THE FIRST 6 HOURS OF THE FCST THEN CLOUD TRENDS
OVERNIGHT WILL BE THE BIGGEST FORECAST CHALLENGE.

MODELS INITIALIZED WELL LAST NIGHT AND APPEAR TO HAVE A GOOD HANDLE
ON THE SYNOPTIC FEATURES.  NO MAJOR MODEL DIFFERENCES WERE NOTED
THROUGH MID-WEEK.  MODEL QPF PROGS WERE SIMILAR WITH H5 TROF MOVING
THROUGH CWA.  MODELS APPEARED TO HAVE A GOOD HANDLE ON THE QPF NORTH
OF THE SYSTEM...WHILE BARELY ACKNOWLEDGING THE AREA OF WRAP AROUND
LIGHT SNOW MOVING OUT OF CENTRAL IA.  ALTHOUGH...THE 06Z MESOETA
WAS CATCHING ON.  WILL EXTRAPOLATE PCPN ACROSS CWA THIS MORNING.
LOOKS LIKE MAINLY SNOW WEST CENTRAL AND NW SECTIONS WITH MINOR
ACCUMULATIONS BASED ON GROUND TRUTH VIA DMX.  PCPN MOVING INTO
NORTHWEST ILLINOIS SHOULD BE BE RAIN/SNOW MIX WITH WARMER LOW LEVEL
TEMPS IN VCNTY OF WEAK SFC TROF.  BY THE TIME THE PCPN MAKES IT TO
THE RIVER AND WEST CENTRAL IL...AFTER 12Z...BELIEVE LOW LEVEL TEMPS
SHOULD HAVE ENOUGH TIME TO RECOVER TO ALLOW A MIX OF RAIN AND
SNOW. LOOKS LIKE AREAS SOUTH OF HIGHWAY 34 WILL BE LEAST LIKELY TO
SEE ANY PCPN THIS MORNING...BUT WILL KEEP A LOW CHANCE POP FOR -SN.

CLOUDS AND CAA TODAY WILL KEEP TEMPS FROM RISING MUCH AND WILL ALLOW
FOR A 5 TO 10 DEGREE RISE...IN LINE WITH COOLER MAV NUMBERS.
TRAJECTORIES ALSO SUPPORT THESE NUMBERS.  CLEARING TONIGHT LOOKS
QUESTIONABLE.  MODELS SHOW A BRIEF DECREASE IN 850 RH THIS EVENING...
BUT BRING ANOTHER AREA OF HIER RH IN OUT OF THE NORTHERN PLAINS.
WILL CONTINUE PARTLY CLOUDY WORDING AND USE A COMPROMISE OF MAV/FWC
NUMBERS.

FAST NW FLOW WILL DOMINATES REGION TUESDAY THROUGH THURSDAY.  A WEAK
SYSTEM MOVES NORTHEAST OF CWA AND SHOULD HAVE LITTLE IMPACT ON
REGION TUESDAY. WEDNESDAY INTO THURSDAY...GFS BRINGS A SURFACE LOW
THROUGH THE NORTHERN PLAINS INTO THE GREAT LAKES.  LOOKS LIKE CWA
WILL BE UNDER THE INFLUENCE OF STRONG WAA WEDNESDAY.  WILL BUMP MAV
TEMPS UP A CATEGORY.  MAY HAVE TO GO HIGHER...BUT AMOUNT OF CLOUD
COVER IS QUESTIONABLE AT THIS TIME.

NO CHANGES TO THE EXTENDED.


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

DLF