[LeArc] Forecast Discussion : MLI@ 10/20/02 2:41:42 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 200749
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
250 AM CDT SUN OCT 20 2002

MUCH HIGHER DEGREE OF CONFIDENCE WITH FORECAST TONIGHT...AS MOST MODELS
COMING IN LINE WITH GFS MODEL RUN OF 24 HOURS AGO.
IN NUTSHELL...TURNING ACTIVE WITH INVERTED TROUGH TO BRING DECENT POTENTIAL
OF PCPN MIDWEEK...WITH SNOWFALL LOOKING MORE LIKELY IN THE NORTH.
SO...WILL BE MAKING SOME WHOLESALE CHANGES TO GOING FORECAST 
TO ACCOUNT FOR THIS...THUS WILL NEED TO KEEP AFD SHORT TO ALLOW TIME.

MAIN CONCERNS WITH TEMPS NEXT 24 HRS...PCPN CHCS/TYPE MON AND TEMPS...THEN
FOCUS SHIFTS TO ACTIVE PATTERN MIDWEEK.  

NEAR TERM...QUIET AS SURFACE HIGH WILL SHIFT ACROSS REGION INTO THIS EVE.
VERY COLD START WITH SOME AREAS IN M20S...AND WITH
LIMITED MIXING WITH SURFACE HIGH OVERHEAD NOT EXPECTING MUCH OF WARMUP
OVER YESTERDAY/S MAXES. SO...WILL STAY CLOSER TO BLEND OF FWC/MAV GUIDANCE.
OVERALL SUNNY WITH SOME INCREASE IN MID/HIGH LEVEL MOISTURE
THIS AFTN...ESPECIALLY NORTH/WEST.  

CYCLOGENESIS EXPECTED IN PLAINS TONIGHT WITH SURFACE LOW MOVING E THROUGH
MID MISSISSIPPI VALLEY ON MON AFTN/EVE DRAGGING COLD FRONT
ACROSS REGION. NOT LOOKING GREAT FOR PCPN CHCS TONIGHT AS IT APPEARS
BEST ISENTROPIC LIFT AND SATURATION TO OCCUR ACROSS MN INTO WI.
THUS...WILL MAINTAIN DRY FORECAST. ON MON...WITH SURFACE WAVE PASSING
NORTH OF I-80 ENHANCING LLVL CONVERGENCE AND AIDING IN SATURATION WILL MAINTAIN
CHC POPS ALONG AND NORTH OF HIGHWAY 30. MAINLY -RA WITH 
FEW SNOWFLAKES POSSIBLE AS SOUNDINGS SHOW LOTS OF POTENTIAL FOR EVAPORATIONAL 
COOLING. OTHERWISE...FRONT EXPECTED TO COME THROUGH MAINLY DRY DUE TO
LACK OF LLVL CONVERGENCE AND MOISTURE...THOUGH CAN/T RULE OUT SOME SPRINKLES.
TEMPS ON MON BIG CHALLENGE. MET GUIDANCE LOOKS TOO WARM IN SOUTH. 
HOWEVER...IN RECENT WARM ADVECTION EVENTS IT HAS BEEN MORE REALISTIC...AND
GIVEN THAT 60S NOT FAR OFF YESTERDAY (SOUTHERN MO AND NORTHERN OK) WILL
SIDE TOWARD BLEND OF FWC/MET GUIDANCE...LEANING TOWARD FWC END.

TUESDAY...COOLER POST FRONTAL...WITH SOME VERY LIGHT PCPN (-DZ OR EVEN --SN
IN NORTH) NOT OUT OF QUESTION EARLY ON. 

LATE TUE NIGHT...AND ESPECIALLY WED/WED NIGHT MODELS COMING INTO
BETTER CONSENSUS DEPICTING CONVERGENT LLVL FLOW DEVELOPING OVER REGION WITH 
INVERTED SURFACE TROUGH. THIS IS EFFICIENT PCPN PRODUCER FOR US...AND 
WILL INTRODUCE POPS...IN FACT WILL GO WITH LIKELY POPS WITH AMOUNTS EXPECTED 
TO BE LIGHT TO MODERATE. H85 PROGGED THERMAL FIELDS
SUGGEST SNOW REAL POSSIBILITY WITH COLD LLVL NE FETCH FROM GREAT LAKES
HIGH. MOST LIKELY AREA ALONG AND NORTH OF HIGHWAY 30...THOUGH CAN/T RULE OUT 
SOME SNOW MIXED IN WITH RAIN AS FAR SOUTH AS I-80 CORRIDOR.


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