[LeArc] Forecast Discussion : MLI@ 6/19/2003 4:20:17 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 190913
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
400 AM CDT THU JUN 19 2003

HIGH PRESSURE CENTERED OVER SW ONTARIO EARLY THIS MORNING WAS 
SETTLING SOUTH...WITH RESULTING NORTHEAST FLOW FEEDING COOLER AND 
DRIER AIR INTO FORECAST AREA. MAIN COLD FRONT AT 06Z ANALYZED FROM 
FROM OK ACROSS CENTRAL MO TO SERIES OF WEAK LOWS FROM CENTRAL IL TO 
NORTHERN OHIO. WEAK TROUGH WITH LOW LEVEL THETA E RIDGE AXIS 
EXTENDED NORTH FROM WEST CENTRAL IL ACROSS EASTERN IA...RESULTING IN 
PATCHY MVFR CIGS AND FOG. SHORT TERM FORECAST CHALLENGE IS 
TEMPERATURES TODAY AND TONIGHT AS COOL AND DRY CANADIAN AIRMASS 
DOMINATES. 

1022 MB HIGH CENTERED OVER SW ONTARIO AT 07Z PUSHES SOUTH ACROSS 
UPPER MI INTO WI TONIGHT. PATCHY LOW CLOUDS SHOULD CONTINUE TO 
DISSIPATE AND DRIFT SOUTH AS DRIER AIR PUSHES IN FROM NORTHEAST THIS 
MORNING WITH FEW CU IN AFTERNOON. SURFACE TRAJECTORY AND H85 
TEMPERATURES POINT TOWARD COOLER GFS MOS HIGHS IN MID TO UPPER 70S 
TODAY. TONIGHT...HIGH PRESSURE AND DEEP DRY AIRMASS WILL PROVIDE 
CLEAR SKIES WITH SURFACE DEWPOINTS AS LOW AS UPPER 30S OVER NW IL 
TO SET UP IDEAL RADIATIONAL COOLING CONDITIONS. TEMPERATURES 
WILL DIP WITHIN A FEW DEGREES OF RECORDS...WHICH WERE 45 TO 46 AT 
CLIMO SITES. WITH CURRENT OBSERVATIONS IN UPPER 30S TO LOWER 40S 
UNDER HIGH THIS MORNING...COOLER GFS LOWS IN UPPER 40S TO LOWER 50S 
PREFERRED FOR FRIDAY MORNING.   ...SHEETS 

FRIDAY AND SATURDAY...SURFACE RIDGING DOMINATES WHILE GRADUALLY 
SHIFTING INTO THE OHIO VALLEY LATE IN PERIOD. EXPECT A CONTINUATION 
OF GORGEOUS LATE JUNE WX FEATURING SEASONAL TEMPS...VERY COMFORTABLE 
HUMIDITY LEVELS AND CLEAR SKIES. SOME INCREASE IN HUMIDITY IS 
EXPECTED LATE SATURDAY AS RETURN FLOW DEVELOPS ON BACKSIDE OF DEPARTING
SURFACE RIDGE AXIS.

STRONG THERMAL AND MOISTURE ADVECTION FOCUSES TO OUR WEST EARLY 
SATURDAY NIGHT AHEAD OF ADVANCING FRONTAL ZONE IN THE PLAINS.
EVENTUALLY THIS TAKES AIM AT CWA LATER SATURDAY NIGHT...AND AS RESULT
INTRODUCED CHANCE POPS. 

SOME UNCERTAINTY BY EARLY NEXT WEEK WITH POSITION OF FRONTAL ZONE.
WHAT IS CERTAIN HOWEVER IS THAT SUMMER WILL RETURN WITH A VENGEANCE 
SOUTH OF THE FRONT WITH HEAT AND HUMIDITY REALLY REVVING UP. 
00Z/19 GFS VERY AGGRESSIVE IN LIFTING FRONT TO OUR NORTH BY MONDAY 
WITH HEAT BLAST OVER ENTIRE CWA...AND MID LEVEL WARMING CAPPING 
ATMOSPHERE THEREBY LIMITING PCPN CHANCES. UKMET AND ECMWF THOUGH 
FURTHER SOUTH SUGGESTING NORTH/SOUTH GRADIENT TO TEMPS WITH
DAILY THREAT OF CONVECTIVE COMPLEXES WITH POTENTIAL FOR SEVERE WX 
AND HEAVY RAIN. DUE TO THE UNCERTAINTY HAVE OPTED TO MAKE 
VERY LITTLE CHANGE TO EXTENDED. ...MCCLURE



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


$$