[LeArc] Forecast Discussion : MLI@ 6/17/2003 3:46:17 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 170844
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
343 AM CDT TUE JUN 17 2003

RATHER WEAK SYNOPTIC PATTERN THIS MORNING OVER REGION WITH SURFACE 
HIGH CENTERED NORTHEAST OF LAKE HURON. THIS PUSHED ANOTHER LAKE 
AIRMASS FRONT THROUGH MOST OF FORECAST AREA LATE MONDAY EVENING... 
RESULTING IN INFLUX OF COMFORTABLE DEWPOINTS IN MID 40S TO MID 50S. 
AT UPPER LEVELS...STRONG CUTOFF VORT AT H5 WAS SPINNING OVER CHI 
WITH FEW RELATED TSRA SHOWING UP TO ITS EAST. MORE SIGNIFICANT H5 
SHORTWAVE WITH WIDESPREAD TSRA WAS MOVING OUT OF CENTRAL ROCKIES 
INTO HIGH PLAINS WITH SURFACE COLD FRONT FROM NEB PANHANDLE TO 
CENTRAL ND ON 06Z ANALYSIS. THIS LATTER FEATURE IS MAIN SHORT TERM 
FORECAST CHALLENGE AS FRONT MOVES THROUGH LATE TONIGHT THROUGH 
MIDDAY WEDNESDAY.

00Z ETA IS FASTEST OF SHORT RANGE MODELS WITH THIS COLD FRONT 
REACHING EAST CENTRAL IA JUST BEFORE 06Z THEN EXITING SOUTHEAST 
ZONES JUST AFTER 12Z. GFS AND UKMET SLOWEST WITH THE FRONT NOT 
EXITING UNTIL AFTER 18Z WED. QUICK LOOK AT 06Z META TRENDS TOWARD 
SLOWER MODEL SOLUTION AND WILL FOLLOW OVERALL BLEND. LOW LEVEL 
INSTABILITY AND MOISTURE LOOK SUFFICIENT FOR SHOWERS AND FEW 
THUNDERSTORMS ALONG FRONT AS OCCURRING UPSTREAM TONIGHT...ALTHOUGH 
MID LEVEL FORCING NOT IMPRESSIVE AND LAGS FRONTAL PASSAGE UNTIL WELL 
INTO WED OVER MOST OF AREA. FOLLOWING THE MODEL BLEND...CHANCE POPS 
BROUGHT IN EARLIER TONIGHT THAN PREVIOUS PACKAGE ACROSS THE 
NORTHWEST 2/3RDS OF CWFA AND WILL END CHANCES ACROSS NORTHWEST HALF 
WEDNESDAY AFTERNOON. RAISED MAX TEMPERATURES SOME TODAY WITH 
INITIALLY LOW DEWPOINTS...LOTS OF MORNING SUNSHINE AND LIGHT WINDS. 
ONLY MINOR CHANGES TO TEMPS TONIGHT INTO WED...THEN WED NIGHT MINS 
WERE LOWERED SOME CLOSER TO COOLER GFS MOS AS HIGH SETTLES INTO MN 
WITH ANOTHER SHOT OF COOL NORTHEAST FLOW.   SHEETS

COOL...DRY CANADIAN AIRMASS SETTLES OVER REGION ON THURSDAY AND 
DOMINATES THROUGH SATURDAY RESULTING IN BENIGN WX WITH SEASONAL 
TEMPS AND COMFORTABLE CONDITIONS WITH LOW HUMIDITY. GIVEN DRY NATURE 
OF AIRMASS WILL CONTINUE WITH SUNNY DAYS/CLEAR NIGHTS INTO 
SATURDAY...THOUGH HAVE SOME CONCERN THAT WE COULD SEE LAKE EFFECT 
CLOUDS ESPECIALLY ON THURSDAY WITH FAVORABLE TRAJECTORY. PATTERN 
THEN UNDERGOES CHANGE BY LATE IN THE WEEKEND BECOMING MORE ACTIVE 
WITH UPPER LEVEL FLOW TURNING SOUTHWESTERLY. THIS WILL RESULT IN 
INCREASE IN HEAT/HUMIDITY. PCPN CHCS WILL ALSO ENTER THE PICTURE AS 
SEVERAL DISTURBANCES EJECT OUT INTO THE NATION/S MIDSECTION AHEAD OF 
MEAN WESTERN U.S. TROUGH.

MCCLURE 

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

$$