[LeArc] Forecast Discussion : MLI@ 5/22/2003 3:13:56 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 222009
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
300 PM CDT THU MAY 22 2003

MORNING UA ANALYSIS SHOWED AN H5 TROUGH FROM SCENTRAL CANADA INTO 
THE NORTHERN PLAINS.  BY 18Z A REFLECTION OF THE TROUGH WAS SHOWING 
UP AT THE SURFACE IN THE FORM OF WEAK LOW PRESSURE OVER SERN SD. THE 
MODELS ALL SHOW THIS FEATURE TO SOME DEGREE...BUT THE MESO ETA SEEMS 
TO BE THE MOST REPRESENATIVE.  MESO ETA ALSO DEVELOPS AN AREA OF 
PCPN IN THE VCNTY OF THE LOW THIS AFTERNOON. REGIONAL RADAR COMPOSITE
IS SHOWING SOME NEW DEVELOPMENT OVER SWRN MN SINCE 20Z. MODELS ARE 
IN GOOD AGREEMENT AS THEY MOVE THE UPPER SYSTEM SE INTO NRN MI BY 18Z 
FRIDAY AND CLOSE IT OFF.  CONSIDERING CURRENT AND MODELS 
TRENDS...WILL SPREAD CHANCE POPS ACROSS THE ENTIRE CWA BEGINNING IN 
THE NW CWA AROUND 03Z AND THEN DROP POPS BY MID MORNING FRIDAY AS H5 
TROUGH MOVES TO THE EAST.  HIGHEST POPS WILL BE ACROSS THE N NEAR 
THE VORT TRACK.  LITTLE DIFFERENCE NOTED IN MOS TEMPS FOR TONIGHT 
AND WILL USE A BLEND.  INCREASED CLOUD COVER TONIGHT SUPPORTS MINS 
SEVERAL DEGREES WARMER THAN THIS MORNING.

OVER THE WEEKEND AND INTO EARLY NEXT WEEK...COOLER THAN NORMAL TEMPS 
WILL BE THE RULE AS H5 VORTEX PLANTS ITSELF OVER THE EASTERN GREAT 
LAKES. WILL KEEP TEMPS NEAR OR JUST BELOW COOLER MAV NUMBERS.  SOME 
INSTABILITY SHOWERS CAN'T BE RULED OUT DURING THE PERIOD BUT RATHER 
THAN PEPPER TO FCST WITH LOW POPS FOR SPOTTY CONVECTION...WOULD 
PREFER TO HANDLE IT ON A DAY TO DAY BASIS.  

EXTENDED
COOL/DRY WEATHER TO CONTINUE INTO THE FIRST HALF OF THE EXTENDED 
PERIOD WITH UPPER LOW LOCKED IN OVER OVER NEW ENGLAND UNTIL 
WEDNESDAY.  GFS IS AGRESSIVE WITH NEXT SYSTEM SHOWING A
NEARLY CLOSED OFF LOW OVER ND BY 00Z THURSDAY WITH A COLD FRONT 
ENTERING WRN IA. GFS IS OUT OF PHASE WITH EUROPEAN MODELS WITH THIS 
SYSTEM.  HOWEVER...ECMWF IS SUGGESTING A WEAK FRONTAL BOUNDARY WILL 
MOVE THROUGH AT LATE NEXT WEEK...SO WILL GO WITH CHC TSRA POPS FOR 
WEDNESDAY NIGHT AND EARLY THURSDAY.  WILL PUSH TEMPS UP TO NEAR 
NORMAL AHEAD OF SYSTEM WITH BELOW NORMAL TEMPS RETURNING FOR THE END 
OF THE WEEK.

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

$$
DLF