[LeArc] Forecast Discussion : MLI@ 6/18/02 2:12:45 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 180710
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
210 AM CDT TUE JUN 18 2002

MAIN FORECAST CHALLENGE IS REFINEMENT OF SHRA/TSRA CHANCES THROUGH 7 
DAYS AS UPPER FLOW BECOMES MORE DEAMPLIFIED INTO A MORE TYPICAL 
SUMMER PATTERN. NW FLOW THAT PREVAILED OVER WEEKEND BECOMES MORE 
ZONAL AS UPPER JET AND MID LEVEL SHORTWAVE MOVING INTO NW CONUS 
FLATTENS RIDGE OVER ROCKIES RESULTING IN BACKING FLOW ALOFT...THEN 
RIDGING OVER CENTRAL CONUS BY END OF WEEK OVER CWFA. 

25KT H85 FLOW INTO WESTERN IA WITH AND EASTERN EDGE OF SURFACE 
THROUGH H85 MOISTURE RIDGE AXIS HELPING SUSTAIN SLOW MOVING TSRA 
OVER CENTRAL IA TONIGHT TRIGGERED BY UPPER DIVERGENCE AND SHORTWAVE 
IN NW H5 FLOW. DRIER AND MORE STABLE AIR SHOULD KEEP MOST OF THIS 
CONVECTION OUT OF CWFA THIS MORNING...BUT WILL MONITOR UNTIL 
ISSUANCE. NEXT H5 VORT MAX INDICATED BY SATELLITE AND LIGHTNING DATA 
OVER SE MT SHOWN BY MODELS TO PROGRESS INTO FAR NE IA TOWARD 
00Z...WHICH WILL BE MAIN TRIGGER FOR NEXT THREAT OF TSRA. MODEL QPF 
DID NOT HAVE GOOD HANDLE WITH ON-GOING CONVECTION...WITH ETA MISSING 
CENTRAL IA TSRA ENTIRELY. ALL AGREE TO KEEP EASTERN HALF CWFA DRY 
TODAY AND THIS LOOKS REALISTIC AS AREA LACKING MOISTURE AND HAS 
WEAKER MID LEVEL LAPSE RATES. LOW POPS WILL BE PLACED IN NORTHERN IA 
ZONES FOR LATE AFTERNOON...WHERE FORECAST CIN VERY LOW AND MID LEVEL 
LAPSE RATES AND FORCING MOST FAVORABLE. H85 TEMPERATURES RISE 1 TO 2 
DEG C HIGHER THAN MONDAY AND WITH MAINLY DEBRIS CI...FWC HIGHS IN 
LOW 80S LOOK REASONABLE. 

GRADUAL INCREASE IN SURFACE TEMPS AND HUMIDITY WED AND THURSDAY WITH 
CONVECTION CHANCES BECOMING MORE FOCUSED ON SURFACE TROUGH/FRONT 
FROM NEB INTO MN THAT DOES NOT APPROACH CWFA UNTIL FRIDAY. MODELS IN 
BASIC AGREEMENT WITH FEATURES...WITH SOME DIFFERENCES IN LEE SIDE 
LOW CENTER. WITH BACKING FLOW ALOFT...CAP INCREASES WED AND THURSDAY 
ESPECIALLY OVER SOUTH WITH BEST CHANCES FOR CONVECTION BEING 
NOCTURNAL WITH GULF OPEN AT H85 AND MOISTURE AXIS OVER OR JUST NW OF 
CWFA. MODEL QPF HAS THIS IDEA...KEEPING RAIN MAINLY TO OUR NW 
THROUGH THURSDAY AND LOOKS REASONABLE TO KEEP SCATTERED POPS 
CONFINED MAINLY TO NW HALF WITH SLIGHT TO NONE OVER CENTRAL AND SE. 

WEAK FRONT SLIDES S OVER EASTERN IA FRIDAY. MEDIUM RANGE MODELS HAVE 
E-W H5 RIDGE OVERHEAD OR JUST TO SOUTH WHICH WOULD CAP OR LIMIT 
CONVECTION...BUT WILL LEAVE IN CHANCE MENTION FOR NOW. ON 
SATURDAY...UPPER RIDGE WILL LIMIT CONVECTION TO RING OF FIRE PATTERN 
AND WELL TO OUR NORTH. MRF ALONE WITH STRONG SHORTWAVE ALONG CAN 
BORDER PUSHING SURFACE FRONT THROUGH ON SUNDAY...WITH UK AND ECMO 
HOLDING FLAT UPPER RIDGE OVER MIDWEST. WILL LET DAYSHIFT GET A 
BETTER LOOK AT THIS AND LEAVE IN TSRA CHANCES FOR SUNDAY. 

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

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