[LeArc] Forecast Discussion : MLI@ 7/21/02 2:37:40 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 210738
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
237 AM CDT SUN JUL 21 2002

MODELS STILL HAVING TEETHING PROBLEMS COMPARED TO REAL DATA. NGM
SLOWEST OF THE MODELS AND BASED ON CURRENT DATA HAS BEEN THROWN OUT.
ETA/META A LITTLE SLOW AND AVN A LITTLE FAST. THEREFORE AN AVERAGE OF
THE THREE SHOULD GIVE A GOOD FRONTAL POSITION INTO THE FUTURE. INTENSE
HEAT TO BE THE THEME TODAY UNDER 20 MEGATON CAP. COMPARED TO OBSERVED
MAXES...ANY AREA THAT HAD H85 TEMPS OF 25C WERE 100 OR HIGHER WITH 23-
24 BEING UPPER 90S OR 100 BASED ON DEW POINTS. COMBINATION OF
ADVECTION/MIXING TO DROP DEW POINTS INTO THE LOWER 70S BEFORE CLIMBING
AGAIN IN ADVANCE OF COLD FRONT. THIS PUSHES HEAT INDICES WELL INTO
ADVISORY AREA...AND I WOULD NOT BE SURPRISED IF PARTS OF FAR
WEST/NORTHWEST GO TO 115 OR HIGHER FOR SEVERAL HOURS. COLD FRONT TO
ENTER NORTHWEST THIRD CWFA IN THE 06-09Z TIME FRAME WITH NORTHWEST HALF
SEEING PRECIP BY 12Z. MODELS NOT HANDLING PRECIP WELL AND ATTEMPT TO
BRING FRONT THROUGH NEARLY DRY. THIS IS PHYSICALLY NOT POSSIBLE WITH
MOISTURE AND EXTREME INSTABILITY. PRECIP TO BE ALONG FRONT WITH POST
FRONTAL PRECIP BACK TO H85 FRONT. THIS SAID SOUTHEAST HALF OF CWFA
WILL NOT SEE PRECIP UNTIL AFTER DAYBREAK MONDAY. TSRA TO OCCUR DURING
DAY MONDAY WITH PRECIP ENDING DURING THE AFTERNOON FROM NORTHWEST TO
SOUTHEAST.

WILL KEEP HEAT ADVISORY GOING INTO TONIGHT AS HEAT INDICES NOT TO DROP
BELOW 80 FOR MUCH OF THE NIGHT. THIS WILL BE A HIGH END ADVISORY
EVENT FOR THE CWFA. META ALSO SHOWS H85 TEMPS REMAINING STEADY/SLOWLY
RISING DURING THE NIGHT ACROSS CWFA...ALA COMPRESSIONABLE HEATING AHEAD
OF FRONT.

FWC/MAV NUMBERS FAIRLY SIMILAR. HOWEVER MAX TEMPS HAVE GENERALLY BEEN
WARMER THAN FWC PAST TWO DAYS. WILL MAKE ADJUSTMENTS AS NEEDED.

COORDINATED WITH DSM..LSE...CHI...ILX...AND STL.

.DVN...
IA...HEAT ADVISORY TODAY/TONIGHT.
IL...HEAT ADVISORY TODAY/TONIGHT.
MO...HEAT ADVISORY TODAY/TONIGHT.

86