[LeArc] Forecast Discussion : MLI@ 5/23/2003 1:47:59 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 231846
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
145 PM CDT FRI MAY 23 2003

.OVERVIEW...REGION IN ENTRENCHED NORTHWEST FLOW KEEPING TEMPERATURES
AND DEWPOINTS BELOW NORMAL AND THUS LIMITED RISK OF SIGNIFICANT
PRECIPITATION.  CLOSED UPPER SYSTEM AND ASSOCIATED SHRA MOVING EAST BUT
AREA STAYING UNDER CYCLONIC FLOW AND THEREFORE SUPPORTING MODERATE TO
SIGNIFICANT LOW LEVEL MOISTURE AND DAYTIME CUMULUS CLOUDS.  UPPER AIR
ANALYSIS SUGGEST LITTLE CHANGE TO PATTERN WITH EMBEDDED SHORT WAVE TO
DROP INTO UPPER TROUGH FROM NW NEXT 24-36 HOURS.

...TEMPERATURES AND AMOUNTS OF CLOUDS MAIN ISSUE THIS FORECAST
THROUGH DAY 7 WITH ONLY MINOR RISKS OF WIDESPREAD AND SIGNIFICANT
PRECIPITATION AMOUNTS...

.DIAGNOSIS...DAYS (1-3)...LITTLE SENSIBLE VARIANCE NOTED BETWEEN MODELS
ON REGION STAYING IN CYCLONIC NORTHWEST FLOW EXCEPT FOR NORMAL BL TEMP
AND MOISTURE REGIME DIFFERENCES.  18Z ANALYSIS SUGGESTS ETA SLIGHTLY TOO
MOIST...SO BLENDED WITH SOME INPUTS FROM NGM AND PERSISTENCE. THIS MEANS
SKIES BECOMING MOSTLY CLEAR AS WEAK SURFACE RIDGE COMES IN TONIGHT AND
TEMPS NEAR TO SLIGHTLY BELOW GUIDANCE BLEND.  SATURDAY ANOTHER BEAUTIFUL
DAY WITH SOME FAIR WEATHER CUMULUS EXCEPT FOR MORE CLOUDS AND SHOWERS
ALONG AND WEST OF I-380 CORRIDOR WITH NEXT SHORT WAVE DROPPING JUST TO
WEST FROM CANADA.  THEN PARTLY CLOUDY WITH UPPER TROUGH PASSING SATURDAY
NIGHT.  THEN...NORTHEAST LAKE ENHANCED NORTHEAST WINDS SETS UP FOR
SEASONABLY COOL AND MILD TEMPERATURES WITH LOW HUMIDITY. WILL USE BLEND
OF PERSISTENCE AND MODEL BLEND...STAYING WITHIN A CATEGORY OF MODEL
BLEND. SLIGHT RISK OF SOME LATE DAY LIGHT SHOWERS SUNDAY INTO MONDAY BUT
WILL HOLD OFF FOR NOW TO BETTER ASCERTAIN CONVECTIVE TEMPS AND
INSTABILITY TRIGGERS REACHABLE.

.EXTENDED (TUE-FRI)...NEXT SHORT WAVE APPROACHES LATE THURSDAY AND
FRIDAY.  APPEARS TO BE OF MODERATE STRENGTH IN NORTHWEST FLOW AND
TO HAVE ADEQUATE RETURN MOISTURE AND FORCING IN FORM OF FRONT AND UPPER
TROUGH FORN CHANCE POPS LATE THURSDAY INTO FRIDAY.

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

$$

NICHOLS