[LeArc] Forecast Discussion : MLI@ 7/28/2003 3:46:05 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 282034
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
334 PM CDT MON JUL 28 2003

STUBBORN CLOUD COVER LINGERING OVER MOST OF FORECAST AREA THIS 
AFTERNOON KEEPING LID ON TEMPERATURES OVER ALL BUT FAR NORTHWEST.
MAIN SYNOPTIC FRONT NOW WELL TO SOUTH...FROM CENTRAL KS/OK BORDER 
EAST TO OHIO RIVER VALLEY. LOW PRESSURE TROUGH EXTENDED NORTH FROM 
FRONT AT 19Z FROM SOUTHERN IL ACROSS EASTERN IA TO WEAK LOW IN 
SOUTHEAST MN. HIGH PRESSURE RIDGE WAS FROM SOUTHWEST MN TO NORTHEAST 
CO. LAKE ENHANCED NORTHEAST FLOW RUNNING INTO WEAK EASTERN IA 
BOUNDARY CONTRIBUTING TO WIDESPREAD LOW CLOUDS. INITIAL FORECAST 
CHALLENGE IS CLOUD AND PRECIP CHANCES THIS EVENING...THEN PRECIP 
CHANCES FROM WED INTO WEEKEND AS ANOTHER UPPER LOW IN NW FLOW BRINGS 
UNSETTLED WEATHER. 

SHORTWAVE EMBEDDED IN NW FLOW PRODUCING TSRA IN EAST CENTRAL MN
TO NEAR LAKE SUPERIOR REACHES NORTH CENTRAL IL AFTER 06Z NOT TOO FAR 
FROM MID LEVEL VORT MAX POSITION IN MODELS. DIURNAL TIMING AND LACK 
OF INSTABILITY UNFAVORABLE FOR THUNDERSTORMS...BUT MAY BE ENOUGH 
LIFT FOR FEW SHOWERS AND WILL KEEP ISOLATED POPS GOING THERE THROUGH 
MIDNIGHT. WILL ALSO NEED TO ADD LOW POPS FOR EVENING SHOWERS IN 
SOUTHEAST IA AND NORTHEAST MO...WHERE SATELLITE AND KDVN 88D SHOWING 
SHOWERS DEVELOPING ALONG DIFFERENTIAL HEATING BOUNDARY FROM CLOUD 
COVER AND AFOREMENTIONED NORTH TO SOUTH TROF/BOUNDARY. SHORT TERM 
MODELS DISSIPATE THE INVERTED TROF OVERNIGHT WITH RIDGE SHIFTING 
SOUTH OVER AREA. SOME DEGREE OF LOW LEVEL MOISTURE INDICATED TO 
LINGER...WHICH WILL LEAD TO LINGERING CLOUDS OR POSSIBLY FOG AS 
SURFACE DEWPOINTS CURRENTLY ABOVE EXPECTED MINS. BEST FOG POTENTIAL 
APPEARS TO BE ALONG AND SOUTH OF I-80 CORRIDOR IN IL...BUT WITH LOW 
CONFIDENCE IN CLOUD TRENDS...WILL LEAVE OUT OF GRIDS AND LET 
FOLLOWING SHIFTS UPDATE IF FAVORABLE TRENDS DEVELOP. OVERALL...WENT 
WITH DIMINISHING CLOUD COVER OVERNIGHT WITH LOWS ON COOL SIDE OF 
GUIDANCE.

SURFACE RIDGE DOMINATES TUESDAY WITH TEMPERATURES CLOSE TO MODEL 
BLEND IN LOWER 80S. NEXT UPPER WAVE SEEN ON WATER VAPOR CHURNING 
INTO NORTHERN SASKATCHEWAN SHOWN IN MODEL CONSENSUS TO SLIDE SOUTH 
TO UPPER MISS VALLEY AND THEN SPIN IN BLOCKING PATTERN LATE WEEK 
INTO WEEKEND. FIRST RELATED SURFACE FRONT PUSHES THROUGH IN 
WEDNESDAY NIGHT AND THURSDAY TIMEFRAME...THEN ANOTHER THURSDAY 
NIGHT. IN EXTENDED...NOCTURNAL CONVECTION LOOKS A GOOD BET SATURDAY 
NIGHT WITH H85 MOISTURE RETURN. UPPER LOW FINALLY DRIFTS NORTHEAST 
MONDAY HIGH UPPER RIDGE BUILDING INTO SOUTHERN PLAINS FOR WARMING 
TREND AND RESPITE FROM TSRA CHANCES. 

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

$$
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