[LeArc] Forecast Discussion : MLI@ 8/13/2003 3:41:45 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 130839
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
338 AM CDT WED AUG 13 2003

MAIN FORECAST CHALLENGE NEXT FEW DAYS IS CHANCES FOR AFTERNOON 
SHOWERS AND THUNDERSTORMS. SURFACE HIGH WAS CENTERED OVER WI THIS 
MORNING WITH UPPER RIDGE FROM NORTHERN PLAINS TO DESERT SOUTHWEST. 
UPPER LOW HAS SHIFTED FURTHER SOUTH TO EASTERN TX...RESULTING IN MID 
LEVEL FLOW BECOMING MORE EASTERLY ACROSS CWA. 

UNSEASONABLY STRONG 1028 MB HIGH OVER WI MOVES LITTLE TODAY... 
KEEPING LOW LEVEL EASTERLY FLOW GOING. HIGH CENTER AT H85 SHIFTS 
SOUTHEAST IN AFTERNOON...RESULTING IN MORE SOUTHEAST COMPONENT TO 
H85 FLOW AND INCREASE IN MOISTURE. VORT LOBE AT TIP OF INVERTED 
UPPER TROUGH OVER NORTHERN IN AND IL WILL PROVIDE SOME WEAK LIFT IN 
AFTERNOON AS IT DRIFTS W-SW. WITH SIMILAR MOISTURE PROFILE TO 
YESTERDAY AND WEAK LIFT...MORE AFTERNOON CONVECTION EXPECTED. BASED 
ON CURRENT CLOUD TRENDS...SOME STRATUS WILL BE OVER AREA AT 
SUNRISE...BUT MUCH LESS THAN YESTERDAY AND CU SHOULD GET OFF TO AN 
EARLIER START. MUCH LIKE THE PAST FEW DAYS...SHOWERS WILL BE PULSE 
TYPE DUE TO WEAK SHEAR WITH RAINFALL SPOTTY AND THUS WILL INTRODUCE 
AS ISOLATED POPS WITH THUNDER MENTIONED ONLY IN FAR SOUTHEAST ZONES 
WHERE INSTABILITY HIGHEST. WILL HAVE POPS LASTING INTO EARLY 
EVENING AS INVERTED UPPER TROUGH MOVES OVERHEAD. KEPT HIGHS CLOSE TO 
MET GUIDANCE.

ON THURSDAY...INVERTED TROUGH SHIFTS WEST WITH SURFACE HIGH OVER 
LOWER MI. AFTERNOON CONVECTION LOOKS LIKELY AGAIN OVER SOUTHEAST AND 
RAISED POPS TO 30 PERCENT. FRIDAY AFTERNOON COULD ALSO SEE SOME 
DIURNAL PRECIP WITH WEAK FLOW REGIME AND INCREASING BOUNDARY LAYER 
MOISTURE AS SUGGESTED BY GFS QPF...BUT WITH SILENT POPS IN GOING AND 
SURROUNDING GRIDS AT THIS TIME...WILL LET DAYSHIFT GET A BETTER LOOK 
BEFORE INTRODUCING POPS. SIGNIFICANT DIFFERENCES IN MODEL SURFACE 
FEATURES AND THROUGH COORDINATION FOLLOWED ETA SOLUTION FOR WIND 
FIELDS WITH HIGH TO EAST ON FRIDAY. 

FEW CHANGES TO EXTENDED GRIDS WITH CURRENT PACKAGE HAVING GOOD 
HANDLE HAVING ALREADY RAISED TEMPS CLOSER TO NEWER GUIDANCE VALUES 
WITH FLAT UPPER RIDGE OVERHEAD OR JUST TO WEST. LATEST MEDUIM RANGE 
GUIDANCE STILL INDICATES BEST CHANCES FOR PRECIP IN SUNDAY INTO 
MONDAY TIMEFRAME WITH FORECAST AREA IPMACTED BY SHORTWAVE IN STRONG 
ZONAL FLOW JUST TO OUR NORTH.     

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

$$
SHEETS