[LeArc] Forecast Discussion : MLI@ 7/30/02 3:12:12 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 300812
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
312 AM CDT TUE JUL 30 2002

QUIET NIGHT TONIGHT WITH WEAK HIGH PRESSURE RIDGE ORIENTED ALONG MS
RIVER AT 07Z.  A FEW SITES REPORTING LOW VISIBILITIES IN FOG...BUT IT
APPEARS TO BE TRANSIENT.  WILL HAVE TO WATCH NEXT HOUR TO DETERMINE
NEED FOR INCLUSION IN FORECAST PACKAGE.  00Z UA ANALYSIS SHOWS ZONAL
FLOW SETTING UP ACROSS  NRN U.S. BEHIND S/W MOVING INTO NERN U.S.

FORECAST FOR TODAY APPEARS TO BE STRAIGHT FORWARD WITH SURFACE RIDGE
MOVES EAST...SETTING UP WEAK RETURN FLOW OVER CWA.  MAIN CONCERN WILL
BE TEMPS...ESPECIALLY WITH FWC SUGGESTING MID 90S MOST AREAS.  THIS
LOOKS TO WARM CONSIDERING WEAK SURFACE WINDS AND LIMITED MIXING.
ALSO...SHOULD SEE DEWPOINTS INCH BACK UP TO AROUND 70 BY THIS
AFTERNOON.  CURRENT FORECAST HAS TEMPS NEAR COOLER MAV NUMBERS...WHICH
LOOK REASONABLE.  THUNDERSTORM THREAT TONIGHT IS IN QUESTION WITH
MODELS SHOWING BEST FORCING NORTH OF CWA.  HOWEVER...MID LEVEL
THICKNESSES SUGGEST THAT STORMS THAT DEVELOP COULD MOVE SE.  SO WILL
CONTINUE CHANCE POPS ACROSS THE NORTHWEST.  CONVECTION SHOULD HAVE A
HARD TIME PENETRATING MID LEVEL CAP OVER SOUTHERN CWA AND WILL CUT
POPS BACK TO SLIGHT CHANCE AND LET DAY SHIFT RE-EVALUATE.

MODELS SHOW SOME DISAGREEMENT WITH TIMING OF FRONT MOVING THROUGH
THURSDAY.  ETA/AVN SUGGEST FRONT WILL BE ALL THE WAY THROUGH CWA BY
MID MORNING THURSDAY.  ON THE OTHER HAND...30/00Z UKMET HOLDS BOUNDARY
OVER NORTHWEST CWA AT 12Z THURSDAY.  DUE TO TIMING DISCREPANCIES AND
PRESENCE OF CAP OVER SOUTHERN CWA WILL CUT POPS BACK TO CHANCE
CATEGORY.  TIMING DIFFERENCES CONTINUE INTO WEEKEND WITH AVN
SUGGESTING NEXT FRONT WILL MOVE THROUGH SATURDAY...WHILE UKMET/ECMWF
HOLDS SYSTEM BACK UNTIL SUNDAY.  CURRENT PACKAGE IS IN LINE WITH SLOWER
UKMET/ECMWF SOLUTIONS...AND WILL NOT CHANGE AT THIS TIME.


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

DLF