[LeArc] Forecast Discussion : MLI@ 7/22/02 2:46:30 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 221947
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
245 PM CDT MON JUL 22 2002

INITIAL COLD FRONT NOW EAST AND SOUTH OF CWA WITH HIGH DEWPOINT AIR
LAGGING WELL BEHIND FRONT.  SCATTERED TSRA JUST DEVELOPING ALONG AND
BEHIND FRONT.  ANOTHER AREA OF ELEVATED -RA OVER NRN CWA NEAR 850
BAROCLINIC ZONE APPEARS TO BE GETTING SOME HELP FROM S/W MVNG ACROSS
CENTRAL IA.  MODELS IN GOOD AGREEMENT WITH BROAD SCALE FEATURES
THROUGH MID WEEK.  WNW FLOW DEVELOPS AFTER TROUGH ROTATES THROUGH
REGION TONIGHT.  AT THE SURFACE HIGH PRESSURE MOVES THROUGH GREAT LAKES
PROVIDING REGION WITH A...COMFORTABLE...EASTERLY FLOW TUESDAY AND
WEDNESDAY.

WILL GENERALLY FOLLOW ETA SOLUTION THROUGH WEDENSDAY WHICH SEEMS TO
HAVE A BETTER HANDLE ON CANADIAN AIRMASS MOVING IN.  LOOKS LIKE ETA
INITIALIZED SURFACE HIGH CLOSER TO 12Z ANALYSIS.  WILL HAVE TO KEEP
CHANCE POPS THIS EVENING ROUGHLY OVER SOUTHEAST HALF OF CWA...AND KEEP
AN EYE ON EXTREME EAST/SOUTHEAST FOR SEVERE DEVELOPMENT WHERE AIRMASS
IS VERY UNSTABLE.  SKIES SHOULD CLEAR OVER CWA BY MIDNIGHT AS HIGH
BUILDS INTO WRN MN.  TUESDAY/WEDNESDAY SHOULD BE DRY AND MILD WITH
EASTERLY LOW LEVEL FLOW OVER AREA.  HOWEVER...ON TUESDAY ETA DEVELOPS
WEAK INVERTED TROF OVER SOUTHEAST CWA ASSOCIATED WITH LOW MOVING ALONG
FRONT OVER SOUTHERN IL. ETA SUGGESTS MID 60 TO AROUND 70 DEWPOINTS
POOLING NEAR THE TROUGH...WHICH APPEARS TO BE OVERDONE. HOWEVER...IF
TROUGH DEVELOPS...WILL HAVE TO WATCH FOR CONVECTION WITH STEEP AFTERNOON
LAPSE RATES AND TROUGH PROVIDING SOME LOW LEVEL CONVERGENCE.  NEXT
CHANCE FOR RAIN IS THURSDAY AS S/W AND SURFACE FRONT APPROACH EARLY
THURSDAY.  AVN SHOWING SOME H5 DIFFLUENCE AND GOOD THETA E ADVECTION
HEAD OF SYSTEM. WILL GO WITH CHANCE POPS FOR NOW AND CONTINUE
CHANCE POPS INTO FRIDAY WITH BOUNDARY STALLING JUST SOUTH OF CWA.

EXTENDED (SAT THRU MON)
LONG RANGE MODELS IN AGREEMENT ON BROAD TROF REMAIN OVER NRN TIER OF
STATES WITH E/W ORIENTED UPPER DOMINATING SOUTHERN STATES.  SERIES OF
IMPULSES BRING A COUPLE OF FRONTS THROUGH DURING THE PERIOD MAKING IT
DIFFICULT TO REMOVE THUNDERSTORM CHANCES FOR ANY ONE DAY.  SUCCESSION
OF BOUNDARIES AND CLOUD COVER WILL ALSO MAKE A TRICKY TEMP FORECAST
DURING THE PERIOD.  WILL STAY CLOSE TO GOING FORECAST TEMPS WHICH ARE
IN AGREEMENT WITH MEX NUMBERS.  FOR MONDAY WILL PUSH TEMPS A LITTLE
ABOVE MEX WITH MRF INDICATING AREA UNDER SUSTAINED SWLY FLOW MOST OF
DAY AND H850 TEMPS AROUND +20C.

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

DLF