[LeArc] Forecast Discussion : MLI@ 7/25/2003 3:10:59 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 252005
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
305 PM CDT FRI JUL 25 2003

.OVERVIEW...SURFACE HIGH HAS MOVED EAST INTO OHIO VALLEY ALLOWING FOR
SOUTH WINDS OF 15 TO 25+ MPH TO MOVE IN ALONG WITH WARMER AND MORE MOIST
CONDITIONS.  NEXT SYSTEM GATHERING IN NORTHERN PLAINS AND ROCKY MOUNTAIN
REGION.  SATELLITE SHOWS LOTS OF CONVECTION DEVELOPING OVER COLORADO TO
SLIDE TOWARD SURFACE LOW IN SD.  UPPER AIR PATTERN SHOWS ZONAL FLOW TO
CONTINUE WITH SOME MOVEMENT SOUTH OF JET AXIS NEXT 24-36 HOURS TO ALLOW
SURFACE BOUNDARY TO MOVE SOUTH.  DEWPOINTS PUSHING NEAR 70 APPROACHING
IOWA.  LATE SUMMER MONSOON FLOW VERY CONDUCIVE TO GET WRAPPED UP INTO
SURFACE BOUNDARY IN NORTHERN PLAINS TO SUPPORT DECENT CONVECTION NEXT
FEW DAYS.

...ARRIVAL OF POPS AND THEN FRONT THROUGH MONDAY MAIN FORECAST
CHALLENGE...

.DIAGNOSIS (DAYS 1-3)...LATEST INDICATIONS ARE SURFACE FRONT CLOSER
TO GFS/AVN SOLUTIONS WITH PASSAGE SUNDAY.  STILL...MCS SHOULD DEVELOP IN
SOUTH DAKOTA THIS EVENING INTO MINNESOTA WITH PROPAGATION VECTORS
SUGGESTING AREAS NORTH OF HIGHWAY 30 TO RECEIVE DISSIPATING DEBRIS OF
SHOWERS WITH ISOLATED STORM OR TWO.  THEN...BREEZY VERY WARM TO HOT AND
HUMID WITH WINDS PUSHING 30+ MPH ALONG AND WEST OF I-380 BY PM. LOWS
TONIGHT GO ON LOW SIDE OF BLEND AS SE WINDS PUSH HIGHEST DEWPOINTS WEST
OF AREA TIL SATURDAY.  LATEST INDICATIONS STILL ON TRACK FOR CONVECTION
TO DEVELOP OR MOVE IN ALONG AND AHEAD OF SAGGING COLD FRONT SATURDAY PM
WITH BEST CHANCES NORTH  OF I-80. SOME POTENTIAL PER BLEP CALCULATIONS
FOR STRONG 60+ KTS WITH TEMPS NEAR 90 AND 70+ DEWPOINTS AND ISOLATED
TORNADOES POSSIBLE DUE TO BOUNDARY UP TO LOWER END F1 SCALE...OR 60+ KTS
BASED ON 0-1 KM SHEAR ~14 KTS.  AGAIN "CROSSOVER" TEMPS TO WINDS BELOW
50S KTS SUGGEST TO 0CCUR ~02-04Z AS TEMP/DEWPOINTS SLIDE TO/BELOW ~82-83
OVER 72-73F.  SUNDAY APPEARS BEST CHANCE PRECIPITATION AND WENT AS HIGH
ON POPS AS COULD WHILE STILL MEETING NATIONAL DIGITAL FORECAST DATABASE
CONTINUITY (NDFD) GUIDELINES.  MONDAY TO BE INTERESTING AS WAVE TO
DEVELOP ON FRONT WITH SOUTH SECTIONS VULNERABLE FOR NICE SOAKER OF
RAINFALL.  PULLED POPS MONDAY NIGHT AS FRONT SLIDES SOUTH.

.EXTENDED (TUE-FRI)...KEEP WEDNESDAY DRY WITH WEAK SURFACE RIDGE IN
PLACE AND ADDED POPS THURSDAY WITH NEXT SHORT WAVE OUT OF CANADA PER
GFS/UKMET/ECMWF.  MINOR ADJUSTMENTS OF TEMPS OF MEX WHILE STILL
TRYING TO STAY WITHIN NDFD CRITERIA. OVERALL...TEMPS NEAR NORMAL
THROUGH PERIOD.

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

$$

NICHOLS