[LeArc] Forecast Discussion : MLI@ 7/24/2003 4:34:29 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 240931
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
430 AM CDT THU JUL 24 2003

COOL START AGAIN THIS MORNING WITH GOOD RADIATIONAL CONDITIONS WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES. RECORD LOWS WOULD APPEAR TO 
BE SAFE MOSTLY DUE TO EVAPOTRANSPIRATION WITH DEWPTS POOLING IN THE 
L/M 50S. 00Z ANALYSIS SHOWS RIDGING CONTINUING OVER WESTERN
CONUS...WITH NORTHWEST FLOW ALOFT OVER NATION/S MIDSECTION. EASTERN
TROUGH SHOWING SIGNS OF LIFTING OUT WITH JET ENERGY NOW ON THE
EASTERN SIDE AND HEIGHT RISES BUILDING INTO THE MID MISSISSIPPI 
VALLEY. BARRAGE OF SHORTWAVE ENERGY MOVING THROUGH SOUTHWEST AND SOUTH
CENTRAL CANADA ALSO FORCING EASTERN TROUGH TO LIFT OUT. 
END RESULT WILL BE WARMING TREND THROUGH THE END OF THE WEEK WITH
INCREASE IN MOISTURE/HUMID CONDITIONS. 

LITTLE CONCERN IN SHORT TERM WITH MAINLY TEMP FORECAST...WITH CONCERNS
FOCUSED PRIMARILY ON TIMING OF FRONTAL ZONE SAT AND ASSOCIATED 
PCPN CHCS AND SEVERE POTENTIAL. 

SHORT TERM...
VORT MAX OVER MT WILL MOVE SOUTHEAST WITH THE FLOW DURING THE DAY.
CU RULE SUGGESTS SCT CU DEVELOPING LATE MORNING. SOME CONCERN THAT 
INCOMING VORT MAX COULD ENHANCE COVERAGE WITH HIGH CLOUDINESS.
REVIEW OF SATELLITE FROM EARLY AFTERNOON ON WED SHOWED SCT TO FEW BKN
CU TO OUR NORTH/WEST. WITH ALL BEING SAID...WITH LEAN TOWARD
MOSUNNY START THEN PTCLDY LATE MORNING AND AFTN. LIMITED MIXING WITH 
HIGH SUGGESTS LEANING TOWARD LOWER END OF GUIDANCE...WITH TEMPS
2-4 DEGS WARMER THAN MAXES ON WED WITH BIT MORE SOLAR INSOLATION. 

FRI NIGHT FRONT PROGGED FROM NORTH CENTRAL WI INTO SOUTHWEST NE.
STRONG CAP SHOULD SUPPRESS CONVECTION TIL EVE ALONG 
FRONT WHEN STRONG LLJ OF 40-50 KTS KICKS IN. INITIATION WOULD APPEAR TO
BE VICINITY OF SOUTHEAST SD...SOUTHWEST MN...NORTHWEST IA AND
NORTHEAST NE WHERE LLVL CONVERGENCE MAXIMIZED WITH SURFACE LOW NEARBY.
STRONG UPPER LEVEL DIFFLUENCE AND LLJ SHOULD FUEL CONVECTIVE
COMPLEX AS IT PROPAGATES SOUTHEAST ON COOL SIDE OF H85-H7 THERMAL 
GRADIENT WHICH 06Z META SHOWS LYING ACROSS CWA. IF META SOLUTION WERE
TO VERIFY THEN WOULD NEED TO INCREASE POPS ESPECIALLY NORTH
FOR POTENTIAL LATE MATURE-DISSIPATING MCS. LOT OF VARIANCE THOUGH IN
MODEL SOLUTIONS WITH MOST SUGGESTING STRENGTHENING MID LEVEL CAP AND
FURTHER NORTH FRONTAL POSITION...THEREBY LIMITING CONVECTION POTENTIAL.
DUE TO UNCERTAINTIES AND TO STAY WITHIN NDFD REQUIREMENTS HAVE 
KEPT PREVIOUS SHIFTS TIER OF POPS LATE FRI NIGHT WITH HIGH CHC IN THE
NORTH.   ..05..

.LONGER RANGE(SAT-WED)...XGFS AND ETA VARY A BIT ON EXTENT OF FRONT 
LAYING OUT IN A NORTHEAST-TO-SOUTHWEST FASHION FROM WI THROUGH 
CENTRAL IA ON SAT...WITH ETA FURTHER TO THE SOUTHEAST. GFS AND ECMWF 
FURTHER NORTH WITH RIDGE AXIS FROM THE CENTRAL PLAINS INTO SOUTHWEST 
IN...AND THUS FURTHER NORTH WITH INCOMING BOUNDARY. BUT SOLUTIONS 
ARE CLOSE ENOUGH TO SUGGEST FEATURE WILL INTERMINGLE WITH ROBUST 
CAPES AND THTA-E ADVECTION AND CONVERGENCE FOR CONTINUED STORM 
THREAT. TEMPS MAY VARY WIDELY FOR HIGHS SAT WITH POTENTIAL OF 
ONGOING STORM CLUSTERS AND CONVECTIVE DEBRIS...AROUND 80 TO UPPER 
80S. ONGOING MID 80S FOR MOST OF THE CWA MAY BE BEST HAPPY MEDIUM. 
LATEST MEDIUM RANGE MODELS CONTINUE TO SHOW DISCREPANCIES ON 
SOUTHWARD EXTENT OF FRONTAL PROGRESSION ON SUNDAY...BUT AT LEAST 
SOUTHERN CWA STILL TO BE UNDER THE INFLUENCE AND IN LINE OF SLIGHTLY 
ELEVATED CONVECTIVE THREAT JUST TO THE NORTH OF THE FRONT. CYCLONIC 
NORTHWEST FLOW ALOFT AND SFC RIDGING OVER MUCH OF THE HEARTLAND TO 
RULE EARLY NEXT WEEK. THIS NORTHWEST FLOW TO USHER IN DISTURBANCES 
...BUT DEFINITE UNCERTAINTIES THERE ON LLVL BOUNDARIES AND MOISTURE 
ON WHICH TO ACT UPON FOR SHOWER AND STORM CHANCES.  WILL KEEP 
ONGOING CHANCES FOR MON...BUT TUESDAY NOW LOOKING TO BE IN-BETWEEN 
DAY WITH COOLING NORTHEAST FLOW OFF RIDGE AXIS. PORTIONS OF THE 
NORTHEAST CWA MAY NOT GET OUT OF THE 70S. NEW MRF AND LATEST ECMWF 
WAVE EXTRAPOLATION DOWN IN NORTHWEST FLOW PAST 168 HRS SUGGEST 
PRECIP CHANCE MAY NOW BE WARRANTED FOR WED.    ..12..

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

$$