[LeArc] Forecast Discussion : MLI@ 3/17/03 2:07:07 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 170815 CCA
AFDMLI

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1250 AM CST MON MAR 17 2003

SYNOPSIS...
ACTIVE REGIME ACROSS CONUS. SHORTWAVES LOCATED IN WI...MID/LOWER MISSISSIPPI
VALLEY. MEANWHILE...UPPER LOW CHURNING IN SOUTHWEST STATES.
POSITION OF JET SUGGESTS LIMITED CONVECTION POTENTIAL WITH MAIN SEVERE WX
EXPECTED FROM SOUTHERN PLAINS THROUGH LOWER MISSISSIPPI VALLEY NEXT 
COUPLE OF DAYS. MUCH WARMER START THIS MORNING WITH MOST AREAS IN THE U40S
TO L50S AT 06Z WITH PATCHY LIGHT FOG.  

TODAY...
SEVERAL ITEMS OF INTEREST. FIRST IS SHORTWAVE MOVING THROUGH WI.
SURFACE REFLECTION DEPICTED BY WEAK WAVE OF LOW PRESSURE IN SOUTHEAST MN.
POSITIVE VORTICITY ADVECTION IN COMBINATION WITH THETA-E RIDGE
EXTENDING FROM KOSH-KDLL-KMRJ RESPONSIBLE FOR SCTD SHOWERS/TSTMS IN
SOUTHERN/EASTERN WI. POTENTIAL FOR DEVELOPMENT FURTHER SOUTH INTO
NORTHEAST IA AND NORTHWEST IL AS THIS REGION BRUSHED BY PVA AND IN CLOSE
PROXIMITY TO THETA-E RIDGE. NEXT ITEM OF INTEREST IS WEAK VORT MAX
LIFTING THROUGH NORTHWEST MO. SATELLITE SUGGESTS MODELS HAVE DECENT HANDLE
WITH VORT MAX PASSING WEST OF CWA THOUGH SOME PVA DEPICTED 
GLANCING THE WESTERN ZONES...THUS WILL BE MONITORING FOR DEVELOPMENT 
OF ISOLD SHOWERS THIS MORNING MAINLY ALONG AND WEST OF KCID-KAWG LINE. 
MODELS DEPICT BACK DOOR COLD FRONT FROM LAKE MI DEVELOPING THIS AFTN WITH
SOME DISCREPANCIES ON PLACEMENT. OVERALL FAVOR PLACEMENT OF GFS/UKMET
WHICH SUGGEST CHC POPS NORTH OF I-80 THIS AFTN WITH LLVL CONVERGENCE.
ELSEWHERE...ISOLD SHOWERS AND COUPLE STORMS POSSIBLE WITH
MODELS SOUNDINGS SHOWING CONVECTIVE TEMPS NR 70 TO LOWER 70S DEPENDING
ON MODIFICATION. THUS LEANING TOWARD SLIGHT CHC POPS ELSEWHERE.
TEMPS CHALLENGING. TRAJECTORIES SUGGEST SIMILAR READINGS TO YESTERDAY WITH
READINGS PERHAPS FEW DEGS COOLER IN THE NORTH. 

TONIGHT...
BACK DOOR COLD FRONT FROM LAKE MI TO SWING THROUGH CWA WITH WINDS BECOMING
NORTHEAST. LLVL CONVERGENCE AHEAD OF FRONTAL ZONE WARRANTS CHC POPS
HOWEVER...FEW MODELS INDICATE VORT MAX TO LIFT NORTH THROUGH MID MISSISSIPPI
VALLEY INTO AREA LATE. THUS POTENTIAL FOR MORE COHERENT AND ORGANIZED PCPN.
BUT FOR NOW...WILL UP POPS INTO CHC CAT AND LET DAY SHIFT RE-EVALUATE.
POTENTIAL FOR AREAS OF FOG ESPECIALLY LATE AND NORTH.
TEMPS AGAIN CHALLENGING. MODELS TYPICALLY FEW DEGS TOO WARM IN THIS REGIME
THUS WILL LEAN TOWARD COOLER FWC GUIDANCE.

TUESDAY...
VORT MAX LIFTS THROUGH AREA. EXPECT LOW CLOUDS/FOG/DRIZZLE WITH AREAS OF RAIN
DUE TO DEPTH OF COLD AIR WHICH ALSO SUGGESTS STRATIFYING THUNDER SOUTH.
CLOUDS...PCPN AND LLVL NORTHEAST WINDS TO LIMIT TEMP RISE.
META 2M TEMPS (L-M60S) WAY TOO WARM AND DISCARDED...AS USUALLY THE CASE IN
ACTIVE WX. WILL SIDE TOWARD BLEND OF FWC/GFS.

TUESDAY NIGHT...
MORE OF THE SAME...LOW CLOUDS/FOG/DRIZZLE AND AREAS OF RAIN.
 
WEDNESDAY...
MODELS INDICATE INVERTED TROUGH TO SET UP OVER REGION...ONE OF I/M SURE
HALF DOZEN OR MORE TIMES WE/LL SEE THIS FEATURE THIS SPRING. 
THIS CONDUCIVE FOR WIDESPREAD PCPN...AND WILL GO WITH CATEGORICAL POPS.
SURFACE SYSTEM OCCLUDES TO OUR SOUTH. THIS COUPLED WITH JET 
WELL SOUTH SUGGESTS THUNDER THREAT MINIMAL WITH REGION IN COLD CONVEYER BELT
THUS WILL GO TYPICAL RAIN WORDING. TEMP RISES AGAIN LIMITED WITH CLOUDS
AND PCPN. LOOKS TO BE A NASTY/RAW/DISMAL DAY. 

NO BIG CHANGES TO EXTENDED ATTIM. THURSDAY WILL HAVE TO BE WATCHED FOR INCREASE
IN POPS WITH OCCLUSION PASSING JUST SOUTH. 


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

$$

M^2