[LeArc] Forecast Discussion : MLI@ 5/5/2003 4:22:39 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 052108
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
400 PM CDT MON MAY 5 2003

SURFACE LOW POSITIONED OVER SOUTH CENTRAL WI EARLY THIS AFTERNOON WITH
TROUGH EXTENDING WESTWARD INTO EASTERN SD. RADAR MOSAIC 
SHOWS SHOWER ACTIVITY CONFINED TO THE VICINITY OF TROUGH AND LOW. 
ABUNDANT MOISTURE WRAPPING AROUND LOW RESULTING IN EXTENSIVE CU FIELD 
OVER THE NORTHERN HALF OF CWA WITH DIURNAL CU ACROSS THE SOUTH.
FURTHER WEST...RADAR MOSAIC SHOWS PRECIPITATION DEVELOPING OVER PORTIONS
OF SD. UPPER LEVEL PLOTS REVEAL LOW OVER WI AND SECONDARY LOW IN
NORTHERN HIGH PLAINS WITH SOUTHWEST FLOW DOMINATING REGION.
HEIGHT FALLS OVER NORTHERN ROCKIES AND GREAT BASIN WITH SPLIT FLOW 
RESULTING IN PHASING ISSUES AND SOMEWHAT LOW CONFIDENCE ON PCPN 
THREAT FOR THE AREA LATE TUE-TUE NIGHT.  

NEAR TERM...LOW CLOUDS SHOULD THIN AND LIFT NORTH AS LOW SHEARS AND
LIFTS THROUGH THE GREAT LAKES. ANY SHOWERS APPEAR WILL STAY NORTH
CLOSER TO TROUGH AND LOW...SO WILL REMOVE PCPN CHCS. 

SHORTWAVE DRIVING PCPN IN SD AND NORTHERN NE TO DIVE E/SE. MOISTURE RETURN 
LIMITED ON TUE...WITH MOST OF THIS ENERGY PASSING SOUTH 
WHERE POTENTIAL WILL EXIST FOR SHOWERS. MOISTURE ADVECTION AND SHORTWAVE
ENERGY LIFTING OUT OF THE SOUTHWEST TUE NIGHT TO INTERACT WITH
FRONTAL ZONE IN THE LOWER MISSISSIPPI VALLEY TO LIKELY PRODUCE MCS. 
THIS SHOULD STAY TO OUR SOUTH...ALTHOUGH ETA AND GFS TO LESSER EXTENT
INDICATES UPPER LEVEL DIVERGENCE WITH COUPLING OF JETS AND WEAK SHORTWAVE. 
MOISTURE RETURN SOMEWHAT LIMITED...THOUGH ETA PROGGING DEWPTS IN L-M 50S.
LEANED TOWARD MET/GFS POPS AND INTRODUCED CHC POPS SOUTHERN HALF OF 
CWA. 18Z META SUFFERS BADLY FROM CONVECTIVE FEEDBACK ISSUES AS IT IS 
GENERATING 1 TO 1.5 INCHES NEAR IOWA AT 09Z WED.

SHORTWAVE PASSES EAST EARLY WED WITH HIGH BUILDING IN RESULTING IN 
SLIGHLY COOLER TEMPS. 

NEXT PIECE OF ENERGY LIFTS OUT LATE WED NIGHT AND THU WITH SAME
SCENARIO OF CONVECTION TO OUR SOUTH ALONG FRONT.
EAST/NORTHEAST WINDS MAY KEEP PCPN AT BAY UNTIL LATER IN DAY ON THU
WHEN STRONG UPPER DIFFLUENCE KICKS IN. WENT SEVERAL DEGS
COOLER THAN MEX GUIDANCE FOR MAXES.

EXTENDED (FRI-MON)...

QUITE ACTIVE AND UNSETTLED PERIOD...WITH DIFFICULTY NAILING DOWN 
DRY TIME. PATTERN OF LATE HOLDS THROUGH THE EXTENDED WITH 
SOUTHWEST UPPER FLOW AND SERIES OF IMPULSES INTERACTING 
WITH WAFFLING FRONTAL ZONE OVER MISSISSIPPI VALLEY...WITH POTENTIAL
FOR A COUPLE OF ROUNDS OF SEVERE WX AND HEAVY RAIN. FAVORED BLEND
OF UKMET AND ECMWF MODELS. WARM FRONT PROGGED TO LIFT NORTH 
EARLY ON FRI WITH COLD FRONTAL PASSAGE QUICK ON IT/S HEELS. NEXT 
DISTURBANCE LIFTS OUT OVER WEEKEND AND WILL CONTINUE RAIN CHANCES.
WILL GO WITH DRY CONDITIONS LATE SUN AND MON BEING BETWEEN 
SYSTEMS. 

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

$$