[LeArc] Forecast Discussion : MLI@ 7/6/2003 4:07:52 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 062054
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
350 PM CDT SUN JUL 6 2003

SPOTTY STRONG CONVECTION ON GOING ALONG AND EAST OF THE MS RIVER 
LATE THIS AFTERNOON IN ASSOCIATION WITH MCV OVER CENTRAL WI. NICE 
OUTFLOW SHOWING UP FROM KAWG EAST TO KMLI ON 88D IMAGERY WITH 
VISIBLE SAT IMAGE SHOWING BOUNDARY AS FAR WEST AS
KDMX.  19Z LAPS ANALYSIS SHOWING AIR SOUTH OF BOUNDARY QUITE 
UNSTABLE WITH CAPES AROUND 4000J/KG COURTESY OF LOW TO MID 70 
DEWPOINTS AND TEMPS AROUND 90.  SURFACE OBS ALSO SHOWING GOOD FLOW 
INTO THE BOUNDARY WITH SSW WINDS AROUND 15 KTS AND GUSTS AROUND 
20KTS.  ALSO OF INTEREST IS THE BAND OF CU FROM SOUTHEAST INTO 
NORTHWEST IOWA.  SO FAR NOT MUCH INDICATION OF ANY HAPPENING IN THIS 
VICINITY. HOWEVER CU IS IN A  REGION OF  LOW LEVEL MOISTURE 
CONVERGENCE AND WAA.  BEST 3HR PRESS FALL LOCATED OVER CENTRAL AND 
NW IOWA AT 19Z. WILL HAVE TO WATCH THIS CU FIELD FOR DEVELOPMENT 
THOUGH THE EVENING HOURS.  MID LEVEL S/W MOVING THROUGH SOUTH 
CENTRAL CANADA THIS AFTERNOON NOT PRODUCING MUCH IN THE WAY OF TSRA 
SO FAR.

RATHER MESSY FORECAST THROUGH MID WEEK WITH BOUNDARIES REMAINING IN 
THE AREA THROUGH THE PERIOD AND IMPULSES MOVING ALONG SOUTHERN 
PERIPHERY OF STRONGER MID LEVEL FLOW.  AS A RESULT WILL HAVE ALMOST 
CONTINOUS CHANCE POPS FOR TSRA THROUGH MID WEEK.  FOR TONIGHT...TWO 
AREAS OF CONCERN.  ONE IS THE CU FIELD FROM SOUTHEAST INTO NORTHWEST 
IOWA...THEN THE CONVECTIVE COMPLEX EXPECTED TO DEVELOP OVER THE 
NORTHERN PLAINS AND DIVE SOUTHEAST INTO THE MS VALLEY LATE TONIGHT.  
EXPECT TO SEE SOME TSRA DEVELOPMENT ALONG THE CU FIELD BY MID 
EVENING.  DUE TO THE EXTREME INSTABILITY OVER SOUTHERN HALF OF 
IOWA...IF CONVECTION TAKES OFF IT SHOULD GO QUICKLY TO SEVERE.  ALSO 
WITH AMPLE MOISTURE (KILX 18Z SOUNDING HAD PWS OF 1.6) LOCALLY HEAVY 
RAINS WILL BE POSSIBLE. LATER TONIGHT...COMPLEX EXPECTED TO MOVE OUT 
OF NRN PLAINS AND ACROSS THE NERN HALF OF THE CWA. BECAUSE OF THESE 
TWO ISSUES...WILL INCLUDE SEVERE WORDING FOR MUCH OF CWA TONIGHT. 
THERE STILL SHOULD BE SOME ONGOING CONVECTION IN THE EAST MONDAY  
MORNING. SURFACE BOUNDARY PROGGED TO SETTLE IN OVER CENTRAL/SOUTHERN 
IOWA BY MONDAY AFTERNOON AND REMAIN THERE THRU TUESDAY MORNING.  
THUS HAVE KEPT HIGHEST POPS NORTH OF THE BOUNDARY OVER NORTHERN HALF 
OF CWA.  MODELS SUGGEST THAT BOUNDARY MAY BE FORCED FUTHER SOUTH 
TUESDAY AND HAVE BACKED OFF POPS ACROSS THE NORTH TUESDAY EVENING.  
GFS/ETA SUGGEST THAT SURFACE WAVE WILL DEVELOP ALONG THE BOUNDARY 
TUESDAY NIGHT OVER THE NORTHERN PLAINS AND DROP SOUTHEAST THU 
SOUTHERN  CWA WEDNESDAY NIGHT. IF THIS SCENARIO VERIFIES...WE SHOULD 
SEE ANOTHER ROUND OF SIGNIFICANT SEVERE WX AND HEAVY RAINS.  LATER 
SHIFTS WILL HAVE TO MONITOR FOR POSSIBLE FFA.  

THURSDAY THROUGH SUNDAY
LONG RANGE MODELS ARE IN DECENT AGREEMENT THAT BOUNDARY WILL BE 
FORCED WELL SOUTH OF CWA IN RESPONSE TO RIDGE BUILDING OVER WESTERN 
U.S.  WILL GO WITH DRY FORECAST UNTIL SUNDAY WHEN GFS DRIVES ANOTHER 
FRONT THROUGH THE REGION.


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

$$
DLF