[LeArc] Forecast Discussion : MLI@ 9/29/02 2:13:19 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 290717
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
215 AM CDT SUN SEP 29 2002

...UNSEASONABLE WARMTH NEXT COUPLE OF DAYS WITH SUMMERLIKE HEAT...

00Z UA ANALYSIS SHOWS H85 WARM FRONT DRAPED FROM SOUTHEAST NE INTO NORTHERN IL. 
WATER VAPOR IMAGERY SHOWS SEVERAL SHORTWAVES IN SOUTHWEST UPPER FLOW. 
LEAD SHORTWAVE INTERACTING WITH FRONTAL ZONE AND THETA-E ADVECTION TO IGNITE
ELEVATED CONVECTION OVER NORTHEAST IA. SECOND SHORTWAVE LIFTING 
INTO PLAINS TRIGGERING ADDITIONAL ELEVATED CONVECTION INTO SOUTHEAST NE SHIFTING
INTO WESTERN IA ATTIM. 

SHORT TERM CONCERNS REVOLVE AROUND ELEVATED CONVECTION AND UNSEASONABLY WARM
TEMPS...THEN FOCUS SHIFTS TO LOCATION OF FRONTAL ZONE ON TUE AND ASSOCIATED
PCPN CHCS AND TEMPS. 

LATEST IR SATELLITE IMAGE SHOWS CLOUD TOPS COOLING WITH EASTERN NE CONVECTION.
SHORTWAVE AIDING CONVECTION PROGGED TO LIFT E/NE. PVA AND STRONGEST THETA-E
ADVECTION SHIFTS FROM SOUTHWEST IA INTO NORTHEAST IA BY 18Z 
ROUGHLY ALONG A RDK-DSM-DBQ LINE. BASED ON THIS WILL HAVE HIGHEST POPS NORTH.
PCPN THREAT LOOKING MEAGER IN THE SOUTH AND LEANING TOWARD KEEPING
DRY FORECAST...BUT WILL CONTINUE TO MONITOR RADAR TRENDS FOR ANY CHANGES TO
THIS THINKING. 00Z MON FRONT EXPECTED TO LIE NORTH OF REGION
ROUGHLY ALONG THE IA/MN BORDER INTO SOUTH CENTRAL WI. INSTABILITY INCREASES
THIS AFTN WHILE LAPSE RATES STEEPEN...BUT FOCUS LOOKS TO SHIFT JUST TO OUR NORTH
WITH FRONTAL ZONE WHILE CAP SUPPRESSES CONVECTION POTENTIAL OVER REGION.
BIG STORY WILL BE HEAT. GIVEN PROGGED H85 TEMPS AND DEVELOPING LLVL SOUTHWEST 
WIND SHOULD BE EVEN WARMER TODAY WITH TRAJECTORIES SUGGESTING 
U80S TO AROUND 90 DEGS CENTRAL/SOUTHERN SECTIONS. MET VERIFIED BEST YESTERDAY
AND WILL LEAN TOWARD NEXT COUPLE OF DAYS WITH THERMAL RIDGE.
CLOUDS/NO CLOUDS WILL HAVE BIG IMPACT ON TEMPS...CASE IN POINT SAT MAXES.
SO TEMPS TRICKY ACROSS NORTH TODAY WHERE CONVECTION EXPECTED.
HOWEVER...ANY SUNSHINE AND TEMPS WILL TAKE OFF AS AGAIN WE SAW YESTERDAY GIVEN
STRENGTH OF ADVECTION AND MIXING. 

TONIGHT...SOME CONCERN FOR SOME CONVECTION GRAZING FAR NORTHERN COUNTIES.
HOWEVER...IT APPEARS BEST FORCING AND INSTABILITY FOCUS TO OUR NORTH 
OVER FAR NORTHERN IA/SOUTHERN MN AND SOUTHERN WI IN VICINITY OF FRONTAL ZONE
WITH CORFIDI VECTORS SHOWING NE MOVEMENT...HENCE WILL CONTINUE
DRY FORECAST. 

MODELS OFFER TIMING DIFFERENCES ON NEXT FRONTAL ZONE WITH ETA QUICKEST.
GIVEN SOUTHWEST UPPER FLOW WILL SIDE TOWARD SLOWER AVN/UKMET BLEND WHICH STALL
BOUNDARY TO OUR NORTH SHORTWAVE AND ASSOCIATED SURFACE LOW LIFT E/NE
FROM PLAINS. PATTERN LOOKS SIMILAR TO THAT OF TONIGHT...WHERE BEST CONVECTIVE
POTENTIAL WOULD BE ACROSS THE NORTH. IN ANY EVENT WILL BUMP UP TEMPS 
FEW DEGS AND LET DAY CREW RE-EVALUATE.  

AS WAVE PASSES...FRONT ACCELERATES SOUTHWARD THROUGH MUCH OF REGION DAYBREAK
WED. AVN GENERATES DECENT QPF THU WITH INVERTED TROUGH.
CURRENT FORECAST DRY. WON/T BITE ON ONE MODEL RUN AND WILL CONTINUE DRY AND
PASS CONCERNS ON TO DAY CREW.  


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