[LeArc] Forecast Discussion : MLI@ 5/4/2003 4:02:29 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 042100 CCA
AFDMLI

AREA FORECAST DISCUSSION...CORRECTED TO ADD HYDRO INFORMATION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
350 PM CDT SUN MAY 4 2003

MORE CONCENTRATED BAND OF RAIN AND THUNDER EXITING NORTH/EAST BUT
CONTINUED SCATTERED DEVELOPMENT OBSERVED WITH CWA IN ZONE
OF STRONG LIFT WITH H85 FRONT TO OUR SOUTH. 19Z SURFACE ANALYSIS
SHOWS LOW PRESSURE NEAR CONCORDIA KS AT 988MB AND FALLING...WHICH
IS 1-3 MBS DEEPER THAN MODELS. WARM FRONT EXTENDS FROM THE
LOW ACROSS SOUTHWEST MO INTO NORTHEAST AR...WHILE DRYLINE EXTENDS
FROM CENTRAL KS INTO CENTRAL OK. INGREDIENTS COMING TOGETHER
NOW FOR SEVERE WX OUTBREAK IN THE MIDSECTION OF THE COUNTY...AS
ENERGY LIFTS OUT OF THE ROCKIES. REGIONAL RADARS SHOW INCREASE IN
CONVECTION TO OUR WEST AND SOUTH.

GENERALLY FOLLOWED BLEND OF ETA AND UKMET IN SHORT TERM AS THEY HAD
THE BEST HANDLE ON SURFACE LOW IN THE PLAINS. THE SURFACE
LOW IS EXPECTED TO LIFT NORTHEAST AND BE POSITIONED IN THE VICINITY
OF WATERLOO IA 12Z MON. ETA AND UKMET SUGGEST TRIPLE POINT
WILL PASS ROUGHLY FROM SOUTH OF CEDAR RAPIDS TO NEAR FREEPORT IN
ABOUT THE 09Z-15Z TIMEFRAME...THUS EXPECT BULK OF ANY SEVERE WX
SOUTH OF THIS AXIS. THINKING ANY SEVERE THREAT THIS EVENING
WILL BE MAINLY LARGE HAIL IN THE SOUTH...THOUGH SOMEWHAT ISOLATED.
INGREDIENTS LOOK TO COME TOGETHER LATE THIS EVE AND OVERNIGHT
FOR BETTER SEVERE POTENTIAL...THOUGH CLIMO WORKING AGAINST IT.
NONETHELESS...ANTICIPATE A SQUALL LINE RACING E/NE ACROSS AT LEAST
THE SOUTHERN 2/3RDS OF CWA WITH DAMAGING WINDS AND LARGE HAIL.
TORNADO THREAT DIMINISHING AS CLOUDS AND PCPN HAVE KEPT WARM FRONT
AND BEST INSTABILITY FURTHER SOUTH.

FLOODING IS SOMEWHAT OF A CONCERN...BUT MAINLY FOR THOSE AREAS WHICH 
WERE HIT HARD ON WED (LOUISA...MERCER...HENRY...BUREAU AND PUTNAM). 
ALTHOUGH CAN/T RULE OUT SOME MINOR FLOODING ELSEWHERE...BUT
ACTIVITY SHOULD BE MOVING FAST ENOUGH TO PRECLUDE WIDESPREAD PROBLEMS
THUS...WILL HOLD OFF ON ANY HIGHLIGHTS AND CONTINUE MENTION 
OF HEAVY RAIN. 

DRY SLOT WITH SURGE OF WARMER AIR STILL LOOKS TO ROTATE UP ACROSS
MUCH OF CWA LATE TONIGHT AND MON MORNING...IN WAKE OF
CONVECTION. THUS...EXPECT TEMPS TO SLOWLY CLIMB TONIGHT WITH NICE
WARMUP ON MONDAY WITH SOME LOCATIONS SOUTH/EAST PUSHING 80 DEGS.
MODEL SOUNDINGS SHOW UNSTABLE ATMOSPHERE WITH LI/S
PUSHING -3 TO -5 IN THE AFTERNOON AND CAPES ON ORDER OF 1500-2000
J/KG. TRIGGER APPEARS TO BE LACKING OVER MUCH OF AREA THOUGH
WITH SURFACE CONVERGENCE NIL. NORTHERN ZONES WILL BE ON THE EDGE
OF A VORT ROTATING AROUND UPPER LOW OVER MN...WHICH COULD BE ENOUGH
TO TRIGGER SCATTERED CONVECTION ALONG AND NORTH OF I 80.
WILL GO WITH CHC POPS ALONG AND NORTH OF I 80 WITH HIGHEST POPS
NORTH OF HIGHWAY 30. JUST SLIGHT CHC POPS SOUTH. ANY CONVECTION THAT
DEVELOPS WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL AND DAMAGING
WINDS. STEEP LAPSE RATES AND MIXING SUPPORT BREEZY/WINDY CONDITIONS
AS WELL. THEREAFTER...IT APPEARS THE WX WILL BE QUIETING
DOWN WITH ONLY CONCERNS BEING CLOUD COVER AND LOW PCPN CHCS AS
UPPER LOW TO OUR NORTH SLOSHES MOISTURE BACK INTO PORTIONS OF THE
CWA.

EXTENDED (THU-SUN)...
GENERALLY ACTIVE PERIOD. FRONTAL ZONE PROGGED TO OUR SOUTH EARLY IN
EXTENDED. SOUTHWEST UPPER FLOW WILL SEND SEVERAL DISTURBANCES INTO
THE MID MISSISSIPPI VALLEY. LLVL E/NE FLOW WILL MAKE TIMING PCPN
TRICKY...AS TYPICALLY IT TAKES LONGER TO SATURATE IN THIS FLOW
REGIME. EXPECT MAINLY RAIN WITH COOLER...MORE STABLE AIR IN PLACE.
UNDERCUT MEX GUIDANCE ON TEMPS WITH CLOUDS AND LLVL E/NE WINDS.
BROUGHT A BREAK IN THE PCPN ON FRI...BEFORE NEXT DISTURBANCE
INTERACTS WITH FRONTAL ZONE TO OUR SOUTH WITH CHANCE OF RAIN ONCE
OVER THE WEEKEND. CONTINUED GENERALLY BELOW MEX GUIDANCE ON MAXES
INTO SAT...THEN AT OR ABOVE ON SUNDAY WITH SUGGESTIONS
OF FRONT LIFTING THROUGH...THOUGH CONFIDENCE ON THIS HAPPENING IS
QUITE LOW.

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

$$

05