[LeArc] Forecast Discussion : MLI@ 6/6/02 1:57:25 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 061856
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
150 PM CDT THU JUN 6 2002

MAIN FORECAST CHALLENGES NEXT FEW DAYS REVOLVE AROUND IMPACTS OF WET GROUND
AND EVAPORATION ON TEMPS...AND PCPN CHCS NORTH.

MORNING UA ANALYSIS SHOWS DIFFLUENT FLOW ALOFT OVER NORTHERN PLAINS
AND UPPER MIDWEST IN ADVANCE OF APPROACHING 
UPPER JET MAX AND ASSOCIATED SHORTWAVE ENERGY. 18Z SFC/MSAS ANALYSIS 
SHOWS HIGH PRESSURE OVER SOUTHERN WI. REGIONAL VISIBLE SATELLITE
PICS SHOW AREA OF LOW CLOUDS IN CENTRAL/EASTERN IL WITH LAKE FETCH ON
NORTHEAST LLVL WINDS. MEANWHILE...TROUGH/WEAK FRONT EXTENDS
FROM CENTRAL ND INTO WESTERN NE. THIS WILL BE FOCUS FOR SOME THUNDERSTORM
DEVELOPMENT LATE PM/EVE.

NEAR TERM...SURFACE HIGH WILL SLOWLY RETREAT INTO MICHIGAN WITH 
LLVL FLOW BECOMING SE ALL AREAS. THIS POSES CONCERNS 
WITH LOW CLOUDS OVER CENTRAL/EASTERN IL POSSIBLY MOVING BACK INTO 
PORTIONS THE AREA...ESPECIALLY IN A ZONE 
FROM BURLINGTON TO CEDAR RAPIDS. NO SURPRISE MODELS NOT HANDLING
LOW CLOUDS WELL...SO WILL MAKE LAST MINUTE DECISION ON
SKY COVER BASED ON SATELLITE TRENDS. CONVECTION EXPECTED TO DEVELOP ON
SURFACE TROUGH WITH UPPER FLOW STEERING CONVECTION 
INITIALLY TO THE EAST...THEN EVENTUALLY A LITTLE SOUTH OF EAST.
DON/T SEE THREAT FOR ANYTHING SNEAKING IN TO THE NORTHWEST LATE TONIGHT
OR FRI MORNING WITH REGION STILL UNDER INFLUENCE OF RIDGING
AND DRIER AIR. 

ON FRI...SOME DEBRIS CLOUDINESS MAY MOVE ACROSS THE REGION 
ESPECIALLY NORTH. OTHERWISE...LOOKS LIKE ANOTHER GORGEOUS DAY WITH
TRANQUIL CONDITIONS. MAX TEMPS WILL BE TRICKY...WITH
SOME IMPACT STILL LIKELY FROM WET GROUND...IMPEDING SOME WARMING WITH
INSOLATION GOING INTO EVAPORATION. IMPACTS SHOULD NOT BE
AS GREAT AS TODAY WITH TRAJECTORY SE AND FULL DAY OF DRYING...BUT
STILL LEANING A FEW DEGS BELOW GUIDANCE IN MOST FAVORED
LOCATIONS FROM FREEPORT...TO THE QUAD CITIES...TO PRINCETON.
ELSEWHERE...SIDING NEAR BLEND OF MAV/FWC GUIDANCE.
CONVECTION EXPECTED TO FIRE ONCE AGAIN LATE PM/EVE ALONG TROUGH FROM
SOUTHERN MN INTO CENTRAL NE. SAME SITUATION...AS IT DOESN/T
LOOK GREAT FOR PCPN SNEAKING INTO THE NORTH WITH DRIER AIR STILL
INFILTRATING REGION FROM GREAT LAKES SURFACE HIGH.
CONVECTION ADVANCING TOWARD CWA SHOULD DIMINISH WITH TIME AS IT OUTRUNS
BETTER FORCING AND MOISTURE...THUS WILL STICK WITH DRY FCST.

ON SAT...POTENTIAL FOR SOME OUTFLOW FROM PREVIOUS CONVECTION TO SET
UP BOUNDARY JUST TO THE NORTH. BUT APPEARS FOCUS WILL BE
SHIFTING BACK NORTH ALONG WITH MAIN SYNOPTIC BOUNDARY WITH LLVL SOUTH
WINDS. THEREFORE WILL CONTINUE DRY FCST. EARLIER LOOKED 
AS THOUGH FRONT/TROUGH COULD SNEAK INTO THE NORTHERN ZONES ON SAT BUT
OLD RULE OF THUMB APPLIES...IF FRONT REACHES SOUTHWEST NE
(MCCOOK...IMPERIAL) THEN IT WILL REACH ATLEAST THE NORTHERN ZONES
NEXT 24 TO 36 HOURS. AS FOR TEMPS...GRADUAL WARMING WITH
LESS IMPACT FROM EVAPORTIAN AND WET GROUND. 
THIS TREND TO CONTINUE INTO SUN...WITH TRANSITION TO MORE SUMMERLIKE
REGIME AHEAD OF UPPER TROUGH DEEPENING IN THE WESTERN STATES.

EXTENDED (MON-THU)
MEDIUM RANGE MODELS IN BETTER AGREEMENT ON LIFTING ROCKIES TROUGH
NORTHEASTWARD THROUGH NORTHERN PLAINS AND UPPER MIDWEST 
BY MIDWEEK. HOWEVER...SOME DIFFERENCES EXIST WITH REGARD TO TIMING 
OF FRONTAL PASSAGE. AVN HAS MOVED UP THE TIMING LAST FEW RUNS.
HOWEVER...WITH MAIN ENERGY LIFTING NORTH...THINK FRONT WILL SLOWLY 
PASS ACROSS REGION TUE...THUS WILL FOLLOW SLOWER UKMET.
BELIEVE MODELS ARE PUSHING FRONTAL ZONE TOO FAR SOUTH OF REGION 
BY THU. IT IS THAT TIME OF YEAR WHERE FRONT/S HAVE
MORE DIFFICULTY PUSHING WELL SOUTH. WILL TRY AND DRY THINGS OUT WED 
THEN BRING IN CHC OF PCPN THU WITH THE IDEA THAT THE FRONT WILL BE TRYING
TO LIFT BACK NORTH. 

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

MCCLURE