[LeArc] Forecast Discussion : MLI@ 10/5/02 1:58:12 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 051904
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
200 PM CDT SAT OCT 5 2002

GORGEOUS EARLY FALL AFTERNOON. 18Z SFC/MSAS ANALYSIS SHOWS RIDGE AXIS 
ALONG MISSISSIPPI RIVER. ON BACK SIDE...LLVL SOUTH WINDS
USHERING IN WARMER AIR WITH WARM ADVECTION MID CLOUDS NOTED ON SATELLITE
THROUGH WESTERN AND CENTRAL IA. STRONG DYNAMICAL SYSTEM TO AFFECT
REGION ON SUN PRESENTLY DIVING E/SE THROUGH MT PER LATEST WATER VAPOR IMAGE.
COLD AIRMASS IN CANADA WITH TEMPS THIS MORNING WELL INTO THE 20S AND
TEENS. IT/S THIS COLDER AIR WITH MODIFICATION THAT WILL SETTLE 
IN BEHIND DEPARTING SYSTEM TO BRING COLDEST MORNING THIS EARLY FALL BY MON.

SEVERAL CONCERNS INCLUDING PCPN CHC/TIMING AND POTENTIAL FOR THUNDER WITH
CLIPPER SYSTEM...STRONG POST FRONTAL WINDS SUN AFTERNOON/EVENING...AND
MINS MON MORNING WITH KILLING FROST/FREEZE PROBABLE. 

POTENT SHORTWAVE TO AFFECT MIDWEST AND GREAT LAKES SUN-SUN NIGHT...WITH
160-180M H5 HEIGHT FALL BULLSEYE VICINITY OF LAKE SUPERIOR 00Z MON.
STRONG COLD FRONT TO PUSH ACROSS REGION BY LATE MORNING/EARLY AFTERNOON
WITH DEEPENING SURFACE WAVE LIFTING N/E THROUGH MN AND WI WITH
NEG TILT SHORTWAVE. SOME SNOW IN DEFORMATION THROUGH NORTHERN MN AND WI
WHERE H85 TEMPS DROP TO -6C. THIS COLDER AIR WITH MODIFICATION TO DIVE SOUTH
ON STRONG NORTH TO NORTHWEST WINDS...WITH H85 TEMPS PROGGED BETWEEN
-1C AND -4C 12Z MON SO LOOKS TO BE COLDEST MORNING IN SOME TIME WITH KILLING
FROST/FREEZE. WIND SPEEDS SUN AFTN/EVE COULD APPROACH ADVISORY CRITERIA
FOR A TIME...SIMILAR TO FRI GIVEN STRONG RISE/FALL ISALLOBARIC 
COUPLET. FOR NOW...WILL HIT WINDY IN ZONES WITH STRONG POST FRONTAL MOMENTUM
TRANSFER AND LET MID CREW RE-EVALUATE ADVISORY POTENTIAL. AS FOR PCPN 
BEST DYNAMICS MAINLY PASS NORTH BUT DO GRAZE NORTHERN ZONES...WHILE MOISTURE
LACKING. COULD SEE SOME -RA/--RA IN THE NORTH/WEST AS EARLY AS THIS EVE 
WITH SOME RETURNS SHOWING UP IN WESTERN IA PER KDMX WSR-88D SHIFTING E/NE.
LAPSE RATES BY 12Z SUN PROGGED BETWEEN 6-7C/KM SO CAN/T RULE 
OUT SOME ELEVATED CONVECTION...ESPECIALLY NORTH CLOSER TO BETTER DYNAMICS.
SURFACE RIDGE SETTLES IN BY 12Z MON...WITH READINGS IN THE U20S/L30S 
PROBABLE WITH WINDS DIMINISHING AND SKIES CLEARING. WILL LIKELY NEED HIGHLIGHTS.  

EXTENDED (WED-SAT)...
MODELS FAIRLY CONSISTENT WITH SHORTWAVE ON THU AND FRONTAL ZONE LIFTING NORTH.
WILL ADD SMALL CHC PCPN NORTH WHERE BETTER CHC OF SATURATION WITH DYNAMICS
TO PRODUCE MAINLY -SHRA/--RA. SURFACE RIDGING TO PRECLUDE MENTION ELSEWHERE. 
UPPER FLOW TO TRANSITION FROM NEARLY ZONAL TO SOUTHWEST BY LATE WEEK RESULTING
IN GRADUAL WARMING TREND. TROUGH DEEPENS IN WEST WITH IMPULSES
EJECTING E/NE FROM ROCKIES INTO MIDWEST...DIFFICULT TO TIME THIS FAR OUT.
OVERALL PATTERN SUGGESTIVE OF UNSETTLED/WET WX LATE WEEKEND.
MEX GUIDANCE LOOKS TOO COOL...ESPECIALLY LATE IN THE EXTENDED WHEN COMPARED
WITH MRF BOUNDARY LAYER TEMPS AND GIVEN LLVL SOUTHERLY FLOW...SO WILL
CONTINUE GOING ABOVE BY 1-2 CATS.    

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


M^2