000
FXUS63 KMKX 080857
AFDMKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
357 AM CDT MON SEP 8 2008
.SHORT TERM...A STRONG SHORTWAVE TROUGH IS CURRENTLY OVER NRN WY
WITH MID LEVEL FRONTOGENESIS AND RAINFALL EXTENDING EWD OVER NE
AND WRN IA. MODELS STILL BRING SHORTWAVE AND STRONGEST MID LEVEL
FRONTOGENESIS DIRECTLY ACROSS SRN WI THIS AFTERNOON AND EVENING.
GFS CONTINUES TO OVERSPREAD ALL OF CWA WITH APPROXIMATELY 0.60 TO
0.80 INCHES OF RAIN WITH THE UKMET SIMILAR IN COVERAGE BUT LESS
WITH QPF. THE ECMWF...NAM...AND NGM ALL FOCUS MOST OF QPF IN THE
SRN CWA WITH VERY LITTLE IN THE NORTH.
FOR THE MOST PART THOUGH MODELS AGREE ON PLACEMENT AND TRACK OF
SHORTWAVE AND ASSOCIATED FRONTOGENESIS AND LIFT. CROSS SECTIONS
SHOW IMPRESSIVE SLOPING FRONTOGENESIS AND ISENTROPIC LIFT FROM
SOUTH TO NORTH ACROSS THE REGION. LACK OF QPF ON SOME OF THE
MODELS IN THE NORTH IS DUE TO DRIER AIR FROM 850 MB AND BELOW BUT
STRONG LIFT ABOVE AND EXPERIENCE SUGGESTS THIS LAYER SHOULD EASILY
SATURATE WITH WIDESPREAD RAIN STILL EXPECTED OVER ALL OF REGION.
DID LOWER QPF AMOUNTS TO AROUND 0.25 INCHES IN THE FAR NRN CWA TO
0.60 INCHES IN THE FAR SOUTH BUT WILL LEAVE SOME ROOM FOR MORE
RAIN AT LEAST IN THE SOUTH. WITH PASSAGE OF SHORTWAVE TROUGH IN
THE EVENING...DAVA AND CAA KICK IN WITH SUBSIDENCE AND DRYING
EXPECTED OVER ALL OF REGION BY 06Z.
LARGE HIGH PRESSURE WILL THEN PREVAIL OVER THE CENTRAL USA AND WRN
GREAT LAKES TUE AND INTO EARLY WED WITH RELATIVELY WEAK ZONAL FLOW
ALOFT. A RELATIVELY COOL AND DRY AIRMASS WILL BE IN PLACE.
.LONG TERM...
THE LARGE HIGH PRESSURE AREA WILL SHIFT EWD ON WED AS AN UPPER
TROUGH OVER THE PACIFIC NW BEGINS TO PROGRESS EWD. SLY WINDS
BETWEEN THE DEPARTING HIGH AND DEVELOPING LEE SIDE TROUGH OVER THE
HIGH PLAINS WILL BEGIN A PERIOD OF WARM ADVECTION THAT WILL CARRY
INTO THU AHEAD OF A COLD FRONT. A CHANCE OF SHOWERS AND TSTORMS
WILL EXIST LATE WED NT AS WAA AND THETAE ADVECTION MAY TRIGGER
SOME STORMS. THE COLD FRONT WILL THEN BRING A GOOD CHANCE OF PCPN
THU INTO THU EVENING.
&&
.AVIATION...EXPECT -RA TO SPREAD BACK INTO SRN WI LATER THIS MRNG AS
MID LEVEL DEFORMATION AREA AND ENHANCED FORCING FROM FN VECTOR
RESPONSE TO 2D FULL WIND FRONTOGENESIS INCREASES. -RA SHOULD
EVENTUALLY LOWER CIGS AND VSBYS TO MVFR AND POSSIBLY IFR FOR A TIME
THIS AFTN AS BEST FORCING MOVES THRU. EXPC CLEARING TNGT WITH
POTENTIAL FOR LIGHT FOG AT KMSN LATE.
&&
.MARINE...WILL HOLD OFF ON ISSUING SMALL CRAFT ADVY AT THIS TIME DUE
TO UNCERTAINTY OF AMOUNT OF STRENGTHENING OF LOW PRESSURE ALONG
FRONTAL BOUNDARY TO THE SOUTH OF LAKE MICHIGAN THIS AFTN/EVE AND
RESULTANT PRESSURE GRADIENT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
SHORT/LONG TERM...20
AVIATION/MARINE...11
