000
FXUS63 KGRB 272024
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
324 PM CDT WED AUG 27 2008
.SHORT TERM...TONIGHT AND THURSDAY
QUESTION OF FORECAST IS PCPN CHANCES WITH PASSAGE OF COLD FRONT
CURRENTLY OVER NORTHEAST MN. FRONT MOVING SLOWLY EAST AS UPPER
FLOW PARALLEL TO FRONT. FRONTAL PASSAGE EXPECTED THU
AFTN/EVE...DRIVEN EAST BY SHORT WAVE NOW MOVING THROUGH HIGH
PLAINS.
MODELS HIGHLIGHT TSTM COMPLEX TO FORM THIS EVENING...SOUTHERN
MN/NORTHERN IA AS STRENGTHENING LLVL JET FOCUSED INTO THAT AREA.
EXPECT COMPLEX TO SHIFT EAST OVERNIGHT/EARLY MORNING...WEAKENING AS
MOVES INTO MORE STABLE REGION AND FORCING FROM LLVL JET WEAKENS.
EXPECT ADDITIONAL SHOWERS/STORMS TO FORM WITH FRONT DURING DAY ON
THU...AIDED BY RRQ OF JET LIFTING INTO LAKE SUPERIOR REGION. HAVE
TRIED TO SHOW SOME RESOLUTION OF TWO PCPN EVENTS IN GRIDS.
HAVE BACKED OFF SOME ON TSTM WORDING AS INSTABILITY VERY LIMITED.
TEMPERATURES TO BE VERY DEPENDENT ON AMOUNT OF CLOUDINESS...
ESPECIALLY GIVEN WIDESPREAD LOWER CLOUDS CURRENTLY ALONG FRONT.
MADE LITTLE CHANGE TO PREVIOUS FORECAST...THOUGH LATER SHIFTS MAY
WANT TO DROP THEM A BIT.
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY.
THE MAIN FORECAST CONCERN DURING THIS PERIOD IS PRECIPITATION
TIMING. SHOWERS AND THUNDERSTORMS ARE EXPECTED THURSDAY EVENING AS
A 500MB TROUGH AND SURFACE FRONT PUSH THROUGH NORTHEAST WISCONSIN.
BUT IT APPEARS THAT THE ACTIVITY WILL BE OUT OF MOST OF THE AREA
BY 06Z SO HAVE ONLY LEFT SLIGHT CHANCE POPS IN THE EAST 06Z TO
12Z. MEDIUM RANGE MODELS THEN SHOWED A LOW AMPLITUDE RIDGE AND SURFACE
HIGH PRESSURE SLOWLY MAKING THEIR WAY ACROSS THE REGION THROUGH
EARLY NEXT WEEK. SO FAR IT WOULD SEEM THAT TUESDAY IS THE BEST BET
FOR THE ONSET OF PRECIPITATION ASSOCIATED WITH THE NEXT SHORT WAVE
AND COLD FRONT. HAVE CHANCE POPS GOING FOR CENTRAL WISCONSIN BUT
ONLY SLIGHT CHANCE FOR MOST OF THE REST OF THE FORECAST AREA. THE CHANCE
POPS WERE EXPANDED TO COVER ALL BUT THE FOX VALLEY AND LAKESHORE ON
TUESDAY NIGHT. WOULD NOT BE SURPRISED TO SEE MODELS BRINGING THE
NEXT SYSTEM INTO THE AREA EVEN SLOWER ON THE NEXT SEVERAL RUNS.
TEMPERATURES SHOULD BE AT OR ABOVE NORMAL IN MOST CASES...THE MAIN
EXCEPTION BEING FRIDAY NIGHT UNDER HIGH PRESSURE.
&&
.AVIATION...VFR CONDITIONS WILL CONTINUE THROUGH 06Z THURSDAY
WITH POTENTIAL FOR MVFR/IFR CONDITIONS THEREAFTER...AS
THUNDERSTORM COMPLEX HEADS EAST FROM MN/IA INTO WI AND WEAKENS.
LIMITED INSTABILITY OVER NORTHEAST WI MAKES ME DOWNPLAY TSTM
ACTIVITY IN TAFS THROUGH 18Z THU...HIGHER CHANCES FOR TSTM AFTER
THAT TIME AS COLD FRONT MOVES THROUGH.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TE/MG
