FXUS63 KGRB 291051
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
451 AM CST SUN NOV 29 2009

.SHORT TERM...TODAY THROUGH MONDAY. RIGHT ENTRANCE REGION OF 65
KNOT 500MB JET WILL HELP TO PRODUCE A BAND OF LIGHT SNOW ACROSS
NORTHERN AND CENTRAL WISCONSIN TODAY. RADAR ECHOES AT 930Z
CORRELATE WELL WITH GFS 700 MB OMEGA FIELD AND WILL USE THAT FIELD
TO TIME PRECIPITATION. BOUNDARY LAYER TEMPERATURES SHOULDBE COLD
ENOUGH TO SUPPORT MOSTLY SNOW...BUT INCLUDED A CHANCE OF RAIN IN
THE SOUTH AS THERE HAS BEEN SOME RAIN MIXED IN UPSTREAM OVER
WESTERN WISCONSIN AND SOUTHEAST MINNESOTA. AN INCH OF SNOW SEEMS
LIKELY IN THE NORTH BASED ON MODEL .10 INCH QPF AND A 10 TO 1 SNOW
TO WATER RATION. LITLE OR NO ACCUMULATION IN THE SOUTH DUE TO
LOWER TOTALS...WARM GROUND AND POSSIBILITY OF RAIN MIXED IN.
SYNOPTIC PRECIPITATION EXITS BY LATE AFTERNOON WITH A CHANCE OF LAKE
EFFECT IN THE FAR NORTHCENTRAL IN THE EVENING HOURS BEFORE WINDS
BECOME MORE WESTERLY. CLIPPER LIKE SYSTEM PASSES NORTH OF THE
REGION MONDAY. IT SHOULD PRODUCE CLOUDS AND PERHAPS SOME LIGHT
SNOW IN THE NORTH WHERE DYNAMICS ARE BETTER. AIR IS DRY
THOUGH...SO ANY SNOW WOULD BE LIGHT.

.LONG TERM...MONDAY NIGHT THROUGH SATURDAY.

THE MAIN CONCERNS DURING THIS PART OF THE FORECAST ARE THE ONSET
AND PLACEMENT OF PRECIPITATION CHANCES.

WEAK SURFACE AND UPPER LEVEL RIDGES PASSING ACROSS THE AREA MONDAY
NIGHT LED TO A DRY FORECAST FOR THAT PERIOD AS A SYSTEM DEPARTS
THE REGION. AN UPPER LEVEL SHORT WAVE AND SURFACE LOW OVER THE CANADIAN
PLAINS WILL MOVE TOWARD WISCONSIN ON TUESDAY BUT NEITHER THE 00Z
GFS NOR THE 00Z HIRES ECMWF HAVE ANY QPF IN THE AREA DURING THE
DAY SO THE TUESDAY FORECAST IS DRY. MODELS WERE NOT INDICATING ANY
QPF ALONG OR AHEAD OF A COLD FRONT THAT WAS EXPECTED TO PASS
THROUGH THE AREA TUESDAY NIGHT. MODELS DID HAVE QPF BEHIND THE
FRONT WITH AN UPPER LEVEL TROUGH...AND DOWNWIND FROM LAKE
SUPERIOR. HAVE GONE WITH AT A SLIGHT CHANCE OF SNOW SHOWERS IN THE
NORTH FOR LATE TUESDAY BUT...AFTER THAT...HAVE CHANCE POPS GOING FOR
THE NORTH THROUGH THURSDAY NIGHT AS THE AREA REMAINS IN A COLD
NORTHERLY FLOW BETWEEN LOW PRESSURE EAST OF THE REGION AND A RIDGE
OVER THE PLAINS.

ADJUSTED TEMPERATURES DOWNWARD A BIT IN MOST CASES SINCE IT
APPEARS THAT THE AIR MASS WILL BE RATHER COLD.
&&

.AVIATION...AN AREA OF IFR CIGS AND VSBYS WITH LIGHT SNOW WILL
MOVE FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA TODAY. IT WILL
EFFECT THE RHI/AUW/EGV/AIG/IMT/TKV/CWA AIRPORTS THIS MORNING. NOT
SURE IF WE WILL GET IFR OR MVFR CIGS/VSBYS FURTHER SE AT
CLI/ATW/OSH/GRB/MNM/SUE/MTW THIS AFTERNOON. MAINLY VFR EXPECTED
TONIGHT AND MOST OF MONDAY.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$
RDM/MG