FXUS63 KGRB 260922
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
322 AM CST SAT DEC 26 2009

.SHORT TERM...TODAY THROUGH SATURDAY.

MESOANALYSIS SHOWS SFC LOW JUST S OF KDSM AT 08Z THIS AM...AFTER
MAKING A LOOP AROUND THE STATE OF IA. COLD OCCLUSION FINALLY PUSHED
THRU THE FAR N PART OF FCST AREA AND TEMPS FALLING THERE.

26/00Z AND 26/06Z MODELS SHOW SFC LOW MOVING ACROSS EASTERN WI
NEAR KMTW AND KSBM BY SAT NIGHT. AREA OF STEADIER SNOW WILL MOVE
BACK INTO SE PART OF FCST AREA BY AFTN. BEFORE THAT...HOWEVER...
SCT SNOW SHOWERS MOVING OFF LAKE MICHIGAN AND WILL AFFECT THE FAR
ERN PART OF FCST AREA. MODEL SOUNDINGS INDICATE SOME LAKE-INDUCED
CAPE WITH MODERATELY FAVORABLE AIR/LAKE DELTA T AND WINDS.
SYNOPTIC LIFT ASSOC WITH UPPER SYSTEM ALSO FAVORABLE. THINKING 1-2
INCHES ACROSS FOX VALLEY N THROUGH HWY 141 CORRIDOR. A COUPLE OF
INCHES MORE POSSIBLE IN LAKESHORE COUNTIES. WILL HOLD OFF ON
ADVISORY FOR NOW...BUT LAKESHORE COUNTIES WILL HAVE TO BE
MONITORED AS ACCUMS COULD APPROACH 3-4 INCHES IN SPOTS.

HIGH TEMP FCST TODAY TWEAKED A BIT GIVEN CURRENT CONDITIONS...BUT
NO SIGNIFICANT CHANGES MADE. MINS TNGT AND MAX SUNDAY CHANGED
LITTLE FROM PREV FCST.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY.

TWO MAIN CONCERNS DURING THIS PART OF THE FORECAST ARE THE
DEPARTURE OF THE CURRENT SYSTEM AND ARRIVAL OF A CLIPPER SYSTEM
LATER IN THE WEEK.

MEDIUM RANGE MODELS HAD A CLOSED 500MB LOW CENTERED AROUND
SOUTHERN LOWER MICHIGAN AND A SURFACE TROUGH FROM NORTHERN QUEBEC
TO NORTHERN LAKE MICHIGAN AT 00Z MONDAY. NORTHERLY FLOW OF COLD
AIR ON THE BACK SIDE OF THESE DEPARTING FEATURES SHOULD RESULT IN
ENOUGH INSTABILITY AND FAVORABLE WIND DIRECTION FOR SOME LAKE
EFFECT SNOW SHOWERS IN THE SNOWBELT REGION...ALONG WITH A CHANCE
OF FLURRIES FOR THE REST OF THE AREA. SOME CLEARING IS LIKELY FOR
MONDAY NIGHT AS A SURFACE HIGH AND AN UPPER RIDGE SLOWLY MAKE
THEIR WAY TOWARD THE REGION. TIMING OF THE CLIPPER SYSTEM THAT
WILL BRING THE NEXT CHANCE OF SNOW TO THE AREA IS STILL A BIT
UNCERTAIN RIGHT NOW...BUT GRIDS HAVE SLIGHT CHANCE POPS GOING FOR
WEDNESDAY AND CHANCE POPS IN THE EAST ON WEDNESDAY NIGHT. NOT THE
GREATEST OF CONFIDENCE IN THIS TIMING BUT LATER SHIFTS CAN ADJUST
THINGS BASED ON NEWER MODEL DATA.

DID NOT REALLY MAKE MAJOR CHANGES TO MAX AND MIN TEMPERATURES
DURING THE EARLY HALF OF THE WEEK. EXPECT COLDER LOWS AS WINDS
DECREASE AND SKIES START TO CLEAR ONCE THE CURRENT SYSTEM STARTS
MOVING AWAY FROM THE STATE.
&&

.AVIATION...MVFR CONDITIONS WILL CONTINUE AT MOST PLACES THROUGH
THE DAY...THOUGH THERE IS A TEMP BREAK IN THE LOWER CLOUDS
AFFECTING SOUTHERN AIRPORTS (AUW/CWA/GRB) VERY EARLY THIS AM. OCNL
IFR WITH LOWER CIGS AND VSBY ASSOCIATED WITH SNOW SHOWERS. BEST
CHANCE IN FAR EASTERN PART OF FORECAST AREA ASSOCIATED WITH LAKE
ENHANCED SNOWS.
&&

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

$$
JKL/MG