Area Forecast Discussion
Issued by NWS Green Bay, WI

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756
FXUS63 KGRB 132019
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
219 PM CST SAT FEB 13 2016

FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 219 PM CST SAT FEB 13 2016

MAIN FCST FOCUS TO BE ON THE IMPENDING LIGHT SNOW EVENT ARRIVING
ON SUNDAY AND CONTINUING INTO SUNDAY NGT.

THE 20Z MSAS SFC ANALYSIS INDICATED A RDG OF HI PRES STRETCHED
FROM WRN ONTARIO SEWD THRU WRN WI TO THE MID-MS VALLEY. A VERY
WEAK AREA OF LOW PRES WAS SITUATED OVER ERN UPR MI WITH A TROF
EXTENDED WWD TOWARD IWD. FARTHER WEST...A SERIES OF WEAK LOW PRES
AREAS WERE LOCATED OVER THE FRONT RANGE OF THE ROCKIES FROM
SATKATCHWAN TO NE NM. VSBL SATL IMAGERY SHOWED A LARGE AREA OF
CLOUDS OVER THE CNTRL/NRN PLAINS AS WARMER AIR ATTEMPTS TO PUSH
BACK AT THE ARCTIC CHILL OVER THE NRN TIER OF STATES.

THE SFC RDG AXIS WL PUSH ACROSS WI THIS EVENING AND ALREADY BE
APPROACHING THE ERN GREAT LAKES BY DAYBREAK. EXPECT TO SEE A
PERIOD OF CALM OR NEARLY CALM WINDS THRU MUCH OF THE NGT OVER NE
WI...THUS TEMPS SHOULD HAVE NO PROBLEM DROPPING BELOW ZERO ACROSS
ALL BUT THE IMMEDIATE LAKESHORE COUNTIES. LOOK FOR MIN TEMPS TO
RANGE FROM AROUND 15 BELOW ZERO OVER PARTS OF NRN WI...TO AROUND
ZERO ACROSS DOOR CNTY. DO NOT ANTICIPATE THE NEED FOR ANOTHER WIND
CHILL ADVY TNGT DUE TO THE VERY LIGHT WINDS. NONETHELESS...ANYONE
GOING OUT TNGT SHOULD BE PREPARED FOR ANOTHER VERY COLD NGT.

WEAK LOW PRES IS FCST TO CONSOLIDATE OVER THE NRN HI PLAINS AND
MOVE SE ACROSS THE NRN PLAINS ALONG A MODEST WRMFNT SITUATED OVER
THE MIDWEST ON SUNDAY. THERE ARE SEVERAL FACTORS THAT NEED TO BE
DEALT WITH. FOR STARTERS...THE AIR MASS OVER NE WI IS INITIALLY
VERY DRY WITH FCST SOUNDINGS INDICATING WE WOULD NOT SATURATE
COMPLETELY UNTIL SUNDAY AFTERNOON. SECONDLY...THE BETTER ISEN LIFT
WL STAY TO OUR WEST AND SOUTH...PERHAPS BRUSHING SRN SECTIONS OF
THE FCST AREA. THIRD...THE S-SE WINDS COULD BRING A LAKE EFFECT
SNOW BAND TO THE LAKESHORE COUNTIES DURING THE AFTERNOON.
LASTLY...MODELS CONT TO SHOW A VERY DEEP DENDRITIC GROWTH ZONE...
SO IF ENUF LIFT AND SATURATION CAN BE REALIZED...THIS COULD ADD TO
A HIGHER SNOW TOTAL. CURRENT THINKING IS TO HAVE A SNOW
ACCUMULATION RANGE FROM ONE-HALF INCH OR LESS NORTH AND E-CNTRL...
ONE-HALF TO ONE INCH CNTRL AND LAKESHORE BY 00Z MON. MAX TEMPS
SHOULD BE WARMER WITH READINGS IN THE MID TO UPR TEENS NORTH AND
CNTRL...LWR 20S E-CNTRL WI AND LAKESHORE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 219 PM CST SAT FEB 13 2016

FOR THE NEW WORK WEEK...A FEW SWINGS WITH TEMPERATURE TRENDS
EXPECTED ALONG WITH A COUPLE OF PRECIPITATION CHANCES.

FIRST FORECAST ISSUE CENTERS ON THE SUNDAY NIGHT INTO THE EARLY
MONDAY MORNING AS A MID LEVEL SHORT WAVE TROUGH DROPS SOUTHEASTWARD
OVER THE WESTERN GREAT LAKES REGION. DRY AIR WILL HOLD OFF PCPN
OVER NORTHEAST WISCONSIN SUNDAY EVENING BEFORE SOME SATURATION
OCCURS. SURFACE TROUGH GRADUALLY TRACKS OVER LATER SUNDAY NIGHT
BEFORE DEPARTING MONDAY MORNING. WITH THE COLD AIR IN
PLACE...EVENTUALLY A DEEP SNOW GROWTH REGION DEVELOPS SO A FEW
INCHES OF SNOW POSSIBLE WITH THE HIGHER AMOUNTS OVER CENTRAL
WISCONSIN. LAKE ENHANCED SNOW COULD PLAY A ROLE SUNDAY NIGHT FOR
MAINLY DOOR COUNTY AS WINDS TURN MORE S/SE FOR A DURATION SUNDAY
NIGHT. ONSHORE WINDS ALONG KEWAUNEE AND MANITOWOC NOT DEEP WITH
850 WINDS GENERALLY SOUTHWEST SUNDAY NIGHT.

WITH UPPER HEIGHT INCREASES...TEMPERATURES MODERATING TO NEAR
NORMAL MONDAY INTO TUESDAY...BUT THEN TREND DOWN TOWARD WEDNESDAY
DUE TO A PASSING CLIPPER SOUTHWEST OF THE AREA. BUT THIS WILL BE
SHORT LIVED AS THE WESTERN STATES UPPER RIDGE MOVES INTO THE
PLAINS...AND A MILD TREND IS ON THE WAY. PROGS SUGGESTS H850
TEMPS WARMING TO +4 TO +10 BY FRIDAY DEPENDING ON THE MODEL RUN.
THE WARM ADVECTION AND PCPN CHANCE WILL PRODUCE TYPE ISSUES LATER
IN THE WEEK...ESPECIALLY THURSDAY NIGHT.

THE 12Z GFS RUN SUGGESTS THE WARMING WILL CONTINUE INTO THE
WEEKEND...WHILE THE ECMWF BRIEFLY ENDS THE WARMING TREND SUNDAY
WITH A CLIPPER TYPE SYSTEM.  NEVERTHELESS GOING FORECAST TEMPS
WILL PUT A BIG DENT IN THE SNOW COVER.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1123 AM CST SAT FEB 13 2016

VFR CONDITIONS ARE EXPECTED THRU MIDDAY SUNDAY AS A LARGE AREA OF
HI PRES MOVES ACROSS THE GREAT LAKES REGION. WE WL SEE A GRADUAL
INCREASE IN HI CLOUDS LATE TNGT AND MID CLOUDS SUNDAY MORNING AS
AN AREA OF LOW PRES DROPS SE THRU THE NRN PLAINS ALONG A WRMFNT
STRETCHED ACROSS IA/IL. INCREASING ISEN LIFT IS FCST TO GENERATE A
BAND OF LIGHT SNOW THAT WL MAINLY PASS TO OUR WEST AND SOUTH...BUT
STILL BRING SOME LGT SNOW TO NE WI. CIGS/VSBYS COULD DROP INTO THE
MVFR RANGE LATER SUNDAY AFTERNOON ONCE THE LGT SNOW BEGINS.
&&

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

$$

SHORT TERM.....AK
LONG TERM......TDH
AVIATION.......AK



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