Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 031758
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1158 AM CST WED FEB 3 2016

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.UPDATE...
ISSUED AT 354 AM CST WED FEB 3 2016

UPDATED HEADLINES TO REMOVE MOST OF THE WARNING. WILL
FOCUS ON MIXED PCPN THIS AM FOR ADVISORY HEADLINES.
&&

.SHORT TERM...TODAY...TONIGHT...AND THURSDAY
ISSUED AT 335 AM CST WED FEB 3 2016

DEALING WITH WHAT IS LEFT OF THE STORM SYSTEM WILL BE THE PRIMARY
ISSUE THIS MORNING.

AFTER STRONG WARM AIR ADVECTION PCPN LATE TUESDAY AFTERNOON AND
EVENING...THE ISSUE OF PREVIOUS FORECASTS SHIFTS WAS THE DURATION
OF THE MID LEVEL MOISTURE BEING SCOURED OUT. THAT CONTINUES TO BE
THE CASE EARLY THIS MORNING WITH THE MID LEVEL MOISTURE REMOVED AT
THE ONSET OVER THE ENTIRE REGION.  PCPN WITH THE TRAILING
DEFORMATION REGION NOT IMPRESSIVE...BUT DO ANTICIPATE THE MIXED
PCPN TO TURN BACK TO LIGHT SNOW FROM WEST TO EAST AS THE MID LEVEL
TROUGH PASSES THROUGH AND COLDER AIR ALOFT SATURATES THE AIR MASS
AND TURNS TO LIGHT SNOW. INTERESTING CONVECTIVE ELEMENT REMAINS
WITH THE TRAILING SURFACE LOW AND TRACKS ALONG LINGERING H850
BAROCLINIC ZONE FROM SOUTHWEST WISCONSIN TO EAST CENTRAL
WISCONSIN. GFS PRODUCES A 2-4 INCH REGION OF SNOW FOR EAST
CENTRAL WISCONSIN FOR THE MORNING HOURS...WHILE A BLEND OF THE
MODELS SUGGEST A 1-2 INCH SNOW THROUGH NOON TODAY.

ATTEMPTED TO COORDINATE REMOVING THE WARNING AROUND MIDNIGHT
DUE TO HEAVY SNOW STAYED JUST WEST OF CENTRAL AND NORTH CENTRAL
WISCONSIN OVERNIGHT. BUT THIS WOULD COMPLICATE REGIONAL HEADLINES
SO WILL ADDRESS DROPPING IN A FEW HOURS...THIS INCLUDES DROPPING
MOST OF THE ADVISORY WHICH STARTED AT 12Z. EVEN THOUGH A WARNING
WILL LINGER FOR A FEW MORE HOURS...WILL DOWNPLAY WITH THE PCPN
AND FOCUS ON ROAD CONDITIONS DUE TO FREEZING DRIZZLE AND FREEZING
RAIN.

SYSTEM DEPARTS THIS AFTERNOON FOR A CONTINUED DIMINISHING OF THE
LIGHT SNOW. WILL CONTINUE THE LAKE EFFECT SNOW SHOWERS MENTION
ACROSS THE NORTH BUT DIRECTION SUGGESTS NO HEADLINE IS NEEDED A
THIS TIME. A WEAK SHORT WAVE DROPS INTO THE UPPER TROUGH LATE
TONIGHT INTO THURSDAY TO END THE LAKE EFFECT SNOW AND BRING A
CHANCE OF LIGHT SNOW TO WESTERN AREAS THURSDAY AFTERNOON.

.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
ISSUED AT 335 AM CST WED FEB 3 2016

SPLIT FLOW PATTERN TO CONT ACROSS THE CONUS THRU THE END OF THE
WEEK WITH AN ACTIVE NRN STREAM SENDING SEVERAL CLIPPER SYSTEMS
TOWARD THE GREAT LAKES. THE STRONGEST OF THESE CLIPPERS APPEARS TO
IMPACT NE WI DURING THE SUNDAY NGT/MON TIME FRAME. MEAN FLOW TO
CONSOLIDATE EARLY NEXT WEEK AS A LARGE UPR RDG BUILDS ALONG WRN
NOAM AND A DOWNSTREAM UPR TROF DEVELOPS OVER E-CNTRL NOAM. THIS
PATTERN SHIFT WL BRING COLDER AIR INTO THE GREAT LAKES (BELOW
NORMAL TEMPS) WITH LAKE EFFECT CONCERNS FOR N-CNTRL WI.

THE FIRST CLIPPER/CDFNT/SHORTWAVE TROF WL CONT TO TRACK EAST
ACROSS THE GREAT LAKES THU EVENING AND WL CONT TO CARRY CHC POPS
OVER PARTS OF NRN AND ERN WI. A WEAK RDG OF HI PRES IS EXPECTED TO
BUILD TOWARD WI THU NGT AND MAY ALLOW SKIES TO AT LEAST BECOME
PARTLY CLOUDY. THE AMOUNT OF CLOUD COVER WL DICTATE HOW COLD WE
GET WITH WINDS DIMINISHING AND A FRESH SNOW PACK. HAVE LEANED
TOWARD THE COOLER SIDE OF GUIDANCE WITH MIN TEMPS MAINLY FROM 5 TO
10 ABOVE ZERO NORTH...AROUND 10 ABOVE CNTRL/E-CNTRL AND MID-TEENS
NEAR LAKE MI. THE MODEST SFC RDG MOVES ACROSS WI ON FRI...HOWEVER
THE NEXT WEAK CLIPPER TO ALREADY BE DROPPING SE THRU THE NRN
PLAINS...THUS CLOUDS SHOULD BE ON THE INCREASE ESPECIALLY DURING
THE AFTERNOON HOURS. MAX TEMPS FOR FRI WL RANGE FROM AROUND 20
DEGS N-CNTRL...LWR TO MID 20S ELSEWHERE.

THIS CLIPPER RACES EWD INTO THE GREAT LAKES FRI NGT ACCOMPANIED BY
A WEAK CDFNT AND A SHORTWAVE TROF. MOISTURE WL BE AN ISSUE FOR
PCPN POTENTIAL AS THE GULF IS SHUT-OFF BY A SRN STREAM SYSTEM OVER
THE DEEP SOUTH. THEREFORE...DESPITE MODEST LIFT AND MID-LEVEL
FORCING...POPS HAVE BEEN KEPT IN THE CHC CATEGORY WITH LITTLE IN
THE WAY OF SNOW ACCUMULATIONS. THE CDFNT IS FCST TO SAG SWD INTO
SRN WI AND BECOME NEARLY STNRY ON SAT. MEANWHILE...A WEAK SFC RDG
IS ALSO EXPECTED TO MOVE INTO THE WRN GREAT LAKES. THERE MAY BE A
LITTLE LEFT OVER ISOLATED LIGHT SNOW SHWRS ACROSS NRN OR ERN WI
SAT MORNING AS THE CLIPPER DEPARTS...BUT FOR MOST AREAS...SAT WL
BE DRY UNDER MOSTLY CLOUDY SKIES. LOOK FOR MAX TEMPS TO BE IN THE
MID 20S NORTH...UPR 20S TO AROUND 30 DEGS SOUTH.

MODELS CONT TO STRUGGLE WITH THE INTENSITY AND TRACK OF CLIPPER #3
HEADED INTO THE LATTER PART OF THE WEEKEND. THE ECMWF AND GEM
AGREE ON THE TRACK BY TAKING THE SFC LOW E-SE INTO THE UPR MS
VALLEY BY 00Z MON...HOWEVER THE ECMWF IS STRONGER WITH THE
INTENSITY. MEANWHILE...THE GFS MAINTAINS A WEAK SFC LOW...BUT
TRACKS THE LOW PRES EWD ACROSS SRN CANADA. THE GENERAL CONSENSUS
FOR THE TIME BEING WL BE TO BRING THIS CLIPPER INTO SOME PART OF
THE WRN GREAT LAKES REGION ON SUNDAY WITH ENUF MOISTURE TO BRING A
CHC OF LIGHT SNOW TO ALL OF NE WI.

BY THE START OF THE WORK WEEK...THE UPR RDG IS FCST TO STRENGTHEN
OVER WRN NOAM WITH A DOWNSTREAM UPR TROF DEEPENING OVER E-CNTRL
NOAM. SNOW CHCS WL CONT SUNDAY NGT AS THE CLIPPER/ASSOCIATED
CDFNT/SHARPENING UPR TROF MOVE THRU WI. THE QUESTION FOR MON WL BE
HOW LONG THE CLIPPER WOULD IMPACT NE WI AS JET ENERGY ROUNDS THE
BASE OF THE UPR TROF AND COULD STRENGTHEN/SLOW THE MOVEMENT OF THE
SFC LOW JUST TO OUR EAST. CONFIDENCE ON HOW ALL OF THIS PLAYS OUT
IS LOW...THUS WL CONT WITH THE CHC FOR LIGHT SNOW OVER THE ENTIRE
FCST AREA. TEMPS WL START THEIR DOWNWARD TREND AS COLDER AIR
FILTERS INTO THE REGION ON GUSTY NW WINDS. LOOK FOR READINGS IN
THE LWR TO MID 20S N-CNTRL...MID 20S CNTRL AND UPR 20S TO AROUND
30 DEGS E-CNTRL WI. LASTLY...WL HAVE TO WATCH FOR THE LAKE EFFECT
MACHINE TO KICK INTO GEAR FOR N-CNTRL WI.

THE RESULTING AMPLIFIED MEAN FLOW MEANS THAT THIS SYSTEM WL NOT
DEPART QUICKLY FROM WI AND WL NEED TO CARRY CHC POPS THRU AT LEAST
MON NGT...IF NOT INTO TUE IN THE EAST. MAIN CONCERN MAY BE THE
LAKE EFFECT THREAT FOR N-CNTRL WI AS FAVORABLE TRAJS PERSIST AND
COLD AIR (8H TEMPS AROUND -20C OVER WRN LAKE SUPERIOR) CONTS TO
FEED INTO WI.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1157 AM CST WED FEB 3 2016

LIFR/IFR CIGS/VSBYS ACROSS EAST CENTRAL WI ASSOCIATED WITH THE
SNOW WILL IMPROVE TO MVFR THIS AFTERNOON AND EVENING...AS A UPPER
LEVEL DISTURBANCE MOVES NORTHEAST OF THE AREA AND THE SNOW ENDS.
LAKE EFFECT SNOW SHOWERS WILL REMAIN POSSIBLE OVER NORTH CENTRAL
WI THROUGH THE EVENING HOURS...WITH ONLY MINOR ACCUMULATIONS
EXPECTED AT KRHI. A FEW GUSTS OVER 20 KTS ARE POSSIBLE THROUGH
THE LATE AFTERNOON HOURS. MODELS SHOW SOME DRIER AIR MOVING INTO
THE AREA LATE THIS EVENING INTO THE OVERNIGHT HOURS...BRINGING
SOME PARTIAL CLEARING AND VFR CONDITIONS TO THE AREA.
HOWEVER...ANY CLEARING WILL BE BRIEF AS CLOUDS FROM THE NEXT
WEATHER MAKER WILL QUICKLY SPREAD ACROSS THE AREA THURSDAY
MORNING...WITH LIGHT SNOW SPREADING ACROSS THE AREA THURSDAY
AFTERNOON.
&&

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

$$

UPDATE.........TDH
SHORT TERM.....TDH
LONG TERM......KALLAS
AVIATION.......BERSCH


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