Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 252022
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
222 PM CST WED FEB 25 2015

FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND THURSDAY
ISSUED AT 221 PM CST WED FEB 25 2015

PRIMARY ISSUE THROUGH THURSDAY IS THE REINFORCING SHOT OF ARCTIC
AIR TONIGHT AND THURSDAY.

A CLIPPER SYSTEM DROPPING SOUTHEAST OVER IOWA INTO MID MISS
VALLEY REGION WILL PRODUCE A SWATH OF SNOW FROM IOWA INTO
ILLINOIS.  LOCAL RADAR SHOW SOME WEAK RETURNS OVER PARTS OF
CENTRAL AND EAST CENTRAL WISCONSIN BUT NOT REACHING THE GROUND SO
FAR. BLACK RIVER FALLS REPORTED LIGHT SNOW IN 5SM AT 1 PM AND
THEREFORE SOME POTENTIAL OF SOME LIGHT SNOW OR FLURRIES BRUSHING
OVER AREAS SOUTH OF A LINE FROM BABCOCK TO OSHKOSH FOR THE REST OF
THE AFTERNOON AND MAYBE INTO EARLY EVENING. WILL ADD ONLY A SMALL
MENTION DUE TO DRIER AIR WORKING INTO THE AREA.

AS THE CLIPPER SYSTEM DROPS SOUTH...BACK EDGE OF THE MID TO HIGH
LEVEL CLOUDS DROPPING FAST OVER MINNESOTA AND REACHING NW
WISCONSIN. MATTER OF FACT MUCH OF NORTHERN WISCONSIN CLEAR OR UNDER
A THIN HIGH LEVEL CLOUDS THIS AFTERNOON.  ANTICIPATE THIS CLEARING
EDGE TO DROP SOUTH FAIRLY QUICK THIS EVENING...AS THE ARCTIC AIR
REINFORCES OVER THE AREA.

CHALLENGE OVERNIGHT CONCERNS WIND CHILL HEADLINES. WITH THE
ANTICIPATED FASTER CLEARING OVER THE NORTH...TEMPS WILL FALL FAST.
IF WINDS STAY UP A BIT IN THE SURFACE PRESSURE GRADIENT AHEAD OF
THE SURFACE HIGH PRESSURE SYSTEM...WIND CHILL READINGS WILL FALL TO
ADVISORY CATEGORY. ANTICIPATE SOME DECOUPLING LATE TONIGHT BUT
THEN WITH THE COLD AIR MASS IN PLACE AND SOME INCREASE IN THE
WINDS IN THE MORNING...EXPECT WC CATEGORY TO BE REACHED AGAIN.
DUE TO WC NUMBERS REACHING THE -30 TO -35 RANGE AT TIMES...WILL
ISSUE A WC HEADLINE FOR NC AND FAR NE WI STARTING LATE THIS
EVENING.

COLD START AND CONTINUED ARCTIC AIR POURING IN FOR THURSDAY WILL
AGAIN PRODUCE WELL BELOW NORMAL TEMPERATURES.

LAKE EFFECT SNOW LOOKS MARGINAL DUE TO PLENTY OF ICE OVER LAKE
SUPERIOR...BUT A FEW SNOW SHOWERS WERE NOTED NEAR IWD EARLIER
TODAY. WINDS EXPECTED TO TURN MORE NORTH TO NORTHEAST TONIGHT INTO
THURSDAY MORNING. CONTINUED THE SNOW SHOWER CHANCE FOR MTW COUNTY
ON SOUTH BUT THE WIND DIRECTION WOULD SUPPORT A BETTER CHANCE OF
LAKE EFFECT SNOWS TOWARD SOUTHEAST WISCONSIN AND NORTHEAST
ILLINOIS.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 221 PM CST WED FEB 25 2015

MODELS ARE CONSISTENT IN SHOWING A LARGE UPR RDG OVER THE ERN
PACIFIC AND A POSITIVE-TILTED UPR TROF TO EXTEND FROM NEAR HUDSON
BAY SWWD TO THE SW CONUS DEVELOPING THIS WEEKEND AND HOLDING
STEADY THRU THE MIDDLE OF NEXT WEEK. THE UNUSUALLY COLD/DRY
PATTERN WE HAVE BEEN UNDER FOR QUITE SOME TIME...WL CHANGE TO A
MILDER/MORE ACTIVE PATTERN. MAIN FOCUS TO INITIALLY BE ON THE COLD
TEMPS/WIND CHILLS THRU SAT...THEN FOR THE POTENTIAL OF ACCUMULATING
SNOW TUE/TUE NGT.

WL STILL HAVE TO WATCH FOR ANY LIGHT LAKE EFFECT SNOW SHWRS OR
FLURRIES ACROSS VILAS CNTY THU EVENING AS A NW TRAJ COMBINES WITH
AN 8H TEMP OVER WRN LAKE SUPERIOR AT AROUND -18C. DO NOT ANTICIPATE
MUCH SNOW AS LAKE SUPERIOR IS MOSTLY ICE-COVERED. OTHERWISE...A
LARGE CANADIAN HI PRES IS FCST TO MOVE FROM THE NRN PLAINS TO THE
MIDWEST THU NGT AND BRING MOSTLY CLEAR SKIES...LIGHT WINDS AND VERY
COLD CONDITIONS TO NE WI. MIN TEMPS TO RANGE FROM AROUND 5 BELOW
ZERO ALONG LAKE MI...15 TO 20 BELOW ZERO N-CNTRL WI WITH A COUPLE
OF LWR 20S BELOW ZERO POSSIBLE IN THE TYPICALLY COLDER LOCATIONS.
WIND SPEEDS TO ONLY BE AROUND 5 MPH...RELATIVELY LIGHT...BUT ENUF
WHERE A WIND CHILL ADVY MAY EVENTUALLY BE NEEDED.

THIS SFC HI WL EXTEND FROM THE MIDWEST TO THE OHIO RIVER VALLEY ON
FRI AND PROVIDE FOR A MOSTLY SUNNY BUT COLD DAY ACROSS THE FCST
AREA. WINDS WL SLOWLY BACK FROM W-NW TO W-SW DURING THE DAY...THUS
A SLIGHT UPTICK IN TEMPS ARE EXPECTED. LOOK FOR MAX TEMPS TO MAINLY
BE IN THE 10 TO 15 DEG RANGE.

THE WRN EDGE OF THE HI PRES TO REMAIN OVER THE WRN GREAT LAKES
REGION FRI NGT...THEREBY KEEPING QUIET WEATHER INTACT OVER THE
FCST AREA. TEMPS WL STILL BE VERY COLD...JUST NOT QUITE AS COLD
COMPARED TO THU NGT THANKS TO A SW WIND AND WEAK WAA. UNDER MOSTLY
CLEAR SKIES...MIN TEMPS TO RANGE FROM AROUND ZERO NEAR LAKE MI...
5 TO 10 BELOW ZERO N-CNTRL WI. ONE MORE NICE DAY EXPECTED ON SAT
AS WI BEGINS TO LOSE THE INFLUENCE OF THE DEPARTED SFC HI. THERE
MIGHT BE SOME INCREASE IN HI CLOUDS LATE IN THE DAY AS SOUTHERLY
WINDS AHEAD OF A SRN STREAM SYSTEM BEGINS TO DRAW GULF MOISTURE
NWD. LOOK FOR TEMPS TO CONT A SLOW MODERATION UPWARD AS THE MEAN
FLOW STARTS TO CHANGE AND UPR HEIGHTS RISE OVER WI. MAX TEMPS TO
MAINLY BE IN THE 15 TO 20 DEG RANGE.

THE NEXT CHANCE OF PCPN IS PROGGED TO ARRIVE LATE SAT NGT AS
PIECES OF SHORTWAVE ENERGY EJECTS NEWD FROM THE SW CONUS UPR TROF
TOWARD WI. AT THIS POINT...IT APPEARS THE SRN HALF OF WI IS MORE
SUSCEPTIBLE TO ANY PCPN...THUS HIGHER CHC POPS PLACED OVER CNTRL/
E-CNTRL WI. ON SUNDAY...A NRN STREAM CDFNT WL SWEEP ACROSS WI AND
COULD SET OFF A LITTLE LIGHT SNOW OR FLURRIES. BOTTOM LINE HERE IS
THAT ANY SNOW APPEARS TO BE MINIMAL AT BEST. THE WARMING TREND WL
CONT ON SUNDAY WITH MAX TEMPS IN THE MID 20S.

THE PASSAGE OF A NRN STREAM SHORTWAVE TROF SUNDAY NGT WL SWING THE
WINDS TO THE NW AND USHER SLIGHTLY COOLER AIR INTO THE REGION. AS
IS TYPICALLY THE CASE...WL HAVE TO WATCH FOR LAKE EFFECT POTENTIAL
ACROSS N-CNTRL WI. HOWEVER...HI PRES TO ALREADY BE BUILDING ACROSS
THE UPR MS VALLEY...THUS SENDING DRIER AIR INTO WI. ANY LAKE EFFECT
APPEARS TO BE VERY MINOR (IF AT ALL). THIS SFC HI THEN MOVES INTO
THE GREAT LAKES ON MON AND SHOULD BRING MOSTLY SUNNY SKIES/
RELATIVELY LIGHT WINDS TO NE WI. DESPITE THE PASSAGE OF THE
CDFNT...MAX TEMPS ON MON ARE EXPECTED TO REACH THE MID TO UPR 20S.

MODELS CONT TO INDICATE A LARGE PIECE OF ENERGY TO DROP SOUTH
ACROSS THE WRN CONUS MON NGT WHICH WL KICK OUT A SEPARATE PIECE OF
ENERGY FROM THE SW CONUS UPR TROF NEWD INTO THE CNTRL CONUS. EXPECT
TO SEE A LARGE BAND OF PCPN DEVELOP OVER THE CNTRL CONUS AND MAKE A
PUSH TOWARD WI LATE MON NGT. SMALL CHC POPS KEPT PER PREVIOUS FCST...
ESPECIALLY OVER CNTRL WI WHERE THE LEADING EDGE OF PCPN MAY REACH
PRIOR TO DAYBREAK. THERE IS STILL MODEL DISCREPANCY WITH THE EVENTUAL
TRACK OF THE HEAVIEST PCPN ON TUE. THIS IS NOT A SURPRISE WHEN THERE
IS A MAJOR SHIFT IN THE MEAN FLOW ALOFT. EXPECT THE MODELS TO CONT
STRUGGLING WITH THIS SYSTEM FOR THE NEXT COUPLE OF DAYS WITH
VARIED RUN-TO-RUN CONSISTENCY. FOR NOW...HAVE PAINTED HI CHC POPS
ACROSS CNTRL/E-CNTRL WI AND MEDIUM CHC POPS ACROSS THE NORTH. THE
SNOW CHANCES WOULD THEN CONT INTO TUE NGT AS THE SYSTEM TRACKS OFF
TO THE E-NE. MAINLY MOSTLY CLOUDY SKIES EXPECTED FOR WED WITH
PERHAPS SOME LAKE EFFECT OVER N-CNTRL WI AS WINDS TURN W-NW. TEMPS
BY THE MIDDLE OF NEXT WEEK MAY DROP BACK A BIT WITH HI`S ON WED
BACK IN THE UPR TEENS TO LWR 20S.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1036 AM CST WED FEB 25 2015

A CLIPPER LOW PRESSURE SYSTEM WILL TRACK OVER SOUTHWEST IOWA INTO
NORTHEAST MISSOURI THROUGH THIS EVENING BEFORE WEAKENING. THE
SYSTEM WILL SPREAD SNOW OVER THE SOUTHWEST THIRD OF THE STATE BUT
BUT WELL SOUTH AND SOUTHWEST OF CENTRAL AND NORTHEAST WISCONSIN.
ONLY AFFECTS WILL BE INCREASING MID LEVEL CLOUDS OVER THE AREA
TODAY BEFORE DECREASING TONIGHT. SCATTERED MVFR CIGS AND VSBYS DUE
TO LAKE EFFECT SNOW SHOWERS WILL BE CONFINED TO FAR NORTH CENTRAL
WISCONSIN TODAY AND TONIGHT AND THEN ALONG THE LAKE MICHIGAN
SHORELINE COUNTIES LATE TONIGHT INTO THURSDAY MORNING.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO 10 AM CST
THURSDAY FOR WIZ005-010>013-018-019-021-073.
&&

$$

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





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