Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 262025
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
225 PM CST THU FEB 26 2015

FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 225 PM CST THU FEB 26 2015

COLD DRY REGIME WILL CONTINUE FOR THE REST OF THE WEEK AS THE HIGH
PRESSURE CENTER SLIDES FROM THE NORTHERN PLAINS TO THE MID
MISSISSIPPI VALLEY REGION. PRIMARY CHALLENGE WITH BE FORECAST LOWS
TONIGHT.

SOME THIN STRATUS DEVELOPED THIS AFTERNOON MAINLY OVER AREAS JUST
TO THE WEST AND BRUSHING OVER VILAS COUNTY. REGION WAS IN AN AREA
OF STEEPER TEMP LAPSE RATES WITH SOME FEED OF MOISTURE OFF
AVAILABLE OPEN AREAS OF LAKE SUPERIOR. ANTICIPATE THESE CLOUDS TO
DECREASE LATER THIS AFTERNOON AS DRY WEST TO NORTHWEST AIR WITH
THE SURFACE HIGH AFFECTS THE REGION.

WELL SUB ZERO TEMPS LAST NIGHT PRODUCE HIT AND MISS WIND CHILL
READINGS ACROSS THE NORTH DUE TO WINDS DECOUPLING. EXPECT SIMILAR
CONDITIONS TONIGHT WITH VERY COLD OVERNIGHT LOWS AND VARIABLE WIND
SPEEDS AGAIN PRODUCING HIT AND MISS WC CRITERIA READINGS. WILL
DEAL WITH IT USING THE SPS SINCE WIND CHILL POTENTIAL APPEAR A
BIT LESS THAN LAST NIGHT.

COLD START FRIDAY MORNING WILL LEAD TO SIMILAR TO SLIGHTLY HIGHER
MAX TEMPS FRIDAY AFTERNOON COMPARED TO TODAY WITH H850 WINDS
INCREASING A LITTLE IN THE AFTERNOON.

WITH THE WESTERLY THEN SOUTHWEST FLOW ON FRIDAY...LAKE EFFECT CLOUDS
AND PCPN NOT AN ISSUE.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 225 PM CST THU FEB 26 2015

MEAN FLOW TO GENERALLY CONSIST OF A STRONG ERN PACIFIC UPR RDG...A
POSITIVE-TILTED UPR TROF FROM NEAR HUDSON BAY SWWD TO THE SW CONUS
AND A SUB-TROPICAL UPR HI OVER THE SW ATLANTIC. THIS IS A MAJOR
PATTERN SHIFT FROM WHAT THE CONUS HAS BEEN UNDER FOR MOST OF THIS
WINTER SEASON. FOR NE WI...THIS MEANS A CHANGE TO A MILDER/MORE
ACTIVE WEATHER PATTERN. WHILE THERE WL BE A CHC OF LIGHT SNOW SAT
NGT/SUNDAY...THE MAIN FOCUS REMAINS ON THE LATE MON NGT INTO TUE
NGT SYSTEM WHICH COULD BRING ANYWHERE FROM HEAVY SNOW TO A WINTRY
MIX TO THE AREA.

WRN EDGE OF THE SFC HI TO BE SITUATED OVER THE WRN GREAT LAKES
REGION FRI NGT...THEREBY BRINGING MOSTLY CLEAR SKIES AND RELATIVELY
LIGHT WINDS TO NE WI. A SLIGHT MODERATION IN 8H TEMPS IS EXPECTED
THRU THE NGT AS WINDS TO BE FROM THE SW. WHILE TEMPS ARE NOT
EXPECTED TO BE AS BITTER COLD AS THU NGT...READINGS WL STILL BE
CLOSE TO 20 DEGS BELOW NORMAL. THIS WOULD PLACE MIN TEMPS FROM
AROUND ZERO ALONG LAKE MI...8 TO 14 BELOW ZERO ACROSS N-CNTRL WI.

WE BEGIN TO LOSE THE INFLUENCE OF THE SFC HI ON SAT AS INCREASING
SW WINDS BRING A WARMER/MORE MOIST AIR MASS TOWARD WI. THE ONSET
OF WAA...COUPLED WITH A SHORTWAVE THAT WL HAVE EJECTED E-NE FROM
THE BASE OF THE SW CONUS UPR TROF INTO THE MIDWEST...WL BRING SOME
HI CLOUDS INTO WI BY SAT AFTERNOON. THESE CLOUDS COULD TEMPER
TEMPS A BIT AND WITH THE COLD START TO THE DAY...LOOK FOR MAX
TEMPS TO ONLY REACH THE 15 TO 20 DEG RANGE.

THIS SRN STREAM SHORTWAVE (MORE LIKE SEVERAL PIECES OF SHORTWAVE
ENERGY) CONTS TO MOVE E-NE ACROSS SRN SECTIONS OF THE GREAT LAKES
SAT NGT...ALONG WITH A PREVAILING WAA INTO WI THRU THE NGT.
OVERALL...LIFT/FORCING/MOISTURE ARE ALL LIMITED ACROSS NE WI SO
WHILE THERE WL BE A CHC OF LIGHT SNOW IN THE FCST (MAINLY OVER THE
SRN HALF OF THE STATE)...ANY SNOW ACCUMULATION WOULD BE LIGHT
(UNDER AN INCH). MORE CLOUDS/CHC OF SNOW TO PREVENT TEMPS FROM
DROPPING TOO FAR SAT NGT. LOOK FOR MINS TO MAINLY BE IN THE 5 TO
10 ABOVE ZERO RANGE.

JUST AS THIS SRN STREAM WEAK SYSTEM BEGINS TO PULL AWAY ON SUNDAY...
A NRN STREAM SHORTWAVE TROF IS FCST TO MOVE INTO THE WRN GREAT
LAKES. THE CYCLONIC FLOW ASSOCIATED WITH THIS TROF...COMBINED WITH
THE PASSAGE OF A CDFNT...MAY SET OFF SOME LIGHT SNOW SHWRS OR
FLURRIES ACROSS NE WI. DO NOT ANTICIPATE MUCH (IF ANY) ACCUMULATION
WITH THESE FEATURES. MAX TEMPS TO MAKE A JUMP CLOSER TO NORMAL WITH
READINGS TOPPING OUT IN THE LWR TO MID 20S NORTH...MID TO UPR 20S
SOUTH.

WINDS SWING AROUND TO THE W-NW BEHIND THE SHORTWAVE TROF SUNDAY NGT
AND THIS COULD ALLOW FOR SOME LAKE EFFECT SNOW SHWRS TO DEVELOP.
PROBLEM FOR MUCH SNOW IS THAT WRN LAKE SUPERIOR IS MOSTLY ICE-`
COVERED...8H TEMPS ARE NOT THAT COLD (-14C) AND YOU HAVE A SFC HI
BUILDING INTO WI. HAVE KEPT A TOKEN SLGT CHC POP FOR VILAS CNTY...
BUT THIS LOOKS LIKE A NON-EVENT. THIS SFC HI QUICKLY MOVES ACROSS
WI MON MORNING AND ALREADY BE TO OUR EAST MON AFTERNOON. A RETURN
FLOW TO ALREADY BE UNDERWAY DURING THE AFTERNOON AND WITH THE MEAN
FLOW TO AHVE BECOME W-SW BY THIS TIME...A SURGE OF WAA TO OUR SW
MAY ALREADY BRING MID/HI CLOUDS BACK TO THE FCST AREA BY LATE IN
THE DAY. MAX TEMPS ON MON TO GENERALLY REACH THE MID TO UPR 20S.

LOTS OF QUESTIONS REMAIN STARTING MON NGT WITH THE HANDLING OF
INITIAL SHORTWAVE ENERGY EJECTING OUT OF THE SW CONUS UPR TROF AND
THE DEVELOPMENT OF A SFC LOW SOMEWHERE OVER THE CNTRL HI PLAINS.
EXPECT AT BEST A CHC OF PCPN TO OVERSPREAD WI MON NGT AS THIS
SHORTWAVE ENERGY WORKS WITH STRENGTHENING WAA AND INCREASING MID-
LEVEL FORCING. THE REAL ISSUE IS THE STRENGTH/MOVEMENT OF THE SFC
LOW ON TUE. THE GFS DEEPENS THE LOW AND TRACKS IT NE INTO THE
GREAT LAKES BY 00Z WED. THE GEM HAS MORE OF A SFC REFLECTION WITH
MOST OF THE PCPN FOCUSED ON A QUASI-STNRY FNT DRAPED JUST NORTH OF
THE OHIO RIVER VALLEY. THE ECMWF HEDGES TOWARD THE GFS BUT IS A
GOOD 12 HOURS SLOWER. THE UKMET TAKES THE MODEST SFC LOW NORTH OF
THE OHIO RIVER VALLEY. ALL OF THIS PROVIDES AN OPPORTUNITY FOR
HEAVY SNOW TO FALL ANYWHERE FROM NRN WI TO SOUTH OF CHICAGO. FOR
NOW...HAVE PLAYED THE FCST SOMEWHERE IN BETWEEN WITH HI CHC POPS
THROUGHOUT THE ENTIRE FCST AREA UNTIL THIS SYSTEM BECOMES BETTER
HANDLED. THERE EVEN COULD BE A WINTRY MIX OVER PARTS OF CNTRL/
E-CNTRL WI IF A NRN TRACK TURNS OUT TO BE CORRECT. STAY TUNED!

ON THE BACKSIDE OF THIS SYSTEM...SNOW COULD EASILY CONT THRU TUE
NGT BEFORE COMING TO AN END. THE AFOREMENTIONED UPR TROF IS PROGGED
TO MOVE EAST MID-WEEK WITH NE WI BECOMING MORE INFLUENCED BY THE
NRN STREAM. THIS WOULD GRADUALLY LOWER TEMPS ONCE AGAIN WITH ONLY
SPOTTY PCPN CHCS AS FORCING/MOISTURE TO BE MARGINAL.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1139 AM CST THU FEB 26 2015

LAKE EFFECT CLOUDS FROM LAKE SUPERIOR WILL PRODUCE A
PERIOD OF MVFR CIGS OVER NORTH CENTRAL WISCONSIN THIS AFTERNOON. A
FEW OF THESE MVFR CIGS MAY BRIEFLY REACH INTO PARTS OF CENTRAL
WISCONSIN THIS AFTERNOON AS WELL.  VFR CONDITIONS ARE EXPECTED
ELSEWHERE TODAY.  DEVELOPING WESTERLY FLOW WILL DIMINISH THE LAKE
EFFECT CLOUDS ACROSS THE NORTH TO PRODUCE VFR CONDITIONS OVER THE
ENTIRE REGION TONIGHT INTO FRIDAY.
&&

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

$$

SHORT TERM.....TDH
LONG TERM......KALLAS
AVIATION.......TDH






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