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000
FXUS63 KGRB 242333
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
533 PM CST TUE FEB 24 2015

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 238 PM CST TUE FEB 24 2015

THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN ARCTIC
COLD FRONT STRETCHING FROM AROUND WAUTOMA TO MARINETTE AND MOVING
EAST EARLY THIS AFTERNOON.  SNOW SHOWERS DEVELOPED AHEAD OF THE
FRONT EARLIER TODAY AND LOCALLY DROPPED VSBYS TO A QUARTER OF A
MILE.  THESE SNOW SHOWERS ARE NOW ENTERING LAKE MICHIGAN.  OTHER
WEAKER SNOW SHOWERS EXIST RIGHT BEHIND THE FRONT.  EXCEPT FOR THE
SNOW BELT...THESE SNOW SHOWERS SHOULD EXIT BY THE START OF THE
EVENING.  WINDS ARE BECOMING STRONG AND GUSTY BEHIND THE FRONT WITH
SOME OBS REACHING UP TO 35 KNOTS OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN.  THESE GUSTY WINDS WILL SPREAD INTO EASTERN WISCONSIN
LATER THIS AFTERNOON.  SOME CONCERN FOR THE DOOR PENINSULA AS WIND
DIRECTION AND PRESSURE RISES ARE FAVORABLE FOR NEAR WIND ADVISORY
WIND GUSTS FOR A FEW HOURS.  THINK WILL FALL JUST SHORT OF THOSE
TYPES OF GUSTS THOUGH.  PLENTY OF STRATO-CU AND SNOW SHOWERS WITHIN THE
ARCTIC AIR OVER THE ARROWHEAD AND HEADING TOWARDS NORTHERN
WISCONSIN.  WINDS/TEMPS/WIND CHILLS/AND SNOW POTENTIAL ARE THE MAIN
FORECAST CONCERNS.

TONIGHT...THE ARCTIC COLD FRONT WILL EXIT NORTHEAST WISCONSIN LATE
IN THE AFTERNOON OR EARLY THIS EVENING.  SHOULD SEE PRETTY GOOD WIND
GUSTS UP TO 40 MPH OVER DOOR COUNTY AS STRONG PRESSURE RISES ARRIVE
BEHIND THE FRONT EARLY THIS EVENING.  GUSTS BETWEEN 30 AND 35 MPH
ARE POSSIBLE ELSEWHERE. THE WINDS SHOULD THEN SUBSIDE PRETTY
QUICKLY BY MID-EVENING AS ARCTIC AIR PLUNGES ACROSS NORTH-CENTRAL
AND NORTHEAST WISCONSIN...THOUGH WINDS SHOULD NOT DECOUPLE.
SCATTERED SNOW SHOWERS WILL LIKELY FOLLOW THE ARRIVAL OF THE
ARCTIC AIR ACROSS THE NORTH THIS EVENING...THEN DIMINISH/RETREAT
TO THE SNOWBELT AREAS OVERNIGHT. THE COMBINATION OF TEMPS FALLING
TO AROUND 10 OR 12 BELOW OVER N-C WISCONSIN AND PERSISTENT
NORTHWEST WINDS WILL HAVE WIND CHILLS FALLING BETWEEN 20 TO 25
BELOW OVER N-C WISCONSIN AND GENERALLY 10 TO 15 BELOW ELSEWHERE.
IN COORDINATION WITH WFOS MARQUETTE AND DULUTH...WILL NOT ISSUE A
WIND CHILL ADVISORY AND WILL INSTEAD HIGHLIGHT THE THREAT IN A
SPS.

WEDNESDAY...ARCTIC HIGH PRESSURE WILL REMAIN IN CONTROL ACROSS THE
REGION AS A WEAK DISTURBANCE SLIDES SOUTHEAST ACROSS THE CENTRAL
GREAT PLAINS.  WILL SEE MID AND HIGH CLOUDS SPREAD OVERHEAD FROM
THIS DISTURBANCE...BUT NO REAL THREAT OF PRECIP THIS FAR INTO THE
ARCTIC AIR.  BITTERLY COLD WIND CHILLS WILL BE MODERATING BY 9 OR 10
IN THE MORNING TO BETWEEN 10 AND 20 BELOW OVER N-C WISCONSIN.  HIGHS
WILL BE RANGING FROM 5 TO 10 ABOVE OVER N-C WI TO 10 TO 15 FARTHER
SOUTH AND EAST.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 238 PM CST TUE FEB 24 2015

PATTERN ALOFT IS BEGINNING TO CHANGE...BUT NOT BEFORE ONE MORE
BATCH OF ARCTIC AIR PUSHES INTO THE AREA. EVENTUALLY A WESTERN
TROUGH WILL EMERGE AS THE RIDGE PREVIOUSLY IN PLACE REFORMS MORE
OVER THE PACIFIC. THE EASTERN TROUGH WILL RETREAT NORTH...AND
SOMETHING RESEMBLING A SOUTHERN STREAM WILL START TO BRING
SOUTHWEST FLOW ALOFT INTO WISCONSIN. THIS WILL BRING A WARMER AND
MORE MOIST AIRMASS FROM THE SOUTHWEST. THE RESULT WILL BE A SLOW
MODERATION OF TEMPERATURES THROUGH THE REST OF THE WEEK...FOLLOWED
BY CHANCES FOR SNOW LATE THIS WEEKEND AND EARLY NEXT WEEK.

WEDNESDAY NIGHT THROUGH SATURDAY...
PRIMARY FORECAST CHALLENGE IN THIS STRETCH WILL BE EARLY ON AS A NEW
ARCTIC AIRMASS SURGES INTO THE AREA WITH WEDNESDAY AND THURSDAY
NIGHTS SEEING THE LOWEST TEMPERATURES. HOWEVER...THE DEEP EASTERN
TROUGH PATTERN WE HAVE SEEN LATELY WILL BE DEAMPLIFYING. THIS MAY
HELP BLUNT THE DROP IN TEMPERATURES. IT WILL STILL BE VERY COLD
AND A PORTION OF THE AREA...PRIMARILY IN NORTH CENTRAL
WISCONSIN...MAY REQUIRE WIND CHILL ADVISORIES. EACH NIGHT HAS
ISSUES THOUGH. A SHORTWAVE WILL BE PASSING RELATIVELY NEAR THE
AREA WEDNESDAY NIGHT...AND THOUGH IT HAS APPEARED FOR SOME TIME
THAT IT WILL PASS WELL TO OUR SOUTH...GUIDANCE HAS DRIFTED NORTH
TODAY. IT IS POSSIBLE THAT FURTHER DRIFT MAY RESULT IN MORE
CLOUDINESS WHICH WOULD HELP ARREST THE FALL OF TEMPERATURES. ON
THURSDAY NIGHT...COLD TEMPERATURES WILL BE DRIVEN LARGELY BY THE
POTENTIAL FOR STRONG RADIATIONAL COOLING. BUT JUST HOW LOW WE GO
WILL DEPEND ON CLOUD COVER AND WHETHER OR NOT WINDS WILL BE CALM
OVERNIGHT...BOTH DIFFICULT THINGS TO FORECAST AT THIS RANGE. AFTER
THESE NIGHTS...THE AFOREMENTIONED PATTERN CHANGE SHOULD ENCOURAGE
A MODERATION OF TEMPERATURES FOR THE REST OF THE WEEK...THOUGH WE
ARE ONLY LOOKING TO AN INCREASE TO A LITTLE BELOW NORMAL FROM WELL
BELOW NORMAL.

ADDITIONALLY...THERE IS A SLIGHTLY INCREASED AREA OF OPEN WATER ON
LAKES SUPERIOR AND MICHIGAN AFTER RECENT GUSTY WINDS. THOUGH THE
WATER IS SURELY COLD...THE AIR MASS WILL BE COLDER AND WITH SOME
ONSHORE WIND TRAJECTORIES WEDNESDAY NIGHT...LAKE EFFECT FLURRIES
ARE NOT IMPOSSIBLE FOR THE VILAS COUNTY SNOW BELT AND PORTIONS OF
THE LAKE MICHIGAN SHORELINE IN EAST CENTRAL WISCONSIN...PARTICULARLY
THE BIT OF MANITOWOC COUNTY THAT JUTS OUT INTO THE LAKE AT
DIFFERENT ANGLE THAN THE REST OF THE SHORELINE.

SATURDAY NIGHT THROUGH TUESDAY...
WITH MORE SOUTHWEST FLOW ALOFT...A MID-LEVEL SHORTWAVE AND A WEAK
SURFACE LOW REFLECTION WILL BRING A CHANCE FOR SNOW TO THE AREA IN
THE SECOND HALF OF THE WEEKEND. AFTER A LARGE JUMP NORTH IN THE
MODEL GUIDANCE YESTERDAY THE ENVELOPE HAS SETTLED BACK TO THE
SOUTH A LITTLE BIT TODAY. THOUGH AT FIRST GLANCE IT APPEARS LIKE
THE AREA MAY STILL SEE A FAIR SHOT FOR SOME SYNOPTIC LIFT...A
DEEPER INVESTIGATION REVEALED LESS POTENTIAL THAN IT FIRST SEEMED.
STILL...THE WARMER AND MOISTER ADVECTION FROM THE SOUTHWEST MAKES
THE IDEA OF AT LEAST A LITTLE SNOW REASONABLE...PARTICULARLY IN
CENTRAL AND EAST CENTRAL WISCONSIN. IN THIS SCENARIO...IT WOULD BE
APPROPRIATE TO EXPECT SNOW TOTALS OF AROUND TWO INCHES OR LESS. A
COLD FRONT ASSOCIATED WITH A LOW AND ITS ATTENDANT SHORTWAVE IN
THE NORTHERN STREAM WILL SHIFT WINDS TO NORTHWESTERLY AND CUT OFF
THE SNOW. FORTUNATELY THE MORE ZONAL FLOW LOOKS TO PREVENT A
STRONG SURGE OF COLD AIR TO CHOP DOWN TEMPERATURES BEHIND THE
FRONT AT THIS TIME.

HOWEVER...AFTER ALL THIS TALK...IT IS IMPORTANT TO REMEMBER THAT
IT IS ONLY TUESDAY. THOUGH A BROAD SCENARIO IS PRESENT IN ALL THE
GUIDANCE AND CONFIDENCE IN THAT IS MODERATE TO HIGH...CONFIDENCE
IN THE DETAILS THIS FAR OUT IS RELATIVELY LOW...AND COULD HAVE
SIGNIFICANT INFLUENCES ON THE SENSIBLE WEATHER WITH THIS FEATURE.
IT WOULD NOT BE WISE TO RULE OUT A SOUTHERN MISS NOR HIGHER
SNOWFALL POTENTIAL FROM A NORTHWARD DEVIATION JUST YET.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 529 PM CST TUE FEB 24 2015

ARCTIC COLD FRONT WILL SWEEP ACROSS THE REGION THIS EVENING...BRINGING
MUCH COLDER AIR AND DIMINISHING WINDS THIS EVENING. VFR CONDITIONS WILL
PREVAIL ACROSS MUCH OF THE REGION...EXCEPT ACROSS THE FAR NORTH THIS
EVENING WHERE SOME PATCHY MVFR/IFR CIGS ARE POSSIBLE IN LIGHT SNOW
SHOWERS OR FLURRIES. ADDED A 2 HOUR WINDOW FOR LIGHT SNOW IN THE 00Z
KRHI TAF FROM 00Z-02Z BASED ON SURFACE OBSERVATIONS ACROSS NORTHERN
WISCONSIN. VFR CONDITIONS WILL CONTINUE ON WEDNESDAY WITH NORTHWEST
TO NORTH WINDS OF 5 TO 10 KNOTS. WINDS AT KGRB/KATW MAY TURN TO THE
NORTHEAST WEDNESDAY AFTERNOON.

&&

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

$$

SHORT TERM.....MPC
LONG TERM......LUCHS
AVIATION.......ECKBERG