Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 240436
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1036 PM CST MON FEB 23 2015

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 253 PM CST MON FEB 23 2015

THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE SETTLING OVER THE MID-MISSISSIPPI VALLEY AND EXTENDING
ACROSS THE EASTERN GREAT LAKES.  CLEAR SKIES REMAIN ACROSS MOST OF
THE REGION EARLY THIS AFTERNOON WITH WIND CHILLS WARMING INTO THE 5
TO 15 BELOW RANGE.  CLOUDS ARE INCREASING OVER THE NORTHERN PLAINS
AHEAD OF A SHORTWAVE DIVING SOUTHEAST OVER LAKE WINNIPEG.  LIGHT
SNOW AND BLOWING SNOW ARE OCCURRING AHEAD OF THIS SHORTWAVE BUT
THESE ARE OCCURRING MAINLY NORTH OF THE BORDER.  SOME WIND GUSTS ARE
REACHING BETWEEN 30 AND 35 KNOTS.  AS THIS SHORTWAVE AND A MORE
POTENT WAVE BEHIND IT MOVING INTO THE REGION...SNOWFALL POTENTIAL
AND IMPACTS ARE THE MAIN FORECAST CONCERNS.

TONIGHT...LEAD SHORTWAVE TROUGH OVER THE LAKE WINNIPEG REGION WILL
WEAKEN AS IT MOVES INTO THE REGION THIS EVENING.  THE ARCTIC AIRMASS
AHEAD OF THIS WAVE IS VERY DRY...WHICH SHOULD KEEP THE AREA
PRECIP-FREE THROUGH THE EVENING.  THEN AS A SECONDARY AND STRONGER
SHORTWAVE ARRIVES LATE TONIGHT...STRONG FORCING SHOULD PUSH AN AREA
OF LIGHT SNOW ACROSS THE REGION FROM NORTHWEST TO
SOUTHEAST...POSSIBLY MAKING IT INTO THE FOX VALLEY BY 12Z.  ALTHOUGH
ACCUMULATIONS ARE EXPECTED TO REMAIN UNDER AN INCH...GUSTY SOUTHWEST
WINDS AHEAD OF THE SHORTWAVE WILL LEAD TO BLOWING AND DRIFTING SNOW
IN THE OPEN COUNTRY.  THE CLOUDS AND WIND WILL PREVENT TEMPS FROM
FALLING MUCH TONIGHT...AND WILL GO WITH LOWS IN THE MIDDLE SINGLE
DIGITS ABOVE ZERO.  WIND CHILLS WILL CONTINUE TO RANGE FROM 10 TO 20
BELOW THIS EVENING...THEN WARM AS TEMPERATURES RISE OVERNIGHT.

TUESDAY...THE LIGHT SNOW WILL CONTINUE TO SPREAD ACROSS THE FOX
VALLEY AND LAKESHORE AREAS EARLY IN THE MORNING BEFORE EXITING LATE
IN THE MORNING.  MID-LEVEL MOISTURE PEELS OUT BEHIND THE SHORTWAVE
DURING THE AFTERNOON...BUT STEEPENING LOW LEVEL LAPSE RATES WITHIN A
BROKEN CLOUD DECK COULD YIELD SCATTERED FLURRIES.  ADDITIONAL
ACCUMULATIONS COULD REACH UP TO A HALF INCH.  GUSTY SOUTHWEST WINDS
IN THE MORNING WILL TURN TO THE WEST AND THEN NORTHWEST IN THE
AFTERNOON AND WILL PROMOTE BLOWING AND DRIFTING SNOW.  WIND
TRAJECTORIES WILL BE PARALLEL TO DOOR COUNTY INITIALLY...BUT AS
WINDS VEER TO THE WEST AND THEN NORTHWEST...BLOWING AND DRIFTING
SNOW WILL INCREASINGLY BECOME A HAZARD TO THE WESTERN HALF OF THE
COUNTY EVEN AS WINDS SUBSIDE SOMEWHAT WITH THE APPROACH OF A SURFACE
TROUGH. SOME DISCUSSION WHETHER DOOR COUNTY WILL NEED A SNOW AND
BLOWING SNOW ADVISORY FOR TOMORROW.  THINK WINDS WILL BE SOUTHWEST
THROUGH MOST OF THE SNOW FALL TOMORROW MORNING AND AM UNCERTAIN HOW
CONDITIONS WILL BE AFTER SEVERAL HOURS OF BLOWING/DRIFTING SNOW
PRIOR TO THIS. WILL ISSUE AN SPS HIGHLIGHTING THIS HAZARD.
TEMPERATURES WILL BE THE WARMEST IN SEVERAL DAYS...AND RANGE FROM
THE LOWER 20S TO LOWER 30S.

.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 253 PM CST MON FEB 23 2015

A BIT OF A CHANGE IN THE UPPER FLOW PATTERN IS IN THE
OFFING...WITH THE WESTERN RIDGE DRIFTING WEST OVER THE PACIFIC AND
A CUT OFF LOW DEVELOPING OVER THE SOUTHWEST...SETTING UP SOMETHING
MORE AKIN TO A SPLIT FLOW PATTERN AS THE WEEK GROWS LATE. THE
NORTHERN STREAM STILL HOLDS SIGNIFICANT SWAY IN OUR AREA
UNFORTUNATELY...AND THE IMPACT ON SENSIBLE WEATHER IS UNLIKELY TO
BE SIGNIFICANT UNTIL LATE THIS WEEKEND OR EARLY NEXT WEEK.

SATELLITE IMAGERY INDICATES A PATCH OF SOMEWHAT OPEN WATERS ON
LAKE SUPERIOR ALONG A LAKE EFFECT FETCH FOR NORTH CENTRAL
WISCONSIN...AND BREEZY SOUTHWEST WINDS IN THE SHORT TERM SHOULD
KEEP THAT AREA FROM FREEZING OVER. THIS LEAVES POTENTIAL FOR
LINGERING LAKE EFFECT FLURRIES OR SNOW SHOWERS TUESDAY NIGHT
IN THE NORTH CENTRAL SNOW BELT...THOUGH ACCUMULATIONS SHOULD BE
SLIGHT TO NIL. GUSTY WINDS WILL BE DIMINISHING THROUGH THE EVENING
HOURS AS THE PRESSURE GRADIENT LOOSENS...BRINGING AN END TO
POTENTIAL FOR BLOWING SNOW.

ANOTHER BEEFY HIGH WILL FOLLOW IN TO GIVE US ANOTHER PLUNGE IN
TEMPERATURES...BUT BEFORE THAT A SHORTWAVE WILL SHOOT THROUGH
THE UPPER TROUGH. THE GEM STUBBORNLY BRINGS FLURRIES OR EXTREMELY
LIGHT ACCUMULATIONS TO PORTIONS OF CENTRAL AND EAST CENTRAL
WISCONSIN. THE REST OF THE GUIDANCE SHUNTS EVERYTHING WELL SOUTH
OF THE AREA...AND THE FORECAST JOINS THAT CAMP IN KEEPING THINGS
DRY HERE.

THE MAIN STORY FOR THE SECOND HALF OF THE WORK WEEK...AGAIN...WILL
BE SIGNIFICANTLY BELOW NORMAL TEMPS. THE COLD AIR REACHES ITS
NADIR WEDNESDAY AFTERNOON INTO THURSDAY. HIGHS IN THE SINGLE
DIGITS TO LOW/MID TEENS ARE EXPECTED WITH LOWS BELOW ZERO. WIND
CHILL ADVISORIES MAY RETURN FOR ANOTHER SEQUEL...BUT THIS COLD
PUSH DOES NOT LOOK TO MATCH PREVIOUS ITERATIONS...SO THERE IS LESS
CONFIDENCE IN THAT AT THIS TIME. THE ARCTIC AIR MASS BEGINS TO
MODERATE ON FRIDAY AND ESPECIALLY THIS WEEKEND...BUT TEMPERATURES
STILL LOOK TO REMAIN BELOW NORMAL.

HEADING INTO THE WEEKEND...AS A TROUGH DIGS OVER THE WEST COAST
AND THE FLOW ALOFT BECOMES SOUTHWESTERLY. THIS FLOW WILL PUSH IN A
SLUG OF MOISTURE FROM THE SOUTHERN PLAINS FOR THE SECOND HALF OF
THE WEEKEND. MODELS ARE IN AGREEMENT SHOWING THE MOISTURE AND
PUSH OF WARMER AIR. HOWEVER...THERE IS SPREAD IN HOW FAR NORTH
THIS AIR GETS...WITH SIGNIFICANT IMPACTS ON SNOW POTENTIAL. THE
CANADIAN HOLDS COLD AIR OVER THE GREAT LAKES AND SENDS YET ANOTHER
WINTER STORM THROUGH THE MID-SOUTH AND FAR AWAY FROM OUR AREA. THE
GFS AND ECMWF ARE MORE READY TO BRING A MORE SIGNIFICANT SYSTEM
TOWARDS THE GREAT LAKES. AT THIS TIME IT AGAIN APPEARS THAT THE
HIGHEST SNOWFALL TOTALS WILL MISS THE AREA. HOWEVER...IT IS
POSSIBLE...GIVEN THE CURRENT GUIDANCE ENVELOPE...FOR ENOUGH
SNOWFALL TO MEET ADVISORY CRITERIA IN CENTRAL AND EAST CENTRAL
WISCONSIN. ULTIMATELY...THE MODEL SOLUTIONS ARE RELATIVELY FRAGILE
THIS FAR OUT...AND THE BEST ADVICE IS TO FOLLOW UPDATED FORECASTS
AS THE WEEK CONTINUES.

&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1000 PM CST MON FEB 23 2015

GUSTY SOUTHWEST WINDS WILL CONTINUE OVERNIGHT INTO TUESDAY MORNING...
THEN SHIFT TO THE WEST OR NORTHWEST DURING THE DAY TUESDAY. LOW LEVEL
WIND SHEAR WILL CONTINUE INTO TUESDAY MORNING. LIGHT SNOW ACROSS
NORTHERN MINNESOTA WILL OVERSPREAD MUCH OF NORTH-CENTRAL AND NORTHEAST
WISCONSIN LATE TONIGHT INTO TUESDAY MORNING. PROGRESSION OF THE SNOW
IS A LITTLE SLOWER DUE TO SATURATION ISSUES. LIGHT WILL END ACROSS
SOUTH LATE TUESDAY MORNING OR EARLY AFTERNOON...LINGERING LONGER INTO
THE AFTERNOON ACROSS THE NORTH. VFR CIGS WILL GIVE WAY TO MVFR CIGS
LATE TONIGHT AND TUESDAY MORNING ACROSS THE NORTH...THEN BECOME VFR
AGAIN LATER TUESDAY AFTERNOON.

&&

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

$$

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





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