Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 262349
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
549 PM CST FRI DEC 26 2014

UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 326 PM CST FRI DEC 26 2014

PRIMARY FCST CONCERN WILL BE BAND OF MODERATE SNOW EXPECTED TO
DEVELOP AFTER MIDNIGHT ACROSS PARTS OF CENTRAL AND NORTHERN
WISCONSIN.

SLOW MOVING COLD FRONT STILL SAGGING SOUTHWARD ACROSS THE FOX
VALLEY LATE THIS AFTERNOON. FRONT HAS JUST MOVED SOUTH OF GREEN
BAY AS OF 3 PM. FROM WILL CONTINUE TO DRIFT INTO SOUTHEAST
WISCONSIN THIS EVENING.

MODEL GUIDANCE SEEMS TO BE IN FAIRLY GOOD AGREEMENT ON DEVELOPMENT
OF SURFACE WAVE ON THE FRONT OVER NORTHWEST MISSOURI THIS
EVENING...THEN TAKING THE SURFACE LOW NORTHEAST ALONG THE
BAROCLINIC ZONE ACROSS THE SOUTHERN HALF OF WISCONSIN DURING THE
MORNING ON SATURDAY. A FAIRLY ROBUST SHORTWAVE IMPULSE IN CONCERT
WITH MID-LEVEL FRONTOGENETIC FORCING WILL PROVIDE DECENT MESOSCALE
LIFT OVER THE FORECAST AREA GENERALLY FOCUSED ON THE 12Z TO 18Z
TIME FRAME. FEEL THIS WILL BE THE PERIOD OF HIGHEST SNOWFALL RATES
AND MOST RAPID SNOWFALL ACCUMULATIONS. SHORTWAVE IMPULSE SHOULD
QUICKLY SWEEP EAST OF THE FORECAST AREA SATURDAY AFTERNOON PUTTING
AN END TO THE SNOWFALL. IT APPEARS THAT THE SOUTHERN EDGE OF THE
DEFORMATION ZONE PRECIPITATION SHIELD SHOULD TRACK FROM ABOUT LSE
TO GRB WITH THE AXIS OF HEAVIEST SNOW NORTH OF THERE...FROM ABOUT
MERRILL TO IRON MOUNTAIN MICHIGAN. BASED ON FORECAST QPF...MODEST
SNOW-TO-LIQUID RATIOS AND PROGRESSIVE NATURE OF THE SYSTEM...MAX
STORM TOTAL SNOWFALL AMOUNTS SHOULD GENERALLY BE IN THE 3 TO 5
INCH RANGE. MODEL THERMAL PROFILES SUGGEST THAT THE ELEVATED ABOVE
FREEZING LAYER MAY MAKE IT AS FAR NORTH AS SUE TO GRB TO ABOUT
KPCZ BY 12Z SATURDAY...THUS FEEL SNOW WILL BE MIXED WITH RAIN OVER
THE SOUTHERN PORTION OF THE ADVISORY AREA...THUS REDUCING SNOW
TOTALS THERE. ALTHOUGH THE SOUTHERN PORTION OF THE ADVISORY AREA
WEST OF THE FOX VALLEY MAY STRUGGLE TO REACH THE 3 INCH
MARK...GIVEN THE TIMING OF THE MAXIMUM LIFT FOR SATURDAY MORNING
AND HOLIDAY WEEKEND TRAVEL....PLAYED IT SAFE AND DECIDED TO
INCLUDE WOOD THROUGH WAUPACA COUNTIES IN THE ADVISORY.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 326 PM CST FRI DEC 26 2014

BIG CHANGES ARE COMING TEMPERATURE-WISE WITH MUCH COLDER WEATHER
ON ITS WAY. ENJOY THE WARMTH TODAY AND SUNDAY...BECAUSE BY MID-
WEEK TEMPERATURES WILL DROP WELL BELOW NORMAL AND REMAIN COLD FOR
A WHILE. OTHERWISE...NO MAJOR STORMS ON THE HORIZON...WITH SUNDAY
NIGHT AND MONDAY LOOKING LIKE THE ONLY TIME FRAME FOR MEASURABLE
PRECIP CHANCES.

LOW PRESSURE SYSTEM WILL BE PULLING AWAY SATURDAY NIGHT. PRECIP
SHOULD END THROUGH OUT MOST OF THE AREA BY 00Z SUNDAY...WITH JUST
A SLIGHT CHANCE OF SNOW ALONG THE NORTHERN LAKESHORE AND NE
WISCONSIN.

A WESTERN RIDGE WILL SET UP BY EARLY NEXT WEEK...AND ALLOW FOR THE
ARCTIC TO OPEN UP AND SPILL COLD AIR OVER MUCH OF THE US. COLD
FRONT SLIPS SOUTH SUNDAY AND USHER IN THE FIRST WAVE OF COLDER
TEMPS. MODELS A BIT FASTER WITH THE FRONTAL PASSAGE. CAA THEN
CRANKS UP MONDAY AND REINFORCES THE BITTERLY COLD AIR. COLDEST
TIME THROUGH THE PERIOD LOOKS TO BE TUESDAY INTO TUESDAY NIGHT
WITH CLEAR SKIES AND FALLING 850MB TEMPS ALLOWING FOR BELOW ZERO
LOWS TUESDAY NIGHT. THIS COLD AIR PATTERN HOLDS TIGHT THROUGH THE
FIRST WEEK OF THE NEW YEAR...WITH ONLY SOME HINTS OF THE WESTERN
RIDGE BREAKING DOWN TOWARDS THE END OF NEXT WEEK.

AN ARCTIC FRONT WILL DROP SOUTH SUNDAY AFTERNOON AND MONDAY.
MODELS DISAGREE WHETHER THIS FEATURE WILL PRODUCE ANY
PRECIPITATION. SOME OF THE MODELS HAVE LIGHT SNOW WITH THE FRONT
AS IT GETS SOME HELP FROM A MIDLVL DISTURBANCE SWINGING THROUGH
THE STATE MONDAY. IN FACT...THE LATEST NAM RUN INCREASED QPF AND
PRECIP COVERAGE WITH LIGHT SNOW CONTINUING INTO TUESDAY. ON THE
OTHER SIDE...SOME MODELS HAVE ALMOST NO PRECIP WITH THIS FRONT AS THE
MIDLVL WAVE IS NEARLY NON- EXISTENT. SEEMS LIKE MODELS ARE
TRENDING TOWARDS THE NON-DRY SOLUTION WITH MORE MODELS IN THE
PRECIP-BOAT THAN THE DRY-BOAT. ADDED SLIGHT CHANCE ACROSS THE
CWA. NOT ENOUGH CERTAINTY EITHER WAY TO BUMP UP POPS MORE OR
HIGHLIGHT ANY SPECIFIC TIME FRAME/AREA...SO SLIGHT CHANCES FOR
EVERYONE.

SOME LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE NORTHWOODS
THROUGH WEDNESDAY WITH THE NORTHWEST FLOW...BUT NOTHING
SIGNIFICANT IS EXPECTED AT THIS TIME. OTHERWISE...DRY WEATHER
SHOULD CONTINUE FOR THE REST OF NEXT WEEK.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 548 PM CST FRI DEC 26 2014

MAINLY LOWER END MVFR OR IFR CIGS WILL LINGER OVER
THE AREA THIS EVENING. THE LOW CIGS WERE NORTHWEST OF A FRONT
WHICH AS OF 500 PM FRIDAY AFTERNOON EXTENDED FROM NORTHERN LOWER
MICHIGAN TO EAST CENTRAL WISCONSIN TO NORTHEAST IOWA. CONDITIONS
WILL FURTHER DETERIORATE OVERNIGHT INTO SATURDAY MORNING AS A LOW
PRESSURE SYSTEM SLIDES NORTHEASTWARD ALONG THIS FRONT. WIDESPREAD
SNOW WITH IFR/MVFR VSBYS WILL SPREAD OVER THE AREA OVERNIGHT.
PARTS OF EAST CENTRAL WISCONSIN MAY SEE A MIX OF RAIN AND SNOW.
AS THIS SURFACE WAVE DEPART NORTHEASTWARD LATER SATURDAY...CONDITIONS
WILL BEGIN TO IMPROVE ACROSS THE REGION.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST
SATURDAY FOR WIZ005-010>012-018>020-030-031-035>037.

WINTER WEATHER ADVISORY FROM 3 AM TO 3 PM CST SATURDAY FOR
WIZ013-021-073-074.
&&

$$

SHORT TERM.....ESB
LONG TERM......ALLEN
AVIATION.......TDH





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