Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 152131
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
331 PM CST SAT NOV 15 2014

FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 329 PM CST SAT NOV 15 2014

THE MAIN CONCERNS DURING THIS PART OF THE FORECAST ARE SNOW TIMING
AND AMOUNTS.

SNOW THAT WAS OVER IOWA AND MINNESOTA EARLIER TODAY WAS JUST
ENTERING CENTRAL WISCONSIN EARLY THIS AFTERNOON. THE SNOW WAS
AHEAD OF A SURFACE TROUGH AND A SIGNIFICANT UPPER LEVEL
TROUGH...AND WAS IN THE LEFT EXIT REGION OF A 250MB JET MAX. THE
TROUGHS CONTINUE EASTWARD DURING THE SHORT TERM AND STRONGER UPPER
DIVERGENCE DEVELOPS ACROSS THE FORECAST AREA DUE TO A COUPLED
UPPER JET STRUCTURE.

12Z ECMWF HAD QPF SPREAD ACROSS MUCH OF THE AREA BY 00Z SUNDAY...FASTER
THAN THE 12Z NAM OR 12Z GFS. HAVE OPTED TO TAKE THE SLOW ROUTE
BASED ON HOW DRY THE MORNING SOUNDINGS WERE IN THE REGION. THERE
WERE RADAR ECHOES ACROSS MUCH OF THE AREA BUT THE ONLY SNOW
REACHING THE GROUND WAS IN CENTRAL WISCONSIN AT 21Z. MODELS IN
AGREEMENT ON QPF ACROSS THE AREA 00Z-12Z BUT QPF TOTALS WERE LOW.
SO TONIGHT LOOKS LIKE IT WILL SEE THE MAJORITY OF THE SNOW. PWATS
WERE MOSTLY IN THE 0.11 TO 0.21 INCH RANGE...CARIBOU SNOW AMOUNT
TOOL FROM 12Z NAM...12Z GFS...09Z SREF ALL HAD ABOUT 1 TO 2 INCHES
OF ACCUMULATION ACROSS THE AREA AND WPC INTERNAL GUIDANCE HAD LESS
THAN 2 INCHES FROM 00Z SUNDAY THROUGH 00Z MONDAY. BASED ON THESE
FACTORS AND COLLABORATION WITH ARX AND MKX...HAVE OPTED NOT TO
ISSUE AN ADVISORY.

THE SNOW SHOULD BE MOVING OUT OF THE AREA BY MIDDAY ON SUNDAY WITH
LITTLE ADDITIONAL ACCUMULATION. THERE MAY BE PARTIAL CLEARING...BUT
THERE WILL LIKELY STILL BE PLENTY OF CLOUDS THROUGHOUT THE DAY.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 329 PM CST SAT NOV 15 2014

COLD AIR WILL REMAIN ENTRENCHED OVER THE REGION FOR MUCH OF THE
NEW WORK WEEK DUE TO THE PERSISTENT WESTERN UPPER RIDGE AND
NORTHWEST FLOW ALOFT REGIME. MODELS REMAIN CONSISTENT WITH A SHIFT
TO A MORE ZONAL FLOW BY THE END OF THE WEEK AND INTO THE WEEKEND
FOR A BREAK FROM THE WELL BELOW NORMAL TEMPERATURES TO PERHAPS
BELOW NORMAL TEMPERATURES. WILL BE TOUGH TO DISLODGE THIS COLD AIR
MASS.

A DEEP SHORT WAVE TROUGH OR UPPER LOW WILL DROP INTO THE GREAT
LAKES REGION SUNDAY NIGHT INTO MONDAY BEFORE SHIFTING EAST OF THE
AREA MONDAY NIGHT. A COLD FRONT WILL SLIDE OVER SUNDAY NIGHT INTO
MONDAY MORNING. NORTHWEST WINDS IN THE FRONTS WAKE WILL SERVE TO
REINFORCE THE COLD AIR MASS FOR THE EARLY PART OF THE WEEK. SYSTEM
PRECIPITATION IS NOT EXPECTED TO BE MUCH WITH PWATS LESS THAN 0.25
BUT LIGHT SNOW SHOWERS OR FLURRIES WILL BE ON THE INCREASE SUNDAY
NIGHT INTO MONDAY WITH THE FALLING UPPER HEIGHTS.

ANTICIPATE BRUNT OF ANY ACCUMULATION MONDAY INTO EARLY TUESDAY WILL
BE WITH LAKE EFFECT SNOW ACTIVITY. WITH THE WIND DIRECTION
BECOMING MORE NORTHWEST AT THE H850 LEVEL...EXPECT LAKE EFFECT
SNOWS TO INCREASE FOR LAKE SUPERIOR...WITH POSSIBLY A PERIOD OF
FAVORABLE DIRECTION FOR FAR NORTH CENTRAL OR VILAS COUNTY LATE
MONDAY AFTERNOON INTO MONDAY NIGHT. BEING NOVEMBER WITH THIS COLD
AIR MASS...DELTA T/S NEAR 20 WITH FORECAST SOUNDINGS INDICATING
LITTLE OR NO INVERSION. GOING FORECAST ALREADY FOCUSED ON THIS
POTENTIAL SO NO CHANGES NEEDED AT THIS TIME BUT WILL CONTINUE TO
HIGHLIGHT IN THE HWO.

WITH THE DEVELOPING BLUSTERY NORTHWEST WINDS ON MONDAY...WIND
CHILL READINGS MAY DROP TO THE -4 TO -9 RANGE OVER PARTS OF
CENTRAL AND NORTH CENTRAL WISCONSIN MONDAY MORNING FOLLOWED WITH
AN EVEN COLDER -8 TO -15 WIND CHILL MINIMUM TUESDAY MORNING. THE
SURFACE PRESSURE GRADIENT BECOMES QUITE STRONG MONDAY NIGHT INTO
TUESDAY. WHILE NOT QUITE IN THE WIND CHILL READINGS...LATEST
NUMBERS GETTING CLOSE SO WILL START TO HIGHLIGHT IN THE HWO DUE TO
BEING STILL NOVEMBER.

A WEAK RIDGE PASSING OVER LATER TUESDAY INTO TUESDAY NIGHT WILL
BRIEFLY END THE LAKE EFFECT SNOW SHOWERS ACROSS THE
NORTH...HOWEVER ANOTHER SHORT WAVE TROUGH WITH COLD FRONT IS
EXPECTED TO DROP OVER MID WEEK TO KEEP THE COLD AIR MASS IN PLACE
ALONG WITH ANOTHER CHANCE LAKE EFFECT SNOWS FAR NORTH AND A CHANCE
FOR SNOW SHOWERS ELSEWHERE. THE NORTHWEST FLOW OFF LAKE SUPERIOR
HANGS AROUND INTO THURSDAY FOR CONTINUED SNOW SHOWERS FAR NORTH.

PROGS CONTINUE TO HINT AT A MORE ZONAL FLOW DEVELOPING BY THE
WEEKEND...WITH TEMPS MODIFYING SOME BUT STILL BELOW NORMAL.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1151 AM CST SAT NOV 15 2014

VFR CONDITIONS AT TAF ISSUANCE TIME ARE EXPECTED TO DETERIORATE
LATER THIS AFTERNOON AND OVERNIGHT AS LOWER CLOUDS AND SNOW SPREAD
ACROSS THE AREA FROM THE WEST. LIGHT SNOW WILL REACH CENTRAL
WISCONSIN THIS AFTERNOON AND CONTINUE ACROSS THE REST OF THE AREA
THROUGHOUT THE NIGHT. THE SNOW WILL BRING MVFR/IFR CONDITIONS WITH
IT. SNOW SHOULD BE DECREASING SUNDAY MORNING...AND VSBYS WILL
IMPROVE AS THE IT WINDS DOWN. CIGS SHOULD STILL BE MOSTLY IN THE
MVFR CATERGORY.
&&

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

$$

SHORT TERM.....MG
LONG TERM......TDH
AVIATION.......MG






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