Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 201759
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1259 PM CDT MON OCT 20 2014

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 404 AM CDT MON OCT 20 2014

CYCLONIC UPPER FLOW AND COLD ADVECTION OVER LAKE SUPERIOR WILL
COMBINE TO BRING INCREASING CLOUDS TO THE REGION TODAY.
TEMPERATURES ALOFT ARE NOT REALLY COLD ENOUGH FOR LAKE EFFECT
SHOWERS THOUGH THERE COULD BE A FEW SPRINKLES. IT IS DEFINITELY
COLD ENOUGH TO PRODUCE LAKE EFFECT CLOUDS. HIGHS TODAY WILL DEPEND
ON HOW QUICKLY CLOUDS ARRIVE BUT SHOULD TURN OUT TO BE WITHIN A
FEW DEGREES OF THE SEASONAL NORMALS.

CLOUDS SHOULD DIMINISH TONIGHT AS DRIER AIR ARRIVES FROM THE
NORTH. CLOUDS WILL BE SLOWEST TO LEAVE NEAR LAKE MICHIGAN WHERE A
NORTHEAST FLOW IN THE LOW LEVELS WILL GENERATE LAKE EFFECT CLOUDS.
CLOUDS AND A BIT OF A BREEZE WILL KEEP TEMPERATURES NEAR NORMAL.

TUESDAY SHOULD BE SUNNY AND COOL AS SURFACE HIGH PRESSURE MOVES IN
FROM THE NORTH. HIGHS SHOULD BE AROUND 5 DEGREES BELOW NORMAL.

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 404 AM CDT MON OCT 20 2014

PRIMARY FCST CONCERN CONTS TO BE THE MDL INCONSISTENTCY BETWEEN A
WEAKENING UPR TROF OVER THE GREAT LAKES AND INCOMING SHORTWAVE
TROF/CDFNT COUPLET LATE WED NGT INTO THU EVENING. WL THERE BE ENUF
FORCING/MOISTURE FROM THIS SYSTEM TO BRING PCPN INTO NE WI? BEYOND
THU...A BROAD UPR RDG TO EXTEND FROM THE SRN PLAINS NWD INTO
S-CNTRL CANADA WITIH UPR TROFS OVER THE WEST COAST AND THE NE
CONUS. THIS BRINGS A W-NW MEAN FLOW INTO WI WITH THE MAIN STORM
TRACK PASSING US BY TO THE NORTH. THIS TRANSLATES TO A BELOW
NORMAL PCPN TREND WITH TEMPS ABOVE NORMAL.

NE WI TO RESIDE UNDER AN UPR RDG AXIS...WHILE THE SFC RDG TO BE
SITUATED JUST TO OUR EAST TUE NGT. OTHER THAN SOME PASSING LAKE
CLOUDS FROM LAKE MI...THE REST OF THE FCST AREA WL SEE MAINLY
CLEAR SKIES...LIGHT WINDS AND COOL TEMPS. LOOK FOR MIN TEMPS TO
RANGE FROM THE MID TO UPR 20S NORTH AND PARTS OF CNTRL WI...TO THE
MID TO UPR 30S OVER DOOR CNTY.

THE UPR RDG AXIS TO REMAIN ANCHORED OVER THE WRN GREAT LAKES
REGION THRU WED...THUS A MOSTLY SUNNY DAY IS ANTICIPATED WITH
RELATIVELY LIGHT S-SE WINDS. WARMEST TEMPS SHOULD BE OVER CNTRL WI
WHERE THE WIND TO HAVE MORE OF A SOUTHERLY COMPONENT. LOOK FOR
READINGS TO REACH THE LWR 50S NEAR LAKE MI...TO THE MID TO UPR 50S
ACROSS N-CNTRL/CNTRL WI.

THE MDLS AGREE IN THE GENERAL PRINCIPLE OF WEAKENING THE UPR RDG
WED NGT AS A SHORTWAVE TROF/ASSOCIATED CDFNT MAKE A PUSH TOWARD
THE UPR MS VALLEY BY 12Z THU. SOME MID/HI CLOUDS MAY BE ABLE TO
WORK INTO CNTRL WI LATER WED NGT WITH AN ISOLATED SHWR POSSIBLE
OVER N-CNTRL WI TOWARD DAYBREAK. OTHERWISE...THE REST OF THE FCST
AREA SHOULD EXPECT MOSTLY CLEAR SKIES TO HOLD OVER MOST OF THE
AREA. MORE OF A SOUTH BOUNDARY LAYER WIND IN PLACE BY THIS TIME...
SO TEMPS WL NOT BE AS COOL AS TUE NGT. INSTEAD...LOOK FOR READINGS
TO RANGE FROM THE LWR TO MID 30S FAR NE WI...TO AROUND 40 DEGS
OVER DOOR CNTY.

MDLS ARE STILL STRUGGLING WITH THE STRENGTH OF THE SHORTWAVE TROF...
AMOUNT OF FORCING AND MOISTURE AVAILABLE...AND EXACTLY HOW FAR EAST
TO BRING THE PCPN CHCS. SEEMS LIKE EVERY NEW MODEL RUN IS DIFFERENT
THEN THEIR RESPECTIVE PREVIOUS RUN...THUS CONFIDENCE IS LAGGING
OVERALL WITH THIS SYSTEM. FOR NOW...HAVE FOLLOWED THE CONSENSUS
SOLUTION OF BRINGING LOW-END POPS ACROSS ALMOST ALL OF THE FCST
AREA ON THU. MAX TEMPS SHOULD BE GENERALLY IN THE MID TO UPR 50S.

IF THE SLOWER MODEL SOLUTION TURNS OUT TO BE CORRECT...PCPN CHCS
WOULD NEED TO BE CARRIED OVER INTO THU NGT. ANY PCPN BY THIS POINT
WOULD BE VERY LIGHT AS THE MAIN FORCING/LIFT SHIFT TO OUR EAST. BY
FRI...THE SOMEWHAT FLAT-LOOKING UPR RDG TO BUILD NORTH AND EAST
ACROSS THE PLAINS INTO THE UPR MIDWEST...SENDING DRIER/WARMER AIR
MASS INTO WI. AS SKIES BECOME PARTLY CLOUDY...TEMPS WL JUMP UPWARD
WITH READINGS IN THE UPR 50S TO LWR 60S.

AN INCOMING SHORTWAVE TROF IS PROGGED TO APPROACH THE WEST COAST
ON SAT AND HELP TO STRENGTHEN THE DOWNSTREAM UPR RDG OVER THE
CNTRL CONUS. A PACIFIC SYSTEM IS FCST TO MOVE ACROSS SRN CANADA
FRI NGT INTO SAT AND SEND A WEAK CDFNT THRU NE WI. FORCING IS ALL
BUT NEGLIGIBLE AND MOISTURE IS ALSO LOOKING RATHER MEAGER...EXPECT
TO SEE A DRY FROPA LATE FRI NGT WITH A WIND SHIFT TO THE NW FOR
SAT. NOT MUCH CHANGE TO THE AIR MASS BEHIND THE FRONT...THUS LOOK
FOR MAX TEMPS TO BE SIMILAR TO FRI.

UPR RDG TO STILL DOMINATE THE CNTRL CONUS THRU SUNDAY ALONG WITH
THE PASSAGE OF A SURFACE HI. QUIET AND PLEASANT AUTUMNAL WEATHER
CAN BE EXPECTED WITH TEMPS 5 TO 10 DEGS ABOVE NORMAL.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1259 PM CDT MON OCT 20 2014

CLOUDS CONTINUED TO SPREAD ACROSS THE AREA DURING THE
MORNING...LEAVING MOST LOCATIONS WITH BKN TO OVC CONDITIONS BY
MIDDAY. CIGS WERE MOSTLY MVFR IN CENTRAL AND NORTH CENTRAL
WISCONSIN. THERE WERE ISOLATED IFR CIGS IN FAR NORTH CENTRAL
WISCONSIN AND THERE HAS BEEN SOME LIGHT RAIN AND/OR DRIZZLE
THERE...WHICH SHOULD END BY SUNSET. VFR CIGS PREVAILED IN THE
EAST WHERE DOWN SLOPE KEPT CLOUD BASES ABOVE 3000FT. CIGS OVER
DOOR COUNTY WERE MVFR DUE TO BAY EFFECTS.

THE CLOUD FORECAST WILL BE TRICKY DURING THIS TAF VALID PERIOD.
SURFACE HIGH PRESSURE WILL BE MAKING ITS WAY INTO THE REGION AS A
MID LEVEL RIDGE APPROACHES FROM THE WEST. AS LOW LEVEL WINDS
BECOME MORE NORTH THAN NORTHWEST ANY RAIN OR DRIZZLE WILL COME TO
AN END. CLOUDS BASES SHOULD BEGIN TO RISE BEFORE CONDITIONS BECOME
SCT LATE TONIGHT/EARLY TUESDAY. CANADIAN CLOUD FORECAST OFF THE
GEM-REG HAD CLOUDS STARTING TO BREAK UP IN CENTRAL...AND PARTS OF
EAST CENTRAL...WISCONSIN THIS EVENING. CLOUDS OVER LAKE MICHIGAN
THEN MOVE INLAND EARLY IN THE MORNING AS CLOUDS ACROSS THE REST OF
THE AREA DISSIPATE...WHICH MAKES SENSE BASED ON 925MB WIND
FORECASTS. EXPECT THESE CLOUDS TO BRING MVFR CIGS. TIME HEIGHT
PLOTS FORM 12Z NAM/09Z SREF/12Z GFS ALL INDICATED DRYING AT LOW
LEVELS...SO LOOKS LIKE CLOUDS SHOULD BE BREAKING UP ACROSS MOST OF
THE AREA AROUND MIDDAY.
&&

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

$$

SHORT TERM.....RDM
LONG TERM......KALLAS
AVIATION.......MG





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