Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 222017
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
317 PM CDT TUE APR 22 2014

FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 317 PM CDT TUE APR 22 2014

THE MAIN CONCERNS DURING THIS PART OF THE FORECAST ARE LOW
TEMPERATURES TONIGHT AND TIMING OF RAIN CHANCES ON WEDNESDAY.

CLOUDS IN COLD CYCLONIC FLOW ACROSS NORTHEAST WISCONSIN HAD NOT
YET EXITED THE STATE AS OF 1930Z. SOME CUMULUS DEVELOPED IN AREAS
THAT CLEARED...BUT WAS MAINLY SCATTERED IN NATURE. EXPECT CLOUDS
TO CLEAR OUT DURING THE LATE AFTERNOON AND EVENING WITH LOSS OF
DAYTIME HEATING AND SURFACE AND UPPER RIDGES APPROACHING. WINDS
WILL DIE OFF AS A SURFACE RIDGE OVER MINNESOTA MOVES TO WISCONSIN
BY 12Z WEDNESDAY. DEW POINTS AT 19Z WERE ONLY IN THE 20S SO IT
LOOKS LIKE LOWS SHOULD BE IN THE UPPER TEENS AT SOME LOCATIONS
ALONG THE UPPER MICHIGAN BORDER AND MOSTLY 20S ACROSS THE REST OF
THE AREA. CIRRUS THICKENING AND INCREASING AHEAD OF A DEVELOPING
SYSTEM OVER THE WESTERN CONUS SHOULD KEEP TEMPERATURES FROM
FALLING TOO MUCH BELOW DEW POINTS.

BUFKIT TIME SECTIONS FROM 12Z NAM/12Z GFS/09Z SREF SHOWED CLOUD
BASES STEADILY LOWERING ON WEDNESDAY. THE 12Z NAM KEPT RAIN AWAY
UNTIL AFTER 00Z THURSDAY AND 12Z ECMWF QPF ONLY REACHED THE FAR
SOUTHWEST CORNER OF THE FORECAST AREA BY THAT TIME. FORECAST
SOUNDINGS FROM THE SREF AND GFS STILL HAD DRY AIR AT LOWER LEVELS
WEDNESDAY AFTERNOON...AT THE SAME TIME THEY WERE FORECASTING
PRECIPITATION. WITH THIS IN MIND...SIDED WITH SLOWER MODELS WHICH
IS ALSO WHAT MKX WAS THINKING. CHANCE POPS AND A SMALL AREA OF
LIKELY POPS CONFINED TO CENTRAL WISCONSIN LATE WEDNESDAY
AFTERNOON. KEPT TEMPERATURES CLOSE TO 12Z MOS AND THE PREVIOUS
FORECAST FOR HIGHS ON WEDNESDAY.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 317 PM CDT TUE APR 22 2014

PRIMARY FOCUS FOR THIS PERIOD OF TIME CENTERS ON THE UPPER LOW
SYSTEM WITH FRONTAL SYSTEM TRACKING OVER THE GREAT LAKES REGION
WEDNESDAY NIGHT INTO FRIDAY...FOLLOWED WITH DRYING CONDITIONS WITH A
HUDSON BAY HIGH SETTLING IN FOR PART OF THE WEEKEND. THEN MODEL
RUNS BECOME INCONSISTENT WITH RESPECT TO VARIOUS SOLUTIONS EARLY
NEXT WEEK.

AN UPPER LOW SYSTEM PROGGED THE LAST FEW DAYS TO MOVE OVER THE
GREAT LAKES REGION MID WEEK STILL ON TRACK. HOWEVER SOME CHANGES
NEEDED WITH RESPECT TO PCPN TYPE ACROSS THE NORTH FOR PART OF THE
PERIOD THROUGH FRIDAY. INSTABILITY PROGS THE LAST FEW RUNS HAVE
INDICATED VERY MARGINAL INSTABILITY. HAVE NOT BEEN ADVERTISING
SEVERE WEATHER WITH THIS SYSTEM THIS WEEK AND DO NOT SEE ANY
REASON TO CHANGE THAT PLAN. HOWEVER OF NOTICE IS THE AIR COLUMN
ACROSS THE NORTH HAS TRENDED COLDER WITH THIS SYSTEM. PREVIOUS
SHIFT ADDED MORE OF A MIX ACROSS THE NORTH AND LATEST RUNS HAVE
NOT DEVIATED FROM THAT TREND. A FEW INCHES OF SNOW ACCUMULATION
IS POSSIBLE OVER PARTS OF NORTH CENTRAL AND NORTHEAST WISCONSIN
WEDNESDAY NIGHT WITH A COLD DRY AIR MASS TO START WITH...THEN
AGAIN LATER THURSDAY NIGHT INTO FRIDAY MORNING WITH CAA ON THE
BACKSIDE OF THE SYSTEM. AN SPS AND POSSIBLY A WINTER WEATHER
ADVISORY COULD BE ISSUED ACROSS THE NORTH IF THIS COLD TREND
CONTINUES.

OTHERWISE BRUNT OF THE RAIN EXPECTED TO SPREAD INTO CENTRAL
WISCONSIN BY THURSDAY MORNING OVER CENTRAL WISCONSIN AS THE H850
WARM FRONT LIFTS NORTHWARD ON A 35 KNOT LLJ...THEN SPREADING OVER
THE REST OF FORECAST AREA THURSDAY INTO THURSDAY EVENING WITH
CONTINUED WAA AND MOISTURE RETURN. PWATS CLIMB TO NEAR AN INCH
OVER CENTRAL AND EAST CENTRAL WISCONSIN ON THURSDAY.

COOL DRY CONDITIONS FROM A HUDSON BAY HIGH TO WORK INTO THE GREAT
LAKES REGION BY SATURDAY. HOWEVER MODEL SOLUTIONS DIVERT FROM
MODEL TO MODEL AND RUN TO RUN ON WHETHER A BLOCKING UPPER RIDGE
WITH A HUDSON BAY HIGH WILL HOLD SWAY THROUGH EARLY NEXT WEEK OR
BREAK DOWN WITH ANOTHER UPPER LOW SYSTEM WORKING ACROSS THE MID
SECTION OF THE COUNTRY. OVERALL WILL KEEP SMALL CHC POPS GOING
THROUGH MUCH OF THE LATER PERIODS...BUT IF POPS END UP INCREASING
LATE NEXT WEEKEND INTO NEXT WEEK...COLD DRY FEED OF AIR WILL
PRODUCE PCPN TYPE ISSUES AS THE COLDER AIR IS PUSHED NORTH AGAIN.
FORECAST CONFIDENCE AT THIS TIME STARTING SUNDAY IS VERY LOW.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1239 PM CDT TUE APR 22 2014

CLOUDS THAT COVERED MUCH OF THE FORECAST AREA THIS MORNING WERE
SLOWLY EXITING TO THE EAST. CUMULUS WAS DEVELOPING AT MIDDAY IN
LOCATIONS THAT CLEARED OUT EARLY. VFR CONDITIONS PREVAILED ACROSS
THE AREA AT TAF ISSUANCE TIME...EXCEPT FOR SOME LOCATIONS NEAR THE
UPPER MICHIGAN BORDER WHERE CIGS WERE IN THE 2500-3000FT RANGE.
MVFR CLOUDS SHOULD EXIT AND/OR CIGS INCREASE DURING THE AFTERNOON.
OTHERWISE EXPECT MAINLY SCT-BKN CU ACROSS MUCH OF THE FORECAST
AREA...WITH CLOUDS DISSIPATING LATER THIS AFTERNOON. GUSTY
NORTH/NORTHWEST WINDS SHOULD BECOME LIGHT AS SURFACE HIGH PRESSURE
PUSHES EASTWARD ACROSS WISCONSIN TONIGHT. HIGH CLOUDS SHOULD MOVE
IN OVERNIGHT AND WINDS WILL INCREASE WEST OF THE SURFACE RIDGE
AXIS.
&&

.HYDROLOGY...
ISSUED AT 317 PM CDT TUE APR 22 2014

DRY WEATHER THROUGH MOST OF WEDNESDAY WILL CONTINUE
TO ALLOW RIVERS TO DECLINE THROUGH WEDNESDAY. NEXT SYSTEM TO
IMPACT THE REGION LIKELY TO PRODUCE AN INCH TO 1.25 INCHES FOR A
TWO DAY TOTAL FROM WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. EMBEDDED
STORMS IN THE RAIN ON THURSDAY MAY PRODUCE LOCALLY HIGHER AMOUNTS.
ASSUMING THIS RAIN FALLS OVER THE 2 DAY PERIOD...RIVERS EXPECTED
TO BE NEARLY STEADY OR SOME GRADUAL RISE THROUGH FRIDAY.
&&

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

$$

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






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