Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 120243
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
943 PM CDT THU SEP 11 2014

NEW INFORMATION ADDED TO UPDATE SECTION

.UPDATE...
ISSUED AT 935 PM CDT THU SEP 11 2014

SKIES HAVE CLEARED OVER NORTH CENTRAL WI AND TEMPS HAVE QUICKLY PLUMMETED
INTO THE MID TO UPPER 30S IN THE TYPICAL COLD SPOTS. HAVE LOWERED
MIN TEMPS...EXPANDED THE FROST ADVISORY FARTHER SOUTHEAST...AND UPGRADED
TO A FREEZE WARNING IN VILAS...ONEIDA AND LINCOLN COUNTIES. ALSO
CONSIDERED UPGRADING TO A FREEZE WARNING FOR FLORENCE...FOREST AND
LANGLADE...BUT THINK THAT MIN TEMPS WILL BE RIGHT AROUND THE FREEZING
MARK THERE. MID/HIGH CLOUDS IN ADVANCE OF APPROACHING UPPER TROF
HAVE MOVD INTO SW MN...BUT WERE GENERALLY DISSIPATING AS THEY SHIFTED
TOWARD WI. EXPECT THESE CLOUDS WILL NOT ARRIVE IN THE FROST/FREEZE
AREAS UNTIL 10Z-12Z...SO PLENTY OF TIME FOR TEMPS TO DROP OFF.

SCATTERED SPRINKLES HAVE BEEN DRIFTING SE ACROSS THE FORECAST AREA
THIS EVG...BUT SHOULD END OR MOVE OUT BY AROUND MIDNIGHT.

&&

.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 254 PM CDT THU SEP 11 2014

THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A 1037MB
CANADIAN HIGH PRESSURE SYSTEM BUILDING SOUTHEAST ACROSS THE NORTHERN
PLAINS AND MISSISSIPPI VALLEY.  THE COMBO OF NORTHERLY FLOW OFF LAKE
SUPERIOR AND DIURNAL HEATING HAS MAINTAINED THE BROKEN TO OVERCAST
CONDITIONS ACROSS THE REGION.  CLOUDS ARE LOOKING MORE CELLULAR OVER
N-C WISCONSIN INDICATING A DIURNAL COMPONENT TO THE CLOUD MASS.
SCATTERED SHOWERS ARE OCCURRING OVER NORTHEAST MINNESOTA AND
NORTHWEST WISCONSIN...WITH HELP FROM A WEAK SHORTWAVE OVER THAT
REGION.  THIS WAVE IS LIFTING OFF TO THE NORTHEAST...SO DO NOT THINK
THE SHOWER ACTIVITY WILL REACH INTO N-C WISCONSIN THIS AFTERNOON.
THE NEXT SHORTWAVE IS DIVING SOUTHEAST OVER SOUTHERN MONTANA AND
WILL MOVE EAST TOWARDS THE REGION TOMORROW.  THE MAIN CONCERNS ARE
FROST POTENTIAL TONIGHT AND LIGHT RAIN CHANCES TOMORROW.

TONIGHT...CANADIAN HIGH PRESSURE WILL BUILD TOWARDS THE REGION AS A
POTENT SHORTWAVE MOVES ACROSS THE NORTHERN PLAINS.  AS SURFACE
PRESSURE RISES...LOW LEVEL FLOW WILL BECOME BROADLY
ANTICYCLONIC...WHICH WILL PROMOTE BREAKING UP OF THE LOW STRATUS.
HOWEVER...EVEN THOUGH THE FLOW WILL BECOME LIGHT...TRAJECTORIES ARE
ONSHORE OFF LAKE SUPERIOR WHERE DELTA T/S ARE SUFFICIENT FOR LAKE
CLOUDS.  ADDITIONALLY...THERE IS REALLY NO SOURCE OF DRY AIR TO
BE FOUND ACROSS THE REGION.  EVEN THOUGH CLOUDS OVER THE WESTERN
PART OF THE STATE APPEAR TO HAVE A DIURNAL LOOK TO THEM...CLOUDS
ORIGINATING OFF LAKE SUPERIOR COULD BECOME TRAPPED BENEATH THE
NOCTURNAL INVERSION.  FURTHERMORE...MID AND HIGH CLOUDS WILL BE
INCREASING AFTER MIDNIGHT AHEAD OF THE SHORTWAVE OVER THE PLAINS.
ALL OF THIS MAKES FOR A LOW CONFIDENCE CLOUD/TEMP/FROST FORECAST.
BECAUSE WE ARE ALREADY OFF TO A COLD START...ANY AMOUNT OF CLEARING
WILL CAUSE TEMPS TO FALL QUICKLY OVER N-C WISCONSIN.  MET/MAV/MEX
GUIDANCE ALL SHOW LOW TEMPS IN THE LOWER 30S OVER N-C WISCONSIN.  WILL
ERROR ON THE SIDE OF CAUTION BECAUSE OF THIS POTENTIAL AND ISSUE A
FROST ADVISORY FOR N-C WISCONSIN.  THE REST OF THE AREA SHOULD SEE
TEMPS IN THE UPPER 30S TO MIDDLE 40S.

FRIDAY...THE POTENT SHORTWAVE WILL MOVE ACROSS THE NORTHERN
MISSISSIPPI VALLEY AND INTO WESTERN WISCONSIN.  EVEN THOUGH QG
FORCING AHEAD OF THE WAVE LOOKS RATHER IMPRESSIVE...MOISTURE WILL
ONLY BE 60 TO 80 PCT OF NORMAL AND INSTABILITY IS RATHER POOR.
CHANCES FOR PRECIP WILL IMPROVE DURING THE AFTERNOON AS THE WAVE
APPROACHES AND UPPER DIVERGENCE INCREASES.  MODELS ARE ALSO
INDICATING MID-LEVEL CONVERGENCE OVER NORTHEAST AND EAST-CENTRAL
WISCONSIN THAT COULD PROVIDE A FOCUS FOR A BAND OF LIGHT RAIN.  WILL
INCREASE PRECIP CHANCE IN THIS AREA FOR THE AFTERNOON.
NORTH-CENTRAL WILL HAVE THE NEXT BEST CHANCE OF SEEING RAIN WHERE
THE DEFORMATION ZONE APPROACHES DURING THE AFTERNOON.  SHOULD BE
ANOTHER CLOUDY AND COOL DAY WITH HIGHS IN THE LOW TO MID 50S.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 254 PM CDT THU SEP 11 2014

LIGHT RAIN SHOULD END IN EASTERN WISCONSIN FRIDAY EVENING
AS THE UPPER SYSTEM EXITS. IF THERE IS SUFFICIENT CLEARING THERE COULD
BE A FREEZE OR FROST IN NORTHCENTRAL WISCONSIN FRIDAY NIGHT.

SUNNY AND COOL WEATHER SATURDAY AS A SURFACE HIGH MOVES BY. CLOUDS WILL
INCREASE SUNDAY AS A WEAK FRONTAL SYSTEM APPROACHES FROM THE NORTHERN
PLAINS. NOT MUCH MOISTURE AVAILABLE SO ONLY EXPECT SCATTERED SHOWERS
SUNDAY NIGHT AND MONDAY WITH THE FRONTAL PASSAGE. THEN DRY AND SEASONABLE
FOR MUCH OF THE REMINDER OF NEXT WEEK WITH NORTHWEST FLOW ALOFT.
&&

.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 624 PM CDT THU SEP 11 2014

EXPECT BKN-OVC STRATOCUMULUS TO GRADUALLY SCATTER OUT OVER MOST OF
THE FORECAST AREA DURING THE THE MID TO LATE EVENING HOURS AS A
RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION. COULD SEE A
PERIOD OF PATCHY FOG OVERNIGHT BEFORE MID/HIGH CLOUDS INCREASE
AHEAD OF AN UPPER LEVEL DISTURBANCE. THIS SYSTEM WILL GENERATE
SOME LIGHT RAIN OR SHOWERS OVER THE REGION...MAINLY DURING THE
AFTERNOON. SOME MVFR CIGS MAY ACCOMPANY THE STEADIER RAINFALL
DURING THE MID TO LATE AFTERNOON.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY UNTIL 8 AM CDT FRIDAY FOR WIZ011>013-019>021-030-
031.

FREEZE WARNING UNTIL 8 AM CDT FRIDAY FOR WIZ005-010-018.
&&

$$

UPDATE.........KIECKBUSCH
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH





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