Area Forecast Discussion
Issued by NWS Green Bay, WI

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000
FXUS63 KGRB 160335
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1035 PM CDT MON SEP 15 2014

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 252 PM CDT MON SEP 15 2014

MAIN CONCERN FOR TONIGHT IS MIN TEMPERATURES AND HEADLINES FOR FOR
A FROST OR FREEZE. AT 19Z...EAST-WEST BAND OF RAIN WAS BEGINNING
TO EXIT EAST CENTRAL WISCONSIN AND SHOULD BE OUT OF HERE BY 21Z.
MEANWHILE...UPPER TROUGH SWINGING ACROSS THE WESTERN LAKES
TRIGGERED ISOLATED TO SCATTERED SHOWERS ACROSS PORTIONS OF
NORTHEAST WISCONSIN INTO UPPER MICHIGAN. THIS ACTIVITY SHOULD END
BY SUNSET AS THE UPPER TROUGH PUSHES EAST OF THE AREA.

CLEARING SKIES AND LIGHT WINDS TONIGHT WILL ALLOW FOR TEMPERATURES
TO FALL INTO THE LOWER TO MIDDLE 30S NORTH AND WEST OF THE FOX
VALLEY. ONE PROBLEM TO THE FORECAST FOR FREEZING TEMPERATURES IS THAT
RIDGE AXIS WILL REMAIN TO THE WEST OF THE AREA WHICH WOULD ALLOW
WINDS NOT TO GO COMPLETELY CALM IN MOST SPOTS. ON THE FLIP SIDE...
DEW POINTS UPSTREAM IN PORTIONS OF MINNESOTA WERE IN THE UPPER 20S
TO MIDDLE 30S TO SUPPORT TEMPERATURES IN THE UPPER 20S AT OUR
TYPICAL COLD SPOTS. DEBATED TO GO WITH A FREEZE WARNING FOR VILAS...
ONEIDA...AND LINCOLN COUNTIES...BUT NOT CONFIDENT THERE WILL BE
WIDESPREAD FREEZING TEMPERATURES. DID INCLUDE TEMPERATURES IN THE
UPPER 20S IN THE TYPICAL COLD SPOTS WHEN I UPDATED THE 11 AM FROST
ADVISORY. DID EXPAND FROST ADVISORY FOR MARATHON...WOOD AND PORTAGE
COUNTIES. WITH RIDGE AXIS TO THE WEST/SOUTHWEST OF THE AREA...THIS
AREA COULD GET AS LOW AS SOME PORTIONS OF NORTH-CENTRAL WISCONSIN
DUE TO WINDS GOING CALM IN THIS REGION.

MOSTLY SUNNY SKIES WILL PREVAIL ON TUESDAY WITH HIGHS IN THE MIDDLE
TO UPPER 60S.

.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 252 PM CDT MON SEP 15 2014

PCPN TRENDS LATE IN THE WEEK WILL BE THE PRIMARY FCST CONCERN.

AMPLIFIED UPPER LEVEL FLOW...WITH A RIDGE OVER THE ROCKIES AND
NORTHWEST FLOW OVER THE WESTERN GREAT LAKES...WILL TRANSITION TO
MORE OF A ZONAL PATTERN FROM THURSDAY THROUGH SATURDAY. A RETURN
TO A MORE AMPLIFIED PATTERN IS EXPECTED TO REDEVELOP BY SUNDAY AND
MONDAY. NEAR OR SLIGHTLY BLO NORMAL TEMPS WILL MODERATE LATE IN
THE WEEK...THEN COOL DOWN AGAIN BY MONDAY. THE MAIN PCPN CHANCES
WILL OCCUR IN ASSOCIATION WITH AN APPROACHING COLD FRONT AND UPPER
TROF FROM FRIDAY INTO SATURDAY.

A WEAK COLD FRONT WILL SHIFT SOUTH THROUGH THE FORECAST AREA
WEDNESDAY AND WEDNESDAY NIGHT. A FEW SHOWERS MAY DEVELOP OVER
NORTHERN WI ON WEDNESDAY...AS A WEAK S/W TROF PASSES THROUGH
DURING THE DAY. OTHERWISE...THE FRONT IS EXPECTED TO REMAIN
GENERALLY DRY. CANADIAN HIGH PRESSURE RIDGED OVER SE ONTARIO/
WESTERN QUEBEC SHOULD BRING GENERALLY DRY WEATHER TO THE REGION
THURSDAY AND THURSDAY NIGHT.

AS THE HIGH SHIFTS EAST AND A COLD FRONT APPROACHES FROM THE
NORTHERN PLAINS...STRONG SOUTHERLY RETURN FLOW WILL DEVELOP. A
35-45 KT LLJ IS FORECAST TO DEVELOP ON FRIDAY...AND CONTINUE
INTO FRIDAY NIGHT. THE RESULTING WAA AND MOISTURE CONVERGENCE
SHOULD CAUSE SCT SHRA/TSRA TO DEVELOP. PCPN TRENDS DURING THIS
PERIOD ARE A BIT SKETCHY...AS MODEL CONSISTENCY HAS BEEN POOR.
AS AN EXAMPLE...THE 00Z ECMWF FOCUSED PCPN OVER THE SOUTHERN
HALF OF WI (NORTH OF A SFC WARM FRONT)...WHILE THE 12Z RUN
FOCUSED ON THE NW HALF OF WI (AHEAD OF THE COLD FRONT). WITH
LOW CONFIDENCE IN THE DETAILS...WILL NOT GO ABOVE CHC POPS
DURING THIS PERIOD.

HAVE BOOSTED POPS TO LIKELY ON SATURDAY AS THE COLD FRONT MOVES
THROUGH. IT REMAINS TO BE SEEN HOW MUCH PCPN WILL LINGER INTO
SATURDAY NIGHT...AS THE TIMING OF THE FRONT VARIES FROM MODEL TO
MODEL. A FEW SHOWERS MAY PERSIST OVER N WI INTO SUN/SUN NGT...AS
A SECONDARY COLD FRONT MOVES THROUGH...AND COOL NORTH FLOW OFF
LAKE SUPERIOR DEVELOPS.

DRY CONDITONS SHOULD RETURN ON MONDAY...AS CANADIAN HIGH PRESSURE
DROPS INTO THE REGION.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1035 PM CDT MON SEP 15 2014

HIGH PRESSURE SYSTEM DRIFTING OVER THE GREAT LAKES REGION WILL
PRODUCE VFR CONDITIONS THROUGH TUESDAY EVENING...WITH THE
EXCEPTION OF PATCHY IFR FOG BETWEEN 08Z AND 12Z TUESDAY MORNING.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY UNTIL 8 AM CDT TUESDAY FOR WIZ005-010>013-018-019-
021-030-035-036.
&&

$$

SHORT TERM.....ECKBERG
LONG TERM......KIECKBUSCH
AVIATION.......TDH






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