890
FXUS63 KGRB 162033
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
333 PM CDT WED OCT 16 2013
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND THURSDAY
ISSUED AT 333 PM CDT WED OCT 16 2013
THE AMOUNT AND TIMING OF CLEARING...IS THE FIRST AREA OF CONCERN
DURING THIS PART OF THE FORECAST. VIS AND IR SATELLITE IMAGERY
INDICATED A LARGE CLOUD SHIELD OVER WISCONSIN TODAY...WITH THE
BACK EDGE OF THE CLOUDS REACHING NORTHWEST WISCONSIN AROUND 18Z.
CLOUDS WERE GENERALLY EAST OF A SURFACE RIDGE AXIS THAT EXTENDED
FROM SOUTHWEST ONTARIO TO THE PLAINS AT 20Z. THE RIDGE LOOKS LIKE
IT WILL BE OVER OR JUST TO THE WEST OF THE FOX VALLEY AND
LAKESHORE AREAS DURING THE NIGHT...WHERE WE ARE STILL ISSUING
FROST ADVISORIES. HAVE GONE WITH A PROGRESSIVE CLEARING TREND
OVERNIGHT WHICH MATCHES UP WITH GRIDS FROM ADJACENT FORECAST
AREAS. THERE SHOULD BE LITTLE WIND IN THE VICINITY OF THE
RIDGE...SO CONDITIONS FOR RADIATIONAL COOLING WOULD BE QUITE GOOD
IF SKIES DO CLEAR. IF NOT...IT WOULD LIKELY REMAIN WARM ENOUGH TO
PREVENT WIDESPREAD FROST FROM DEVELOPING. WAS LEANING TOWARD
CANCELING THE FROST ADVISORY...BUT HAVE OPTED TO LEAVE IT IN
EFFECT SINCE CONFIDENCE LEVEL IS LOW-MEDIUM.
THE NEXT FORECAST ISSUE IS TIMING OF PRECIPITATION CHANCES AS A
COLD FRONT OVER THE PLAINS PUSHES INTO WISCONSIN ON THURSDAY. THE
12Z GFS HAD SOME QPF REACHING NORTH CENTRAL WISCONSIN BETWEEN 18Z
THURSDAY AND 00Z FRIDAY WHILE THE 12Z EC KEPT THAT QPF NORTHWEST OF
THE AREA THROUGH 00Z FRIDAY. HOWEVER...THE EC DID BRING SOME QPF
INTO THE EASTERN PART OF THE FORECAST AREA DURING THE DAY AS A
500MB LOW...EJECTING OUT OF A TROUGH SOUTHWEST OF THE REGION...MOVES
TO NORTHERN LAKE MICHIGAN/LOWER MICHIGAN BY 00Z FRIDAY. HAVE LEFT
THE EAST DRY BUT THE MIDNIGHT SHIFT MAY WANT TO ADD SOME POPS TO
THE EAST IF OTHER MODELS START TO SHOW THIS SAME TREND.
.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 333 PM CDT WED OCT 16 2013
PCPN TRENDS/TYPE AND TEMPERATURES WILL BE THE PRIMARY FCST CONCERNS.
A COLD FRONT AND S/W TROF WILL MOVE THROUGH THE FCST AREA THURSDAY
NIGHT AND FRIDAY. PCPN SHOULD SPREAD ACROSS THE NW TWO-THIRDS OF
THE CWA THU NGT...REACH THE FOX VALLEY/LKSHR AREAS FRIDAY MORNING...
THEN DIMINISH OVER THE REGION DURING THE AFTERNOON. WILL CARRY THE
HIGHEST POPS (50 PERCENT) OVER NC WI...WITH LOWER CHC POPS FARTHER
SE. THERE SHOULD BE A GENERAL LULL IN PCPN ON FRIDAY NIGHT...AS
GRB CWA IS IN BETWEEN SYSTEMS AND A WEAK SFC RIDGE MOVES THROUGH.
A DEEPENING UPPER LEVEL TROF AND ASSOCIATED COLD FRONT WILL MOVE
THROUGH THE REGION ON SATURDAY. HAVE RAISED POPS TO HIGH CHC OVER
MOST OF THE FA...WITH LIKELY POPS OVER NC WI. ALTHOUGH CONFIDENCE
IS NOT HIGH...THERE COULD BE A BRIEF MIX OF RAIN/SNOW OVER NC WI
EARLY IN THE DAY.
FORECAST CONFIDENCE WANES FOR THE WEEKEND INTO EARLY NEXT WEEK...
AS MODELS EXHIBIT POOR CONTINUITY AND TIMING DIFFERENCES. THERE
SEEMS TO BE A TREND TOWARD A SIGNIFICANT CLIPPER SYSTEM PASSING
THROUGH THE WESTERN GREAT LAKES SUNDAY NIGHT (ECMWF) INTO MONDAY
(GFS/GEM)...AND THE LATEST RUNS SUGGEST A TRACK THROUGH THE HEART
OF GRB CWA...WHICH IS PROBLEMATIC FOR PCPN TYPE. GIVEN TIMING
DIFFERENCES...WILL NOT CARRY ANYTHING HIGHER THAN CHC POPS FOR
NOW...AND WILL FOCUS ON A RAIN/SNOW MIX ACROSS NC/NE WI SUNDAY
NIGHT INTO MONDAY MORNING.
AN UNSEASONABLY COLD AIR MASS WILL POUR INTO THE REGION AFTER
THE CLIPPER LOW PULLS OUT. GUSTY W-NW WINDS AND SCATTERED
RAIN/SNOW SHOWERS ARE EXPECTED EARLY IN THE WEEK...WITH A
TREND TOWARD MAINLY LAKE-EFFECT PCPN IN THE AREAS FAVORED IN
NW FLOW BY MIDWEEK.
TEMPERATURES WILL BE BLO NORMAL THROUGH THE PERIOD...WITH MUCH
BLO NORMAL READINGS POSSIBLE BY TUES/WEDS.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 100 PM CDT WED OCT 16 2013
ISOLATED SHOWERS AND AREAS OF DRIZZLE...MAINLY IN THE EAST...SHOULD
COME TO AN END DURING THE EARLY PART OF THE AFTERNOON.
HOWEVER...THE WESTERN EDGE OF THE MVFR CIGS EXTENDED ALL THE WAY
TO THE WI/MN BORDER AT 17Z. THERE WERE EVEN AREAS OF MVFR CIGS
UNDER THE SURFACE RIDGE IN MN. SO AM NOT ALL THAT OPTIMISTIC ABOUT
CLEARING SKIES ANY TIME SOON. CIGS WILL PROBABLY INCREASE TO VFR
ACROSS MUCH OF THE AREA THIS AFTERNOON BEFORE FALLING BACK TO MVFR
DURING THE EARLY EVENING. WOULD NOT EXPECT CLEARING UNTIL LATE
TONIGHT BUT SOME MVFR VSBYS IN FOG WILL PROBABLY DEVELOP BY THEN.
CONDITIONS SHOULD BE VFR FOR THE LATE AFTERNOON THROUGH AT LEAST
MIDDAY ON THURSDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 1 AM TO 7 AM CDT THURSDAY FOR WIZ022-038>040-
048>050.
&&
$$
SHORT TERM.....MG
LONG TERM......KIECKBUSCH
AVIATION.......MG