Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 080349 AAA
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1049 PM CDT MON JUL 7 2014

UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE

.UPDATE...
ISSUED AT 920 PM CDT MON JUL 7 2014

INITIAL AREA OF STORMS FROM WEST CENTRAL WISCONSIN TO PARTS OF
CENTRAL TO SOUTHERN CENTRAL WISCONSIN HAVE DIMINISHED THE LAST
FEW HOURS. LARGE AREA OF STRATIFORM TYPE RAIN WAS SPREADING OVER
CENTRAL WISCONSIN NORTH OF MOSINEE WHILE A FEW CONVECTIVE ELEMENTS
WHERE WIND GUSTS TO 40 MPH WILL STILL BE POSSIBLE FROM WOOD COUNTY
TO WAUSHARA FOR THE REST OF THE EVENING. NEW FOCUS OF CONVECTION
TURNS TO NORTHWEST WISCONSIN NEAR A FRONTAL BOUNDARY NEAR THE LAKE
SUPERIOR SHORELINE AND THE INTERSECTION OF THE COLD FRONT AND
SHORT WAVE TROUGH WITH A VORT CENTER ON THE NOSE OF THE LFQ OF THE
UPPER JET WORKS OVER NORTHWEST WISCONSIN BEFORE SLIDING OVER THE
NORTHERN HALF OF THE STATE OVERNIGHT. REPORTS OF HEAVY RAIN IN
THIS AREA LATELY BUT WILL STILL NEED TO MONITOR FOR ISOLATED
STORMS WITH HAIL AND DAMAGING WINDS LATER TONIGHT IF THE STORMS
HOLD TOGETHER.
&&

.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 225 PM CDT MON JUL 7 2014

IMMEDIATE CONCERN TO BE SEVERE POTENTIAL LATE THIS
AFTERNOON THRU THE EVENING AS A CDFNT COMBINES WITH A SHORTWAVE
TROF AND JET STREAK ALOFT. LATER CONCERNS TO BE ON EXTENT OF PCPN
AND MAX TEMPS ON TUE AS UNSETTLED WEATHER TO CONT.

THE 19Z MSAS SFC ANALYSIS INDICATED AN AREA OF LOW PRES OVER
ONTARIO WITH A CDFNT EXTENDED SWWD FROM THIS LOW THRU CNTRL MN TO
NE NEBRASKA. ELEVATED TSTMS HAD DEVELOPED THIS AFTERNOON OVER
PARTS OF CNTRL AND WRN WI AS DAYTIME HEATING AND DEW POINTS IN
THE LWR TO MID 60S HAD CREATED ENUF INSTABILITY.

SCATTERED CONVECTION TO SEE A NOTICEABLE INCREASE IN ACTIVITY THRU
THE EVENING AS THE CDFNT INTERACTS WITH AN APPROACHING STRONG
SHORTWAVE TROF AND A 100 KT UPR JET DIVING SE THRU THE MIDWEST.
EVEN THO INSTABILITY IS NOT AS POTENT AS YESTERDAY...THE STRENGTH
OF THE MID-LEVEL FORCING AND THE FAVORABLE LEFT EXIT REGION OF THE
UPR JET SHOULD BRING ANOTHER SWATH OF SHWRS/TSTMS ACROSS NE WI
TNGT. TIMING OF ROUGHLY FROM 22Z-04Z FOR CNTRL WI...00Z-06Z FOR
ERN WI STILL LOOKS GOOD AND HAVE CONTINUED TO HIT THE POPS HARD.
AS FOR THE SEVERE POTENTIAL...CURRENT ACTIVITY ALREADY REACHING
MARGINALLY SEVERE LEVELS AND WITH FORCING/LIFT INCREASING...DO
NOT SEE WHY ACTIVITY WOULD NOT BE ABLE TO MAINTAIN ITS STRONG TO
SEVERE LEVELS THRU THE EVENING. MIN TEMPS TO RANGE FROM THE MID
50S NORTH TO THE LWR 60S SOUTH.

THE BROAD SHORTWAVE TROF TO RESIDE OVER THE GREAT LAKES ON TUE AND
CONTRIBUTE TO STEEP MID-LEVEL LAPSE RATES. THIS COMBINATION OF
CYCLONIC FLOW AND INSTABILITY SHOULD BE SUFFICIENT TO GENERATE AT
LEAST A CHC OF SHWRS/ISOLATED TSTMS ACROSS THE ENTIRE FCST AREA.
MAX TEMPS TO BE A GOOD DEAL COOLER COMPARED TO MON WITH READINGS
ONLY IN THE MID TO UPR 60S FAR NORTH...TO THE MID 70S OVER PARTS
OF CNTRL WI.

.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 225 PM CDT MON JUL 7 2014

COOLER TEMPERATURES AT THE BEGINNING OF THE PERIOD AND PCPN TRENDS
FOR NEXT WEEKEND ARE THE MAIN FCST CONCERNS DURING THE EXTENDED
PERIOD.

A STRONG S/W TROF AND THE LFQ OF AN 80 KT JET STREAK WILL IMPACT
THE NE HALF OF THE FORECAST AREA TUESDAY NIGHT...ESPECIALLY DURING
THE LATE EVENING AND EARLY MORNING HOURS. ALTHOUGH INSTABILITY
WILL WANE QUICKLY AFTER SUNSET...STEEP MID-LEVEL LAPSE RATES OF
6-7 C/KM WILL ARRIVE WITH THE S/W TROF...SO WILL KEEP A MENTION
OF ISOLD TSTMS IN THROUGH THE NIGHT. ANY LINGERING SHOWERS SHOULD
EXIT WEDS MORNING...WITH CANADIAN HIGH PRESSURE AND A BUILDING
RIDGE ALOFT EXPECTED DURING THE AFTERNOON. A MUCH COOLER CANADIAN
AIR MASS WILL ARRIVE DURING THE PERIOD...WITH H8 TEMPS DROPPING TO
+4 TO +8 C BY WEDS MORNING...AND ONLY MODERATING SLIGHTLY DURING
THE DAY. HAVE LOWERED MAX TEMPS A FEW DEGREES...WITH READINGS IN
THE MID 60S TO LOWER 70S EXPECTED.

CANADIAN HIGH PRESSURE WILL DOMINATE OUR WEATHER WEDNESDAY NIGHT
THROUGH THURSDAY NIGHT...BRINGING DRY AND PLEASANT WEATHER. CLEAR
SKIES AND LIGHT WINDS ON WEDS NGT WILL RESULT IN COOL TEMPS. HAVE
LOWERED MIN TEMPS BY ABOUT 5 DEGREES...AND WENT WITH LOWER TO
MIDDLE 40S IN THE TYPICAL COLD SPOTS. AN INCREASE IN CLOUD COVER
MAY BE SEEN IN OUR WESTERN COUNTIES LATE THURSDAY NIGHT...BUT PCPN
SHOULD HOLD OFF UNTIL FRIDAY.

MODELS OFFER A VARIETY OF SOLUTIONS WITH REGARD TO PCPN CHANCES
THROUGH THE WEEKEND. THE ECMWF AND GEM BOTH SHOW A WELL-DEFINED
S/W TROF MOVG THROUGH WI ON FRIDAY...ACCOMPANIED BY WIDESPREAD
SHRA/TSRA...WHILE THE GFS HAS THE UPPER LEVEL FORCING SPLITTING
NORTH AND SOUTH OF THE REGION...AND VERY LITTLE QPF. WITH THE
RETURN OF A MORE MOIST AND UNSTABLE AIR MASS...WOULD EXPECT AT
LEAST SCT SHRA/TSRA TO DEVELOP.

A COUPLE COLD FRONTS ARE EXPECTED TO MOVE THROUGH THE FORECAST
AREA OVER THE WEEKEND...THE FIRST ON FRIDAY NIGHT/SATURDAY...AND
THE SECOND ON SUNDAY/SUNDAY NIGHT. MODELS DISAGREE ON THE TIMING
OF THESE FEATURES...SO WILL USE THE BLENDED MODEL GUIDANCE FOR
POPS UNTIL THERE IS A BETTER CONSENSUS.
&&

.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1048 PM CDT MON JUL 7 2014

PERIODS OF SHOWERS WITH SCATTERED THUNDERSTORMS WILL
CONTINUE TO TRACK OVER THE NORTH HALF OF WISCONSIN OVERNIGHT.
SCATTERED MVFR CIGS AND VSBYS CAN BE EXPECTED WITH THE BANDS OF
SHOWERS AND STORMS OVERNIGHT. A STRONG MID-LEVEL SHORTWAVE TROF
WITH COLD FRONT WILL SWEEP OVER THE AREA OVERNIGHT FOR A FOCUS FOR
THE CONVECTION. IN THE WAKE OF THE CONVECTION OVERNIGHT A PATCHY
PERIOD OF IFR CIGS COULD DEVELOP LATE TONIGHT AND CONTINUE EARLY
TUESDAY MORNING. AFTER A PERIOD OF VFR CONDITIONS FOR
TUESDAY...SCATTERED MVFR CIGS POSSIBLY IN THE AFTERNOON WITH
DEVELOPING SHOWERS AND STORMS.
&&

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

$$

UPDATE.........TDH
SHORT TERM.....AK
LONG TERM......TSK
AVIATION.......TDH






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