Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 061736
AFDGRB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1236 PM CDT MON JUL 6 2015

UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE

.SYNOPSIS...
ISSUED AT 348 AM CDT MON JUL 6 2015

THUNDERSTORMS SPREADING ACROSS THE AREA TODAY AND TONIGHT...SOME
OF WHICH WILL PRODUCE HEAVY RAIN AND POSSIBLY SOME MINOR FLOODING.
COOLER AND DRIER TOMORROW.

HIGHLY AMPLIFIED UPR FLOW OVER CENTRAL AND SRN CANADA WL FLATTEN
DURING THE EARLY PART OF THE FCST PERIOD. THAT WL ALLOW SOME
SEPARATION OF THE WESTERLIES...AND THE EVOLUTION OF A SRN BRANCH
OF THE FLOW ACRS THE CONUS. THE SRN STREAM WL INITIALLY BE
DOMINATED BY UPR TROF NR THE WEST COAST...BUT DURING THE LATTER
PART OF THE PERIOD AN UPR ANTICYCLONE IS EXPECTED TO FORM INVOF
THE LOWER MISSISSIPPI VALLEY/SERN CONUS.

IT LOOKS LIKE WE ARE HEADING BACK INTO A MUCH WETTER WX REGIME.
COLD FRONT CROSSING THE AREA WL GENERATE SIG RAINFALL THE NEXT 24
HRS. THEN AFTER A FEW DRY DAYS...THE CHC FOR SIG RAINS WL RETURN
DURING THE LATTER PART OF THE PERIOD AS THE FCST AREA COMES UNDER
THE INFLUENCE OF SHRTWVS IN EVOLVING SRN STREAM. COOL TEMPERATURES
ARE EXPECTED MID-WEEK...THEN READINGS WL RETURN TO AOA NORMAL
FOR LATE IN THE WEEK AND NEXT WEEKEND.
&&

.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 348 AM CDT MON JUL 6 2015

FAIRLY STRONG FRONTAL SYSTEM WITH INCRG UPR SUPPORT WL PUSH ACRS
THE AREA TDA AND TNGT. IN RESPONSE TO THE UPPER LEVEL ENERGY...
SEVERAL WAVES ARE EXPECTED TO RIDE NEWLY ALONG THE FRONT AS IT
CROSSES THE RGN. GIVEN THE UPR SUPPORT...INCRG MOISTURE...AND
WAVES RIDING ALONG THE BOUNDARY...THIS LOOKS LIKE IT WL BE A SIG
PCPN EVENT. IT/S BEEN A LITTLE WHILE SINCE MOST AREAS HAD
SUBSTANTIAL RAINS...AND AT THIS POINT IT/S HARD TO PINPOINT ANY
SPECIFIC AREAS WHERE HVY PCPN WL FOCUS. IT/S LIKELY WE/LL NEED
SOME ADVISORIES FOR URBAN/MINOR FLOODING AT SOME POINT LATER TDA.
IT/S ALSO NOT OUT OF THE QUESTION THAT A LOCALIZED FLASH FLOOD
SITN COULD DEVELOP...BUT WITHOUT BEING ABLE TO DELINEATE THOSE
LOCATIONS AS OF YET...WL FOREGO A WATCH AND HANDLE WITH THE HWO.

EVEN THE DETAILS OF THE TIMING OF THE PCPN ARE ELUSIVE. CONVECTION
GOT WAY AHEAD OF WHERE THE MODELS WERE FCSTG IT TO BE OCCURRING
LATE YDA EVENING...BUT NOW SEEMS TO HAVE HIT THE WALL. EXPECT
CURRENT RAIN BAND TO MAKE IT INTO N-C WI THIS MORNING. ADDITIONAL
DEVELOPMENT TO THE S COULD AFFECT CENTRAL WI BY MID-LATE
MORNING...AND EVEN WORK INTO E-C WI. THOSE RAINS WOULD BE IN
ADVANCE OF THE MAIN RAIN BAND WITH THE FRONT...WHICH IS LIKELY TO
CROSS THE AREA IN THE 18Z-06Z TIME FRAME. VERY LOW CONFIDENCE IN
INDIVIDUAL 1 HR POP FCST TDA...BUT CONFIDENCE IN 12 HR POP FOR
TDA WITH CATEGORICALS NW 1/2 RANGING DOWN TO CHC IN THE FAR SE
S...AND AN INVERSE OF THAT FOR TNGT...IS PRETTY HIGH.

HIGH CLDS HAVE ALREADY SPREAD ACRS THE ENTIRE AREA. IF BREAKS IN
THE CLDS CAN DEVELOP...THEY WOULD GREATLY INCREASE THE SVR RISK
THIS AFTN. BUT AT THIS POINT THAT SEEMS RATHER UNLIKELY. SPC
MAINTAINED MARGINAL RISK ACRS THE ENTIRE AREA IN THEIR NEW DAY 1
CONVECTIVE OUTLOOK...AND THAT SEEMS RIGHT ON TARGET. BEST CHC FOR
SVR MAY BE FM WET MICROBURSTS/LOCALIZED DAMAGING WIND GUSTS.

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 348 AM CDT MON JUL 6 2015

THE LATEST ENSEMBLE MEANS CONTINUE TO INDICATE FLATTENED TROUGHING
WILL PERSIST THROUGH THE END OF THE WORK WEEK.  BUT THE ENSEMBLES
ARE NOW MORE AGGRESSIVE BUILDING SUB-TROPICAL RIDGING INTO THE
REGION BY FRIDAY AND SATURDAY.  THIS WOULD PUT NORTHERN WISCONSIN IN
THE SO CALLED RING OF FIRE...OR AN AREA THAT IS TYPICALLY ASSOCIATED
WITH PERIODS OF SHOWERS AND STORMS.  THE OPERATIONAL MODELS SHOW
THIS PATTERN...BUT HAVE A LARGE SPREAD WITH MOVING SHORTWAVE ENERGY
ACROSS THE WESTERN GREAT LAKES DURING THE WEEKEND.  TOUGH TO HAVE
MUCH CONFIDENCE IN THIS SORT OF PATTERN.  REGARDLESS...WILL SIDE
WITH THE ECMWF THROUGH FRIDAY AND THE EXTENDED INITIALIZATION
THEREAFTER.

TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...HIGH PRESSURE WILL BE MOVING
ACROSS THE REGION TUESDAY NIGHT AND WEDNESDAY.  WITH CLEAR SKIES AND
LIGHT WINDS...WILL SIDE WITH THE COLDEST GUIDANCE FOR LOWS TUE
NIGHT.  SOME COLD SPOTS OVER N-C WI COULD SEE UPPER 30S FOR MINS.
HIGHS ON WEDS MAINLY IN THE LOW TO MID 70S.  WILL SEE AN INFLUX OF
HIGH CLOUDS WEDNESDAY NIGHT WHICH SHOULD MAKE FOR WARMER TEMPS.
OTHERWISE...STILL TRANQUIL WITH LOWS IN THE 50S.

REST OF THE FORECAST...YESTERDAYS MODELS WERE SHOWING A WEAK
DISTURBANCE MOVING THROUGH ON THURSDAY...BUT TONIGHTS RUNS HAVE
WAFFLED BACK TO THE DRY SIDE.  TEMPS WILL START A WARMING TREND BACK
INTO THE MID TO UPPER 70S.  BY FRIDAY...A WARM FRONT WILL BEGIN
SURGING NORTHEAST INTO THE SOUTHWEST GREAT LAKES.  THOUGH PRECIP
WILL PRIMARILY RESIDE SOUTH OF REGION ON FRIDAY...BETTER CHANCES
WILL ARRIVE BY FRIDAY NIGHT AND CONTINUE RIGHT THROUGH THE WEEKEND.
TEMPS NEXT WEEKEND COULD BE APPROACHING 90 IN MANY LOCALES IF
RAINFALL DOES NOT SURPRESS TEMPS.  BEST CHANCE OF RAINFALL APPEARS
TO BE SUNDAY.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1236 PM CDT MON JUL 6 2015

CDFNT TO SLOWLY MOVE EAST ACROSS CNTRL WI LATE THIS AFTERNOON AND
ERN WI EARLY THIS EVENING. TOO MUCH IN THE WAY OF CLOUD COVER TO
ALLOW SUFFICIENT HEATING/DESTABILIZATION TO OCCUR...THUS THE
PROSPECTS FOR STRONGER STORMS APPEARS MINIMAL AT THIS TIME. THERE
COULD STILL BE SOME BOUTS OF HEAVIER SHWRS ACROSS NE WI UNTIL
FROPA OCCURS. CIGS OVER WI ARE ALL OVER THE PLACE...HOWEVER NEAR
THE VCNTY OF THE CDFNT...CIGS APPEAR TO HAVE SETTLED INTO THE HI-
END IFR/LOW-END MVFR CATEGORIES AND ANTICIPATE THIS TREND TO PUSH
EAST ACROSS THE REST OF WI. EVEN ONCE THE CDFNT CLEARS ERN WI...
LOW-LEVEL MOISTURE LINGERS FOR A WHILE...THUS EXPECT LOW CLOUDS
TO HANG ON FOR MOST OF THE NGT BEFORE MIXING AND ADVECTION OF
DRIER AIR TUE MORNING ALLOWS FOR MORE SUNSHINE AND A RETURN TO
VFR CONDITIONS.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
BEACH HAZARDS STATEMENT UNTIL 10 PM CDT THIS EVENING FOR WIZ022-
040-050.
&&

$$

SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......MPC
AVIATION.......AK


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