465
FXUS63 KGRB 291726
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1226 PM CDT THU JUL 29 2021
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
SHORT TERM...TODAY...TONIGHT
AND FRIDAY
ISSUED AT 327 AM CDT THU JUL 29 2021
SHOWERS AND THUNDERSTORMS HAVE ENDED ACROSS THE REGION, BUT
AREAS OF LOW STRATUS AND FOG WERE FORMING IN NORTHERN WI, IN THE
WAKE OF A COLD FRONTAL PASSAGE. THERE SHOULD BE ENOUGH WIND TO
PREVENT WIDESPREAD DENSE FOG FROM OCCURRING, AND WOULD EXPECT
A QUICK IMPROVEMENT IN VSBYS EARLY IN THE MORNING. STRATUS WILL
LIKELY LINGER UNTIL MID TO LATE MORNING, FOLLOWED BY SCATTERED
DIURNAL CUMULUS FOR THE REST OF THE DAY. RAP/HRRR SMOKE MODELS
DEPICT A BAND OF SMOKE DRIFTING SOUTH THROUGH THE FORECAST TODAY
INTO EARLY TONIGHT, BUT SUGGEST THAT MOST OF THE NEAR-SURFACE
IMPACTS WILL OCCUR WELL TO OUR WEST IN MN. NORTH TO NORTHEAST
WINDS WILL GUST TO AROUND 20 MPH, AND BRING A LESS HUMID CANADIAN
AIR MASS TO THE REGION. HIGH TEMPERATURES SHOULD RANGE FROM THE
MIDDLE TO UPPER 70S NORTH TO THE LOWER TO MIDDLE 80S SOUTH.
CANADIAN HIGH PRESSURE WILL BRING PARTLY CLOUDY SKIES AND COOLER
WEATHER TONIGHT INTO FRIDAY. LOWS TONIGHT SHOULD RANGE FROM THE
MIDDLE TO UPPER 40S NORTH TO THE 50S SOUTH. HIGHS ON FRIDAY WILL
BE IN THE 70S, WITH VERY COMFORTABLE DEW POINTS IN THE UPPER 40S
TO MIDDLE 50S.
LONG TERM
FRIDAY NIGHT THROUGH WEDNESDAY
ISSUED AT 327 AM CDT THU JUL 29 2021
THE LATEST ENSEMBLE MEANS POINT TOWARDS AMPLIFICATION OF THE UPPER
AIR PATTERN THIS WEEKEND, FOLLOWED BY DEAMPLIFICATION NEXT WEEK. AS
THE UPPER RIDGE BUILDS OVER NORTHWEST NORTH AMERICA IN THE FRIDAY-
SATURDAY TIME PERIOD, DIGGING SHORTWAVE ENERGY WILL PASS ACROSS THE
REGION ON SATURDAY AND PROVIDE THE NEXT CHANCE OF THUNDERSTORMS.
POTENTIAL FOR SEVERE WEATHER ON SATURDAY IS THE MAIN FORECAST
CONCERN IN THIS PART OF THE FORECAST.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...HIGH PRESSURE WILL BE CENTERED
OVER THE SOUTHERN GREAT LAKES AT THE START OF FRIDAY NIGHT. IT WILL
SHIFT SOUTH THROUGH THE NIGHT AS CLOUDS INCREASE AHEAD OF A COLD
FRONT, WHICH IS FORECAST TO ARRIVE INTO FAR NORTHERN WI BY LATE
FRIDAY NIGHT OR EARLY SATURDAY MORNING. MINOR ELEVATED INSTABILITY
WILL ACCOMPANY THE FRONT, SO WILL KEEP A LOW CHANCE OF STORMS OVER
THE FAR NORTH. WHILE THERE IS SOME DIFFERENCES OF TIMING OF THE
FRONT ON SATURDAY, INDICATIONS ARE THAT THE FRONT WILL CROSS THE
FORECAST AREA DURING THE AFTERNOON. MID-LEVEL HEIGHT FALLS WILL
PROVIDE LARGE SCALE ASCENT IN A REGION OF 1000-1500 J/KG OF
INSTABILITY AND DEEP LAYER SHEAR AROUND 30 KTS. THESE PARAMETERS
WILL FAVOR SOME STRONG STORMS IF TIMING REMAINS AROUND THE TIME
OF PEAK HEATING. THEN CLEARING SHOULD OCCUR ON SATURDAY NIGHT.
REST OF THE FORECAST...ANOTHER SHORTWAVE IS FORECAST TO MOVE ACROSS
THE AREA ON MONDAY. THE ATMOSPHERE WILL BE CONSIDERABLY LESS
UNSTABLE THAN ON SATURDAY, SO PERHAPS ONLY A SPOTTY SHOWER OR STORM
WILL BE POSSIBLE (MOST GUIDANCE IS DRY FOR MONDAY). WITH HIGH
PRESSURE AT THE SURFACE, DRY AND SEASONABLE WEATHER LOOKS TO BE IN
THE CARDS THROUGH THE MIDDLE OF NEXT WEEK.
AVIATION
FOR 18Z TAF ISSUANCE
ISSUED AT 1226 PM CDT THU JUL 29 2021
EXPECT A MIX OF VFR/MVFR CONDITIONS THIS AFTERNOON WITH SCATTERED
TO BROKEN CLOUDS WITH BASES AROUND 2500 FEET. SITES WILL LIKELY
OSCILLATE BETWEEN SCT AND BKN AS THE CLOUDS MOVE THROUGH.
MEANWHILE, SATELLITE IMAGERY DEPICTING AND LARGE AREA OF SMOKE
ACROSS MN WITH A PIECE STRETCHING INTO CENTRAL WI. THIS SMOKE MAY
PRODUCE A HAZE AT TIMES, BUT NOT EXPECT MUCH FOR SURFACE IMPACTS
ACROSS NE WI. A COUPLE SITES HAVE HAD VISIBILITY DROP TO 6SM OR
7SM FROM THE SMOKE, BUT DO NOT EXPECT ANY VISIBILITY DROP TO LAST
VERY LONG AT ANY SITE; THEREFORE, DID NOT INCLUDE IN 18Z TAF
UPDATE. OTHERWISE, NORTH WINDS WILL GUST TO 15 TO 20 KNOTS THROUGH
EARLY THIS EVENING THEN BECOME LIGHT OVERNIGHT. LOW CLOUDS WILL
ALSO DISSIPATE THIS EVENING WITH ONLY SOME PASSING HIGH CLOUDS OR
HIGH SMOKE OVERNIGHT AND INTO FRIDAY MORNING.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM.....KIECKBUSCH
LONG TERM......MPC
AVIATION.......KLJ
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