862
FXUS63 KGRB 062341
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
641 PM CDT TUE JUN 6 2023
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
SHORT TERM
TONIGHT AND WEDNESDAY
ISSUED AT 222 PM CDT TUE JUN 6 2023
A COLD FRONT HAD SHIFTED WELL SOUTH OF THE FORECAST EARLY THIS
AFTERNOON, AND HUDSON BAY HIGH PRESSURE WAS BUILDING INTO
NORTHERN WI. SMOKY CONDITIONS HAD IMPROVED OVER GRB CWA, AT LEAST
AT THE SURFACE, WHERE ALL OBSERVING SITES WERE REPORTING
VISIBILITIES IN THE 7-10SM RANGE. PARTLY SUNNY SKIES WERE
OBSERVED, ALONG WITH COOLER TEMPERATURES IN THE UPPER 60S AND
70S.
DRY WEATHER WILL PREVAIL TONIGHT AND WEDNESDAY, WITH SKIES
BECOMING MOSTLY CLEAR LATER TONIGHT. AFTER A BIT OF A REPRIEVE
TODAY, AN ELEVATED LAYER OF SMOKE IS EXPECTED TO ARRIVE IN NE WI
OVERNIGHT, THEN OVERSPREAD THE REST OF THE FORECAST AREA ON
WEDNESDAY. THERE ARE INDICATIONS THAT NEAR-SURFACE SMOKE MAY
RETURN TO PARTS OF NORTHERN WI WEDNESDAY AFTERNOON.
A VERY DRY AIR MASS AND DAYTIME MIXING WILL CAUSE DEW POINTS AND
RELATIVE HUMIDITIES TO CRASH WEDNESDAY AFTERNOON. GIVEN THE DRY
CONDITIONS OF THE PAST TWO WEEKS AND RELATIVE HUMIDITIES DROPPING
INTO THE 15 TO 25 PERCENT RANGE, THERE WILL CONTINUED CONCERN FOR
WILDFIRES, ESPECIALLY IN THE SANDY SOIL REGIONS OF NORTHERN WI.
LOWS TONIGHT ARE EXPECTED TO MAINLY BE IN THE 40S ACROSS THE
NORTH, AND AROUND 50 IN CENTRAL AND EAST CENTRAL WISCONSIN. HIGHS
ON WEDNESDAY SHOULD BE IN THE 70S, WITH SOME 60S NEAR LAKE
MICHIGAN.
LONG TERM
WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 222 PM CDT TUE JUN 6 2023
THE MAIN FORECAST CONCERN WILL BE PRECIPITATION CHANCES,
ESPECIALLY FRIDAY NIGHT INTO SATURDAY.
FOR MUCH OF THE WORK WEEK, THE FORECAST AREA WILL HAVE NORTHERLY
FLOW ALOFT ON THE EAST SIDE OF A HIGH AMPLITUDE UPPER LEVEL
RIDGE, WITH CANADIAN HIGH PRESSURE AT THE SURFACE. DRY AND
COMFORTABLE CONDITIONS, INCLUDING LOW AFTERNOON RELATIVE HUMIDITY,
CAN BE EXPECTED THROUGH AT LEAST THURSDAY NIGHT. HIGH
TEMPERATURES WILL GENERALLY RANGE FROM 75 TO 80 DEGREES, EXCEPT
NEAR LAKE MICHIGAN, WHERE PERSISTENT NE WINDS WILL KEEP
TEMPERATURES COOLER. OVERNIGHT LOWS WILL BE IN THE 40S AND LOWER
50S, THOUGH THE COLDER SPOTS IN NORTHERN WI WILL LIKELY DROP INTO
THE 30S EARLY THURSDAY MORNING. WILL NEED TO MONITOR FOR POSSIBLE
FROST HEADLINES THEN.
TEMPERATURES WILL INCREASE A BIT BY FRIDAY, AS WARMER AIR PUSHES
INTO THE REGION AHEAD OF A COLD FRONT. THIS WILL BE SHORT-LIVED,
AS THE COLD FRONT IS FORECAST TO MOVE THROUGH FRIDAY NIGHT INTO
SATURDAY. THE FRONTAL PASSAGE AND ASSOCIATED SHORT-WAVE TROUGH
WILL OFFER THE BEST POSSIBILITY FOR PRECIPITATION DURING THE
EXTENDED FORECAST PERIOD. THE BEST CHANCE SHOULD OCCUR OVER C/EC
WI SATURDAY AFTERNOON, AS INSTABILITY INCREASES TO AROUND 1000
J/KG AND PWATS INCREASE TO 1-1.4 INCHES IN THE VICINITY OF THE
FRONT, AND THE RRQ OF AN UPPER LEVEL JET PASSES THROUGH. WITH DEEP
LAYER SHEAR OF 25 TO 35 KNOTS ANTICIPATED, WE WILL NEED TO
MONITOR THE POTENTIAL FOR A FEW STRONG STORMS AS WELL. MOST OF
THE PRECIPITATION SHOULD SHIFT SOUTH OF THE REGION SATURDAY
NIGHT.
THERE IS SOME UNCERTAINTY WITH THE FORECAST FOR THE END OF THE
WEEKEND INTO EARLY NEXT WEEK. MODELS ALL CLOSE OFF AN UPPER LOW
OVER THE WESTERN GREAT LAKES ON SUNDAY, BUT THE ECMWF IS SLOWER
THAN THE GEM/GFS TO SHIFT IT TO THE EAST. DEPENDING ON THE
POSITION/MOVEMENT OF THE UPPER LOW, PRECIPITATION CHANCES MAY NEED
TO BE INCREASED, TEMPERATURES LOWERED SEVERAL DEGREES, AND WINDS
INCREASED AT TIMES.
AVIATION
FOR 00Z TAF ISSUANCE
ISSUED AT 640 PM CDT TUE JUN 6 2023
SOME STRATOCUMULUS AROUND 5000-6000 FEET WILL CONTINUE INTO THIS
EVENING ACROSS MAINLY CENTRAL WI, WITH OTHER HIGHER MID AND UPPER
CLOUDS OVER THE ENTIRE AREA. THESE CLOUDS WILL SLOWLY EXIT FROM
NORTHEAST TO SOUTHWEST OVERNIGHT. A SPRINKLE COULD CLIP AUW/CWA
LATER TONIGHT, BUT WILL HAVE NO IMPACT TO CEILINGS.
EAST TO NORTHEAST WINDS WILL CONTINUE, WITH ANY GUSTS DIMINISHING
LATE THIS AFTERNOON AS THE BETTER MIXING ENDS NEAR SUNSET. WINDS
WILL REMAIN LIGHT TONIGHT THEN INCREASE AGAIN WEDNESDAY, GUSTING
UP 12-22 KTS, HIGHEST IN THE FOX VALLEY AND LAKE SHORE.
WHILE A LITTLE SMOKE REMAINS ALOFT THIS EVENING, A THICKER AREA IS
LURKING OVER LAKE SUPERIOR AND ONTARIO, SEEN NICELY ON THE GOES
VISIBLE IMAGERY (PLUS YOU CAN SEE SOME VERY LARGE FIRES RAGING IN
EASTERN ONTARIO AND WESTERN QUEBEC). RAP/HRRR DON'T FULLY AGREE
ON WHERE THE AREA OF SMOKE WILL GO, BUT RAP SEEMS TO HAVE A BETTER
HANDLE ON THINGS (LIKELY DO TO A BIGGER DOMAIN WHICH CAPTURES MORE
OF THE CURRENT SMOKE), SO WILL FOLLOW IT. THIS BRINGS THE THICKER
SMOKE BACK ACROSS MOST OF THE AREA INTO WEDNESDAY. IT LOOKS TO
STAY MAINLY ALOFT, CREATING HAZY SKIES, BUT LITTLE IMPACT IN
SURFACE CONDITIONS (VSBYS) IS EXPECTED FOR THIS TAF PERIOD. WHILE
A 6SM IS POSSIBLE WHERE THE SMOKE IS THE THICKEST, NOT MUCH
UPSTREAM SUPPORT FOR THE SMOKE MAKING IT DOWN TO THE SURFACE SO
WILL KEEP P6SM FOR ALL SITES.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM.....KIECKBUSCH
LONG TERM......KIECKBUSCH
AVIATION.......BERSCH
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