963
FXUS63 KGRB 211143
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
643 AM CDT MON APR 21 2025
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
KEY MESSAGES
- RAIN ENDS SOUTHWEST TO NORTHEAST THROUGH THE DAY. SNOW WILL MIX
IN ACROSS NORTH-CENTRAL WISCONSIN, WHERE MINOR ACCUMULATIONS ARE
POSSIBLE ON GRASSY SURFACES.
- PERIODIC CHANCES FOR RAIN THROUGHOUT THE WEEK MAY LEAD TO RISES
ON AREA RIVERS AND PONDING OF LOW LYING AREAS.
- COOLER TEMPERATURES WILL START THE WORK WEEK, ALTHOUGH A GRADUAL
WARM UP IS IN STORE THROUGH MID-WEEK. SOME AREAS MAY SEE HIGHS
IN THE LOW 70S WEDNESDAY AND THURSDAY.
DISCUSSION
ISSUED AT 344 AM CDT MON APR 21 2025
SHORT TERM...TODAY...TONIGHT...AND TUESDAY
PRECIP TRENDS / HYDRO CONCERNS:
SURFACE LOW PRESSURE WILL TRACK TO NEAR OCONTO THIS MORNING, AS A
POTENT SHORTWAVE TRACKING ACROSS THE STATE. THE WILL DEPART INTO
THE U.P. AND ONTARIO THIS AFTERNOON/EVENING. EXPECT ONLY ISOLATED
TO SCATTERED SHOWER ACTIVITY ACROSS EASTERN WI THIS MORNING, AHEAD
OF THE LOW. THE PRECIP IN THE DEFORMATION ZONE WILL BE MORE
WIDESPREAD ACROSS CENTRAL AND NORTH CENTRAL WI THROUGH THE MORNING
HOURS. ALL THE PRECIP WILL END DURING THE LATE MORNING AND
AFTERNOON HOURS FROM SOUTHWEST TO NORTHEAST. CAN'T RULE OUT A
STRAY RUMBLE OF THUNDER WITHIN THE WARM SECTOR OVER FAR EASTERN WI
EARLY THIS MORNING WITH A LITTLE MUCAPE AROUND, BUT CHANCES LOOK
TO BE UNDER 15% SO WILL NOT INCLUDE.
SOME SNOW MIXED IN ACROSS FAR NORTH CENTRAL WI AT TIMES DURING
THE OVERNIGHT HOURS, BUT RAIN WAS THE PREDOMINATE P-TYPE. AS THE
LOW TRACKS ACROSS THE REGION, COLDER AIR WILL GET DRAWN INTO
NORTH CENTRAL WI, WITH MORE SNOW MIXING IN TOWARD DAWN. AS THE
COLUMN CONTINUES TO COOL, A SWITCH TO ALL SNOW IS POSSIBLE,
ESPECIALLY VILAS CO. AS THE TRANSITION OCCURS, A LITTLE SLEET MAY
BRIEFLY MIX IN AS SOUNDINGS SHOW WARM LAYER ALOFT FOR A TIME THIS
MORNING. HREF PROBABILITIES INDICATING A 20-70% CHANCE OF 1" OF
SNOW, HIGHEST ACROSS NORTHWEST VILAS COUNTY. ACCUMULATIONS WILL BE
LIMITED TO GRASSY SURFACES AS THE WARM/WET GROUND AND STRONG
APRIL SUN WILL MAKE IT DIFFICULT FOR THE SNOW TO STICK/ACCUMULATE.
WILL CARRY UP TO AN INCH OF SNOW FOR FAR NORTH-CENTRAL WI TODAY.
THE WARM SIDE OF THE SYSTEM HAS UNDER-PERFORMED FOR THE MOST PART
AS THE LULLS WERE MORE PERSISTENT THAN THE SHOWER/STORM ACTIVITY,
SO NO FLOODING CONCERNS ARE EXPECTED. CENTRAL WI ON THE OTHER
HAND HAS OVER-PERFORMED SLIGHTLY, WITH TOTALS APPROACHING 1.5" IN
SPOTS. THIS WILL LIKELY LEAD TO SOME LOW-LYING PONDING AND SOME
RIVER/STREAM RISES. MINOR FLOODING IS LOOKING LIKELY AT BABCOCK
TONIGHT OR EARLY TUESDAY, BUT OVERALL IMPACTS WILL BE VERY MINOR.
AFTER A BRIEF PERIOD OF DRY CONDITIONS TONIGHT, THE NEXT SYSTEM
PUSHES ACROSS THE REGION ON TUESDAY. THIS SYSTEM WILL BE MUCH
WEAKER AND WON'T HAVE MUCH MOISTURE TO WORK WITH. PROBABILITIES OF
EXCEEDING 0.25" ARE STILL ONLY 15-25% ACROSS CENTRAL AND EAST-
CENTRAL WISCONSIN. THUNDER CHANCES WILL BE LOW (UNDER 20%) WITH
SLIGHTLY BETTER CHANCES TO OUR SOUTH.
WINDS / FOG / TEMPS:
THE GUSTY EAST/SOUTHEAST WINDS AHEAD OF THE LOW PRESSURE WILL
SHIFT TO THE WEST/NORTHWEST AS THE LOW DEPARTS. A PRETTY TIGHT
PRESSURE GRADIENT/PRESSURE COUPLET WILL WORK ACROSS THE AREA
DURING THE LATE MORNING AND AFTERNOON, WITH SOUNDINGS SUPPORTING
WIND GUSTS OF 25-40 MPH FOR MUCH OF THE AREA. A FEW SPOTS COULD
SEE A 40+ MPH GUST ACROSS EAST CENTRAL WI DURING PEAK MIXING IN
THE EARLY TO MID-AFTERNOON. WINDS WILL QUICKLY DIMINISH
TOWARD/AFTER SUNSET, WITH LIGHT WINDS EXPECTED TONIGHT. WINDS
WILL SHIFT TO THE SOUTHEAST ON TUESDAY, GUSTING TO 20 MPH IN THE
AFTERNOON.
AS WINDS DIE OFF THIS EVENING, THE CLEARING SKIES AND RECENT RAIN
WILL LEAD TO SOME FOG DEVELOPMENT OVERNIGHT INTO TUESDAY MORNING,
ESPECIALLY ACROSS CENTRAL AND NORTH CENTRAL WI, BUT INCREASING
CLOUDS FROM THE WEST MAY LIMIT THE EXTENT OF THE FOG.
TEMPS FALL BACK BELOW NORMAL TODAY AS CAA WORKS ACROSS NORTHEAST
WI IN THE AFTERNOON. HIGHS WILL RANGE FROM THE UPPER 30S AND LOW
40S IN NORTH CENTRAL WI TO THE UPPER 40S TO NEAR 50 IN THE FOX
VALLEY. LOWS TONIGHT WILL RANGE FROM THE MID 20S ACROSS NORTH
CENTRAL WI TO THE MID 30S IN EAST CENTRAL WI. TEMPS JUMP BACK
CLOSE TO NORMAL ON TUESDAY WITH HIGHS IN THE 50S FOR MOST OF THE
AREA.
LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
WE WON'T BE AFFORDED MUCH OF A BREAK FROM PRECIP AS THE 500 MB
WAVE TRAIN GETS GOING THIS WEEK, BRINGING WITH IT PERIODIC
CHANCES FOR RAIN. MID-WEEK SYSTEM, THOUGH NOT AS DYNAMIC AS THE
ONGOING EARLY-WEEK SYSTEM, ARRIVES ON TUESDAY, AS WELL AS OUR NEXT
CHANCES FOR THUNDER. BETTER PRECIP CHANCES THEN ARRIVE LATER IN
THE WEEK, ALTHOUGH ENSEMBLE SPREAD IS STILL RELATIVELY HIGH AT
THIS TIME.
TUESDAY EVENING/WEDNESDAY... NOT TOO IMPRESSED WITH PRECIP
CHANCES TUESDAY/TUESDAY NIGHT AS SURFACE LOW PRESSURE STRUGGLES TO
ORGANIZE, FIGHTING AGAINST ZONAL FLOW ALOFT. THIS BEING SAID, 850
MB MOISTURE TRANSPORT FROM RETURN FLOW UP INTO WISCONSIN WILL
LIKELY BE SUFFICIENT TO KICK OFF SOME SHOWERS STARTING TUESDAY
MORNING. ELEVATED THUNDER WOULD ALSO BE POSSIBLE TUESDAY
AFTERNOON AND EVENING AS AN ISENTROPICALLY-INDUCED CORRIDOR OF 200
TO 400 J/KG MUCAPES WORKS INTO CENTRAL AND EAST-CENTRAL
WISCONSIN. BEST CHANCES FOR EMBEDDED THUNDER WOULD LIKELY BE ALONG
AND SOUTH OF HIGHWAY 29 TUESDAY EVENING.
THURSDAY/FRIDAY... ENSEMBLE CONSENSUS SHOWS A SURFACE LOW EJECTING
FROM THE SOUTHERN PLAINS INTO THE GREAT LAKES BY THURSDAY EVENING,
BRINGING OUR NEXT MEASURABLE PRECIP CHANCES. HOWEVER, CONSENSUS
ENDS THERE, AS THERE ARE STILL CONSIDERABLE DISCREPANCIES
REGARDING TIMING, AMOUNT, AND LOCATION OF HEAVIEST RAIN.
THIS BEING SAID, GRAND ENSEMBLE CURRENTLY SHOWS A WIDESPREAD 30 TO
50% CHANCE OF RECEIVING HALF AN INCH OF QPF, WITH A LESSER SIGNAL
EVEN EXISTING FOR ONE INCH. WOULD EVEN VENTURE TO SAY THAT CENTRAL
WISCONSIN COULD GET SOME THUNDER THURSDAY AFTERNOON WITHIN WAA
REGIME, THOUGH WILL CONTINUE TO MONITOR IN THE COMING DAYS.
TEMPERATURES... TEMPERATURES WILL READ ABOVE AVERAGE STARTING
MID-WEEK, PLATEAUING IN THE UPPER 60S TO LOW 70S WEDNESDAY AND
THURSDAY. WEDNESDAY LOOKS TO BE THE WARMER OF THE TWO DAYS, WITH
COMBINATION OF PERSISTENT SOUTHERLY WIND COMPONENT AND WINDOWS
FOR CLEARING. CAA BEHIND AN UPPER TROUGH THEN TAKES STAGE LATER IN
THE WEEK, COOLING TEMPERATURES BACK DOWN INTO THE 50S AND 60S FOR
MOST.
AVIATION
FOR 12Z TAF ISSUANCE
ISSUED AT 643 AM CDT MON APR 21 2025
POOR FLYING CONDITIONS WILL CONTINUE THIS MORNING WITH A MIX OF
MVFR/IFR/LIFR CEILINGS AND VISIBILITIES AS LOW CLOUDS, RAIN, AND
DRIZZLE CONTINUE. SOME SNOW WILL MIX IN ACROSS FAR NORTH CENTRAL
WI AS WELL. THE PRECIP WILL END FROM SOUTHWEST TO NORTHEAST
THROUGH THE DAY, WITH IMPROVING CONDITIONS TO VFR BY LATE
AFTERNOON OR EARLY EVENING. WINDS WILL BE VARIABLE FOR A TIME
THIS MORNING AS LOW PRESSURE MOVES OVERHEAD, THEN WINDS SHIFT TO
THE WEST/NORTHWEST LATER THIS MORNING AND AFTERNOON. GUSTS TO
30-35 KTS ARE EXPECTED.
AS WINDS DIMINISH AND SKIES CLEAR THIS EVENING, SOME FOG WILL BE
POSSIBLE MAINLY ACROSS CENTRAL AND NORTH CENTRAL WI LATE TONIGHT
INTO TUESDAY MORNING.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....BERSCH/GOODIN
AVIATION.......BERSCH
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