719
FXUS63 KGRB 312032
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
332 PM CDT MON MAR 31 2025
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
KEY MESSAGES
- ANOTHER WINTRY WEATHER SYSTEM IS EXPECTED TO IMPACT OUR AREA
TUESDAY EVENING THROUGH WEDNESDAY EVENING. ACCUMULATING SNOW,
ICING, GUSTY WINDS, RAIN, AND SOME THUNDERSTORMS ARE ALL
POSSIBLE WITH THIS SYSTEM. BE SURE TO MONITOR THE FORECAST AS
THERE IS STILL SOME UNCERTAINTY WITH THE SYSTEM'S STORM TRACK.
DISCUSSION
ISSUED AT 332 PM CDT MON MAR 31 2025
SHORT TERM...TONIGHT AND TUESDAY
QUIET CONDITIONS ARE EXPECTED THROUGH THIS FORECAST PERIOD AS
SURFACE HIGH PRESSURE REIGNS OVER THE AREA. TODAY'S PERIODS OF
SUNSHINE SHOULD HAVE HELPED MELT SOME OF THE ICE AND SNOW FROM
THE RECENT WINTER WEATHER EVENT, BRINGING IMPROVEMENT TO AREAS
ACROSS THE NORTHWOODS WHERE SEVERAL TENS OF THOUSANDS WERE WITHOUT
POWER AS OF EARLY THIS MORNING. GIVEN THE HIGH PRESSURE WILL BE
OVERHEAD TONIGHT, SKIES WILL CLEAR AND WINDS WILL BE CALM,
ALLOWING TEMPERATURES IN THE TYPICAL COLD SPOTS TO DROP WELL BELOW
NORMAL TO THE SINGLE DIGITS. HAVE LOW TEMPERATURES RANGING FROM
THE SINGLE DIGITS TO LOW 10S ACROSS THE NORTH TO THE LOW 20S
ACROSS CENTRAL AND EAST-CENTRAL WI.
AS THE SURFACE HIGH BEGINS TO DEPART ON TUESDAY, THE NEXT WEATHER
MAKER WILL BE APPROACHING THE AREA FROM THE SOUTHWEST. THE WARMER
AIR WILL REMAIN TO THE SOUTH OF THE REGION ON TUESDAY, LEADING HIGH
TEMPERATURES TO REMAIN ABOUT 10 DEGREES BELOW NORMAL RANGING FROM
THE MIDDLE 30S TO LOW 40S.
LONG TERM...TUESDAY NIGHT THROUGH MONDAY
MAIN FOCUS FROM THIS FORECAST PERIOD REVOLVES AROUND THE NEXT
WEATHER SYSTEM BRINGING THE POTENTIAL FOR ACCUMULATING SNOW, SOME
ICING, GUSTY WINDS, RAIN, AND THUNDERSTORMS FROM TUESDAY EVENING
THROUGH WEDNESDAY EVENING.
TUESDAY EVENING THROUGH WEDNESDAY NIGHT...A POTENT LOW PRESSURE
SYSTEM IS PROGGED TO TRACK NORTH/NORTHEAST FROM THE CENTRAL PLAINS
ACROSS THE UPPER MISSISSIPPI VALLEY THROUGHOUT THIS TIME PERIOD.
THERE WILL BE MANY FACTORS SUPPORTING THIS SYSTEM INCLUDING STRONG F-
GEN AND SUPPORT FROM THE LFQ OF AN UPPER-LEVEL JET AT THE ONSET FOR
TUESDAY EVENING/NIGHT FOLLOWED BY ADDITIONAL F-GEN AND A STRONG LOW-
LEVEL JET (50-60KTS) PAIRED WITH MUCAPE OF A COUPLE HUNDRED BY
WEDNESDAY AFTERNOON. DESPITE ALL OF THESE SUPPORTING FACTORS, THERE
IS STILL UNCERTAINTY IN THE EXACT TRACK OF THE SURFACE LOW, WHICH
WILL PLAY A LARGE ROLE IN DETERMINING P-TYPE, PRECIPITATION AMOUNTS,
AND THUNDERSTORM POTENTIAL. IF THE SURFACE LOW TRACKS FURTHER
NORTHWEST OF THE FORECAST AREA, THERE WOULD BE A BETTER CHANCE FOR
THUNDERSTORMS ACROSS THE ENTIRE FORECAST AREA ON WEDNESDAY. BUT, IF
THE LOW TRACKS ACROSS NORTHWEST WI (OR CLOSER TO THE FORECAST AREA),
THE POTENTIAL FOR THUNDERSTORMS WILL LESSEN. FORECAST SOUNDINGS
INDICATE THERMAL PROFILES STARTING OUT WITH SNOW AS THE INITIAL P-
TYPE FOR TUESDAY EVENING LIFTING FROM THE SOUTHWEST AND MOVING
NORTHEAST. HOWEVER, AS THE SURFACE LOW NEARS, AN ELEVATED WARM LAYER
WILL MOVE INTO THE AREA. THIS WILL LEAD TO A CHANGE OVER TO A WINTRY
MIX WITH SLEET AND FREEZING RAIN MIXING WITH THE SNOW. THEN, AS
SURFACE TEMPERATURES WARM ABOVE FREEZING WEDNESDAY MORNING INTO THE
EARLY AFTERNOON, THE PRECIP WILL TRANSITION TO RAIN. THE BEST CHANCE
FOR THUNDERSTORMS WOULD BE LATE WEDNESDAY MORNING THROUGH THE
AFTERNOON ACROSS THE ENTIRE AREA. THERE IS SOME POTENTIAL FOR A FEW
STRONG ELEVATED STORMS ACROSS CENTRAL AND EAST-CENTRAL WI THAT COULD
PRODUCE HAIL AND STRONG WIND GUSTS, BUT AGAIN, THE LOW TRACK WILL
PLAY A LARGE ROLE IN THIS OUTCOME. ANY PRECIPITATION SHOULD COME TO
AN END BY WEDNESDAY EVENING.
GENERALLY, SNOWFALL AMOUNTS OF 1 TO 4 INCHES IS ANTICIPATED FROM
TUESDAY EVENING THROUGH WEDNESDAY AFTERNOON. IN ADDITION TO THE
SNOWFALL, MINOR ICE ACCUMULATIONS UP TO 0.10 OF AN INCH ARE
POSSIBLE, MAINLY FOR LOCATIONS IN CENTRAL AND NORTH-CENTRAL WI.
HOWEVER, DUE TO THE UNCERTAINTY WITH THE LOW TRACK, A LIGHT GLAZE
CANNOT BE RULED OUT FROM OCCURRING EVERYWHERE. THESE SNOW AND ICE
AMOUNTS WILL LIKELY LEAD TO TRAVEL IMPACTS FOR THE WEDNESDAY MORNING
COMMUTE.
ADDING TO THIS SYSTEM WILL BE GUSTY SOUTHEAST WINDS UP TO 30 TO 40
MPH DUE TO THE TIGHTENED PRESSURE GRADIENT FROM THE CLOSE PROXIMITY
OF THE SURFACE LOW. SINCE THE GUSTY WINDS WILL BE OCCURRING
THROUGHOUT THE EVENT, REDUCTIONS IN VISIBILITY ARE LIKELY TO OCCUR
FROM THE COMBINATION OF THE GUSTY WINDS AND FALLING PRECIPITATION
(MAINLY SNOW).
REST OF THE EXTENDED...SOME LINGERING LIGHT PRECIP IS POSSIBLE
ACROSS FAR NORTH-CENTRAL WI WEDNESDAY NIGHT AS SOME WRAP AROUND
MOISTURE FROM THE SURFACE LOW MOVES OVER NORTHERN WI. OTHERWISE, A
LESS ACTIVE PATTERN IS ANTICIPATED THROUGH THE WEEKEND WITH
TEMPERATURES AT OR SLIGHTLY ABOVE NORMAL.
AVIATION
FOR 18Z TAF ISSUANCE
ISSUED AT 1237 PM CDT MON MAR 31 2025
VFR CONDITIONS PREVAILED ACROSS MUCH OF THE REGION THIS AFTERNOON.
HOWEVER, AN AFTERNOON SCT/BKN CU FIELD WITH MVFR CIGS (BETWEEN
2500 AND 3000 FT AGL) DEVELOPED OVER PORTIONS OF NORTHERN AND
EASTERN WI. BASED ON CLOUD TRENDS AND MODELS, HAVE THE MVFR CIGS
AT ALL TAF SITES EXCEPT RHI THROUGH LATE THIS AFTERNOON. SKIES
BECOME CLEAR OVERNIGHT. GOOD FLYING CONDITIONS WILL CONTINUE
THROUGH THE END OF THIS TAF PERIOD DESPITE HIGH/MID CLOUDS MOVING
INTO THE AREA FROM THE WEST TOWARDS THE END OF THE TAF PERIOD.
NORTHWEST WINDS WILL CONTINUE TO GUST TO 15 TO 20 KTS THROUGH LATE
THIS AFTERNOON BEFORE SUBSIDING THIS EVENING.
HYDROLOGY
ISSUED AT 332 PM CDT MON MAR 31 2025
RIVERS CONTINUED TO RISE OR LEVEL OFF TODAY FROM THE RECENT
PRECIPITATION. SEVERAL LOCATIONS ALONG THE WISCONSIN RIVER HAVE
REACHED OR REMAINED IN MINOR FLOOD STAGE, WHILE MANY OTHERS IN EAST-
CENTRAL AND FAR NORTHEAST WI SAT AT BANKFULL. WHILE THERE WAS SOME
IMPROVEMENT WITH SOME RIVERS LEVELING OFF, THE ADDITIONAL RAINFALL
EXPECTED FROM THE TUESDAY EVENING THROUGH WEDNESDAY SYSTEM WILL
CAUSE ADDITIONAL RIVER RISES. QPF AMOUNTS OF A HALF INCH TO AN INCH
ARE FORECAST FOR THE NEXT SYSTEM, WITH THE HIGHEST AMOUNTS OCCURRING
IN AREAS WHERE RIVERS ARE ALREADY SEEING IMPACTS.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....KRUK/KRUK
AVIATION.......KRUK
HYDROLOGY......KRUK
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