469
FXUS63 KGRB 311128
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
628 AM CDT MON MAR 31 2025
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE...
KEY MESSAGES
- WINTRY PRECIPITATION TO MOVE OUT OF OUR FORECAST AREA BY SUNRISE
THIS MORNING. SUNSHINE AND TEMPERATURES IN THE 30S EXPECTED TODAY.
- CONFIDENCE IS VERY HIGH (90% CHANCE) IN ANOTHER WINTRY WEATHER
SYSTEM TO IMPACT OUR AREA TUESDAY NIGHT/WEDNESDAY MORNING.
- NO HAZARDOUS WEATHER EXPECTED IN THE 7-DAY FORECAST AFTER
WEDNESDAY MORNING.
DISCUSSION
ISSUED AT 300 AM CDT MON MAR 31 2025
HAZARDOUS WINTRY WEATHER ENDING THIS MORNING/TODAY...
AT THE TIME OF THIS PUBLICATION (AROUND 3 AM MONDAY MORNING), LIGHT
WINTRY PRECIPITATION WAS STILL IMPACTING MOST OF THE FOX VALLEY
REGION. BY SUNRISE TODAY, ALL PRECIPITATION WILL BE EAST OF OUR
FORECAST AREA.
LOOKING AT SATELLITE IMAGERY, THERE ARE A LOT OF HOLES IN THE CLOUDS
ACROSS MINNESOTA. THIS WILL FACILITATE PARTLY CLOUDY TO MOSTLY SUNNY
SKIES ACROSS OUR ENTIRE FORECAST AREA BY EARLY THIS AFTERNOON. AS A
RESULT OF THIS REFINEMENT, HAVE BOOSTED TEMPERATURES A FEW DEGREES
EVERYWHERE. CONFIDENCE IS HIGH (OVER 90%) THAT HIGH TEMPERATURES
ACROSS OUR AREA WILL BE AT OR ABOVE FREEZING EVERYWHERE FOR TODAY.
WITH THE INSOLATION FROM THE SUN, ROAD TEMPERATURES WILL EASILY
EXCEED 40 DEGREES, AND SURFACE TEMPERATURES SHOULD ALSO BE WELL
ABOVE FREEZING. THIS WILL HELP MELT REMAINING ICE OFF OF MOST TO ALL
SURFACES TODAY- ESPECIALLY THOSE EXPOSED TO THE SUNLIGHT.
CONFIDENCE IS VERY HIGH (90% CHANCE) IN ANOTHER WINTER WEATHER
SYSTEM TO IMPACT OUR AREA TUESDAY NIGHT/WEDNESDAY MORNING...
BOTTOM-LINE UP FRONT, WE HAVE SEEN INDICATIONS OF THIS SYSTEM FOR
THE PAST FEW DAYS, AND CONFIDENCE THAT THERE WILL BE AT LEAST MINOR
IMPACTS IN OUR AREA IS NOW VERY HIGH. THE LATEST PROBABILISTIC WSSI
OUTPUT HAS THE ZONE OF HIGHEST LIKELIHOOD OF IMPACTS FROM THIS
SYSTEM CENTERED FROM AROUND MARATHON COUNTY INTO PORTAGE AND SHAWANO
COUNTIES. IN THIS ZONE, THERE IS A 90% CHANCE OF AT LEAST MINOR
IMPACTS, AND A 40 TO 50% CHANCE OF MODERATE IMPACTS. TO HELP PUT
THIS INTO PERSPECTIVE, IMPACTS FROM THE PREVIOUS/ENDING WINTER
SYSTEM WERE SOLIDLY IN THE 'MAJOR' CATEGORY.
THIS DOES LOOK TO BE YET ANOTHER EVENT THAT INCLUDES ICE
ACCUMULATION FOR MANY, PLUS WET/HEAVY SNOW ACCUMULATION... THE
COMBINATION OF WHICH SEEM TO BE SHAPING UP TO BE THE BIGGEST DRIVERS
OF ADVERSE IMPACTS.
AIR TEMPERATURE ALOFT WILL BE THE KEY DETERMINER OF PRECIPITATION
TYPE THROUGHOUT THIS EVENT. AS AN AREA OF LOW PRESSURE PROPAGATES
NORTH/NORTHEASTWARD ACROSS MINNESOTA, WARM AIR WILL ALSO BE ADVECTED
NORTH ALONG AN ATTENDANT WARM FRONT. THE 00Z MON NAM SOLUTION SEEMS
TO BE AN AGGRESSIVE OUTLIER WITH ADVECTING WARM AIR THE FURTHEST
NORTH (WHICH WOULD FAVOR HIGHEST FREEZING RAIN AMOUNTS), SO AM
LEANING AWAY FROM THAT ONE AT THIS TIME. FOR PRECIPITATION
TYPE/TIMING/EVOLUTION, LOOKING AT SNOW ARRIVING IN CENTRAL WISCONSIN
TUESDAY EVENING AND SPREADING NORTH/NORTHEASTWARD. AS RELATIVELY
WARMER AIR ALOFT IS BROUGHT NORTHWARD DURING THE EARLY MORNING
HOURS, AM EXPECTING PRECIPITATION TYPE TO TRANSITION TO SLEET/ICE
PELLETS AND THEN TO FREEZING RAIN FROM AROUND 1 AM THROUGH 6 AM OR
SO. ONCE THE SUN COMES UP, TEMPERATURES WARM ENOUGH TO TRANSITION
ALL PRECIPITATION TO RAIN. BY EARLY AFTERNOON, DRY AIR BEGINS TO
WRAP INTO THIS SYSTEM, AND THE LIGHT RAIN DIMINISHES.
OVERALL, SNOW ACCUMULATIONS LOOK TO BE IN THE 2 TO 4 INCH RANGE FOR
MOST OF OUR AREA, AND ICE ACCUMULATION LOOKS TO BE LESS THAN 0.1"
ACROSS CENTRAL TO NORTH-CENTRAL WISCONSIN. WIND GUSTS WILL BE IN THE
20 TO 30 MPH RANGE, SO VISIBILITY DURING PERIODS OF SNOW COULD LOWER
TO 1 MILE OR SO.
NO HAZARDOUS WEATHER EXPECTED IN THE 7-DAY FORECAST AFTER WEDNESDAY
MORNING...
BEHIND WEDNESDAY'S SYSTEM, WE GET A BREAK. NO HAZARDOUS WEATHER IS
IN THE FORECAST INTO THE WEEKEND. THE CPC IS FAVORING BELOW NORMAL
TEMPERATURES AND BELOW NORMAL PRECIPITATION CHANCES ACROSS THE UPPER
MIDWEST THROUGH MID-APRIL. SO ALTHOUGH WE'LL DRY OUT, HIGHS IN THE
30S AND 40S WILL BE MORE COMMONPLACE THAN HIGHS IN THE 60S OR 70S
FOR THE NEXT FEW WEEKS.
AVIATION
FOR 12Z TAF ISSUANCE
ISSUED AT 626 AM CDT MON MAR 31 2025
HIGH CONFIDENCE IN ALL TAF SITES GOING TO VFR BY 1400Z AT THE
LATEST. HIGH CONFIDENCE IN WINDS TO DECOUPLE AND FALL TO UNDER
10KTS THIS EVENING INTO THE OVERNIGHT.
HYDROLOGY
ISSUED AT 300 AM CDT MON MAR 31 2025
MONITORING RIVER RISES IN RESPONSE TO PRECIPITATION OVER THE PAST
FEW DAYS. SEVERAL LOCATIONS ALONG THE WISCONSIN RIVER HAVE REACHED
MINOR FLOOD STAGE. ENCOURAGING NEWS IS THAT THE LATEST OBSERVATIONS
(AS OF EARLY MONDAY MORNING) ARE SHOWING THE RIVER STAGES STARTING
TO TURNOVER... MEANING CONDITIONS MAY GRADUALLY LEVEL OFF AND WATER
LEVELS GRADUALLY DECREASE.
HOWEVER, THIS DECREASE MAY BE SHORT-LIVED AS THE AFOREMENTIONED
WINTER WEATHER SYSTEM FOR WEDNESDAY WILL LIKELY BRING ANOTHER ROUND
OF NOTABLE PRECIPITATION ACCUMULATION WITH IT. AS OF NOW, THERE IS A
AT LEAST A 70% CHANCE THAT OUR FORECAST AREA WILL RECEIVE OVER 0.5
INCHES OF PRECIP, AND A 30% TO 50% CHANCE THAT MOST OF OUR AREA WILL
RECEIVE OVER 1 INCH OF PRECIP. OVER THE NEXT 48 HOURS, WE WILL
COORDINATE MODELING WITH THE NCRFC THE IMPACTS OF THIS EXPECTED
PRECIPITATION.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....KOTENBERG
AVIATION.......KOTENBERG
HYDROLOGY......KOTENBERG
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