714
FXUS63 KGRB 261721
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1221 PM CDT WED MAR 26 2025
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE.
KEY MESSAGES
- A STRONG SPRING STORM WILL BRING A WINTRY MIX OF RAIN, FREEZING
RAIN, SLEET AND SNOW FROM LATE THURSDAY NIGHT THROUGH SUNDAY,
WITH THE BEST CHANCE OF SIGNIFICANT SNOW AND ICE ACCUMULATIONS
OVER NORTHERN WI.
- A WARM FRONT WILL SET UP ACROSS CENTRAL OR SOUTHERN WISCONSIN
FRIDAY AFTERNOON AND EVENING. THUNDERSTORMS ARE POSSIBLE ALONG
AND NORTH OF THE WARM FRONT. SOME OF THE STRONGER STORMS COULD
PRODUCE HAIL.
- PRECIPITATION TOTALS OVER AN INCH ARE EXPECTED WITH THE STRONG
SPRING STORM FRIDAY INTO THE WEEKEND, WITH SOME PLACES
APPROACHING 2 INCHES. PROBABILITIES OVER AN INCH ARE AT 55 TO
70% WITH A 35 TO 50% CHANCE OF AN INCH AND A HALF.
DISCUSSION
ISSUED AT 358 AM CDT WED MAR 26 2025
THE MAIN FORECAST CONCERN WILL BE THE PROLONGED PERIOD OF
RAIN, FREEZING RAIN, SLEET AND SNOW AT TIMES FROM LATE THURSDAY
NIGHT INTO SUNDAY. THE BEST POTENTIAL FOR ACCUMULATION SNOW WILL
BE SATURDAY NIGHT INTO SUNDAY.
TRANQUIL CONDITIONS ARE EXPECTED TODAY UNDER PARTLY TO AT TIMES
MOSTLY CLOUDY SKIES. HIGH TEMPERATURES SHOULD TOP OUT IN THE
MIDDLE 40S TO LOWER 50S. FOR TONIGHT, A WEAK UPPER LEVEL
DISTURBANCE WILL MOVE SOUTHEAST ACROSS THE REGION. SOME OF THE
MODELS NOTED A NORTHWARD TREND IN THE QPF FIELDS, THUS ADDED A
SMALL CHANCE OF LIGHT RAIN LATE TONIGHT INTO THURSDAY MORNING FOR
PORTIONS OF CENTRAL WISCONSIN INTO THE LOWER FOX VALLEY.
FOR THURSDAY NIGHT, TEMPERATURES ARE EXPECTED TO FALL BELOW
FREEZING ACROSS THE NORTH, GENERALLY NORTH OF HIGHWAY 29 DURING
THE NIGHT. PRECIPITATION IS EXPECTED TO ARRIVE TOWARDS DAYBREAK
ACROSS THE NORTH. BUFKIT SOUNDINGS INDICATED THE WARM LAYER AROUND
850MB WARMS TO AROUND VAT LEAST +6C WHILE THE AIR TEMPERATURE AT
THE GROUND WAS A FEW DEGREES BELOW FREEZING. ACROSS THE NORTH,
PRECIPITATION WILL START OUT AS FREEZING RAIN. THERE IS SOME
QUESTION ON THE SOUTHWARD EXTENT OF THE FREEZING RAIN. A
SUBSTANTIAL DIFFERENCE IN THE AIR TEMPERATURES AT THE SURFACE FROM
WISC. RAPIDS TO WAUSAU THAT MAKE THE DIFFERENCE IN THE
PRECIPITATION TYPE. TEMPERATURES ACROSS THE NORTH SHOULD RISE A
FEW DEGREES ABOVE FREEZING DURING THE AFTERNOON WITH RAIN
EXPECTED. ROAD TEMPERATURES SHOULD ALSO CLIMB ABOVE FREEZING BY
LATE MORNING.
ON FRIDAY, A SHARP WARM FRONT IS GOING TO LIFT NORTHWARD TOWARDS
THE AREA. A FEW OF THE MODELS BRING THE WARM FRONT INTO OUR
SOUTHERN COUNTIES WHILE A FEW OF THEM KEEP IT TO THE SOUTH.
SPRING TIME IS THE TIME OF YEAR THE WARM FRONT CAN STRUGGLE
MOVING NORTHWARD AS FAR THE MODELS WOULD INDICATE. ON GOING
PRECIPITATION NORTH OF THE WARM FRONT, EASTERLY FLOW BRINGING IN A
STABLE MARINE LAYER, AND NO REALLY STRONG LOW MOVING NORTHEAST TO
HELP DRAG THE WARM FRONT NORTHWARD. CURRENT EXPECTATION IS THE
FRONT WILL STAY SOUTH OF OUR SOUTHERN COUNTIES. TEMPERATURES SOUTH
OF THE WARM FRONT WILL CLIMB INTO THE 60S AND 70S, WHILE NORTHERN
WISCONSIN WILL LIKELY STAY IN THE 30S AND 40S. DURING FRIDAY
AFTERNOON AND EVENING, A 40+ KNOT 850MB JET WILL OVERRIDE THE
SURFACE WARM FRONT, COMBINED WITH STEEP MID LEVEL LAPSE RATES OF
8-8.5C/KM WOULD SUPPORT THUNDERSTORM ACTIVITY THAT COULD BRING
HAIL WITH THE STRONGER STORMS. SINCE EXPECTATIONS THAT WE WOULD
STAY IN THE COOL SECTOR, COULD NOT RULE OUT SOME LARGER HAIL
STONES.
A SURFACE WAVE WILL MOVE ALONG THE FRONT FRIDAY NIGHT. AS THIS
FEATURE MOVES EAST, THE FRONT WILL DROP SOUTHWARD AS A COLD
FRONT. WILL NEED WATCH AIR TEMPERATURES AT THE GROUND TO SEE IF
THEY FALL BELOW FREEZING LATE FRIDAY NIGHT INTO SATURDAY MORNING.
ALOFT, 850MB TEMPERATURES WILL WARM ENOUGH TO SUPPORT LIQUID
ALOFT TO ONLY FREEZE ONCE REACHING THE GROUND. SOME OF THE MODELS
WERE SUGGESTING THERE COULD BE A LULL OR BREAK IN THE PRECIPITATION
ACROSS THE NORTH LATE FRIDAY NIGHT INTO SATURDAY MORNING,
ALTHOUGH CONFIDENCE IS LOW IF THIS WOULD OCCUR. ON SATURDAY NIGHT,
THE MAIN STORM SYSTEM WILL MOVE TOWARDS THE WESTERN GREAT LAKES.
SIGNIFICANT DIFFERENCES IN THE TIMING OF THE SYSTEM AND STORM
TRACK THAT WOULD GREATLY IMPACT THE AMOUNT OF COLD AIR MOVING INTO
THE AREA, PRECIPITATION TYPES AND WHEN A WINTRY MIX WOULD CHANGE
OVER TO ALL AND HOW MUCH SNOW WOULD ACCUMULATE.
BEYOND THAT, IT LOOKS LIKE THERE POTENTIAL FOR ANOTHER SIGNIFICANT
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
AVIATION
FOR 18Z TAF ISSUANCE
ISSUED AT 1220 PM CDT WED MAR 26 2025
MAINLY VFR CONDITIONS ARE FORECAST THROUGH THE TAF PERIOD.
SCATTERED TO BROKEN CLOUDS BETWEEN 5000-8000 FT ARE FORECAST TO
DEVELOP OVER THE FORECAST AREA THIS AFTERNOON BEFORE DISSIPATING
EARLY THIS EVENING.
A NARROW BAND OF LIGHT RAIN WILL GRAZE PAST CENTRAL WI EARLY ON
THURSDAY MORNING. A BRIEF PERIOD OF MVFR CEILINGS ARE POSSIBLE
SOUTH OF A ISW TO OSH LINE FROM ABOUT 10Z TO 18Z WHERE THERE IS A
CHANCE OF LIGHT RAIN. OTHERWISE, CEILINGS COULD LOWER TO AROUND
5000-6000 FT ACROSS CENTRAL AND EAST-CENTRAL WI BEFORE CEILINGS
REBOUND THURSDAY AFTERNOON.
NO SIGNIFICANT IMPACTS FROM WINDS OR VISIBILITIES ARE EXPECTED.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....ECKBERG
AVIATION.......MPC
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