227
FXUS63 KGRB 202330
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
630 PM CDT FRI MAR 20 2026
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
KEY MESSAGES
- SNOWMELT WILL CAUSE INCREASED FLOWS AND RISING LEVELS ON RIVERS
AND STREAMS. SEVERAL RIVERS MAY REACH BANKFULL OR EVEN MINOR
FLOOD STAGE BEGINNING THIS WEEKEND.
- AREAS OF FOG AND LOW CLOUDS EXPECTED AGAIN TONIGHT INTO
SATURDAY MORNING. A 20 PERCENT CHANCE OF RAIN OR FREEZING RAIN
NEAR THE UPPER MICHIGAN BORDER.
- RAIN LIKELY (60-70%) SATURDAY NIGHT INTO SUNDAY MORNING. RAIN
MAY BRIEFLY MIX WITH SNOW OR SLEET BEFORE ENDING, BUT LITTLE OR
NO ACCUMULATION IS EXPECTED.
- WELL ABOVE NORMAL TEMPERATURES EXPECTED SATURDAY, ESPECIALLY IN
CENTRAL WI, WHERE HIGHS COULD REACH WELL INTO THE 60S. MILD
READINGS INTO THE 50S ARE ALSO ANTICIPATED NEXT TUESDAY AND
THURSDAY.
- A WINTRY MIX OF PRECIPITATION POSSIBLE DURING THE MIDDLE OF NEXT
WEEK, ESPECIALLY WEDNESDAY INTO THURSDAY.
DISCUSSION
ISSUED AT 250 PM CDT FRI MAR 20 2026
SUNNY SKIES HELPED BOOST TEMPERATURES INTO THE 50S ACROSS MOST OF
THE REGION THIS AFTERNOON, WITH THE EXCEPTION OF THE LAKESHORE
AREAS, WHERE ONLY MID TO UPPER 40S WERE OBSERVED.
THERE IS A SMALL CHANCE OF RAIN OR FREEZING RAIN ACROSS FAR
NORTHERN WI LATER TONIGHT INTO SATURDAY MORNING, IN RESPONSE TO
WAA IN A MOISTURE-STARVED AIR MASS. PRIOR TO INCREASING CLOUDS
WITH THIS SYSTEM (LATE TONIGHT), PARTLY CLOUDY SKIES, LIGHT WINDS
AND LOW-LEVEL MOISTURE FROM MELTING SNOW WILL SET THE STAGE FOR
FOG AND LOW STRATUS DEVELOPMENT BY LATE EVENING. THE SMALL
PRECIPITATION CHANCES AND FOG THREAT SHOULD WANE SATURDAY MORNING.
SATURDAY WILL LIKELY BE THE WARMEST DAY OF THE WEEK AS AN
APPROACHING LOW PRESSURE SYSTEM FROM THE NORTHERN PLAINS BRINGS A
WARM FRONT AND ASSOCIATED SURGE OF VERY MILD AIR INTO THE FORECAST
AREA. THIS WARMTH WILL PRIMARILY BE FELT IN CENTRAL WI, WHERE
THERE IS A 60-80% CHANCE OF HIGHS >65 DEGREES. FARTHER NORTH AND
EAST, A COMBINATION OF LOW CLOUDS (NORTH OF THE WARM FRONT) AND
SE-S WINDS OFF LAKE MICHIGAN WILL KEEP READINGS IN THE 40S AND
50S.
AS THE LOW SHIFTS EAST, A COLD FRONT WILL SWEEP THROUGH THE
FORECAST AREA DURING THE LATE AFTERNOON/EVENING. MODELS SHOW
STRONG MID-LEVEL FGEN FORCING WITH THIS SYSTEM, WHICH SHOULD
BRING A BAND OF LIGHT RAIN THROUGH THE AREA SATURDAY NIGHT INTO
EARLY SUNDAY. THIS BAND SHOULD SAG SOUTHEAST WITH TIME, WITH THE
LAGGING INFLUX OF COLDER AIR ONLY LEADING TO A BRIEF PERIOD OF
MIXED PRECIPITATION (MAINLY SLEET/SNOW) ON THE NORTHWEST PERIPHERY
OF THE PRECIPITATION BAND. THUS, NOT EXPECTING MUCH (IF ANY) SNOW
ACCUMULATION. MOST OF THE PRECIPITATION SHOULD BE GONE BY SUNDAY
AFTERNOON.
HIGH PRESSURE WILL THEN PROVIDE MAINLY DRY WEATHER AND MORE
SEASONABLE TEMPERATURES FROM SUNDAY AFTERNOON THROUGH MONDAY
NIGHT. ANOTHER CLIPPER SYSTEM WILL MOVE THROUGH DURING THE MIDDLE
OF NEXT WEEK. THIS SYSTEM LOOKS FAIRLY SIMILAR TO THIS WEEKEND'S
SYSTEM, WITH POTENTIAL FOR A LIGHT MIX OF RAIN/SNOW, ESPECIALLY
WEDNESDAY INTO THURSDAY. MILD DAYS OCCUR AHEAD OF THE CLIPPER ON
TUESDAY, AND WITHIN A DRY SLOT ON THURSDAY, WITH POTENTIAL FOR 50S
BOTH DAYS.
AVIATION
FOR 00Z TAF ISSUANCE
ISSUED AT 618 PM CDT FRI MAR 20 2026
VFR CONDITIONS PREVAILED ACROSS THE FORECAST AREA THIS EVENING.
MOSTLY CLEAR SKIES, DECOUPLING WINDS, AND AMPLE LOW-LEVEL
MOISTURE FROM MELTING SNOW WILL THEN RESULT IN A WINDOW FOR FOG
DEVELOPMENT LATE THIS EVENING AND OVERNIGHT, POTENTIALLY DROPPING
VSBYS INTO IFR OR LIFR TERRITORY MAINLY ACROSS THE CENTRAL WI TAF
SITES. HOWEVER, OPTED NOT TO INCLUDE ANY TEMPO GROUPS FOR THE TIME
BEING, AS IT IS STILL UNCERTAIN WHETHER OR NOT THIS WILL
MATERIALIZE AS FOG OR LOW STRATUS. SLIGHT CHANCES FOR RAIN OR
FREEZING RAIN THEN ARRIVE FROM THE NORTH TOWARD THE END OF THE TAF
PERIOD, THOUGH THIS SHOULD REMAIN NORTH OF RHI.
WINDS WILL GRADUALLY VEER TO SOUTH/SOUTHWESTERLY THROUGHOUT THE
DAY ON SATURDAY, PICKING UP SLIGHTLY SATURDAY AFTERNOON. GUSTS
BETWEEN 15 AND 20 KNOTS WILL BE POSSIBLE. LLWS MAY BECOME A
CONCERN LATE SATURDAY MORNING AND AFTERNOON AS 850 MB WINDS RAMP
UP.
HYDROLOGY
ISSUED AT 250 PM CDT FRI MAR 20 2026
AS TEMPERATURES WARM ACROSS THE REGION, THE SNOWMELT WILL RESULT
IN INCREASING FLOWS AND RISING RIVER LEVELS. SOME RIVERS COULD
REACH BANKFULL OR EVEN MINOR FLOOD STAGE STARTING THIS WEEKEND.
THE LACK OF A PROLONGED SIGNIFICANT WARMUP POINTS TO A MORE
GRADUAL RISE IN AREA RIVERS AS OPPOSED TO WIDESPREAD RAPID RISE
FLOODING. THAT BEING SAID, THE FLOODING SITUATION WILL BE
MONITORED CLOSELY GIVEN HOW MUCH WATER IS LOCKED UP IN THE CURRENT
SNOWPACK ACROSS THE REGION. MODELED SNOWPACK TEMPERATURE FROM THE
NOHRSC SITE POINTS TO WIDESPREAD RIPENING OF THE SNOWPACK (AND
HIGHER SUSCEPTIBILITY OF MELTING/RUNOFF) OVER THE AREA ON
SATURDAY.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....KIECKBUSCH
AVIATION.......GOODIN
HYDROLOGY......JLA/KIECKBUSCH
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