736
FXUS63 KGRB 211923
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
223 PM CDT MON APR 21 2025
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
KEY MESSAGES
- 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 222 PM CDT MON APR 21 2025
SHORT TERM...TONIGHT AND TUESDAY
SCATTERED LIGHT RAIN AND LIGHT SNOW SHOWERS CONTINUED ACROSS THE
FAR NORTH EARLY THIS AFTERNOON. UNDER CLOUDY SKIES, TEMPERATURES
RANGED FROM THE MIDDLE 30S FAR NORTH TO THE MIDDLE 40S OVER
CENTRAL AND EAST-CENTRAL WISCONSIN.
FOR THE REST OF THE AFTERNOON INTO EARLY THIS EVENING, WINDS WILL
DIMINISH AND SKIES WILL CLEAR AROUND SUNSET. THE COMBINATION OF
LIGHT WINDS AND MOSTLY CLEAR SKIES WILL ALLOW FOR SOME FOG
DEVELOPMENT OVERNIGHT. MID CLOUDS ARE EXPECTED TO MOVE INTO
MUCH OF THE AREA TOWARDS 12Z, THUS KEEPING THE POTENTIAL FOR
WIDESPREAD DENSE FOG AT BAY. FOR NOW, WILL HAVE PATCHY/AREAS OF
FOG. LOWS TONIGHT SHOULD DROP INTO THE MIDDLE TO UPPER 20S FAR
NORTH WITH LOWER TO MIDDLE 30S ELSEWHERE.
THE MID CLOUDS ARE IN RESPONSE TO 850MB WARM ADVECTION AHEAD OF A
WEAK LOW PRESSURE SYSTEM. RAIN IS EXPECTED TO DEVELOP WEST OF THE
STATE AND THEN SHOULD MOVE INTO PORTIONS OF CENTRAL WISCONSIN
AROUND 12Z. THE RAIN WILL SPREAD EASTWARD INTO NORTHEAST WISCONSIN
DURING THE DAY. HOWEVER, WEAKENING 850MB JET, LACK OF 850MB WARM
ADVECTION AND DRY AIR SHOULD RESULTING IN THE PRECIPITATION DRYING
UP DURING THE AFTERNOON, THUS CHANCES FOR RAIN WILL BE ON THE
DECREASE DURING THE AFTERNOON. HIGH TEMPERATURES SHOULD CLIMB INTO
THE 50S TO AROUND 60.
LONG TERM...TUESDAY NIGHT THROUGH MONDAY
DESPITE A WARM FRONT LIFTING NORTH ACROSS THE REGION TUESDAY NIGHT
AND A LOW PRESSURE SYSTEM ORGANIZING ACROSS THE REGION, RAIN
CHANCES WILL BE MEAGER AS LIFT ACROSS THE REGION WILL BE DE
MINIMIS THROUGH WEDNESDAY MORNING. ISENTROPIC SURFACES SHOW WINDS
ARE BASICALLY PARALLEL TO THE ISENTROPIC GRADIENT, WHICH MEANS
LITTLE TO NO LIFT ACROSS NORTHERN WISCONSIN. BY WEDNESDAY
AFTERNOON, ISENTROPIC WINDS TURN MORE SOUTHERLY, ALLOWING FOR A
MORE ORTHOGONAL COMPONENT OF THE WIND WITH RESPECT TO THE
ISENTROPIC SURFACE.
THE REGION WILL BE IN AN ON AND OFF ACTIVE PATTERN WEDNESDAY NIGHT
THROUGH FRIDAY AS A STRONG 110+ UPPER LEVEL JET ACROSS THE
INTERNATIONAL BORDER COMBINES WITH SEVERAL MID LEVEL SHORTWAVES AS
A SLOW MOVING SURFACE LOW TRACKS THROUGH THE CENTRAL PLAINS
AND SOUTHERN GREAT LAKES REGION. THERE WILL LIKELY BE DRY PERIODS
IN BETWEEN THE WET PERIODS, AS THE MODELS INDICATE. HOWEVER
PINPOINTING THESE PERIODS IS DIFFICULT AS THERE IS LITTLE
CONSENSUS BETWEEN THE MODELS ON WHAT THESE SPECIFIC PERIODS WILL
BE.
HIGH PRESSURE WILL EVENTUALLY SINK SOUTH AND WIN OUT THIS UPCOMING
WEEKEND AS THE LOW TRACKS TOWARDS THE MIDDLE ATLANTIC STATES. AS
THE HIGH MOVES OFF TO THE EAST, THE ACTIVE PATTERN CONTINUES AS
ANOTHER LOW EMERGING OVER THE CENTRAL PLAINS BRINGS RAIN CHANCES
BACK TO THE AREA SUNDAY NIGHT INTO MONDAY.
AVIATION
FOR 18Z TAF ISSUANCE
ISSUED AT 1215 PM CDT MON APR 21 2025
ANY LINGERING RAIN OR SNOW WILL COME TO AN END BY MID AFTERNOON
ACROSS FAR NORTHERN WISCONSIN. GUSTY WEST TO NORTHWEST BETWEEN 25
AND 35 KTS SHOULD PREVAIL, WITH THE HIGHEST GUSTS ACROSS EAST-
CENTRAL WISCONSIN INCLUDING KGRB/KATW/KMTW/KOSH AND POINTS TO THE
SOUTH. WINDS WILL SUBSIDE QUICKLY THIS EVENING WITH WINDS BECOMING
LIGHT AND VARIABLE LATE TONIGHT INTO TUESDAY MORNING, THEN TURN
TO THE SOUTHEAST BY LATE TUESDAY MORNING. MVFR CIGS WILL LIFT INTO
THE VFR CATEGORY LATER THIS AFTERNOON, THEN ERODE AROUND SUNSET.
THE NEXT SYSTEM WILL BRING CLOUDS INTO THE AREA TUESDAY MORNING,
WITH SOME SMALL CHANCES OF RAIN ACROSS MUCH OF THE AREA BY 18Z.
MEDIUM CONFIDENCE IN THE RAIN AT KAUW/KCWA AND VERY LOW AT
KGRB/KATW/KMTW SINCE IT WILL BE ARRIVING LATE IN THE TAF PERIOD.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....ECKBERG/KURIMSKI
AVIATION.......ECKBERG
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