578
FXUS63 KGRB 182330
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
630 PM CDT MON AUG 18 2025
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
KEY MESSAGES
- SHOWERS WILL TAPER OFF THIS EVENING.
- ISOLATED SHOWERS ARE POSSIBLE ON TUESDAY, WITH MUCH OF THE WEEK
REMAINING DRY. FRIDAY WILL BRING THE NEXT CHANCE FOR AREA-WIDE
SHOWERS AND STORMS.
DISCUSSION
ISSUED AT 351 PM CDT MON AUG 18 2025
THIS EVENING/TONIGHT...THIS AFTERNOON'S WATER VAPOR AND RADAR
IMAGERY SHOWED AREAS OF RAIN MOVING NORTHEAST ACROSS THE REGION
ASSOCIATED WITH A 500MB VORT MAX FROM A NEARBY SHORTWAVE. ADDITIONAL
SHOWER ACTIVITY WAS ALSO DEVELOPING IN PORTIONS OF CENTRAL AND EAST-
CENTRAL WI, WHERE A WEAK LLJ WAS LOCATED. THE RAIN AND SHOWER
ACTIVITY IS EXPECTED TO CONTINUE THROUGH LATE THIS EVENING, ENDING
FROM WEST TO EAST. STILL CANNOT RULE OUT A FEW RUMBLES OF THUNDER IN
CENTRAL AND EAST-CENTRAL WI, WHERE THE GREATER INSTABILITY (CAPE OF
500-1000 J/KG) IS LOCATED. HOWEVER, ANY HEAVIER SHOWER OR
THUNDERSTORM WILL GENERATE HEAVY RAINFALL WITH HIGH RAINFALL RATES
(0.5 TO 1"/HR) IN CENTRAL AND EAST-CENTRAL WI, AS PWATS OF 2-2.25
INCHES WILL PREVAIL THROUGH THE EVENING. LOCALIZED FLOODING REMAINS
POSSIBLE, MAINLY IN LOW-LYING AND URBAN AREAS.
AS THE PRECIP COMES TO AN END, THE RECENT RAINFALL AND LIGHT WINDS
WILL CAUSE FOG TO DEVELOP LATE THIS EVENING THROUGH EARLY TUESDAY
MORNING. MODELS INDICATE THE POTENTIAL FOR LOCALLY DENSE FOG, MAINLY
IN CENTRAL AND NORTH-CENTRAL WI, BUT FOG WILL BE POSSIBLE AREA-WIDE.
A DENSE FOG ADVISORY MAY BE NEEDED.
TUESDAY...IN THE WAKE OF THE SHORTWAVE, NORTHWEST WINDS, CAA, AND
LINGERING LOW-LEVEL MOISTURE WILL PREVAIL ACROSS THE REGION. SOME
MODELS INDICATE ISOLATED SHOWERS, WITH A FEW RUMBLES OF THUNDER,
DEVELOPING IN SPOTS DURING THE AFTERNOON AND EVENING, BUT IMPACTS
WILL BE LOW.
REST OF THE FORECAST...SURFACE HIGH PRESSURE WILL SLIDE INTO THE
REGION FROM THE NORTHWEST AS UPPER-LEVEL RIDGING BUILDS OVER THE
AREA. THIS PATTERN, BRINGING DRY CONDITIONS AND NEAR NORMAL TEMPS,
WILL PREVAIL THROUGH AT LEAST EARLY FRIDAY BEFORE THE NEXT CHANCE OF
SHOWERS AND STORMS RETURNS WITH A COLD FRONTAL PASSAGE SOMETIME
FRIDAY INTO SATURDAY.
AVIATION
FOR 00Z TAF ISSUANCE
ISSUED AT 619 PM CDT MON AUG 18 2025
SHOWERS WILL SLOWLY PULL OUT OF NE WI THIS EVENING. THERE IS A
CHANCE FOR REDEVELOPMENT OVER C/EC WI, BUT THE BEST FORCING AND
INSTABILITY IS FOCUSED FARTHER SOUTH. THE THREAT OF THUNDERSTORMS
APPEARS TO HAVE ENDED.
IFR AND MVFR CEILINGS PREVAILED REGIONWIDE EARLY THIS EVENING,
AND THESE WILL CONTINUE TO GRADUALLY LOWER TO IFR/LIFR (AND
PERHAPS VLIFR) OVERNIGHT. ABUNDANT MOISTURE FROM RECENT RAINFALL,
THE ARRIVAL OF HIGH PRESSURE, AND LIGHT WINDS WILL RESULT IN
WIDESPREAD FOG DEVELOPMENT AWAY FROM LAKE MICHIGAN. VSBYS COULD
DROP AS LOW AS LIFR/VLIFR IN NC/C WI, BUT SHOULD BE MOSTLY IN THE
MVFR/IFR RANGE NEAR LAKE MICHIGAN AND THE FOX VALLEY.
CONDITIONS WILL STEADILY IMPROVE TUESDAY MORNING, WITH MOST
LOCATIONS RETURNING TO VFR BY EARLY TO MID AFTERNOON.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....KRUK
AVIATION.......KIECKBUSCH
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