839
FXUS63 KGRB 200526
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
1226 AM CDT WED MAY 20 2026
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
KEY MESSAGES
- FROST OR FREEZE HEADLINES MAY BE NEEDED WEDNESDAY NIGHT AS LOWS
FALL INTO THE LOW TO MID 30S OVER THE NORTHWOODS.
- BELOW NORMAL TEMPERATURES CONTINUE THROUGHOUT THE WEEK, WARMING
BACK UP DURING THE WEEKEND.
- SCATTERED SHOWERS (30 TO 60% CHANCE) ARRIVE FRIDAY AFTERNOON,
LASTING THROUGH SATURDAY.
DISCUSSION
ISSUED AT 1246 PM CDT TUE MAY 19 2026
GOES IMAGERY AND CURRENT OBS SHOW THE COLD FRONT OVER EASTERN
WISCONSIN AS OF THIS AFTERNOON, WITH WINDS HAVING LARGELY SHIFTED
TO THE NORTHWEST IN ITS WAKE. SHOWER ACTIVITY ASSOCIATED WITH THE
FRONT HAS BEGUN TO ERODE AS DRIER AIR FEEDS IN FROM HIGH PRESSURE
TO THE NORTHWEST. HOWEVER, ISOLATED SHOWERS WILL REMAIN POSSIBLE
THROUGH THIS EVENING DUE TO STEEPENING LAPSE RATES WITHIN CAA
REGIME, THOUGH THUNDER CHANCES WILL BE LITTLE TO NONE AS ANY
DAYTIME INSTABILITY WANES.
RAIN CHANCES... NEXT CHANCE (30 TO 60%) FOR SCATTERED SHOWERS
ARRIVES FRIDAY AFTERNOON IN TANDEM WITH DECENT SHORTWAVE ENERGY,
LASTING THROUGH MUCH OF SATURDAY. MOISTURE INFLUX DURING THIS
TIME WILL BE MODEST AS WE SET UP UNDER MARGINAL RETURN FLOW, WITH
PWATS APPROACHING ONE INCH FRIDAY EVENING. HOWEVER, MOST
INSTABILITY LOOKS TO REMAIN HOLED UP TO OUR SOUTH IN PROXIMITY TO
THE WARM FRONT, RESULTING IN LITTLE TO NO SEVERE WEATHER
POTENTIAL. FURTHERMORE, LACK OF UPPER-LEVEL DYNAMICS AND SURFACE
FORCING MECHANISM WOULD SUGGEST VERY LITTLE THUNDER POTENTIAL IN
GENERAL. SYNOPTIC FLOW THEN FLATTENS OUT EARLY NEXT WEEK BEFORE
RIDGING EVENTUALLY BUILDS OVER MUCH OF THE EASTERN CONUS, KEEPING
US MOSTLY DRY THROUGH THE MIDDLE OF NEXT WEEK.
TEMPERATURES... BELOW NORMAL POST-FROPA TEMPERATURES PERSIST
THROUGH THE WEEKEND, WITH HIGHS STRUGGLING TO REACH 60 DEGREES IN
SOME AREAS THROUGH THE END OF THE WORK WEEK. AS HIGH PRESSURE
SITS AND SPINS OVERHEAD, FROST/FREEZE HEADLINES MAY BE NEEDED AT
TIMES AS LOWS DIP DOWN INTO THE LOW TO MID 30S. CURRENT THINKING
IS THAT WEDNESDAY NIGHT WOULD BE THE BETTER SETUP FOR FROST
DEVELOPMENT OVER THE NORTHWOODS DUE TO LIGHT WINDS AND WINDOWS
FOR CLEARING. TONIGHT'S FROST POTENTIAL SEEMS MORE MARGINAL UNDER
MOSTLY OVERCAST SKIES, AND WOULD BE CONFINED MAINLY TO VILAS
COUNTY REGARDLESS. AS SUCH, HAVE OPTED AGAINST A FROST ADVISORY
FOR TONIGHT. HIGHS THEN GRADUALLY MODERATE BACK TO NEAR NORMAL BY
THE END OF THE WEEKEND AND INTO EARLY NEXT WEEK.
AVIATION
FOR 06Z TAF ISSUANCE
ISSUED AT 1225 AM CDT WED MAY 20 2026
LOW-END VFR CLOUDS WILL REMAIN ACROSS THE AREA OVERNIGHT, WITH A
FEW MVFR CEILING OVER FAR NORTH-CENTRAL WI. DOWNSLOPING NORTHWEST
WINDS WILL EVENTUALLY HELP SCATTER OUT SOME OF THE CLOUDS EARLY
WEDNESDAY. ISOLATED SPRINKLES WILL CONTINUE OVERNIGHT, MAINLY
ACROSS NORTH-CENTRAL WI, BUT WILL HAVE NO IMPACTS TO AVIATION.
ADDITIONAL LOW-END VFR CLOUDS ARE EXPECTED ON WEDNESDAY
ESPECIALLY DURING THE MORNING HOURS, WITH A FEW HIGH-END MVFR
CEILINGS POSSIBLE IN NORTH-CENTRAL WI. HIGH CLOUDS WILL ALSO BE IN
THE REGION, ESPECIALLY IN THE WEDNESDAY AFTERNOON/EVENING.
WEST/NORTHWEST WINDS WILL REMAIN UNDER 10 KTS LATE THIS EVENING
AND OVERNIGHT. ONSHORE FLOW NEAR LAKE MICHIGAN COULD SWITCH WINDS
TO THE EAST FOR A TIME OVERNIGHT AT GRB/MTW. NORTH WINDS UNDER 10
KTS ARE EXPECTED ON WEDNESDAY, WITH A LAKE BREEZE SHIFTING WINDS
TO THE EAST ACROSS EASTERN WI IN THE AFTERNOON.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION.....GOODIN
AVIATION.......BERSCH
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