796
FXUS63 KGRB 120900
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
400 AM CDT FRI SEP 12 2025
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
KEY MESSAGES
- A DENSE FOG ADVISORY IS IN EFFECT FOR LAND AND MARINE AREAS
THROUGH 10 AM TODAY.
- SHOWERS AND SCATTERED THUNDERSTORMS RETURN TONIGHT INTO SATURDAY
MORNING. SEVERE WEATHER IS NOT EXPECTED, BUT AN ISOLATED STRONG
STORM OR TWO IS POSSIBLE.
- ABOVE NORMAL TEMPERATURES ARE EXPECTED THROUGH THE PERIOD, WITH
RAIN CHANCES RETURNING FOR THE MIDDLE TO LATE PART OF THE NEXT
WORK WEEK.
DISCUSSION
ISSUED AT 400 AM CDT FRI SEP 12 2025
HIGH PRESSURE, LIGHT WINDS AND GOOD RADIATIONAL COOLING CONDITIONS
HAVE RESULTED IN WIDESPREAD FOG AND LOW STRATUS DEVELOPMENT ACROSS
THE FORECAST AREA THIS MORNING. MOST OBSERVING SITES HAD VSBYS IN
THE 1/4SM-1SM RANGE, EXCEPT IN THE FAR WESTERN TIER OF COUNTIES,
WHERE LOW STRATUS WAS MORE PREVALENT. TEMPERATURES WERE QUITE
COOL, IN THE 40S TO MIDDLE 50S. A DENSE FOG ADVISORY HAS BEEN
ISSUED FOR THE ENTIRE FORECAST AREA THROUGH 10 AM TODAY.
THE HIGH PRESSURE SYSTEM WILL EDGE EAST TONIGHT INTO SATURDAY,
WHICH WILL ALLOW A WARM FRONT TO LIFT INTO FAR SOUTHERN WI.
SOUTHWESTERLY 850 MB FLOW WILL INCREASE TO 20 TO 25 KTS TONIGHT,
RESULTING IN INCREASED WAA, WITH FRONTOGENETIC FORCING AND THE
PASSAGE OF A SHORT-WAVE TROUGH PROVIDING ADDITIONAL LIFT. MODELS
HAVE TRENDED TOWARD MORE INSTABILITY, WITH MUCAPE OF 500-1000
J/KG, AND DEEP LAYER SHEAR HAS ALSO EDGED UP TO 25 TO 35 KTS.
HAVE INCREASED POPS TO HIGH-END CHANCE TO LOW-END LIKELY, AND NOW
ACKNOWLEDGE THE POTENTIAL FOR A STRAY STRONG STORM OR TWO WITH
HEAVY DOWNPOURS AND SMALL HAIL. THE MAIN ITEM OF CONTENTION IS
WHERE THE MAIN PRECIPITATION BANDS WILL SET UP, AS MODELS OFFER
VARYING OPINIONS. FOR NOW WILL FOCUS THE HIGHEST POPS OVER
NORTHERN WI DURING THE EVENING, THEN MAINLY ALONG AND SOUTH OF HWY
29 FOR THE OVERNIGHT PERIOD. THE SHOWERS SHOULD EXIT THE REGION
SATURDAY MORNING.
DRY WEATHER RETURNS FOR THE REST OF THE WEEKEND AS STRONG UPPER
LEVEL RIDGING OCCURS, AND THIS WILL LIKELY LINGER INTO EARLY NEXT
WEEK. A CHANCE OF SHOWERS AND STORMS ARRIVES DURING THE MID TO
LATE PART OF THE NEXT WORK WEEK, AS THE UPPER RIDGE SHIFTS EAST
AND AN UPPER TROUGH AND WEAK COLD FRONT EDGE EAST ACROSS THE
REGION.
TEMPERATURES WILL REMAIN CLOSE TO NORMAL TODAY, THEN RISE ABOVE
NORMAL FOR MUCH OF THE NEXT WEEK, WITH HIGHS REACHING THE UPPER
70S AND LOWER 80S ON MOST DAYS.
AVIATION
FOR 06Z TAF ISSUANCE
ISSUED AT 1107 PM CDT THU SEP 11 2025
WENT MORE AGGRESSIVE WITH THE FOG THIS TAF ISSUANCE, AS TRENDS IN
BOTH CURRENT OBS AND MODELS SHOW INCREASED LIKELIHOOD OF DENSE
FOG DEVELOPING ACROSS MOST OF THE REGION TONIGHT.
AS OF 04Z/THU, STARTING TO SEE SOME VSBYS LESS THAN 1SM, MAINLY
FOCUSED ACROSS NORTHERN WI AND THE DOOR PENINSULA. THIS WILL
EXPAND OVER THE NEXT FEW HOURS AS LOW STRATUS CLOUDS HAVE MOSTLY
CLEARED OUT, WINDS ARE CALM, AND RHS ARE AT OR NEAR 100% AREA
WIDE. GUIDANCE SHOWS MOST PLACES DROPPING TO 1/2SM OR LESS, WITH A
FEW HOURS AT 1/4SM OR LESS LIKELY, TOO. HAVE INCLUDED TEMPO
GROUPS IN THE TAFS TO HIGHLIGHT THE MOSTLY LIKELY TIME RANGE FOR
THE LOWEST VSBYS.
EXPECT FOG/LOW CLOUDS TO LIFT AND SCATTER OUT MID-LATE MORNING ON
FRIDAY. ALTHOUGH NOT VERY CONFIDENT IN THE EXACT TIMING OF THIS
GIVEN. SCATTERED CLOUDS AROUND 4-5KFT ARE THEN EXPECTED FOR THE
REST OF THE DAY.
WINDS WILL BE LIGHT TO CALM THROUGHOUT THE TAF PERIOD. FROM THE
E/SE TONIGHT, VEERING S ON FRIDAY.
GRB WATCHES/WARNINGS/ADVISORIES
DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ005-
010>013-018>022-030-031-035>040-045-048>050-073-074.
DISCUSSION.....KIECKBUSCH
AVIATION.......KLJ
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