Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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327 FXUS63 KGRB 220357 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 957 PM CST Thu Nov 21 2024 Updated aviation portion for 06Z TAF issuance .KEY MESSAGES... - Breezy north/northwest winds will persist through tonight, with gusts between 25 and 30 mph. - Light rain or snow is possible Sunday night through Monday evening. Central into north-central WI has a 20% chance of getting 1 inch of snow or more. - Temperatures trend cooler starting Tuesday. && .DISCUSSION... Issued at 305 PM CST Thu Nov 21 2024 Short Term...Tonight and Friday 1002 mb low continued to book it south along Lake Michigan this afternoon, resulting in a transition to rain as dominant ptype as warm air continued to dig down from the north. This being said, rain showers have continued to diminish in coverage and intensity from north to south as mid-level dry slot wraps in around the center of the low and dries the profile from the top down. Temperatures have likewise rebounded into the upper 30s to low 40s across the forecast area, effectively melting most of the snow accumulation we saw from this morning. Winds have been a bit sporadic/slow to get going, although northwest winds have continued to ramp up early this afternoon under a tight pressure gradient. Suspect that strong push of warm air advection acted to hinder stronger winds at 2 to 3K ft from mixing down to the surface earlier this morning. Wind... Wind concerns quickly subside later this afternoon as 850 mb jet propagates to our south. CAMs seem to be in agreement, so opted to let the Wind Advisory for east-central Wisconsin drop off early. This being said, sub-advisory breezy conditions will persist through tonight as rain continues to fall and mix the lowest 3 to 5K ft of the atmosphere. Gusts from 25 to 30 mph will remain in the forecast overnight, especially across east-central Wisconsin where lake enhancement is possible. Tonight/Friday... Low is progged to track south into the Ohio River Valley by this evening, leaving cloud debris across most of the state through tomorrow. Some light showers may linger along the Lake Michigan side of the Door Peninsula late tonight, although not expecting much in the way of lake effect due to warm temperatures and weak forcing. Highs for tomorrow to read around 5 to 10 degrees above average, ranging from the upper 30s in the far north to the mid 40s along and east of the Fox Valley. Long Term...Friday Night Through Thursday Quiet weather to start the long term forecast from 00/Sat to 00Z/Mon. High pressure axis will move across WI, but enough moisture lingering in the mid-levels will keep some clouds around. Temperatures this weekend will be near or a couple degrees above normal. Highs Saturday and Sunday will range from the mid 30s to mid 40s. Lows will range from the mid 20s to low 30s. An approaching shortwave and surface low will bring a chance for precip from Sunday evening through Monday evening. Cross sections show it will take several hours for the low level to become saturated enough for precip to begin, with onset timing as early as 00Z/Mon, but likely not until around or after 06Z/Mon. East- central Wisconsin will likely remain warm enough for all rain. Northern and parts of central WI are more likely to see a rain/snow mix or all snow. Amounts are currently forecast to remain light, with only a 20% chance of getting 1" of snow or more, with the exception of northern Vilas County which has higher probabilities for getting 1-3" during this time frame. A cooler airmass settles in behind this system, which will bring in below normal temperatures starting Tuesday. High temps Tue-Thu will range from the mid 20s in north-central WI to the mid 30s in the Fox Valley and lake shore. Lows will will be in the teens to mid 20s. An even cooler push of air is possible into next weekend. && .AVIATION...for 06Z TAF Issuance Issued at 951 PM CST Thu Nov 21 2024 Spotty light rain will taper off over east central WI during the early overnight hours, but light lake-enhanced showers or drizzle will persist into Friday morning over far NC WI. Otherwise, expect widespread MVFR ceilings regionwide, except for IFR conditions in NC WI through late morning Friday. A gradual improvement is expected later Friday into Friday evening, with parts of NE/EC WI becoming VFR. Northwest winds will continue to gust to around 20 kts at times through late Friday afternoon, then diminish by evening. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Goodin/KLJ AVIATION.......Kieckbusch