838 FXUS63 KGRB 252338 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 638 PM CDT Wed Mar 25 2020 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Thursday Issued at 336 PM CDT Wed Mar 25 2020 The approach of a strong jet in diffluent upper flow and a couple waves moving along a slow moving cold front will produce a moderate rainfall across most of the area this afternoon and evening. It should change to wet snow before ending across the far north, but accumulations look to be less than earlier anticipated due to warmer boundary layer temperatures. The rain will likely cause a few more rivers to go above their banks, but significant flooding does not appear likely at this time. The precipitation should end by daybreak, with some clearing possible in the afternoon. High temperatures should be close to normal for this time of the year, including the cooler temperatures near the bay and lake. .LONG TERM...Thursday Night Through Wednesday Issued at 336 PM CDT Wed Mar 25 2020 The main focus for this forecast period is the potential for a potent system to impact the region Saturday into Sunday. This system could bring snow, gusty winds, and some higher rainfall totals, which could result in some flooding issues. Aside from the potent system, weaker systems to start and end this forecast period are also possible. Thursday night through Friday afternoon...Although high pressure will be positioned over northern Wisconsin Thursday night, a shortwave, riding the upper-level jet, with low and mid-level moisture could bring some light precipitation to portions of central and east-central Wisconsin. The precipitation would start out as rain and then transition to a wintry mix before ending by Friday morning. Little to no accumulations are expected. After a quiet morning and afternoon, the next system will begin pushing into southern Wisconsin late Friday evening. Friday night through Sunday...A more potent system is expected to eject from the Central Plains with the surface low tracking northeast from Kansas on Friday night to Iowa Saturday evening to northeast Wisconsin by Sunday morning. As the system inches closer to the forecast area late Friday night, WAA driven precipitation is expected to spread from southwest to northeast over the area into Saturday. There are some signs for a few rumbles of thunder in central and east-central Wisconsin Saturday evening, however confidence is not enough to add to the HWO. With the low's center moving into southwestern Wisconsin Saturday night and boundary layer temperatures falling below freezing across the far north, a switch to a rain/snow mix or all snow is expected. It is too early to nail down accumulations with this being on Day 5. The precipitation on the backside of the low will gradually taper off into Sunday afternoon. With PWAT values between 0.75 and 1 inch on Saturday, cannot rule out rainfall amounts of 1 inch across the area. Strong northeast winds are possible ahead of the system on Saturday evening and strong northwest winds are possible behind the system on Sunday. Rest of the extended...High pressure and upper-level ridging will build in behind the potent system for Monday into Tuesday. Model guidance then hints at a cold front bringing some precipitation to the Upper Mississippi Valley for Tuesday afternoon, however, there are some disagreements with this solution. && .AVIATION...for 00Z TAF Issuance Issued at 638 PM CDT Wed Mar 25 2020 A mix of MVFR and IFR conditions will continue during the overnight hours with periods of rain, which will change to snow across the far north. Flight conditions will improve from west to east on Thursday, with VFR conditions expected across most areas by Thursday afternoon. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....RDM LONG TERM......Hykin AVIATION.......Kurimski