Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
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406 FXUS63 KGRB 141731 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1231 PM CDT Tue May 14 2024 Updated aviation portion for 18Z TAF issuance .KEY MESSAGES... - Low relative humidity may cause increased fire potential this afternoon away from the lake and bay. - Areas of frost are possible over north central and far northeast Wisconsin tonight. - An unsettled pattern will arrive Thursday morning, bringing potential for several rounds of rain and storms through the weekend. && .DISCUSSION... Issued at 333 AM CDT Tue May 14 2024 Short Term...Today...Tonight...and Wednesday A Hudson Bay high is setting up to provide northern and central Wisconsin with dry and seasonable weather. The smoke from the wildfires to our northwest should be less evident than the last few days. There may still be some elevated smoke, but little or none close to the ground as low level air is coming in from the northeast. Low level cold advection will make for a cooler day than yesterday, especially near Lake Michigan. Clear skies and light winds should allow temperatures to fall into the low to middle 30s across north central and far northeast Wisconsin tonight. The air is quite dry, so frost formation is uncertain. Wednesday will be around five degrees warmer than this afternoon, with the coolest temperatures again near the Lake Michigan shore. Northeast winds gusting to 20 knots will make for building waves today, but probably below small craft advisory criteria. Long Term...Wednesday Night Through Monday Overall, fairly quiet spring weather is expected to persist through mid-week before a more unsettled pattern arrives Thursday morning. A train of shortwaves is expected to bring several rounds of precip to the forecast area through the end of the week, although forecast confidence significantly drops off toward the weekend due to timing and strength issues within the current ensemble guidance. Otherwise, temperatures begin a gradual incline through the weekend with some locations across central Wisconsin possibly seeing the upper 70s on Saturday. Thursday and Friday precip chances... An upper-level disturbance will spin up a weak surface low over western Minnesota and the Dakotas Wednesday evening, bringing downstream precip chances to the forecast area beginning Thursday morning. As the system approaches from the west and becomes vertically stacked, best chances for rain Thursday into Friday will be across central to north-central Wisconsin. However, QPF is expected to be on the lighter end (~0.1" to 0.4") given the influence of mid-level dry air from Hudson Bay high pressure to the north. Some thunder wouldn`t be out of the question Thursday evening as a corridor of 300 to 400 J/kg of surface-based CAPE makes its way up into central and east-central Wisconsin. Rest of the extended... Another round of rain looks to arrive sometime on Sunday following a brief dry spell Saturday. Models currently disagree about timing and strength of the driving shortwave, and thus timing and intensity of accompanying precip. First impressions suggest that upper-level forcing with this system will be more robust than with Thursday`s, although how much QPF we get out of it is still uncertain. The track of the PV anomaly and attendant surface low will determine how much precip (if any) makes it down into the CWA on Sunday, with the GFS currently depicting a much drier solution than the ECMWF. && .AVIATION...for 18Z TAF Issuance Issued at 1231 PM CDT Tue May 14 2024 Ridge of high pressure to extend from Ontario southward into the Great Lakes over the next 24 hours, thus VFR conditions to prevail. There is still some smoke aloft from Canadian wildfires, but surface visibility will not be impacted. Winds are forecast to subside to light/variable over central WI, but only diminish to 5 to 10 knots from the north-northeast over eastern WI. Winds on Wednesday to veer back to the east-northeast at 5 to around 10 knots. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....RDM/Goodin AVIATION.......Kallas