Area Forecast Discussion
Issued by NWS Green Bay, WI
Issued by NWS Green Bay, WI
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
706 FXUS63 KGRB 130913 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 413 AM CDT Mon May 13 2024 Forecast discussion for routine morning forecast issuance .KEY MESSAGES... - An area of smoke or haze is expected to spread over the region through this afternoon. The smoke or haze may result in poor air quality at times. - Areas of frost are possible over the sandy soil ares of north- central and far northeast Wisconsin tonight and Tuesday night. - After a dry period on Tuesday and Wednesday, the chance of rain and possibly some storms will return at times from Thursday through Sunday. && .DISCUSSION... Issued at 413 AM CDT Mon May 13 2024 Short Term...Today...Tonight...and Tuesday A cold front was moving through the far southern part of the forecast area early this morning. Showers had ended, and skies had cleared across northern WI. Patchy fog was observed across northern WI, and other minor vsby restrictions were likely due to smoke from Canadian wildfires. Temperatures ranged from the upper 30s and lower 40s far north to the middle 50s to lower 60s south. Smoke trends and frost potential will be the primary concerns with the short-term forecast. The close proximity of the cold front, weak short-wave energy and the RRQ of a weak jet streak may bring scattered showers back into the far southern part of the forecast area this afternoon, but skies will remain partly cloudy farther north. Deep mixing should allow dew points to mix out, with relative humidity dropping to 25 to 30 percent in the sandy soil areas. High temperatures should warm to the middle 60s to middle 70s, except near Lake Michigan, where E-NE winds will keep highs in the middle 50s to lower 60s. Canadian high pressure centered over Ontario will bring mostly clear skies, decreasing winds and a dry air mass to the region tonight. This may lead to patchy/areas of frost across far northern WI. This is not a slam dunk, as there is enough of a pressure gradient to support a steady light E-NE wind through the night. Will let the day shift take a closer look at this, and decide on potential frost/freeze headlines. Lows should be in the 30s north, and lower to middle 40s south. On Tuesday, the Canadian high will settle across the Lake Superior region, with northeast winds pushing cooler and drier air into the forecast area. Low relative humidity in the 20 to 30 percent range will be found in the sand areas. Highs will be in the 60s, but gusty NE winds will keep bayshore and lakeshore areas in the middle 50s to lower 60s. Smoke Trends: HRRR/RAP Smoke models show similar trends, with smoke at the surface and aloft impacting the area today. An Air Quality Advisory (issued by the Wisconsin DNR) remains in effect through 10 am, but may be extended through the day. Minor vsby restrictions (mainly 3-6SM) will be possible at times. Surface- based smoke is expected to gradually clear from the north and east late this afternoon and evening, but smoke aloft will likely linger through tonight and part of Tuesday. Long Term...Tuesday Night Through Sunday Generally quiet spring weather is expected through midweek, then becoming the weather will become unsettled from Thursday through the upcoming weekend. Beyond Thursday, forecast confidence in the details drops significantly due to large spread amongst and within various ensemble systems. Rain and thunderstorm chances: Weak high pressure will ensure dry weather sticks around for Tuesday night through Wednesday. This changes on Wednesday night when a broad shortwave trough and associated cold front track across the northern Mississippi Valley and western Great Lakes regions. Chances of light rain have increased on Wednesday night and Thursday, but with little to no instability, will continue to leave out a chance of thunderstorms. Details get murky thereafter, but conceptual models and the NBM indicate that precip chances reach their minimum after the front departs late on Thursday night into Friday. Another period where chances of precip seem to increase is on Sunday when ensembles indicate height falls taking place with shortwave energy moving into the northern Great Lakes. Some instability may surge into the area by this time, so will have a chance of thunderstorms. Temperatures: Weak high pressure, clear skies, and light winds will be favorable for frost development on Tuesday night. Highest probabilities will be across the sandy soil areas of far northern WI. Otherwise, 850mb temps will be rebounding after reaching their minimums on Tuesday and Wednesday. Clouds and precip may impact temps somewhat, but in general, there will be a warming trend starting Wednesday into the weekend. Temps could be approaching 80 degrees again at some locations by Saturday and Sunday. && .AVIATION...for 06Z TAF Issuance Issued at 1103 PM CDT Sun May 12 2024 Last vestiges of showers will exit east-central Wisconsin shortly after midnight. Patchy ground fog is possible over north-central Wisconsin. Winds will be a little erratic into the early overnight before shifting mainly north behind the cold front. Smoke looks to be a bigger concern into Monday as satellite and surface observations showed a pretty thick area of smoke in southern Canada, Minnesota northwest Wisconsin and Lake Superior. Mainly sites reporting 3-6SM and haze. Have maintained the haze for RHI, AUW and CWA where RAP/HRRR have the higher concentrations. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Kieckbusch/MPC AVIATION.......JLA