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
43
799 FXUS63 KGRB 161712 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1212 PM CDT Thu May 16 2024 Updated aviation portion for 18Z TAF issuance .KEY MESSAGES... - Thunderstorms are possible across the forecast area today. A few storms may become strong or severe in central and east central Wisconsin in the late afternoon. Hail and strong winds are the main hazards. - On and off rain/storm chances will continue through the middle of next week. It is too early to determine if any of these storms may become severe. && .DISCUSSION... Issued at 357 AM CDT Thu May 16 2024 Short Term...Today...Tonight...and Friday Showers and elevated thunderstorms are expected in central and northcentral Wisconsin this morning, and in east central and northeast Wisconsin during the early to mid afternoon hours ahead of a northeastward moving warm front. These storms could have brief heavy rain and small hail. A surface trough (not really a cold front, as the air behind it is not any cooler) will approach the area in the late afternoon and could produce a scattered to broken line of thunderstorms in central Wisconsin in the late afternoon and in east central Wisconsin in the early evening hours. The storms along this front could be strong or severe depending on how much instability there is. Models do show dewpoints increasing to the low 50s, and CAPE of 400 to 700 J/kg with 30 to 40 knots of shear. Large hail and strong winds are the main threat if these storms materialize. Temperatures today will probably rise and fall one or more times as areas of showers move by. Highs will be mostly in the 60s, except in the 50s near Lake Michigan. CLearing skies are expected tonight as the front goes by. Lows will be in the 40s. Friday should be sunny and warm as winds become southwest and 850mb temperatures climb into the low teens. High temperatures should reach the 70s, except cooler near the Lake Michigan shore. Long Term...Friday Night Through Wednesday An active spring pattern with multiple rounds of rain and storms to remain in place through the extended. Main change from previous forecasts revolves around models trending drier for this weekend`s system. Focus then turns to more robust precip chances mid-week, although there is still significant model spread with precip timing and amounts. Weekend precip chances... Weekend rain/storm chances associated with a surface low passing to our north are looking considerably less impressive than in previous forecasts. Ultimately, it looks like weak high pressure and dry air building in behind the departing system are winning the battle with any moisture located along the leading edge of the cold front. This being said, windows for clearing during the day paired with a surge of warm temperatures in the upper 70s to low 80s will result in some surface-based instability (~600 to 1000 J/kg CAPE). While organized severe weather is not currently expected, favorable surface instability paired with weak elevated cold air advection may be enough to generate some pulse thunderstorms across portions of central and north-central Wisconsin. Any thunderstorm activity is expected to be short-lived, especially as instability diminishes with the loss of daytime heating. Next week... On and off rain/storm chances will continue through mid- week, although forecast confidence significantly drops off past the weekend. A weak shortwave is expected to bring a round of light rain to much of the forecast area on Monday before attention then turns to a more dynamic system that will eject up from the central Plains to the Great Lakes by Wednesday morning. The track and strength of this system are extremely variable this far out in the forecast period, and will largely depend on how quickly weak high pressure ahead of the system erodes earlier in the week. Will continue to monitor for storm potential as we get closer to the event. && .AVIATION...for 18Z TAF Issuance Issued at 1212 PM CDT Thu May 16 2024 Showers and thunderstorms will track through the east-central Wisconsin TAF sites early this afternoon, with additional showers and thunderstorms possible later this afternoon into early this evening as an occluded front tracks through the region. Any remaining showers and thunderstorms will end from west to east during the afternoon and early evening as the occluded front moves to the east and high pressure builds in from the west. Flight conditions will likely vary from VFR where there isn`t much shower or thunderstorm activity, to MVFR/IFR in shower and thunderstorm activity. Clearing skies are expected overnight along with light winds. This will provide ideal conditions for fog development given the recent rainfall. Therefore will put in low clouds and fog across the TAF sites overnight with IFR/LIFR conditions, with the fog expected to dissipate by 15Z Friday. VFR conditions are then expected after the fog lifts on Friday. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....RDM/Goodin AVIATION.......Kurimski