Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
Issued by NWS Milwaukee/Sullivan, WI
067 FXUS63 KMKX 080229 AAA AFDMKX Area Forecast Discussion...UPDATED National Weather Service Milwaukee/Sullivan WI 929 PM CDT Sun Jul 7 2024 .KEY MESSAGES... - Scattered showers and thunderstorms at times into Monday evening. - Continued near daily chances (30-50%) for showers and thunderstorms through the middle to end of the week. The remnants of Beryl will bear watching for Wednesday. - Increasing potential for above average temperatures heading into next weekend. && .UPDATE... Issued 929 PM CDT Sun Jul 7 2024 A complex of thunderstorms is developing over central Iowa this evening, and there is another area of thunderstorms that extends along a line from central Iowa to the western UP of Michigan. The line is on the leading edge of an upper trough which is not expected to make much eastward progress tonight. The Iowa convection should track northeastward, roughly along/ahead of that line/boundary and toward southwest WI overnight. The 00Z NAM and NAMNest did not initialize with the Iowa convection, but the HRRR has had a handle on it for the past couple of hours. The HRRR diminishes the convection to remnant showers by the time it reaches WI around 09Z in the morning and this makes sense given that the low level jet is displaced from it and there is slightly drier air at 925-850mb here. I pulled back pops from likely to chance in our west to represent our lower confidence in showers and thunderstorms during the early morning hours. Scattered showers and thunderstorms still look possible once again during the day and especially the late afternoon in southeast and east central WI once again. We will have a high- ish CAPE and low shear environment once again, so it will be very similar to what we had this past afternoon. Cronce && .SHORT TERM... Issued 307 PM CDT Sun Jul 7 2024 Tonight through Monday night: The southwesterly low level jet will continue to develop into tonight and ramp up, pointing into the forecast area. Some weak warm air advection and differential CVA from passing vorticity maxima are also expected. These features should help continue to generate scattered showers and storms at times, which is generally depicted by the CAMs. The most areal coverage should be tonight, when the low level jet is at its strongest. Forecast soundings are showing 500 to 900 J/kg of mean layer CAPE with deep layer bulk shear of 20 to 25 knots into early this evening, with values slowly lowering later tonight. Not expecting strong to severe storms given this setup. May see light fog in the typical low lying areas overnight into Monday morning. More scattered showers and storms may occur Monday afternoon and evening, as a weak cold front/surface trough moves through the region. There will also be more upper support from an approaching 500 mb shortwave trough. CAMs are showing a little more activity with this round, and there will be more mean layer CAPE and deep layer bulk shear to work with. Thus, some gusty winds and small hail may occur with the stronger storms Monday afternoon and early evening. Warm and humid conditions will continue during this period. Wood && .LONG TERM... Issued 307 PM CDT Sun Jul 7 2024 Tuesday through Sunday: There may be more scattered showers and storms during the daytime and early evening hours Tuesday, as the right entrance region of a jet streak moves into the region with passing vorticity maxima/differential CVA. Surface features may be tough to come by for lift, though forecast soundings are looking uncapped with weak deep layer bulk shear and mean layer CAPE around 500 J/kg. The remnants of Beryl look to shift northeast through the Middle Mississippi River Valley Tuesday night and perhaps across central Indiana on Wednesday. The ensembles are generally showing this trend, though confidence is still modest as to the exact track of this system. Right now, it seems to be that the best deep moisture and upward vertical motion with this system will remain just to the southeast. Will see how trends in the ensembles play out, as the GEFS at Kenosha is the only ensemble showing more than a few members with over 1.50 inches of rain in a 24 hour period. Any heavy rainfall on top of the already saturated ground would bring a flooding concern, so will monitor this closely over the next few days. Ensembles suggest that there may be a brief period of dry conditions for later in the week, though with the warm and humid conditions lingering, any forcing mechanism that moves through would bring at least some chance for showers and storms. It appears that the ensembles are still showing a warmup for the weekend, so will maintain that trend in the forecast temperatures. Wood && .AVIATION... Issued 929 PM CDT Sun Jul 7 2024 Lower ceilings are possible west of Madison in the morning as a decaying thunderstorm complex rolls into the area after 09Z. Ceilings should be around 3500 ft or barely VFR, but MVFR cigs are possible between 10z and 15z. Scattered showers and thunderstorms are expected to be very random and along outflow boundaries and other weak boundaries once again Monday afternoon. Cronce && .MARINE... Issued 307 PM CDT Sun Jul 7 2024 The dense fog has ended across the nearshore waters north of Port Washington, so will cancel the Dense Fog Advisory there. High pressure around 30.0 inches over Lake Erie will shift to the northeast through Monday, resulting in southerly winds across the open waters. Scattered showers and thunderstorms are anticipated at times tonight into Monday evening. A cold front will move across the open waters late Monday into Monday night, resulting in a wind shift out of the west by Tuesday morning. Later Tuesday night into Wednesday night, there is a potential for stronger winds over the southern portion of the lake, depending on the eventual track of the remains of Tropical Storm Beryl, which may track across central and north central Indiana. This potential will be updated in later forecasts. Wood && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...None. && $$ Visit us at weather.gov/milwaukee Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/NWSMilwaukee www.twitter.com/NWSMilwaukee www.youtube.com/NWSMilwaukee