Lappe Nordic Centre snow report

898 FXUS63 KGRB 100702 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 202 AM CDT Wed Jun 10 2026 Forecast discussion for routine morning forecast issuance .KEY MESSAGES... - Multiple rounds of strong to severe thunderstorms through this evening. There is no one time frame of the day and evening that is more favored than others for thunderstorms. There is an enhanced risk for severe weather as storm complexes move through, including damaging winds, large hail, and an isolated tornado. - Additional strong to severe thunderstorms are expected Thursday afternoon into Thursday evening. - Heavy rain is an increasing hazard today through Thursday. Localized flooding is expected where heavy rain occurs. - Dense fog over northeast WI to Lake Michigan this morning will create hazardous travel conditions. - Very warm and humid through Thursday. Peak of heat today with heat indices potentially into the lower 90s if there is enough break in between rounds of storms. Cooling trend later this weekend into next week. && .DISCUSSION... Issued at 200 AM CDT Wed Jun 10 2026 Main changes: Plethora of upstream convectively induced shortwaves has resulted in multiple waves of storms today. Given instability building in over the area, any of these rounds of storms could be strong to severe. First round arrives over much of the area through mid morning, with additional round moving in earlier in the afternoon. A potential third round could impact the region this evening. All severe hazards still could occur. No change there. However, given multiple rounds of storms with heavy rain, risk of flooding will increase where episodes of heaviest rain overlap. HREF 95th percentile for 24hr rainfall ending at 7am on Thursday shows widespread net of 3-4 inches of rain, maximized over central WI where there is better chance of multiple rounds of heavy rain. Severe and Heavy Rain Potential Through Tonight...First up is squall line over eastern Dakotas, arcing into southern MN. Complex is on leading edge of mid-upper jet and on nose of 60+ kt low- level jet just upstream of MLCAPEs of 4000j/kg. CAPE gradient shifts northeast into WI by 12z as warm front arrives. 00z HRRR and ARW matching reality best and show this line of storms into central/north-central WI by 12z supported by sufficient 0-1km shear downstream of the building instability. Severe thunderstorm watch is in effect until 7a into western WI. Expect the storms to cross northern WI this morning (exiting by 10-11a) with severe winds a possibility. Next round of storms then looks to arrive earlier, during the mid to late afternoon with genesis region in western IA this morning as next shortwave/increasing H5 jet interacts with reservoir of untapped instability ahead of approaching cold front. If something close to the decently agreed CAM guidance is correct, severe storms may be breaking out over central WI by early this afternoon, with the main line moving through soon thereafter. No real change in very favorable, high-end parameter space for developing storms to interact. MLCAPEs over 2500J/kg, mid-level lapse rates over 7c/km and very ample CAPE in hail growth favor very large hail while mid-level dry air and DCAPE up to 1000 j/kg lead to damaging winds. Backed flow in low-levels, likely due to earlier day convection/outflows, results in 0-1km/0-3km SRH that favors the potential for tornadoes, especially with discrete cells that form in the afternoon. Additional convection could occur in bows/lines into the early evening, but trying to get specific how that will unfold is pretty dicey given there could be multiple complexes of storms that occur before then that will no doubt impact the ambient convective environment. The best advice today is to keep up to date with the forecast as it will be changing based on near term trends, and have multiple ways to receive warnings. Again, given the multiple rounds of heavy rain could see the need for a flood watch later today once it becomes clearer where swaths of heavy rain set up and if they overlap in similar areas. Currently HREF PMM/LPMM 24hr rainfall ending at 7am on Thursday suggest the most likely areas to see 2+ inches with maxes up to 4 inches will be over portions of central to north-central WI. WPC highlights almost all of our area in a Slight risk for Excessive Rainfall. Typically when we have a Slight Risk we will see at least isolated flash flooding occur. Just where that occurs in this scenario will be the primary question. Otherwise for today, given the multiple rounds of storms, think it is going to be a challenge to realize heat index values flirting with upper 90s to near 100. Forecast temps have been lowered, with most spots remaining in the 80s. And, some models would indicate that may be even optimisitic, for at least some areas. Fog near Lake Michigan and over northeast WI is expected to fade by late morning, but convection during the morning and outflows could alter that idea along the lake. Will be yet another something to keep eye on today as it leads to hazardous travel with the lower visibility and will have direct impact on instability that is present this afternoon. A lull still looks to be in store later tonight after convection ends by late evening. Still warm and humid with patchy fog. Severe and Heavy Rain Potential Thursday...No large change in the idea that a second and more potent shortwave tracks toward the region on Thursday afternoon, causing an associated surface low to lift northeast directly into southeast or east-central Wisconsin by Thursday evening. Widespread showers and thunderstorms will accompany this system, fueled by a deep plume of moisture with precipitable water values climbing well above normal. Severe threat may develop in the afternoon over east- central Wisconsin where instability increases to around 1000 J/kg under strong deep layer shear of 50 to 60 kts. At current, greatest risk for severe wind and the potential for tornadoes may remain just south of Fox Valley/lakeshore. However, probabilty for hail would be maximized due to the strong shear and sufficient instability. That said, will not take too much of a jog north in the effective warm front to put all severe hazards in play over especially central and east-central WI on Thursday. Other issue will be heavy rain. Signal that showed up yesterday on NBM and LREF remains in place this morning, with widespread higher-end percentiles depicting at least 2 inches of rain along and just north of the track of the sfc low, with 95th percentile showing 2.5 to 3.5 inches for the far southern portions of the area. These amounts would easily lead to urban or low-lying flooding if they impact the Fox Valley. Depending on rainfall amounts today and tonight, these areas could be looking at the need for a flood watch on Thursday. Convection will wind down by mid-evening following the passage of a strong cold front. A much cooler and drier weather pattern will return to the western Great Lakes Friday into early next week as a broad longwave trough sets up from the Hudson Bay down into the region. On the southern periphery of this cold pool aloft, spotty diurnally driven showers and storms look possible on Friday and Saturday afternoons. Saturday still standing out as having the slightly better potential for scattered afternoon showers and storms due to the passage of a secondary cold front and building daytime instability as highs now look to reach back into the lower 80s in parts of the area. In fact, higher end CAPEs around 1000 J/kg now shown could result in at least a small shot of isolated severe potential given enough shear. Will be something to keep eye on in the coming days. By Sunday and early next week, behind the front dry air and persistent high pressure will take hold, dropping temperatures slightly below seasonal normals. && .AVIATION...for 06Z TAF Issuance Issued at 1040 PM CDT Tue Jun 9 2026 Latest guidance/observations continue to show dense fog expanding across far northeast WI and the lakeshore. Model visibility forecast shows the greater potential for widespread dense fog east of an Eagle River to Antigo to Oshkosh line overnight. The fog will likely become more widespread dense as you get closer to the bay and Lake Michigan. Late tonight into Wednesday morning, the first round of thunderstorms will push northeast across the area. Still some uncertainty in how quick the morning convection will clear out, but another round of strong or severe storms is expected later Wednesday afternoon into Wednesday evening. Large hail of 1" or greater and wind gusts over 50 knots are possible with this cluster of thunderstorms. && .GRB WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 10 AM CDT this morning for WIZ013-021- 022-039-040-050-073-074. && $$ DISCUSSION.....JLA AVIATION.......Eckberg