Area Forecast Discussion
Issued by NWS Twin Cities, MN
Issued by NWS Twin Cities, MN
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713 FXUS63 KMPX 171138 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 638 AM CDT Mon Jun 17 2024 .KEY MESSAGES... - Showers and thunderstorms ongoing, with elevated storms posing a risk for severe hail (1" or more) and damaging wind gusts (up to 65 mph). - Scattered showers & storms over the next few days with an increased risk of flooding due to training storms. Exact amounts will vary based on orientation of training thunderstorms. && .DISCUSSION... Issued at 322 AM CDT Mon Jun 17 2024 Moderate to heavy rainfall has begun to push into western and southern Minnesota as of 0730z. Training of thunderstorms is occurring as steering flow is largely orientated parallel to the SW to NE thunderstorm axis. MRMS-derived hourly rainfall rates has peaked in the 1.5 to 2 inch range for parts of Redwood county so far, with more rain still moving through. Because of this, we have extended the Flood Watch further south to capture an increasing risk of flooding and heavy rain with this initial cluster of storms the morning. As these moved through SD and SW MN, FSD has noted multiple reports of gusts up to 50mph. Given the primed environment that these storms are heading into (sufficient instability, steep mid- level lapse rates, and effective shear greater than 35 kts), there will be continued risk for severe weather. Damaging wind gusts up to 40-65 mph will be possible through the morning, along with isolated large hail and a tornado or two. The threat should diminish late this morning, but light to moderate rain could continue through late this evening in some spots. By Tuesday morning, any lingering rain associated with the frontal boundary should push well into the northern half of Minnesota. A trailing cold front will then push through the region, producing a long and narrow band of showers/storms during the afternoon/evening. Low-level moisture transport via a 40-50kt LLJ should provide PWAT values of 2"+ as far north as Lake Superior. This in addition to strong forcing and an unstable airmass (MUCAPE values in excess of 2500 J/kg) along the front will result in another threat for some strong to severe storms within the band. The main threats along this line will be damaging wind gusts and pockets of large hail within the strongest cells. A smaller, but existent tornado risk looks to stretch from northern Minnesota/Wisconsin down to the southern Twin Cities metro where the latest forecast soundings/hodographs highlight more favorable low-level shear. Heavy rainfall and flooding will continue to be a concern with a broad area of 1"+ possible, depending on how slow the front progresses. Storms should begin to weaken and taper off as they head further east into Wisconsin around sunset. Also of note, temperatures could approach the 90 degree mark with dew points in the low 70s resulting in heat indices near 95 degrees. Heading into Wednesday, the passing front will stall southeast of the area, stretching from SE Neb up towards SE WI. Remnant forcing near the front is expected to produce some additional showers/storms, especially along the I-90 corridor. This front will push northward, resulting in continuous opportunities for additional rainfall across the region through Saturday. An additional 2 to 5 inches is possible from Wed-Sat, with the heaviest totals coming on Friday into Saturday where QPF maximum of 2.5" is forecasted over central Minnesota. There is still uncertainty is the exact severity and extent of the storms / heavy rain / flooding, but it will certainly be an active period to continue following. A brief period of relief from rain looks probable sometime early next week, before the pattern becomes unsettled again mid-week. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 627 AM CDT Mon Jun 17 2024 The strongest line of storms has pushed into western Wisconsin, where TS could still impact RNH and EAU for a few hours this morning. Otherwise, mainly light to moderate rain will impact terminals through much of the day. Cigs will be primarily MVFR/VFR, but could push down into IFR at times during the day. Winds will continue to shift more southerly as the frontal boundary moves north this afternoon. They will generally persist at 5-10 kts, but will increase in speed and gustiness overnight. A brief break in rain/clouds will occur overnight into tomorrow morning before another round of showers/storms develop tomorrow afternoon. KMSP...Primarily light rain/showers will impact the terminal through late this evening. Recent models suggest non-stop light rain until around 04/05z, but it could become more of an on and off rain as early as this afternoon. Winds will be 10-15 kts today, but could be gusting up to 25-30 kts from the south by tomorrow morning. /OUTLOOK FOR KMSP/ TUE PM...VFR/MVFR, TSRA/SHRA likely, chc IFR. Wind S15-20G30-35kts. WED...VFR/MVFR, chc -TSRA/-SHRA. Wind N 5-10kts. THU...VFR/MVFR, chc -TSRA/-SHRA. Wind NE 5-10kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...Flood Watch from 1 PM CDT this afternoon through late Tuesday night for Benton-Chippewa-Chisago-Douglas-Isanti-Kanabec- Kandiyohi-Mille Lacs-Morrison-Pope-Sherburne-Stearns- Stevens-Swift-Todd. Flood Watch through late Tuesday night for Anoka-Carver-Dakota- Hennepin-McLeod-Meeker-Ramsey-Renville-Scott-Sibley- Washington-Wright. Flood Watch until 1 PM CDT this afternoon for Blue Earth-Brown- Faribault-Freeborn-Goodhue-Le Sueur-Martin-Nicollet- Redwood-Rice-Steele-Waseca-Watonwan. WI...Flood Watch from 1 PM CDT this afternoon through late Tuesday night for Barron-Polk. Flood Watch through late Tuesday night for St. Croix. Flood Watch until 1 PM CDT this afternoon for Pierce. && $$ DISCUSSION...BED AVIATION...BED