Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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153 FXUS63 KDLH 201921 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 221 PM CDT Thu Jun 20 2024 .KEY MESSAGES... - Some light showers will continue over NW WI this afternoon and evening before a brief dry period on Friday morning. Then chances for showers and thunderstorms return for most of the weekend. - The potential for heavy rainfall has shifted south with the latest model trends and just clips NW WI with more than an inch with amounts decreasing to the north. - Severe storms are possible Monday afternoon into Tuesday morning. && .DISCUSSION... Issued at 220 PM CDT Thu Jun 20 2024 In a bit of a lull at the moment with a few showers crossing over NW WI with not much QPE. Precipitation is expected to completely stop overnight before a surge of moisture arrives Friday as a warm front slowly lifts and stalls over NW WI. A pool of PWATs above 2.0" will reside just south of this warm front (over the Twin Cities), but models have been trending towards keeping this to the south. This makes a bit of sense given that the LLJ is more southwesterly and not too strong. Meanwhile the shear environment and CAPE pools are also located more to our south and are progged to remain along this eventual quasi-stationary boundary. Eventually a surface low develops and will act to force this system out of the region by Saturday evening. While thunderstorms are possible throughout the transition of this system, the best chance for any organized and strong to severe storms is Saturday afternoon across NW WI where CAPE briefly increases to 1000 J/kg in a fairly weak shear environment. The HREF indicates the heavy rain potential largely keeps just south of our forecast boundary with MPX. The overall trend in guidance has been to push the heaviest QPF axis south after a long period of being consistently over our area. While I think we have low probabilities of heavy rain, it`s conceivable that things still could change in the opposite direction, so it`s best to keep an eye on the forecast. On Sunday, a shortwave drops south from Canada giving some potential for thunderstorms over the Minnesota Arrowhead. May have a few strong storms with this feature with CAPE over 1000 again and 0-6km shear broaching 30 knots. This feature does have a little upper level jet max sneaking through which could help with forcing. The better chance in the forecast period for severe weather arrives on Monday afternoon/evening (and possibly even overnight) as an EML washes out over our area with high values of shear > 40 kts and plenty of CAPE. Again PWATS inch up towards 2.0" as strong low level flow converges from the Gulf and also from the northern Great Plains. Upper level flow lags a little behind the surface heating curve, but may help to keep things going into the overnight hours. Afterwards a blob of dry and colder air slides south cooling temperatures and giving a break from convective weather for a few days. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1221 PM CDT Thu Jun 20 2024 Lower flight cats will nose in from the south overnight and really make their way north after 12Z as a warm front approaches. Could be some thunderstorms embedded in the advancing nimbostratus. High confidence in IFR or lower conditions but lower confidence in northward extent of these low flight cats. Winds generally remain light ( less than 10 knots ) and easterly. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 220 PM CDT Thu Jun 20 2024 Light east winds gusting to less than 20 knots will be here until Saturday morning when they build to 25 knots. Waves will also increase in response to the stronger winds. For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt. && .DLH WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. MARINE...None. && $$ DISCUSSION...Wolfe AVIATION...Wolfe MARINE...Wolfe