Area Forecast Discussion
Issued by NWS Duluth, MN
Issued by NWS Duluth, MN
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818 FXUS63 KDLH 060902 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 402 AM CDT Mon May 6 2024 .KEY MESSAGES... - Quiet and breezy weather today with some elevated fire weather conditions as relative humidity falls to around 25-40%. - Rain and thunderstorms move in late Monday night through Tuesday night. Rainfall amounts around a quarter to one inch with locally higher amounts possible. Isolated strong to severe storms possible (~10% chance). - Lingering light rain and possibly some thunder (15% chance) Wednesday and Thursday. More rain is possible into next weekend. && .DISCUSSION... Issued at 402 AM CDT Mon May 6 2024 It`s a very quiet morning out there with light and variable winds and mostly clear skies thanks to ridging aloft. This ridge will lead to plentiful sunshine today (increasing clouds this afternoon). Fire weather will be a bit elevated as the pressure gradient increases this afternoon ahead of approaching low pressure for Tuesday. East to southeast winds will gust up to 20-30 mph this afternoon and min RH is expected to fall to anywhere from 25% to 40%. However, areas falling between that 25%-30% are expected to be isolated mainly to areas near the International Border. With plentiful rain in the past several days/weeks, the ground is starting to moisten up and green up. Thus, near-critical fire weather is not expected. Going into Monday night, a warm front and elevated frontogenesis is expected to bring an initial round of rain through the region as it spreads northward. This rain will be supported by PWATs approaching 1" or so. A little instability is possible Tuesday morning to support a thunder threat (up to ~500 J/kg; 10-15% chance). Any morning convection should be elevated and non- severe. With favorable synoptic forcing and marginally favorable convective forcing possible, the bulk of the total ~0.25-1.0" rain totals may fall Tuesday morning. The thunderstorm threat increases Tuesday afternoon and early evening as some surface-based heating may be realized for convection. Models are still somewhat divergent on how much instability there could be, but the range is from <500 J/kg to nearly 1,000 J/kg. Low and mid-level lapse rates still look marginal for severe storms as do shear profiles (we lose most low-level speed shear by the afternoon). With all that considered, we have a situation where severe weather looks largely unlikely, but we have ~40-50% chances for storms (which could be strong, containing small hail and gusty winds up to 50 mph) and a ~5-10% chance that a storm or two could produce 1" diameter hail and winds gusting to 60 mph. The best timing for thunderstorms currently looks to be about 2 PM to 8 PM, with any severe potential around 4 PM to 8 PM or so. Depending on overall timing of the low and attendant synoptic clouds/rain, the threat for storms Tuesday afternoon/evening could still increase or decrease a bit. Stay tuned to the forecast for updates! Low pressure will move east on Wednesday into Thursday with some lingering showers and perhaps isolated thunderstorms as areas of cyclonic vorticity advect through aloft. Rainfall amounts at this time look to be up to around a tenth of an inch or so through this period. There may be a brief window for dry weather Thursday night before another rainy system potentially moves in from the northwest and sticks around through next weekend, bringing additional rain chances. && .AVIATION /06Z TAFS THROUGH 06Z TUESDAY/... Issued at 1258 AM CDT Mon May 6 2024 Ridging aloft will keep winds light and variable through the early morning hours. Then, a tightening pressure gradient ahead of the next approaching low pressure system will cause winds to increase from the east to southeast gradually through Monday. Warm air advection aloft will lead to the possibility of some LLWS developing late in the period Monday night even despite breezy conditions at the surface as winds around 2-4kft above the surface may approach ~50 kt. Otherwise, quiet weather is expected. && .MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/... Issued at 402 AM CDT Mon May 6 2024 Winds and waves are expected to strengthen from the northeast today ahead of an approaching low pressure system from the west. Gusts from 20 to 25 knots are expected to develop early this afternoon, especially around the head of the lake. Breezy conditions will continue through Tuesday before winds lighten up Tuesday night. Small Craft Advisories are in effect. Probabilities for gales during the period of strongest winds around mid-day Tuesday still look to be around 40-50%, so we will continue to monitor that potential. Rain and a perhaps a thunderstorm or two are expected Tuesday through Tuesday night. 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...Small Craft Advisory from 7 AM Tuesday to 1 AM CDT Wednesday for LSZ140-147-150. Small Craft Advisory from 4 AM Tuesday to 1 AM CDT Wednesday for LSZ141-142. Small Craft Advisory from 3 PM this afternoon to 1 AM CDT Wednesday for LSZ143>146. Small Craft Advisory from 10 AM to 4 PM CDT Tuesday for LSZ148. && $$ DISCUSSION...JDS AVIATION...JDS MARINE...JDS