Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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223 FXUS63 KMQT 120807 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 407 AM EDT Sun May 12 2024 .KEY MESSAGES... -Isolated pockets in the south central could (40% chance) see elevated fire conditions ahead of the showers and thunderstorms this afternoon. -Scattered thunderstorms develop this afternoon into early evening, especially south central. There is a marginal risk (5%) of large hail and/or damaging winds south central. - Dry weather returns by Monday, continuing through Wednesday afternoon. && .SHORT TERM /THROUGH TONIGHT/... Issued at 316 AM EDT Sun May 12 2024 As a shortwave over northern Manitoba heads into northern Ontario this morning, strong theta-e advection and a low-level jet at 35 to 45 knots is bringing some sprinkles across the area early this morning over the western U.P. As cloud cover and warm air advection increase over the area early this morning, we`ve seen temperatures across the area stabilize and slightly rise. Therefore, we`ve almost certainly hit our low temperatures already, ranging from the mid 30s over the interior east to the mid 50s over the far west. As the sprinkle activity moves into the eastern U.P. after dawn this morning, expect to see a little bit of clearing over the west and central. This will allow the sunlight to increase the temperatures at the surface while dewpoints remain generally steady, creating a strong inverted-v sounding near the surface. This is most pronounced over the south central, where RHs could fall down to around 30%. We could (40% chance) see a spot or two in the south central hit elevated fire weather conditions as the highs today look to get to around 80F and winds could gust up to as high as 20-25 mph from the southwest before a cold front moves through this afternoon. However, given the likelihood and possible coverage of the potential elevated fire weather conditions, no notification will be sent this morning. However, fire weather isn`t the only concern over the south central today. With CAMs model soundings showing convection becoming surface- based over the south central this afternoon up to around 1200 J/kg and 0-6 km bulk shear vectors being around 35 to 45 knots perpendicular to a lake-breeze aided cold front moving through Upper Michigan this afternoon, we could see marginally severe wind and hail this afternoon into early this evening across the south central (5% chance). Hail chances are aided by the wetbulb zero heights being in the 7-9 kft range and severe wind chances are increased by the strong lapse rates and evaporation near the surface ahead of the cold front. Thinking the storms will remain fairly discrete this afternoon into this evening over the central and east, but they will mainly be restricted to the cold front as it passes through Upper Michigan. Therefore, we could see the storms congeal into a more linear state late this afternoon into early this evening. As the cold front continues to push south and east out of area this evening, expect the showers and thunderstorms to roll out of area with it. Therefore, the severe weather threat looks to end before midnight tonight, with skies clearing out behind the cold front. Due to the clear skies tonight, expect low temperatures to be around 40, save for around Menominee where lows look to be a few degrees warmer. && .LONG TERM /MONDAY THROUGH SATURDAY/... Issued at 406 AM EDT Sun May 12 2024 Starting on Monday, the trough to our north will be centered over northeastern Ontario with the associated sfc low just east of it over James Bay. A secondary cold front dragging behind the low will be draped over the UP by Monday morning and does not appear to make much southward progression until later in the day. Weak high pressure extending off the sfc high centered over western Hudson Bay begins to build in. Mixing will result in RHs in the interior west nearing 30%, however light winds mostly below 15 mph and any precip from today will keep fire concerns at bay. North to northwest flow off Lake Superior will keep the lakeshores cooler; lake breezes off both lakes will also play a role in keeping the east and lakeshores cooler with higher RHs. Highs are expected in the upper 40s to mid 50s near Lake Superior and upper 50s to upper 60s elsewhere. Although weak PVA increases late in the day into Monday night as a shortwave trough cycles overhead, cool and dry flow from the high pressure at the sfc will mainly keep this to a few mid level clouds. With the sfc high extending in, mostly clear skies, and PWATs around 0.3" ~10-20% of normal, radiative cooling is expected to bringing lows into the 30s with coldest temps in the interior west. Tuesday is shaping up to be a beautiful sunny day in the UP. High pressure continues to hold over the area keeping us dry. Highs are expected to be slightly cooler than Monday in the upper 40s to mid 60s, cooler near Lake Superior. Mixing will result in more RHs approaching 30% in the interior west and some gusts to 20 mph in the Keweenaw and east half of the UP. Another cool night is in store with mostly clear skies allowing for more radiative cooling. PWATs are slightly higher around 0.35-0.4", but lows are still forecast in the 30s. Wednesday looks to be more or less like Tuesday. Highs will be warmer with 50s to low 60s near the lakeshores and upper 50s to upper 60s in the interior. Some spots could reach into the low 70s. High clouds begin to increase from the west throughout the day ahead of the next system. Late Wednesday night/Thursday morning is when showers return to the forecast. A shortwave over the Pacific Northwest Monday morning will track east through the northern Rockies and into the northern Plains early Wednesday. From there there still is some uncertainty, but confidence is growing in a weak low developing on the lee of the northern Rockies and heading with the shortwave into the Upper Great Lakes for Thursday and Thursday night. Looking at the latest ensemble guidance: the CMC, GFS, and ECMWF increase probabilities of at least 0.01" after 0Z Thursday, however none of the ensemble guidance reaches above 50% probabilities of 0.01" until after 12Z Thursday. This does not look to be a soaking event with probabilities of at least 0.5" below 25% on all ensemble guidance. Chances for showers and possibly some thunderstorms continue into the weekend then as guidance begins to diverge. Opted to leave NBM PoPs as is with a second shortwave riding east-southeast from British Columbia Thursday night to the Great Lakes mid weekend. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 112 AM EDT Sun May 12 2024 VFR conditions will prevail thru this fcst period at IWD/CMX/SAW. As low pres drops into far northern Ontario tonight, a low-level jet will develop into Upper MI late tonight into Sun morning, resulting in 2-6hrs of LLWS at all terminals, lasting longest at IWD. The low- level jet will also generate sct showers, but confidence in a shower passing over any of the terminals is low. Not expecting conditions to drop out of VFR if a shower does occur. More showers/possible t-storm will develop Sun afternoon across central Upper MI, possibly affecting SAW before showers sag south in the evening. && .MARINE... Issued at 406 AM EDT Sun May 12 2024 A warm front is lifting northeast through the lake this morning. This frontal passage along with a tightening pressure gradient behind the warm front will result in some 20-25 kt wind gusts through this morning. While some of these higher gusts will linger on into the afternoon over the far east, the increasingly stable airmass over the lake should work against mixing the stronger southerly winds to the surface. Given the environment, higher reporting platforms would be more likely to observed these stronger winds then the surface buoys. A cold front will then press from west to east through Lake Superior this afternoon. A shower or thunderstorm can`t be ruled out this afternoon over the eastern lakeshores, but with the focus for convection being over Upper Michigan and not Minnesota, the probability is low (15-30%). Behind the front, high pressure will settle over the lake, supporting a few days of mostly 20 kts or less over the lake through at least midweek. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... Small Craft Advisory from 2 PM this afternoon to 11 PM EDT this evening for LMZ248-250. && $$ SHORT TERM...TAP LONG TERM...Jablonski AVIATION...Voss MARINE...Jablonski