Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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617 FXUS63 KAPX 071758 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 158 PM EDT Fri Jun 7 2024 .KEY MESSAGES... - Isolated/scattered showers and cool temperatures today. - Another round of showers Saturday into Saturday night. Some thunder possible south. - Next chance of rain and perhaps some thunder Tuesday night into Wednesday. - Warming temperatures through the course of next week into next weekend. && .UPDATE... Issued at 1114 AM EDT Fri Jun 7 2024 Synopsis: Upper low parked to the east of Lake Superior this morning...part of an elongated negatively tilted trough that extends from the northern Prairie provinces southeast through the Great Lakes/New England. Center of the associated cold pool lies over northern Michigan (12z 500mb -20C at APX) with deep layer northwest flow on the cyclonic/cold side of the polar jet axis. Several embedded disturbances within the larger scale trough...one to the east of Lake Superior is rotating back southward and is pushing a larger area of showers southeast across eastern Upper Michigan and into northern Lake Huron/Georgian Bay. A few spottier showers over northern Lower associated with some weak isentropic ascent. Still a lot of moisture hanging around...12z APX sounding was saturated past 450mb so it`s not taking much to squeeze out light rain/drizzle... but it is quite a bit drier not far to the west/southwest. 12z surface analysis shows broad/weakly cyclonic flow across the upper Lakes south of a 994mb low to the west of James Bay. Forecast Update: Until the short wave trough east of Lake Superior rotates through later this evening there is likely going to be a chance for some showers to continue to develop...diurnal heating won`t hurt the cause (won`t take much given morning APX sounding). Do expect skies to improve this afternoon along/west of the M-37 corridor over northwest Lower as drier air nudges in from the west and clouds should mix into a Cu/Sc deck. Eventually clearing should push eastward this evening with far eastern Upper/far northeast Lower likely the last to see clouds break up. && .SHORT TERM /THROUGH TONIGHT/... Issued at 343 AM EDT Fri Jun 7 2024 Pattern Synopsis: Strong troughing draped across the Great Lakes will continue to pivot east over New England today. Low-amplitude ridging on the backside of said troughing will slide overhead later this evening and tonight. A broad surface cyclone will also spin over southeast Canada as relatively high pressure noses into the Great Lakes as aforementioned ridging works overhead. Forecast Details: Isolated/scattered showers, cool temps today -- West to northwest winds will prevail today as the aforementioned system continues to work to our east. Ongoing isolated to scattered showers are also expected to continue at times across parts of the area into this afternoon. Rain chances will gradually wane with time as a drier low- level airmass is advected in and favorable forcing becomes increasingly displaced from the region. Cloud cover also looks to clear as high pressure works into the Great Lakes this evening and tonight. Otherwise, temperatures are expected to stay cool today with highs in the upper 50s to mid 60s. Lows should cool into the mid to upper 40s away from the immediate lakeshores tonight. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 343 AM EDT Fri Jun 7 2024 Pattern Synopsis / Forecast: Rotund area of retrograding longwave troughing set to pivot south and east from the Dakotas through the upper Great Lakes Saturday into Sunday as closed area of surface low pressure is slowly forced eastward by amplifying ridging west of the Plains. The result will be a continued period of occasional showers (with perhaps a rumble of thunder) through the first half of the weekend. Surface high pressure will finally work into the region as some 500mb ridging moves into the Great Lakes by Tuesday, drying things out for the most part. This area of high pressure slowly sags south and eastward into the Outer Banks of North Carolina, directed by the lingering NW flow on the backside of longwave troughing over Atlantic Canada. This will eventually lead to warming temperatures, potentially quite on the warm side, heading into next weekend as a 500mb thermal ridge flexes over the central Plains and return flow draws warmer air into the region. Primary Forecast Concerns: Saturday - Sunday: Embedded vort max within the longwave troughing looks to pass through Michigan Saturday, though with such cool temperatures and lacking steeper lapse rates, not looking at an overly optimistic outlook for thunder. Rain will probably struggle to move into the region initially as dry air aloft holds off saturation, but eventually expecting showers to pass through the region... with northern lower Michigan having the best chance of showers, and lesser chances the closer one gets to the Soo. Wild card could be enough diurnal heating just to the south of the vort max drumming up a few hundred joules of surface based CAPE leaking into the southern reaches of the CWA, but much of this instability is progged to remain south of US 10 at this juncture. Wave passes through. Looks like Sunday probably holds more dry than not for now, though some lingering energy from the passing longwave may be enough to spark some diurnal showers before moisture gets scoured out and drier air moves in by Monday with the approach of surface high pressure. Temps set to be rather chilly by early June standards, largely getting stuck in the 60s to near 70 (perhaps mid 70s closer to Lake Huron Saturday owing to a later onset of rainfall). Rest of the Period: Next item of interest will be a shortwave riding a zonal flow regime around the ridge overhead, which will bring the next chance for shower and thunder later Tuesday night into Wednesday. Suboptimal timing of this feature passing through leads me to believe this will mainly be showers. Somewhat of a subtle convective wave signal building in for Wednesday night into Thursday, which could have some thunder with it if it indeed does originate as an MCS in the Plains, but still a bit far out to get into any more specifics. Thermal ridge axis peaks over the Plains by the end of the forecast period, leaving northern Michigan on the periphery of the larger ridging complex. While the core of the heat and surface moisture will be suppressed well to the south and west, surging 850mb temps suggest that we will indeed be seeing temperatures rise into the weekend... starting in the 70s Tuesday, rising well into the 80s by the weekend for most. && .AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 158 PM EDT Fri Jun 7 2024 IFR conditions at KCIU are expected to persist through the rest of the afternoon before ceilings rise to MVFR after 00z...with clouds expected to scatter out around midnight. MVFR ceilings at KPLN/KAPN are expected to improve to VFR conditions after 00z as clouds thin. KTVC/KMBL expected to remain VFR through tonight...with clouds thickening Saturday morning with rain moving in after 14z. Low level wind shear expected to develop this evening once surface winds decouple. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory until 2 AM EDT Saturday for LHZ345>349. Small Craft Advisory until 8 PM EDT this evening for LMZ341- 342. Small Craft Advisory until 2 AM EDT Saturday for LSZ321-322. && $$ UPDATE...JPB SHORT TERM...DJC LONG TERM...HAD AVIATION...JPB