Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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307 FXUS63 KAPX 220345 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 1145 PM EDT Sat Sep 21 2024 .KEY MESSAGES... - Return of stratus/fog tonight parts eastern Upper/northeast Lower. - Increasing (and needed) rain chances for Sunday...with lingering rain/storms Sunday night into Tuesday. && .UPDATE... Issued at 941 PM EDT Sat Sep 21 2024 Not a whole lot of change needed. Upstream moisture axis and attendant area of showers continue to work east, with those showers slowing and becoming increasingly disorganized as they run into overhead dry air. Still think moisture becomes deep enough to kick off a few showers west of Interstate 75 by sunrise Sunday. A few rumbles of thunder will also be possible, but definitely nothing to significant expected. Otherwise, expecting some fog to expand across northeast lower into eastern upper Michigan overnight (already a quarter of mile visibility at Alpena). && .SHORT TERM /THROUGH SUNDAY/... Issued at 406 PM EDT Sat Sep 21 2024 Pattern Synopsis/Forecast: Skies were mostly sunny across northern Michigan at mid afternoon...save for lingering St over northern Lake Huron and around Drummond Island. Low amplitude short wave trough crossing the upper Great Lakes...stronger short wave trough over Manitoba moving into northwest Ontario. Associated 1005mb surface low over northwest Ontario with a cold front extending south into Minnesota/northwest Iowa/southeast Nebraska. Precipitable water axis > 1.50 inches advancing northward ahead of the front into southwest Minnesota. Cold front will advance eastward across Upper Michigan/Wisconsin tonight...then across northern Lower Michigan during the day Sunday along with the deeper moisture axis. Primary Forecast Concerns: Return of stratus/fog tonight parts eastern Upper/northeast Lower: Lingering St over northern Lake Huron from Thunder Bay north...along with a small patch west of the Straits. Loss of heating and light winds will likely allow low clouds and fog to redevelop this evening across northeast Lower and into parts of eastern Upper. Fog could be locally dense along the Lake Huron shoreline. Increasing (and needed) rain chances for Sunday: Leading area of precipitation moving across central Wisconsin with some active convection especially along the southern periphery northwest of MSN. Deeper moisture axis will work its way across Wisconsin tonight... but low levels expected to remain relatively dry across the area for much of the night. So while showers/thunderstorms should continue to develop/propagate eastward from Wisconsin tonight...a lot of the initial precipitation may just come in as some virga/light showers. Increasing rain probabilities from west to east after 09z or so but may remain mostly dry east of the I-75 corridor until Sunday afternoon...would think we`ll see a nice band of showers with some embedded thunderstorms within it. Average QPF on the order of 0.25- 0.50" expected through 00z Monday with more rain into Sunday evening especially northeast Lower. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... Issued at 406 PM EDT Sat Sep 21 2024 Flow a bit more zonal across the CONUS for a change...ridge axes over the Mid MS Valley and also Quebec...anomalous upper low over the SW US, and troughing over the Central Canadian Prairies down into the northern US. Bulk of the moisture focused over the Mid MS Valley beneath the ridge axis attm...though developing southwesterly low-level flow starting to tap into this better moisture...as mid-level weak stability overspreads the Upper Midwest in the meantime. Sharp LL cold front at the surface associated with the Canadian Prairies troughing...stretching through MN down into NE CO and back into the Intermountain West. Warm front associated with this system stretching down into IL and around through the OH Valley as the remnants of the cold front from yesterday...connecting to occluded front now over Lake Huron into Ontario. Lots of patchy fog early this morning in the wake of this and yesterday`s rainfall...as shortwave ridging slips overhead. Surface high pressure building into the western US attm. Niblet of PV over Canadian Prairies to skate by through the next 24- 36 hrs...dragging a front through the area and ultimately a SW-NE oriented boundary setting up to our south Sunday night into Monday, connecting this northern stream system and ejecting upper low from the western US (moving into the central US by Sunday night). Expecting rain to move out with time Sunday night, hanging out longest near Saginaw Bay...though some potential for a low stratus/fog-esque deck to hang on over northern Lower Sunday night in the wake of the cold front; some potential for lake-related cloud activity over the eastern UP. Meanwhile...energy plows into the western US Sunday night into Monday, building ridging over the central US again...which could allow the lingering BCZ to our south to lift back northward toward the Upper Great Lakes. Aforementioned plowing PV energy drives through the region Tuesday into Tuesday night, which should try to cut off as it slips eastward over the region for midweek. Quite a bit of uncertainty attm in where this occurs, though...given continued changes run-to-run in where this occurs, which has potential to have dramatic changes on the forecast for the middle and latter portion of next week. If the trough cuts off over us to some degree...would expect a much cooler and drearier mid/late week than if the closed low ends up to our southwest or even to our east. Additionally...signals for tropical activity in the Gulf of Mexico later next week suggest even further uncertainty in the forecast for next week, as to how this feature will interact with the closed low...wherever it sets up. Primary Forecast Concerns: Lingering Rain/storms Sunday night into Tuesday: Front and attendant moisture to exit stage right Sunday night...reaching the Saginaw Bay region toward Monday morning. Could be fairly dreary over parts of the region, particularly NE Lower, where it should take longer to burn off. However...think there will be enough lake-based instability Sunday night and beyond...at least into Monday if not longer...that parts of the area could see waterspout potential if clouds hang out. For now...suspect best chance of this would be over the EUP and points downwind... particularly over Lake Huron where there is a greater likelihood of low clouds/stratus hanging on into Monday. Looks like some activity will try to lift back toward us Tuesday into Tuesday night...as that BCZ lifts back northward. For now...not expecting this to be terribly dramatic...but do think a nice little rain is in store as moisture increases again into the area. This being said...not impossible this could remain shunted to our south as we go into midweek...which could keep some areas a bit drier. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1141 PM EDT Sat Sep 21 2024 Initial concern remains LIFR producing fog and cigs at KAPN. Expect to last through the early morning hours. Also expecting IFR producing cigs to build back northwest off Lake Huron into KCIU within the next few hours. More widespread lower cigs and showers are expected to spread west to east across the area on today, with some embedded thunderstorms expected as well. MVFR to potentially IFR cigs are expected at all locations by late morning and afternoon. Likely too some visibility restrictions as well, especially with any pockets of heavier rain. Conditions are expected to slowly improve from west to east this evening. Light winds will become northwest and a bit more gusty this afternoon and evening. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ UPDATE...MSB SHORT TERM...JPB LONG TERM...FEF AVIATION...MSB