Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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360 FXUS63 KAPX 012300 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 700 PM EDT Mon Jul 1 2024 .KEY MESSAGES... - Scattered showers Tuesday, a few breezes as well. - Potential for more widespread showers and thunder (including heavy rainfall) Tuesday night into Wednesday. - Trending dry for the Independence Day holiday (Thursday). - Additional rain chances Friday into Saturday. && .SHORT TERM /THROUGH TUESDAY/... Issued at 235 PM EDT Mon Jul 1 2024 Pattern Synopsis and Forecast: High pressure tonight will begin to slide to the east, moving to the east into Tuesday due to troughing advecting eastward across central Canada. High pressure will remain across portions of the CONUS east and southeast, with southwest flow aloft increasing across northern Michigan through the day. Energy aloft begins to slip into the region riding this southwest flow within a warm air advection regime and top down moistening. Best moisture and precip chances will be into the overnight hours Tuesday but showery activity likely during the day. Pressure gradient tightens and low level winds increase as well. Primary Forecast Concerns: High pressure influence remains tonight, but begins to slide to the east. Relatively cool night anticipated, but overall seasonable as winds shift to the south and clouds begin to filter into northern Michigan. Warm air advection on Tuesday with an increase in moisture and clouds. Additionally, southwest, increasing flow aloft spills over the region. Another scenario with drier low to mid levels and thus top down moistening during the day. As a result, precipitation (reaching the ground) is anticipated to be light and spotty early, but then increase in coverage as the atmospheric column saturates. Pressure gradient will increase and thus mildly breezy conditions expected as well, gusts occasionally up to 20 to 25 mph. Not a ton of precipitation through the evening on Tuesday, upper end probabilities via HREF & NBM 75th-90th%ile suggest ~0.1-0.25" of an inch by the evening hours focusing, seems reasonable for spots west of I-75. Better chances are expected shortly thereafter into Tuesday night, read on for more information. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... Issued at 235 PM EDT Mon Jul 1 2024 Pattern Synopsis / Forecast: Corridor of speedy 500mb flow between troughing over central Canada and a ridge axis over New England will contribute a handful of subtle vort maxes advecting into the upper Great Lakes Tuesday night into Wednesday. Ample low level jet response (SW flow 45-55kts at 850mb) will draw deeper moisture plume into the Great Lakes ahead of an approaching cold frontal boundary being forced eastward by the troughing regime digging into the region and lowering 500mb height. Result will be a period of showers and thunder Tuesday night into early Wednesday as forcing becomes good enough to sustain persistent rising motion overhead. This front will largely clear the area through the day Wednesday, though with some diurnal heating and lingering forcing owing to proximity to the surface low in northern Ontario, could see a returning shower or rumble of thunder across the eastern Yoop Wednesday afternoon. Post-frontal period of drier weather expected on Thursday for the big holiday before another trough digs into the northern Plains and drums up another moisture response, just in time for the end of the week and into the beginning of the upcoming holiday weekend. Primary Forecast Concerns: Tuesday night / Wednesday morning rain: Not much change overall in the thinking, though some specifics are becoming a bit more clear. While heavy rain is on the table, it`s beginning to look like it will happen in brief bouts as opposed to repeated downpours. This will be courtesy of potential shower / storm development across the WI/IA/IL/MO vicinity basically intercepting the flow of the deepest moisture, thus leaving us in the position to receive what can only be described as the "convective leftovers" of much of this activity. Still thinking a stripe of more enhanced rainfall can occur where the 850mb forcing is best, driving a narrow corridor of elevated instability... and just south of there, rainfall totals tail off quite considerably, while areas north of this corridor see more stratiform rainfall with perhaps a rumble of thunder. Latest probabilistic guidance continues to paint the highest probabilities of >1.00" of rainfall generally north and west of an HTL-APN line, so not much change in where this localized max rainfall happens since the previous cycle. Will probably need to fine tune this in the next couple forecast cycles... there is some guidance that tries painting this as basically the only rainfall Tuesday night, so it could be one of those setups where some locales (especially south of this focused corridor) see 0.10" or less of rainfall by the time everything is all said and done by Wednesday evening. Continuing the theme of the last several forecast cycles, flooding does not appear to be of concern considering that this will be a bit of a drawn out event, but given the high moisture volume throughout the atmosphere, downpours will certainly be possible in any storms. Wed. PM in the eastern Yoop: Some indications that low level moisture will be a touch slow to erode from the atmospheric profile. Given the passing of the cold frontal boundary and some diurnal heating magic, wouldn`t be surprising to see some afternoon showers / thunder blossoming for our friends north of the Big Bridge when coupled with lake breeze convergence. This activity is expected to be scattered in coverage, so by no means a guarantee for rain, but certainly can`t be ignored. Independence Day: The big holiday itself will be dry as the cold frontal boundary suppresses the deeper moisture (and thus, showers too) to our south. Expecting highs to top out in the upper 70s to mid 80s across the board. Should get through much of the evening on the drier side, but as low pressure dips into Minnesota, aforementioned frontal boundary will begin to lift back northward. If any spot is going to see a chance of showers Thursday evening, it will probably be areas closer to / south of M-55, though even for these locales, chances are rather low. Next weekend unsettled-ness: Aforementioned low pressure center will continue to move a warm front through the region for the beginning of the upcoming weekend. This system does appear to be an annoyingly slow mover considering the high-activity weekend that revolves around the holiday. Unfortunately, this will result in the return of showers and perhaps some thunder Friday through Sunday... though at this juncture, one positive is that it does not look like a steady rain / washout... more of hit and miss showers. Will have to keep an eye on this with time. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 700 PM EDT Mon Jul 1 2024 High pressure will continue to gradually slide east away from Michigan tonight...as low pressure developing to the lee of the Rockies enters the Western Great Lakes region on Tuesday. Dry wx will persist tonight into Tuesday morning...with only increasing and thickening cirrus expected well in advance of the upstream low. Chances of showers will increase Tuesday afternoon and night as that system moves into Wisconsin and Michigan. Prevailing conditions will remain VFR despite increasing clouds and chances of showers. Light SE surface winds will strengthen to 10 to 20 kts with some higher gusts on Tuesday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ SHORT TERM...JLD LONG TERM...HAD AVIATION...MLR