Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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016 FXUS63 KAPX 111739 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 139 PM EDT Sun Aug 11 2024 .KEY MESSAGES... - Cool with scattered showers today into early evening. - High pressure and quiet weather builds this week. Temperatures return to average for mid August. && .UPDATE... Issued at 930 AM EDT Sun Aug 11 2024 Just some minor PoP tweaks to account for recent trends this morning, but overall, no changes to be made to the forecast. Aforementioned unseasonably strong upper low continues to slowly be forced eastward by ridging to our west. Save for some heavier shower activity across Grand Traverse Bay, mainly light showers have been the rule this morning, particularly in the eastern Yoop and far northeast lower. As of now, coverage has been lackluster at best, but with temps crawling back up into the 60s and 70s, expectation is that enough diurnal instability materializes and a few showers initiate, particularly across northeast lower. Thunder seems rather unlikely at this juncture, but overall can`t rule out a rogue rumble. Oblong area of surface high pressure stretching from Saskatoon to Louisville will slowly move eastward through the day, inducing subsidence and beginning the process of scouring moisture out of the region from west to east later this evening into tonight. && .SHORT TERM /THROUGH MONDAY/... Issued at 231 AM EDT Sun Aug 11 2024 Unseasonably strong closed upper low/deep trough axis currently extends from Quebec thru SE Ontario into the Western Great Lakes early this morning. Enhanced area of shower activity is impacting much of our CWA attm as this sharp trough axis rotates thru Northern Michigan. No thunder to speak of within this area of showers due to lack of instability. Temps are holding mainly in the 50s. Sharp trough axis will continue to swing thru our CWA today...and will gradually slide east of Michigan tonight. Deep cyclonic flow combined with ample low level moisture and colder air aloft will continue to produce scattered showers today into early evening. Shower chances should finally come to an end by 00Z tonight...with clouds gradually diminishing from west to east during the balance of the night as subsidence and drier air begin to build into our region. Expect another unseasonably cool day across our Northwoods...with afternoon highs only warming into the upper 60s to lower 70s. Low temps tonight will cool into the low to mid 50s. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Issued at 231 AM EDT Sun Aug 11 2024 PATTERN SYNOPSIS/FORECAST: Anomalous upper low still hanging over the Upper Great Lakes...centered over Ontario, with a handful of lobes of vorticity swirling around this. Easterly flow through Hudson Bay running into a deformation axis stretching from Alberta to MN/WI...resulting in flow splitting northward into the anomalous ridge over northern Canada...and southeastward into the troughing over us. Coldest air aloft (850mb temps around 6C) focused just to our northeast under the core of the upper low. 100+kt upper jet stretches zonally across the CONUS. Otherwise...bulk of the moisture trapped along/just off the East Coast ahead of the leading edge of the trough...and also beneath the upper ridge centered over TX...though some is being funneled into SoCal with a bit of a Rex Block look out there. Expecting the upper low to hang out for one more day...before slowly exiting stage right Monday. Appears some kind of warm advection activity should develop upstream along the approaching ridge, though uncertain as to how far north this will get and how fast it will move through Monday afternoon into Monday night/early Tuesday. The further north track would bring a greater chance at additional rain (especially for our southwest counties), while a further south track could set us up under a nebulous col region that could lead to patchy fog Monday night. Even behind this for Tuesday/Tuesday night...appears flow could trend nebulous, leaving general high pressure and the potential for patchy fog around into midweek...along with some shot at lake breeze development...though temperatures should slowly moderate toward more normal for mid August. Ridge axis finally arrives Wednesday for a pleasant late summer day. Uncertainty increases in the forecast beyond midweek...as to how the pattern progresses behind the upper ridge axis...though things seem to be coming into better agreement on the idea of an unsettled end to the week. Primary Forecast Concerns: Overnight patchy fog potential...Expecting a nebulous flow regime to slip in for the early part of the week...along with general surface high pressure. Think patchy fog will be possible given the recent showery activity boosting low-level moisture...but do have some concerns that high clouds could diminish some of the radiational cooling potential that might otherwise improve overnight fog potential in this sort of a regime. Afternoon pop-up showers Monday and Tuesday...While there is some uncertainty in the track of that warm advection precip Monday/Monday night...do think that we may still be at risk of diurnal heating driven convection (i.e., afternoon pop-ups) both Monday and again Tuesday, particularly combined with potential for lake breezes given the otherwise light flow. Monday`s activity could be related to lingering cold air aloft still hanging over the area, as guidance soundings suggest a more fall-like, low-topped shower environment. Do think Tuesday will be the better shot, though, as return flow should be a bit better...giving us potential for a bit deeper instability and a better chance of thunder compared to Monday. Not expecting anything dramatic, by any means, and chances are small attm...but will be something to keep an eye on, particularly for the interior. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 139 PM EDT Sun Aug 11 2024 Upper trough over Georgian Bay will continue to slowly slide east as high pressure encroaches later tonight. Potential for scattered showers through the evening (particularly CIU, APN, and PLN) before activity diminishes. Modest west to northwest flow holds from 10- 15kts, perhaps some gusts approaching 20kts at times before diminishing this evening, even becoming calm overnight. Mainly VFR conditions expected, perhaps dropping to MVFR in the vicinity of any shower activity this afternoon. More of a westerly flow of about 10kts expected tomorrow, with VFR conditions holding strong as high pressure moves overhead. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ UPDATE...HAD SHORT TERM...MLR LONG TERM...FEF AVIATION...HAD