Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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969 FXUS63 KAPX 181538 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 1138 AM EDT Tue Jun 18 2024 .KEY MESSAGES... - Very hot, humid conditions continue with scattered showers/storms today. - Warm to hot temperatures will linger through the work week - Rain and storm chances linger through most of the forecast && .UPDATE... Issued at 1138 AM EDT Tue Jun 18 2024 Synopsis: 13z surface/composite analysis shows a 995mb low over eastern South Dakota...warm front extends east-northeast across Minnesota/far western Upper and into northeast Ontario. Second frontal boundary extends north across eastern North Dakota and into far northwest Ontario. Plenty of low level moisture south of warm front with dew points across state (with the exception of the Keweenaw Peninsula) well into the 60s with some lower 70s across Lower Michigan...and surface temperatures across northern Lower already well into the 80s as of 15z. Upper level high centered over the mid Atlantic with deep layer south/southwest flow into the Great Lakes. A mid/high level overcast was spreading northeast from southern Lake Michigan/southern Lower Michigan toward northern Lower...along with some high based radar returns. This is associated with a compact but well-defined vorticity center entering southwest Lower per water vapor imagery. This deep layer southerly flow is also pulling an impressive plume of moisture north... emanating from the area around Potential Tropical Cyclone One in the southwest Gulf. Precipitable water values over 1.75 inches over southern Lake Michigan and 2.00+ inches across parts of Illinois/ Indiana/western Kentucky. Forecast Update: In addition to the approaching mid/high cloud deck..some Cu are starting to bubble up over northern Lower. 12z APX sounding already had over 900J/kg MLCAPE with -95J/kg MLCINH... straight up modification of that sounding for the current 86/66 at KGLR yields 1764 J/kg with an elimination of MLCINH. So the arrival of the short wave trough from the south should increase the chances for showers/thunderstorms to develop. Not much in the way of deep layer shear so organized severe threat will be low but could see some pulse type severe especially with a wet microburst wind threat. Looking at high temperature records today think most of them are safe...will come close at GLR (92/1994) and PLN (93/2007). Records of 96 and 97 at KTVC/KAPN respectively may bit a bit of a reach especially with increasing cloud cover. && .SHORT TERM /THROUGH TONIGHT/... Issued at 403 AM EDT Tue Jun 18 2024 Pattern Synopsis: Impressive, strong ridging will continue to dominate the eastern CONUS today and tonight with surface high pressure centered far off the Atlantic coast. Northern Michigan will remain locked between said high pressure and an elongated cyclone stretching across the Upper Midwest/Ontario into Wednesday morning as the ridge/trough inflection point gradually across the northern Great Plains through the period. Forecast Details: Very hot, humid conditions with showers/storms today -- South- southwesterly low-level flow will continue warm, moist advection across the Great Lakes, keeping very hot, humid conditions in place for many areas today. Widespread highs in the mid 80s to low 90s are anticipated this afternoon with heat indices reaching into the mid to upper 90s. The hottest conditions today are anticipated across northeast lower, the Straits, Grand Traverse Bay region, and the far eastern U.P. Temperatures should quickly rise into the mid/upper 80s across most of northern Michigan by late morning, but the development of scattered showers/storms by early afternoon should work to limit how hot temperatures get -- especially across interior areas. Best chances for showers/storms will be along and east of I- 75 this afternoon and should move southwest to northeast, allowing portions of far northeast lower to warm into the 90s before substantial cloud cover and rain-cooled air lower temperatures. Thus, high temperatures may be seen during the early afternoon hours for many across the area with temperatures cooling from aforementioned convection during mid/late afternoon. While small hail, gusty winds, and locally heavy downpours will be possible with any strong storms, severe weather is not anticipated this afternoon. Tonight will fail to offer meaningful relief from daytime heat as lows only cool into the low to mid 70s across the area. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Issued at 403 AM EDT Tue Jun 18 2024 Pattern Synopsis and Forecast: The upper level high will be centered over northern Mid Atlantic region by Wednesday. At the same time an upper level trough will be over central Canada, continuing southwest flow aloft over the Great Lakes region. A well established Gulf moisture tap will continue to maintain higher moisture amounts in this region, keeping PW values around 1.5" through Sunday. Hot temperatures and intermittent rain and storm chances will be seen over the whole CWA through early next week as the upper level high slowly widens to our south by the end of the work week. Ample moisture will continue to rotate around the high, even as winds become more west. The upper level high will weaken as it widens, allowing an upper trough to reach MI from Canada this weekend. This should finally cool temperatures back down to near or even a few degrees below normal. Rain chances will continue as a progressive patter is hinted to establish early next week. Primary Forecast Concerns/Key Messages: Hot temperatures will likely continue through Thursday as upper level heights continue to trend upward. Moisture will linger, giving way to the uncertainty in the duration of very hot temperatures. However afternoon temperatures will likely continue to feel uncomfortable through the end of the work week. Upper level heights finally start to trend down Friday, and so will temperatures start to gradually decrease. Higher chances of an upper level trough swinging through this weekend, brining more rain chances but will allow temperatures to drop to near seasonal again. Rain and storm chances will exist almost each afternoon as moisture continues to be provided to the region. The lack of a defined trigger will make the exact location and time hard to nail down, however most storms will likely have heavy rain, lightning, and possibly small hail and/or brief gusty winds (however that is less likely at this time). If convection can kick off over a defined boundary, training could be an issue of some storms. This could lead to locally higher amounts of QPF. The wet pattern will likely hang around for the foreseeable future. && .AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/... Issued at 630 AM EDT Tue Jun 18 2024 Mainly VFR conditions are expected across northern Michigan through the TAF period. Scattered showers and thunderstorms will be possible later today, although explicit mention of thunder has not been included in the 12Z TAFs at this time due to uncertainty in coverage and timing. Otherwise, south-southwest winds around 10-15 kts are expected to gust between 20-30 kts at times into this evening. LLWS will also be possible at northern Michigan TAF sites later this evening. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...Small Craft Advisory until midnight EDT tonight for LHZ348-349. Small Craft Advisory until 5 PM EDT Wednesday for LMZ323-341- 342-344>346. Small Craft Advisory until 8 PM EDT this evening for LSZ321. && $$ UPDATE...JPB SHORT TERM...DJC LONG TERM...ELD AVIATION...DJC