Area Forecast Discussion
Issued by NWS Gaylord, MI
Issued by NWS Gaylord, MI
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292 FXUS63 KAPX 201908 AFDAPX Area Forecast Discussion National Weather Service Gaylord MI 308 PM EDT Mon May 20 2024 .KEY MESSAGES... - An isolated strong to severe storm or two possible through this evening. - Better chance for strong to severe storms with a potential squall line Tuesday night in advance of a surface cold front. && .SHORT TERM /THROUGH TUESDAY/... Issued at 245 PM EDT Mon May 20 2024 Marginal instability/winds aloft in advance of a short wave evident on water vapor imagery over southern Illinois tonight. An area of showers and embedded thunderstorms is expected to progress across northern Michigan through the evening and the early overnight hours. Severe potential appears to be on the low side from the combination of the loss of daytime heating, limited moisture and marginal instability (just a few hundred J/kg of mixed layer cape and 0-6 km bulk shear of 30-35 knots). Although not expected, can not totally rule out the possibility of an isolated severe storm or two with damaging winds and large hail the primary threats. A break in the action is then expected late tonight into much of the daylight hours of Tuesday. Can not rule out an instability driven pop up shower or storm Tuesday afternoon (mainly across northeast lower). A bigger threat for severe storms arrives Tuesday night (see long term forecast discussion below). Muggy tonight with lows in the 50s to near 60. Highs Tuesday ranging from the low and mid 70s north to the low and mid 80s south. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Issued at 245 PM EDT Mon May 20 2024 PATTERN SYNOPSIS/FORECAST: A digging trough and its associated surface low is expected to track into the Midwest resulting in an influx of deep moisture to the area. This will be enough forcing to push a warm front, located in southern Michigan, northward into the area, leading to rain showers and possible strong to severe thunderstorms for late Tuesday/ Tuesday night. As the aforementioned surface low tracks out of the region, cooler air will slowly wrap around the low and be pushed into Northern Michigan. As such, temperatures will be warmer to start off the week with daytime highs in the 70s, before more seasonable temperatures set in for later in the week. PRIMARY FORECAST CONCERNS: - Tuesday Night: A digging trough and its associated surface low will track into the western portion of Lake Superior. The aforementioned low will deepen and strengthen as it tracks to the Lake. Along the way, strong southerly winds will push a front north into the APX footprint and provide enough lift to support strong to severe thunderstorms for late Tuesday/ Tuesday night. A deep moisture fetch is had with this setup as southerly winds draw ample moisture in from the Gulf. One thing we will have to watch is if any potential activity downstate materializes and cuts off the deep moisture fetch, essentially hindering the chances of severe weather. With atmospheric conditions being primed for this event, another question will be if the nocturnal nature of the frontal passage will disrupt initiation along the front. As stated by the previous forecaster, the current thinking of linear mode storms (squall line / MCS) is still expected, making the main threat with this event being strong winds. However, a strong low-level jet will take full advantage of this event to help produce strong shear and opens the door for some storms capable of producing hail in stronger updrafts within the line. A quick spin-up tornado along the line as it surges northeastward into northern Michigan will also be possible and cannot be ruled out with ample shear, moisture, and instability/lift? available. SPC (Storm Prediction Center) continues to have a Slight Risk (2/5) across much of northern lower Michigan and Marginal Risk (1/5) elsewhere. Continue to monitor the latest forecast and be sure to have multiple ways of receiving weather alerts to ensure you are weather aware. && .AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 132 PM EDT Mon May 20 2024 Showers and embedded thunderstorms are expected to sweep across the region later this afternoon into early tonight. Cigs are expected to lower to between IFR and LIFR, especially overnight into Tuesday morning. Winds are expected to be light and variable, expect for any gustiness in possible thunderstorms. && .APX WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ SHORT TERM...AJS LONG TERM...NSC AVIATION...AJS