Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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922 FXUS63 KDTX 311918 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 318 PM EDT Fri May 31 2024 .KEY MESSAGES... - Dry weather continues today and most of Saturday. The next chance for rain arrives Saturday evening through Sunday morning. - The weekend finishes dry and warm Sunday with highs near 80. - Potential for multiple rounds of showers next week. && .DISCUSSION... Clear skies have pushed temperatures into the upper 70s this afternoon, slightly above normal for the end of May. Dry conditions persist through the rest of the day into tonight. Overnight lows will depend on timing and extent of clouds moving in, but with enough time under clear skies, full radiative cooling could push temperatures down to the low 50s. Upper level ridge supporting the high pressure center moves out beginning Saturday and a shortwave trough brings the next chance for precipitation. Profiles remain very dry Saturday morning, with only high clouds moving in at first. Southerly flow helps advect moisture into the lower levels, slowly saturating the profile and lowering ceilings as the day progresses. Temperatures Saturday will be a bit inhibited by increasing cloud cover through the day, but the aforementioned southerly flow also provides some warm air advection to heat up to the mid-70s. The gradual saturation process keeps the rain at bay until the late afternoon/evening, but pushes PWAT values from below a half inch in the morning Saturday to 1.5 inches or greater early Sunday morning. Little to no significant CAPE makes its way into the area for this event, and the atmosphere remains relatively stable. As such, thunderstorms look unlikely, although a stray rumble of thunder may pop up. Storm total QPF amounts will generally be greater in the southern part of the CWA, with some areas seeing over a half inch of rain, mainly in Lenawee and Monroe counties. Strong theta-e advection along a 30 knot low-level jet provide some potential for excessive rainfall with this setup. Hi-res models have yet to fully resolve the end of the rainfall on Sunday, but since solutions have tended to keep the system moving, concerns for excessive rainfall are not strong at the moment. Cloud cover keeps the temperature swing down on Sunday, with lows Saturday night into Sunday morning staying up in the 60s and highs cooling down slightly Sunday afternoon reaching the low to mid 70s. Clearer conditions return on Monday as a brief ridge provides some relief from the rain. Southerly flow continues to keep temperatures high Monday with potential to touch 80 degrees across the CWA in spite of advancing cloud cover from the next storm. Upper level shortwave develops another low pressure center over the northern Great Plains and brings it northeast into western Ontario Monday evening. This system brings with it the possibility for additional light rain for the CWA Tuesday morning as a warm front moves across the region, but guidance suggests that the strongest forcing, coming from the system`s cold front, will remain to the north. Ensemble runs give a third of an inch of rain as a reasonable upper limit for this event with this much lead time. Behind Tuesday`s system a large negatively tilted longwave trough begins to take shape, likely bringing multiple rounds of showers for the end of the week. A very tight gradient in the upper levels will bring strong flow aloft, over 100 knots at 500mb, as well as a streak of high relative vorticity. Should this system set up the right way, temperatures will drop significantly as the center of the upper level low drops 540-550dam heights at 500mb into the Great Lakes area in addition to the aforementioned rain. && .MARINE... High pressure continues to influence the area through early Saturday as it gradually drifts toward the mid-Atlantic. Low pressure lifting into northern Ontario drags a cold front into the Great Lakes Saturday as a secondary area of low pressure develops along this boundary over the western Ohio Valley. Secondary low is set to track northeast into southern Great Lakes late Saturday into the first half of Sunday bringing widespread shower chances. A thunderstorm or two remain possible from roughly Port Huron south. Diffuse pressure gradient however results in generally lighter winds (below 20kts) with this system. Weak high pressure then briefly builds in late Sunday and Monday. && .PREV DISCUSSION... Issued at 1258 PM EDT Fri May 31 2024 AVIATION... High pressure centered over the region will maintain a dry and stable environment this taf period. This will continue to support a clear sky, with winds from the south to southeast below 10 knots. High cloud thickens with time Saturday in advance of an approaching low pressure system. For DTW/D21 Convection...Thunderstorms are not expected during this forecast period. DTW THRESHOLD PROBABILITIES... * None. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ DISCUSSION...BC MARINE.......KDK AVIATION.....MR You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.