Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI
Issued by NWS Detroit/Pontiac, MI
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781 FXUS63 KDTX 100407 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 1207 AM EDT Fri May 10 2024 .KEY MESSAGES... - Cooler temperatures (50s to low 60s) hold through Saturday before returning to at or above normal Sunday. - Next chance of showers and thunderstorms comes Saturday with the passage of a compact low pressure system. Severe weather is not expected. - Another chance of showers and thunderstorms comes Monday as a cold front drops through the area.. && .AVIATION... Low pressure exiting the Ohio valley to the mid Atlantic coast leaves Lower Mi between systems by sunrise. A steady north wind across the area during the morning precedes weak high pressure moving in from the upper Midwest. The high settles across the central Great Lakes during the day while reinforcing a cool air mass favorable for expansive high based cumulus development as daytime instability builds. Broken ceiling is VFR above 5000 ft into Friday evening. For DTW/D21 Convection...Thunderstorms are not expected for this forecast period. DTW THRESHOLD PROBABILITIES... * Low for ceiling 5000 feet or less this afternoon. && .PREV DISCUSSION... Issued at 353 PM EDT Thu May 9 2024 DISCUSSION... Models continued to favor the deep layer of dry air north of the elevated frontal surface, over the strength of the fgen aloft resulting in drier conditions holding over much of the CWA through the first half of the day. Latest runs offered weaker fgen and focused it lower on the frontal surface (peaking around 700mb) which has not be enough to overcome the dry layer between 900-600mb. SPC meso analysis page shows the current showers paired perfectly with the 700mb fgen band which is located over our southern 4 counties. We`ll hold on to a chance POP up to around M59 as the moisture is still pushing north with the low now passing directly south of us so there is a chance for minor expansion northward albeit for light showers or trace amounts of rain. Northeast flow will gain more traction this evening as the low directly to our south this afternoon pushes off to the east. The deformation axis will slide through this evening across 00Z keeping some mention of POPs across the far south til around 06Z. Cool period continues Friday as the positively tilted trough axis passes overhead. Cold air advection aloft will steepen low level lapse rates allowing for an expanding coverage of stratocu Friday with dry air advection and shortwave ridging helping to limit duration of thicker clouds and potential for any isolated showers to perk up during peak heating. Highs will be muted in the low 60s as the 850mb thermal trough around 2C slides southward out of the area with cooler northerly flow off the lakes. Next chance of showers and thunderstorms comes on Saturday as the ridge quickly slides out and a clipper type low in the base of a narrow northern stream trough drop southeast through the Great Lakes. Attendant surface low spin up will track across far southern MI with a trailing trough axis and theta e axis extending north/northwest helping spread showers further north through Mid MI as the low passes. Still looking at some embedded thunderstorms being possible with steepening low/mid level lapse rates, a few hundred joules of MUCAPE, and mid level support from the compact mid level vort max. Severe weather is not expected as flow is very weak through the column with winds under 20 knots through 20kft. Stronger mid level ridge slides through Sunday with westerly warm air advection boosted temps back up to at or above normal (which is upper 60s for early/mid May). Next system comes quickly for Sunday night and Monday as a northern stream trough pushes a cold front through the region. Thunderstorms will be possible again with this activity. MARINE... Northern edge of steady rainfall is just now approaching southern Lake St. Clair, with limited additional northward expansion expected this evening which will maintain dry conditions across Lake Huron. Responsible surface low is currently over the Ohio Valley, with prevailing northeast flow as a result. High pressure builds in briefly for Friday resulting in just a subtle shift to northerly flow and drier weather before the next low arrives on Saturday. The low is forecast to track over central Michigan, lending to a brief period of southwest flow Saturday morning ahead of a cold front before returning to the northwest later in the day as the low/front depart. Precipitation chances are once again in play for Saturday especially south of Saginaw Bay before drier weather returns Sunday in the wake of renewed high pressure. No wind/wave headlines are expected through early next week. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...None. Lake St Clair...None. Michigan waters of Lake Erie...None. && $$ AVIATION.....BT DISCUSSION...DRK MARINE.......MV You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.