Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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423 FXUS63 KMQT 151127 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 727 AM EDT Sun Sep 15 2024 .KEY MESSAGES... - A chance (15-50%) of showers and storms today into Monday over mainly the west half. Otherwise, the prolonged dry stretch will continue through this week. - Extended stretch of well above normal temperatures continues through the forecast period with highs mainly in the upper 70s and 80s. && .SHORT TERM /THROUGH THIS AFTERNOON/... Issued at 313 AM EDT Sun Sep 15 2024 Water vapor imagery and RAP analysis show mid-level troffing from the w half of Canada into the western U.S. Downstream, mid-level ridging continues to dominate the Great Lakes region, though it has drifted e a bit over the last 24hrs. Mid-level anticyclone that was centered centered just e of the Soo at this time yesterday is now centered just s of Georgian Bay. Btwn this feature and the troffing to the w, mid-level ssw flow is present across Upper MI early this morning. While nothing of note particularly stands out in this ssw flow, models do depict a couple of subtle shortwaves. Those waves are aiding a modest expansion of sct shra across western Upper MI, especially nw Upper MI, over the last few hrs. Many of the 00z models correctly captured this increase in shra. Otherwise, it`s an unseasonably warm night across the w where clouds and light winds continue to hold temps up into the mid and upper 60s F, 20+degrees above the normal low temps for this time of year. To the e, with only sct thin high cloudiness, temps have fallen into the lwr 50s at traditional interior cool spots. Fcst this morning will follow the model consensus, which suggests shra will continue to lift across western Upper MI thru about 12z, then the shra will depart from sw to ne. With fcst soundings showing a skinny cape profile, thunder potential is very limited early this morning. Might be a rumble of thunder. With departure of the shra, clouds will also thin out. For the most part, a mostly sunny aftn is anticipated, setting up a very warm day under 850mb temps at around 16C. High temps in the low to mid 80s F will be the rule, generally 15-20 degrees above normal for time of year. S to se winds will hold temps to the 70s F near Lake MI and along the e side of the Keweenaw. With dwpts a little higher than recent days, MLCAPE over western Upper MI increases to near 2000j/kg at the high end per NAM. Lower end of the model guidance is down around 800j/kg. General lack of lake breeze development off of Lake Superior is a missing focusing mechanism, but with fcst soundings suggestive of no cap or only a very weakly capped environment and with several of the 00z models indicating some convective development, fcst will reflect 15- 20pct chc of aftn shra/tsra (isold coverage if anything develops) across portions of western Upper MI. && .LONG TERM /TONIGHT THROUGH SATURDAY/... Issued at 308 AM EDT Sun Sep 15 2024 BLUF: Mainly calm weather dominates the extended period, although some light rain showers and some thunderstorms are possible over the west tonight and Monday. Expect the late summer-like conditions to continue through the week, although temperatures may slightly decrease late this week as troughing approaches from the west by next weekend. Therefore, if you can, enjoy those outdoor activities while you still can! Some isolated rain showers and a thunderstorm or two are possible over the western U.P. late tonight through Monday as a shortwave riding along the ridging over the Great Lakes moves overtop us. While plenty of instability is available in the atmosphere by the Monday afternoon hours, with the better forcing located to our west and north, rain showers and storms will have a difficult time firing up. Therefore, any convection that we do see late tonight through Monday will more than likely be dependent on hard to pin down mesoscale/local variables, such as storm dynamics and localized topography. With the better PWATs further to our west and north too, not much rainfall is expected to fall out of the showers and storms we do see; expect no more than a quarter of an inch in the heaviest rain spots, with many areas even over the west failing to receive anything. Expect the rest of this week to be dry as high pressure ridging settles across the Upper Great Lakes while troughing digs into the western U.S.. While the warmest day is expected on Monday with highs possibly getting into the mid to upper 80s in the interior areas, the rest of the work week is very likely (80+%) to see high temperatures in the upper 70s to lower 80s, with mostly sunny skies dominating overhead due to the ridging. Fire weather concerns should be limited this week due to the light winds and more "moist" min RHs. However, fuels may need to be monitored as the lack of rainfall could further dry them out. By next weekend, model spread increases amongst the differing suites. However, there is still a general trend to push the timing of incoming rainfall back to the end or past the end of the extended period. Therefore, I`m highly doubtful (80+% chance) that we will see rainfall over our area until at least early next week. However, we could see cloud cover increase from the west as the troughing slowly tries to battle its way into our neck- of-the-woods this next weekend; this increase in clouds would drop our daytime high temperatures closer to normal. && .AVIATION /12Z TAFS THROUGH 12Z MONDAY/... Issued at 727 AM EDT Sun Sep 15 2024 VFR will prevail thru this fcst period at IWD/CMX/SAW. However, a disturbance tracking across the area has generated shra over nw Upper MI. CMX will see ocnl shra for the next couple of hrs with possible MVFR before the shra depart. && .MARINE... Issued at 308 AM EDT Sun Sep 15 2024 Light winds of 20 knots or less continue through this week as ridging remains over the Upper Great Lakes. Nevertheless, we could see a few showers and thunderstorms over Lake Superior today through Monday as some shortwave action rides along the ridging overtop us. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...TAP AVIATION...Rolfson MARINE...TAP