Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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978 FXUS63 KMQT 180639 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 239 AM EDT Wed Sep 18 2024 .KEY MESSAGES... - Extended stretch of well above normal temperatures continues through at least Saturday with highs mainly in the upper 70s and 80s. - A cold front brings scattered showers and a few thunderstorms late Thursday into Friday. && .SHORT TERM /THROUGH TODAY/... Issued at 121 PM EDT Tue Sep 17 2024 Dry and warm airmass continued to sit over the Upper Great Lakes today. Outside of some mid-high clouds here and there, and some recently developing diurnal cumulus in the west, the forecast area has been mostly clear which enabled many to easily break into the 70s before noon. In fact, many locations were beating hard on the 80 degree door at that point. As of publishing this discussion, most surface observations were in the upper 70s to low 80s, which is approximately 10 to 15 degrees above normal for mid-September. Under mostly light southerly flow, daytime mixing has supported dewpoints in the mid 50s to low 60s. This is yielding RH values mostly in 50s and 40s in areas removed from Lake Michigan`s influence. Some drier locations have fallen into the 30s as well. As we progress through the remainder of the afternoon, I expect temps to climb a little more and RH values in the 40s to be more widespread with some 30s here and there before recovering with the waning heat. Expecting clear skies to continue through tonight, which will yield overnight lows in the 50s and 60s, save the interior portions of south-central and east, which could slip into the 40s. Patchy overnight fog will be possible as well, particularly in the interior spots of central and eastern Upper Michigan. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 412 PM EDT Tue Sep 17 2024 Continued warm and dry weather is expected through the midweek before a cold front brings much needed rainfall and a slight reprieve from the endless summerlike temperatures this weekend. Beginning Wednesday, ridging aloft and high pressure extends from the eastern seaboard across the Great Lakes, while a closed low spins overhead the Northern Great Plains. Some minor fire weather concerns arise Wednesday as forecast high temperatures will generally reach in the 80s across the UP and mixing allows RHs to bottom out near 30% in the afternoon. The recent lack of rainfall and dry fuels have introduced abnormally dry D0 conditions for the entire Upper Peninsula away from the Keweenaw. Luckily, light southerly winds only peaking near 10 kts keep fire danger low. Otherwise, a weak shortwave embedded in the broad southwest flow may kick off some showers over far western Lake Superior and Isle Royale (10-15%). Thursday starts off similarly with warm and dry conditions, although better moisture advection limits fire danger further. The closed low pushes northward into Manitoba, sending height falls and a cold front across the Upper Midwest late Thursday into Friday. Much needed rainfall accompanies the frontal passage, reaching the far western UP Thursday evening. A few thunderstorms are possible as model soundings indicate weak elevated instability, but with shear lacking <20kts no severe weather is expected. Unfortunately, these scattered showers won`t bring much in terms of QPF. Ensembles barely squeeze out 0.25" across portions of the west-central as the front passes to the east through Friday, but any rainfall is welcome to help curtail fire weather conditions. Temps wont drop significantly since positive 850 anomalies near 3-4C continue through the weekend into next week. Cloud cover will bring daily highs down closer but still above normal for this time of year. Finally some more active weather is on the horizon as global models resolve a handful of shortwaves digging across the central US and Canada this late weekend into the beginning of next week. After a brief period of ridging and clearing Saturday, guidance suggests a closing upper low translating into western Ontario Sunday morning and another system entering the lower Midwest Monday. Deterministic models start going catawompus on the placement and timing of these features, however, much needed rainfall is looking more likely. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 239 AM EDT Wed Sep 18 2024 Dry airmass over the region will continue VFR conditions in this TAF period. && .MARINE... Issued at 412 PM EDT Tue Sep 17 2024 Light winds of generally 20 knots or less continue for the next several days has high pressure ridging this week finally gives way to a cold front moving through Thursday night through Friday. This front could bring some showers and storms over Lake Superior, particularly north and east of the Keweenaw, as well as some stronger winds above 20 knots as it slowly crawls from west to east. We may see winds increase above 20 knots again come late this weekend/early next week as a few shortwaves approach the Great Lakes && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JTP LONG TERM...BW AVIATION...07 MARINE...BW