Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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784 FXUS63 KMQT 170730 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 330 AM EDT Tue Sep 17 2024 .KEY MESSAGES... - Extended stretch of well above normal temperatures continues through at least Thursday with highs mainly in the upper 70s and 80s. - Next credible chances of precipitation arrive Thursday night and continues through Friday night. More rain is possible early next week. && .SHORT TERM /THROUGH THIS AFTERNOON/... Issued at 323 AM EDT Tue Sep 17 2024 Water vapor imagery and RAP analysis show mid-level troffing over the western U.S. Downstream, sw flow prevails thru the Upper Mississippi Valley into se Canada overtop ridging over the ne U.S. Within this flow, a couple of shortwaves are supporting clusters of shra/tsra from the ND/Manitoba border eastward along the Ontario/MN border region. Closer to home, conditions across Upper MI early this morning are nearly a carbon copy of 24hrs ago. Stirring southerly winds in the downslope areas near Lake Superior from western to n central Upper MI are resulting in another incredibly warm early morning for mid Sept. Temps as of 07z are in the upper 60s and lwr 70s F in that area, above the normal high temps at this time of year. Same as yesterday morning, Big Bay is the warm spot. At 75F, the temp there is 1 degree lower than 24hrs ago. Across s central and eastern Upper MI, winds are decoupled, and with mostly clear skies, temps have fallen to the low and mid 50s F at many locations. Patchy, shallow fog is forming again in that area as well. The patchy fog will burn off an hr or so after sunrise. With shortwaves supporting the aforementioned shra/tsra heading ene, don`t expect any pcpn for Upper MI today. Mid morning 850mb temps today are indicated to be about 1C lower than yesterday morning, and this should, in general, translate to highs today being a couple of degrees lower than yesterday. So, expect another unseasonably warm day for mid Sept with highs ranging thru the 80s F with a few spots into the upper 80s F under mainly sunny skies. Southerly winds will hold temps to the 70s F along Lake MI. Record high of 82F here at the NWS office location is very likely to be broken. Low-level air mass today is just a bit drier than yesterday as noted by 850mb dwpt depressions, and this will result in sfc dwpts mixing out a bit lwr than yesterday as well. More areas across the central and e not immediately downstream of the southerly flow off of Lake MI should see dwpts fall thru the 50s with low end near 50F. This will bring RH down into the 30s with low end nearing 30 pct. Fortunately, wind gusts will only be in the 10-15mph this aftn. Still, the lengthening dry spell is becoming an ever greater concern for wildfire potential. Over the last 2 weeks, pcpn has been been less than 50 pct of normal across all but nw Upper MI with large areas at less than 25 pct of normal. && .LONG TERM /TONIGHT THROUGH MONDAY/... Issued at 328 AM EDT Tue Sep 17 2024 Expect the dry and very warm weather to remain over the area early in the extended period before a cold front moves in Thursday night through Friday night and brings some much needed rainfall to the Upper Peninsula. After a quick dry spell early this weekend, expect additional rain chances early next week as a low pressure lifts from the Southern Rockies into the Upper Midwest. High pressure ridging persists over the U.P. tonight into Thursday as a vertically-stacked low continues to lift from the Intermountain West into the Canadian Prairies. The ridging will allow sunny skies and the very warm temperatures to continue through the middle of this week; we could still flirt with tying or breaking the max temperature record in several spots on Wednesday and Thursday, even though we aren`t expected to be as warm as we have been the past couple of days. In addition, with the lack of rainfall over the area, especially over the central and east over the last several days, some fire weather partners may be concerned about some of the fuels continuing to dry-out. Nevertheless, with the high pressure ridging persisting overhead, winds are expected to remain fairly light from the south, and min RHs are expected to remain above 30%. While some shortwave action over northern Ontario may bring some showers and storms to Isle Royale and maybe (10% chance or less) to the Keweenaw Wednesday, outside of that the next couple of days will be perfect if you need to get any outside work done; just be sure to take your water breaks given the sun and heat. Some rainfall looks to return to the forecast Thursday night as a cold front looks to meander it`s way into the western U.P. late overnight. The front continues through the rest of the U.P. Friday and Friday night, bringing showers and some storms across the area. While a sharp drop in temperature isn`t expected with this front, with the additional cloud cover overhead, expect high temperatures to drop a little closer to normal (i.e. the 70s). That being said, we could see some record high min temperature records broken Thursday night and possibly even Friday night over the east given the antecedent warm air ahead of the front and the associated cloud cover. In addition, the rainfall along the slow moving front may bring some much-needed relief to our area, particularly because we haven`t had much rainfall over the past week and we are already experiencing abnormally dry conditions (D0) according to the drought monitor. As for severe weather, none is currently expected given the relatively modest lapse rates and wind shear. While model guidance begins to noticeably spread this weekend and continues increasingly so early next week, we should see a short dry period at least early this weekend as some ridging scoots through the Upper Great Lakes. Nevertheless, the differing model suites do bring a stacked low pressure from the Southern Rockies up into the Upper Midwest by early next week. This low looks to bring some much- needed additional rainfall across the U.P. via a front or two. However, the rain chances and timing are still dependent on the low`s placement and timing. In addition, temperatures look to continue decreasing early next week, with highs now projected to only get into the 60s. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 126 AM EDT Tue Sep 17 2024 VFR conditions should prevail through the TAF period. Patchy shallow fog cannot totally be ruled out at SAW in the 08-12Z timeframe, but probability of MVFR or lower is less than 20%. Southerly winds may gust to around 20 kt at times at IWD/SAW this afternoon. && .MARINE... Issued at 328 AM 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 through Friday night. This front could bring some showers and storms over Lake Superior, as well as some stronger winds above 20 knots as it slowly crawls from west to east. Moving into this weekend, there is some model spread on when a low pressure lifting from the Southern Rockies will arrive over the Upper Midwest (as well as it`s placement). However, we may see winds increase above 20 knots again come late this weekend/early next week as the low approaches. Otherwise, the only other thing we might see is some showers and storms over the northern and western lake tonight into Wednesday as a shortwave lifts across northern Ontario. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...TAP AVIATION...Thompson MARINE...TAP