Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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766 FXUS63 KMQT 310523 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 123 AM EDT Fri May 31 2024 .KEY MESSAGES... - Seasonably mild temperatures expected through the weekend. - Scattered showers and isolated thunderstorms possible in the west Friday, and across the UP Saturday, although it will not be a washout. - More widespread showers and thunderstorms expected Sunday night into Monday. && .SHORT TERM /THROUGH TONIGHT/... Issued at 117 PM EDT Thu May 30 2024 Shortwave ridging at midlevels is located along the Upper Mississippi into Ontario, between troughing over the northern Rockies and Northeastern US. This configuration is ideal for subsidence over the local area with high pressure centered near the Door Peninsula. A dry airmass was sampled by the 12Z KGRB/KAPX RAOBs, measuring PWATs of 0.32 and 0.22 inches, respectively. This has resulted in a clear and dry day with a quick warm-up from chilly morning lows. Lake breezes have kicked up and are keeping areas adjacent to the Great Lakes cooler, although CAMs suggest the strengthening southerly gradient on the back side of the highs will limit inland penetration for areas roughly west of Marquette County. Northern Rockies troughing shifts east a bit tonight, but the lead shortwave will take a more northeasterly track into the Canadian Prairies, which will limit the overall eastward push of the better moisture and forcing. Still, a plume of 1" PWATs is expected to approach the western UP by 12Z Friday, and convergence along the weakening low-level cold front will allow some showers to approach that area late tonight. Meanwhile in the east, it looks like another good radiational cooling night with a small area of PWATs around 0.20" forecast. Went toward the NBM10 percentile there with lows in the upper 30s interior east and south, while the continued southerly gradient and increasing clouds will likely keep lows elevated in the 50s for the west. && .LONG TERM /FRIDAY THROUGH THURSDAY/... Issued at 337 PM EDT Thu May 30 2024 Midlevel ridging continues to shift east of the area Friday into Saturday, while anomalous closed low remains relatively stationary over the northern Prairie Provinces. At lower levels, an area of confluence between airflows on the back side of the retreating high and the cyclonic circulation around the Prairies low will remain more or less stationary, wavering over the western and at times central UP. This area of confluence is collocated with a plume of 1- 1.25" PWATs. A few showers will be around over the west on Friday, but overall weak forcing should limit coverage. Meanwhile in the central and east, another pleasant day is expected with slightly warmer highs ranging through the 70s (although staying in the 60s to the lee of Lake Michigan). Forcing increases Friday night into Saturday morning over the west as the right entrance region of the upper jet becomes favorably positioned over the area. On Saturday, the confluent zone and moisture plume expand somewhat to the east, and so too will the coverage of showers and isolated storms. However, the thinning moisture plume, overall fairly weak forcing, and meager instability will mean that it won`t be a washout, and the rain may be more of a minor nuisance than anything. With increased clouds, highs around 70 can be expected. QPF totals should mainly be insignificant, but the 90th percentile of the HREF suggests that some isolated spots in the west could see up to an inch due to possible repeated rounds of rainfall Friday into Saturday. The pattern becomes more zonal on Sunday as the last in a series of shortwaves lifts northeast of the area. This should put us in a lull in terms of forcing and a dry day is expected, with southerly flow boosting highs back in the mid to upper 70s (aside from the Lake Michigan shoreline). Will then watch the potential for a complex of showers and storms firing over MN Sunday evening to push into the UP Sunday night. Sunday night into Monday will be the highest probability of precipitation during the forecast. Some stronger storms cannot be ruled out as deep layer shear looks good and there will likely be some decent low-level moisture return with dewpoints increasing into the 60s by Monday. A dry day is favored Tuesday in the wake of this system, while another trough could generate more showers and storms by the middle of next week. This trough may cut off and linger for the 8-14 day period, with CPC favoring below normal temperatures during this timeframe, although there is uncertainty if the cutoff low will remain over the Great Lakes (EPS mean) or push further into the Northeast (GEFS mean). && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 123 AM EDT Fri May 31 2024 VFR conditions are likely to continue through the TAF period. Moisture will increase from the southwest late tonight into Friday at IWD and CMX with cigs lowering to 4-5kft under isolated showers by late Friday morning into early afternoon. A period of low-level wind shear is expected between roughly 07-14Z at IWD as southwesterly winds increase to around 40kt between 1-1.5kft AGL. && .MARINE... Issued at 337 PM EDT Thu May 30 2024 High pressure slides to the east tonight into Friday, resulting in winds becoming southerly, but stability and a fairly weak gradient should keep winds less than 20 kt. There is a slight (20%) chance of thunderstorms at times Friday into Saturday, with a better chance (30-50%) Sunday night into Monday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Thompson LONG TERM...Thompson AVIATION...Voss MARINE...Thompson