Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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642 FXUS63 KMQT 030942 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 542 AM EDT Fri May 3 2024 .KEY MESSAGES... - Active pattern continues through next week as a series of low pressure systems track across the U.S. and affect Upper MI. Above normal precipitation expected, including chance of thunderstorms at times. - Mostly above normal temperatures expected, generally 5 to 10 degrees above normal on the majority of days thru the middle of next week. && .SHORT TERM /TODAY/... Issued at 504 AM EDT Fri May 3 2024 Current water vapory imagery/RAP analysis highlight a well-defined shortwave rotating over the MN/Canada border with its associated occluded front already well into Upper Michigan. As expected, showers have quickly tapered off with frontal passage with the only activity on latest radar mosaic concentrated over the easternmost portions of the UP. And, even these should taper off by mid- morning. So far, convective activity has been non-existent, but still cannot rule out a few rumbles of thunder over the far eastern counties after sunrise. Most of the forecast area will be sunny this morning as forecast soundings trend toward a dry column. The exception will be the eastern third of the UP where it will take a bit longer for the moisture/cloud cover to clear out. Gusty southwest winds in the 20 to 30 mph range, especially across the western UP will contribute to rapidly falling dew points and temperatures climbing into the upper 60s/low 70s (inland). Recent rainfall will, however, mitigate today`s fire weather threat. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Issued at 542 AM EDT Fri May 3 2024 Overall, the first half of the extended period (tonight through Monday night) is mostly dry and sunny as high pressure tracks across the area with just a brief chance for rain showers on Saturday. Elevated fire wx conditions may occur each day Sat - Mon, but are more likely on Sunday and Monday when sunny skies help us dry out. On the other hand, we return to a pattern with frequent rain chances for the Tuesday thru Friday time frame as a broad area of low pressure spins across the region. There are early signals for a prolonged stretch of drier weather starting the weekend of May 11/12, but temperatures appear to average near normal at this time. Starting with tonight, weak surface ridging to our east results in light southerly flow with upper level cloudiness spreading across the western UP overnight. Mostly clear skies across the east should allow for good radiational cooling into the upper 30s away from downsloping along the Lake Superior shoreline. The next weather maker approaches Saturday morning and most guidance suggests a weak but deepening surface low. Rain chances spread across the western UP during the morning which keeps high temps cooler (around 60F) compared to the central and especially the east where highs approaching 70F are forecast. Warmer temps/deeper mixing across the east within the dry pre-frontal air mass suggests potential for locally elevated fire wx conditions. It`s worth noting that both NAM and GFS soundings show single digit RH values in the mid-level dry layer that we`ll be mixing into. Increasing cloud cover should limit mixing potential, but conditions appear to be trending more volatile across the east ahead of Saturday`s rain chances. The cool front and associated rain chances spread across the central and eastern UP during the afternoon and evening, respectively. The NAM-3km even delays precip at Newberry until around midnight or 3-5 hours later than the GFS. HREF ensemble mean MUCAPE remains less than 100 J/kg, but HRRR simulated radar indicates an increasingly convective pattern as showers track east across the area. Overall, the forecast may still exaggerate the rain potential with this system since model soundings only show a 3-6 hour window of rain chances at any one location. Limited instability and duration indicate light amounts are most likely. Dry high pressure settles across the area on Sunday allowing sunny skies to spread across the area during the morning hours. In fact, CAMs suggest potential for fog resulting from moisture lingering in a boundary layer inversion beneath clearing mid/upper level clouds. A more straight-forward radiation fog setup could materialize Sunday night under high pressure, clear skies and light winds. Otherwise, fire weather is the primary concern for the Sunday-Tuesday period. Sunday and Monday are both likely to see min RH dipping below 30% across the interior, but light winds temper the fire wx threat. Stronger winds are expected on Tuesday and if the dry air mass lingers a bit longer then Tuesday likely represents a more volatile combination of low RH and winds. However, that possibility depends on rain chances being delayed until late in the day which current model blends do not indicate. Late week rain chances are associated with a deep closed low developing across the Northern Plains late on Monday that slowly spins eastward over the subsequent week. Moderate rainfall and embedded thunderstorms are again possible with the warm front passage Tuesday/Wednesday followed by spottier showers Thursday/Friday. A cold core upper low suggests a large diurnal component to the late week shower activity. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 124 AM EDT Fri May 3 2024 IFR/LIFR conditions will continue overnight. Easterly upslope flow at SAW and CMX will result in LIFR prevailing longer than IWD. Expect improvement to VFR at all terminals as a west-southwest wind develops in the wake of the system`s cold front moving across the area. First will be at IWD by later tonight and by morning at CMX and SAW. && .MARINE... Issued at 542 AM EDT Fri May 3 2024 Light winds, mainly out of the south-southeast are currently being observed across Lake Superior and winds are expected increase while veering southwesterly today. While gusts up to 25kt are expected over western Lake Superior this afternoon, winds diminish to less than 20kt tonight. Expect winds mostly below 20kts across Lake Superior this weekend, but northwesterly winds increase to around 20 knots Saturday night behind a cold front before becoming light again on Sunday. High pressure that arrives over the Upper Great Lakes late this weekend shifts eastward on Mon while a deep low pressure emerges over the western Dakotas. This will result in increasing easterly winds late on Mon into Tue when gusts up to 30kts are expected. Patches of locally dense fog are occuring over western Lake Superior this morning, which is expected to push mainly into Canadian waters as south/southwesterly winds increase today. If fog does not clear off of the lake today then additional rain chances on Saturday may result in increasing fog coverage. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...TDUD LONG TERM...EK AVIATION...07 MARINE...EK