Sunrise 6:08 AM   Sunset 9:23 PM Moonrise 4:29 PM   Moonset 3:21 AM

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LSZ249 Expires:202405122228;;102540 Fzus73 Kmqt 122220 Mwsmqt
marine weather statement national weather service marquette mi 620 pm edt Sun may 12 2024
lsz248-249-265-122228- /o.can.kmqt.ma.w.0002.000000t0000z-240512t2245z/ 620 pm edt Sun may 12 2024
.the special marine warning is cancelled - .
the affected areas were - . Huron islands to marquette mi - . Lake superior west of line from manitou island to marquette mi beyond 5nm from shore - . Marquette to munising mi - .
the Thunderstorm has weakened and no longer poses a significant threat to boaters, although there could still be a stray lightning strike or two occurring from shot point eastward in the next half hour.
&&
lat - .lon 4648 8702 4644 8724 4648 8739 4658 8751 4664 8750 4663 8729 4657 8728 4659 8713 4662 8704 4661 8695 4657 8690 4655 8683 4660 8674 4642 8678 4640 8690 time - .mot - .loc 2216z 278deg 31kt 4652 8722

LSZ200
No data

FXUS63 KMQT 192012 AFDMQT

Area Forecast Discussion National Weather Service Marquette MI 412 PM EDT Sun May 19 2024

KEY MESSAGES

- Elevated fire weather conditions continue through this evening, especially on the Keweenaw and across the eastern UP.

- Showers and isolated thunderstorms Monday, especially in the morning and early afternoon.

- Strong storm system will bring rain and thunderstorms late Tuesday into Tuesday night.

- Windy conditions develop behind the system on Wednesday.

SHORT TERM /THROUGH TONIGHT/
Issued at 411 PM EDT Sun May 19 2024

Abundant morning sunshine is giving way to upper level clouds streaming northeast across Upper Michigan. Increasing clouds suggests high temperatures have already occurred as of 330 PM with values ranging from the upper 60s to mid 70s. Winds and humidity have varied substantially across the area today with Houghton consistently gusting near or above 30 mph since sunrise whereas Escanaba has stayed at or below 10 mph all day. To make matters worse, dew points have mixed about as low as forecast with values below 20% across the eastern UP and below 30% elsewhere. The combination of stronger than expected winds and low RHs has increased fire weather concerns and resulted in a special weather statement issuance for the Keweenaw and eastern UP. Fortunately, winds diminish and RH recovers quickly as we lose surface heating this evening.

The area of high pressure that brought sunny skies to the UP today slides east tonight allowing for increasing albeit still light southerly winds. The combination of increasing clouds and southerly flow implies temps may struggle to cool below 50F tonight, especially for the southerly downslope areas that may stay in the mid/upper 50s. The other feature of interest is an approaching upper level shortwave that spreads northeast across the area on Monday.
However, rain chances don't arrive until the very end of the short term and thunder is not expected with the early morning rain.

LONG TERM /MONDAY THROUGH SUNDAY/
Issued at 350 PM EDT Sun May 19 2024

Southwesterly midlevel flow between deepening troughing over the northern/central Rockies and ridging extending form the Deep South through the Northeast will result in the preferred storm track being located over the local area through midweek. This will lead to periods of rainfall through at least Wednesday. Shortwave ridging favors a drier period to end the week Thu/Fri, with precip chances reentering the picture to start the holiday weekend Saturday. Aside from a brief cool-down Thursday, temperatures look to average near to slightly above normal for the upcoming week into the start of next weekend.

Initial shortwave of concern looks to touch off convection over the Central Plains today, and may itself be convectively enhanced as it ejects northeastward to the upper Great Lakes by Monday. Low-level jet strengthening to 30-40 kt at 850 mb will enhance moisture transport into the region, with PWATs increasing to 1.25-1.50 inches, or +1 to +2 stdev. High confidence in an area of rainfall continuing over the western UP by the start of the period (12Z/7 am CDT Mon), continuing into the central UP by mid-morning, and likely reaching the eastern UP by early afternoon. Although a couple rumbles of thunder will be possible, the corridor of better instability should remain well to the south. Confidence is lower on what happens during the afternoon and evening hours. It's reasonable to expect some subsidence on the back of this initial wave to dry things out for the afternoon, especially west/central. However, some CAMs, namely the 12Z.19 NAM3 and HRW-ARW have a trailing convectively- generated wave bringing in another round of rainfall for the afternoon central and east. Reduced PoPs a bit here for the afternoon/evening as I feel that this scenario is not the most likely. Forecast soundings suggest some lower clouds may linger through the day which would limit surface-based instability to redevelop; however, should the convectively generated wave materialize, some elevated convection would be possible. Monday night should be quiet and partly to mostly cloudy in the wake of Monday's rain.

Tuesday morning will start out quiet, then attention turns to the highest potential impact portion of the period, late Tuesday into Wednesday. The culprit is a negatively tilting, vigorous shortwave trough ejecting out of the central Plains into northern MN/Lake Superior. This will foster an unseasonably strong cyclone. The 00Z NAEFS mean has this low bottoming out at 996 mb near the Keweenaw at 12Z Wed, which is below the 1 percentile relative to climatology.
However, the 12Z EPS/GEFS mean have this low at 992 mb, and several members (and the 12Z ECMWF) have this low down in the mid/lower 980s, which is highly anomalous for this time of year. There is still considerable uncertainty on the track, with generally a stronger storm favoring a westward and slightly slower track.
Regardless, this storm will feature incredibly strong dynamics and moisture transport, with PWATs likely above 1.50 inches Tuesday night. Showalter values go negative Tuesday night as steeper midlevel lapse rates move in. With at least modest instability coupled with very strong wind shear, there is potential for large hail along with heavy downpours, as SPC has included portions of the central and southern UP in a Slight Risk (level 2/5). Thinking it's unlikely that we get into the warm sector with model soundings showing convection being elevated, especially as the strongest forcing is likely to arrive after sunset, so wind threat is more uncertain at this time. Heaviest rainfall looks to favor the western UP, with EPS probabilities of 2"+ at 20-30%. However, potential for a more widespread flooding event should be mitigated due to ongoing drought conditions in the region.

A westerly track of the system (e.g., 12Z ECMWF) would open the door for synoptic-scale wind concerns on Wednesday in the favorable location beneath the midlevel dry slot. If low-level moisture scours out, strong mixing could occur and tap into the strong low-level wind field. ECMWF EFI values exceeding 0.8 signify potential for unusually strong winds. EPS mean wind gusts are widespread 40 kt here. Something to monitor in the coming days, and will wait until storm track becomes more certain to message this threat more strongly.

Cold advection on the back side of this system will keep things on the cool and dry side for Thursday, with a modest warming trend Friday and the next system possibly (40-60% chance) bringing rain back Friday night into Saturday.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/
Issued at 225 PM EDT Sun May 19 2024

VFR cigs/vsby prevail through this evening at all terminals. Gusty west winds continue at CMX until closer to sunset when light and variable winds spread across all terminals. Conditions deteriorate late tonight into Monday morning as a wave of rain and perhaps a few embedded thunderstorms lifts north across Upper Michigan. Model guidance drops cigs down to IFR/LIFR on Monday as this area of rain moves through and am most confident in this occurring at CMX/SAW due to east/southeasterly upslope flow.

MARINE
Issued at 350 PM EDT Sun May 19 2024

With the exception of some locally higher gusts of 20-30 kt along the tip of the Keweenaw and in the vicinity of Isle Royale through early this evening, winds should remain around 20kt or less through Tuesday morning. Main period of interest is Tuesday afternoon through Wednesday as an unseasonably strong low pressure system tracks from the central Plains across Lake Superior and into southern Ontario. There are still important model differences that will dictate peak wind speed and direction, but right now the highest probabilities for northeasterly gales are Tuesday night over the western and north-central part of the lake, with 30-60 kt probabilities here. Winds remain elevated as they shift to a westerly component on Wednesday with 25-30 kt expected. If the low track ends up being further west than anticipated, Tuesday night northeasterly gales would be less likely, but Wednesday southwesterly gales would be more likely, possibly lingering into Wednesday night.

MQT WATCHES/WARNINGS/ADVISORIES
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.

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