Sunrise 6:38 AM   Sunset 8:55 PM Moonrise 12:00 AM   Moonset 7:17 AM

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LSZ249 115 Pm Edt Tue Apr 23 2024
a marine weather statement has been issued for the following areas - . Lake superior east of a line from manitou island to marquette mi and west of a line from grand marais mi to the us/canadian border beyond 5nm from shore - . Marquette to munising mi - . Munising to grand marais mi - .
at 114 pm edt, doppler radar indicated a cluster of strong Thunderstorms, capable of producing winds to around 30 knots and small hail. The leading edge of these Thunderstorms were located over shelter bay, moving east at 20 knots.
precautionary/preparedness actions - .
mariners can expect gusty winds to around 30 knots, locally higher waves, and lightning strikes. Boaters should seek safe harbor immediately until this storm passes.
&&
lat - .lon 4648 8702 4647 8712 4654 8714 4669 8651 4653 8642 4640 8663 4640 8671 4643 8677 4640 8690

LSZ200
No data

FXUS63 KMQT 270541 AFDMQT

Area Forecast Discussion National Weather Service Marquette MI 141 AM EDT Sat Apr 27 2024

KEY MESSAGES

-Low pressure systems bring light to moderate rain tonight into Saturday.
-Marginal risk for a few strong thunderstorms capable of hail and gusty winds south-central and east Saturday afternoon and evening, but confidence is low.
-Active pattern continues, with multiple low pressure systems bring chances of precipitation virtually all of Saturday night through next Thursday night.
-The WPC has issued a Marginal Risk of Excessive Rainfall Sunday into Monday for around an inch of rainfall across the UP.

SHORT TERM /THROUGH SATURDAY/
Issued at 432 PM EDT Fri Apr 26 2024

Visible satellite shows high clouds continuing to filter in ahead of the next low pressure system currently centered over NE as noted on RAP analysis and WV imagery. Lingering mid level ridging and the departing high pressure to our east set up another day of above normal temps in the 50s to low 60s. While some spots in the west could warm an additional degree or two into the mid 60s with downsloping flow, peak afternoon temps will occur within the next hour. The mixing this afternoon has brought southwest gusts to 20-30 mph across the UP with RHs in around 20-25% over the west with 25- 40% over the east and in the Keweenaw. This will continue elevated fire weather conditions into the early evening.

The 4/26 12z HRRR has the sfc low around 992 mb over northeast NE at 0z Saturday, continuing northeast tonight toward northwest WI by 12z Saturday as it weakens to around 1000mb. Isentropic ascent will eventually support showers lifting northeast across the UP this evening once the dry air is eroded. Better PVA arriving after 6z Saturday with the mid level shortwave reinvigorates showers and possibly weak elevated convection tonight. MUCAPE peaks around 250- 500 j/kg and bulk shear is around 30 kts as a LLJ lifts into the area, so no severe weather is expected. Lows are expected in the 40s.

The sfc low continues to weaken on Saturday as it moves northeast across Lake Superior to northeastern Ontario. Moisture surges north from the Gulf of Mexico into the Upper Great lakes moisture, mid level lapse rates approach 7 C/km, MLCAPE is around 300-600 j/kg (the NAM is higher around 600-1200 j/kg), and bulk shear of 50-60 kts. This set up is more than adequate for organized updrafts and stronger storms. That being said, there are a few problems regarding storm development. Destabilization may be negated by a mid-level capping inversion, especially with lingering showers and cloud cover. Also, the consensus of CAMs show the stronger convection developing along the cold front once the frontal boundary is already southeast of the UP. Overall confidence in severe thunderstorms in our CWA is low, but the best chances are located along Lake Michigan. Highs are expected above normal in the 60s to low 70s, but could get higher over the south central given more clearing during the day. Gusty southwest winds to 20-30 mph are also expected in the afternoon and evening.

LONG TERM /SUNDAY THROUGH FRIDAY/
Issued at 407 PM EDT Fri Apr 26 2024

The active weather pattern of late shows no signs of stopping through the next week. By Saturday night, a handful of 500mb troughs of various lengths are expected over the CONUS, which of most note to interests in Upper Michigan are a departing trough over Lake Superior and the next upstream trough, an anomalously deep (-13 dam per 12Z GEFS) trough over the Four Corners region. Lagging showers from the departing system will keep low PoPs in the forecast Saturday night before the western trough negatively tilts and races northeast to the Upper Great Lakes basin for the end of the weekend and the beginning of next week. Attention then turns westward again as an anomalous trough races along the USA/Canada border through the early week and has ramifications on the precipitation pattern for the middle of next week and beyond.

Saturday night, the trough affecting the weather earlier in the day will be lifting into northern Ontario, leading to height rises over the Upper Peninsula. This will act against any ongoing lingering showers, but enough remaining shortwave energy and orographic uplift from the northerly flow will keep some slight chance PoPs (15-30%)
in the forecast. GEFS mean precip in that time period is only a couple of hundredths, so any showers that linger will be light in nature.

Sunday morning, ahead of a 500mb trough exiting the Rockies, a near- 1000mb low pressure will be over the Central Plains. Isentropic upglide ahead of the lifting warm front will bring gradually increasing PoPs throughout the day. The warm front of the low should arrive around Sunday evening with the cold front passing Monday evening as the low transits through the Upper Great Lakes at around 1005 mb. Following strong 850mb CAA in the morning, Sunday will be the coldest day of the week, with gridded MOS guidance showing highs only in the 40s and lower 50s. ECMWF EFI SoT between 0 and 1 by Monday indicates the potential for an unusually high precipitation total potential. The NAEFS climatology percentiles for vapor transport, PWAT, and humidity are all in the 90-99.5th percentile range through late Monday, leaving the ingredients for some higher QPF forecasts. Ensemble forecasts do have a somewhat high spread, but the range of plausible forecasts (80% probability) is between a half inch of rain and 2 inches of rain by Monday night, leading to the WPC issuing a Marginal Risk of Excessive Rainfall. A few rumbles of thunder are also possible, with the GEFS and Canadian ensemble showing generally up to 700 J/kg of SBCAPE especially on Monday.

Ensemble spread increases significantly following the passage of the system by Tuesday, but the general idea is that a trough passing along the USA/Canada border will support a low pressure tracking just north of Lake Superior which should support rain showers roughly in the late Tuesday/early Wednesday timeframe. Another system could pass in the Thursday timeframe, but NBM PoPs of only 15- 30% highlight the uncertainty in the timing and location of such a system. Confidence is increasing that ridging will build over the region for next weekend, giving at least some period of time for the UP to dry out. Soils could be particularly soggy by then, as the GEFS accumulated QPF by the end of next week ranges from 1 to 4 inches.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
Issued at 136 AM EDT Sat Apr 27 2024

Shra will be overspreading the area overnight as low pres approaches. Might be thunder as well, but confidence is low on whether IWD/CMX/SAW will be affected, so mention was not included in fcst. Expect a transition to MVFR in the 06-09Z time frame with higher confidence now in further deterioration to IFR after 12Z. A period of LIFR also cannot be ruled out from late morning through the afternoon, but that is lower confidence. Slight improvement to MVFR will be possible by this evening, but that will be best case scenario. Meanwhile, LLWS will be a threat at all TAF sites in the 06-18Z time frame due to an associated low-level jet. And, strong southeasterly surface winds (becoming west-southwesterly) this afternoon will gust to 28 kts. Eventual wind direction will be northwesterly by this evening.

MARINE
Issued at 530 AM EDT Fri Apr 26 2024

Southeast winds gusting up to 25 mph are occurring early this morning with the strongest winds across the east half of the lake.
Southeast winds increase up to 30 knots across the eastern lake Friday afternoon. A few gale force gusts up to 35 knots are possible near the tip of the Keweenaw and the international border through Saturday morning. A low pressure tracks across Lake Superior on Saturday resulting in a period of light and variable winds. Cold air advection increases Saturday night resulting in northerly winds gusting up to 30 kts across north-central portions of the lake.
Another low pressure approaches Lake Superior on Sunday causing winds to back northeasterly and increase to gales across the far western lake. Winds back easterly Sunday night as gales spread across all but far eastern Lake Superior. A local office tool indicates 60-90% chances for 40-45 kt gales across the far western lake Sunday afternoon and evening with lower 25-50% chances across the north-central lake. Gales are forecast to subside on Monday as the low's center lifts across Lake Superior. Winds become west- southwesterly Monday night while decreasing to 20 to 25 knots. Light winds less than 20 knots prevail Tuesday then another system moving through Tuesday night and Wednesday increases west winds to around 25 kts.

Thunderstorms are possible over portions of Lake Superior tonight through Saturday evening then again Sunday evening through Monday evening.

MQT WATCHES/WARNINGS/ADVISORIES
Upper Michigan...
None.
Lake Superior...
Gale Watch from Sunday morning through Monday morning for LSZ162.

Gale Watch from Sunday evening through Monday afternoon for LSZ242>246-264>266.

Small Craft Advisory until 6 PM EDT this evening for LSZ244- 245-249-250.

Small Craft Advisory until 2 PM EDT this afternoon for LSZ246.

Small Craft Advisory until 8 AM EDT this morning for LSZ248.

Small Craft Advisory until 8 PM EDT this evening for LSZ251.

Gale Watch from Sunday afternoon through Monday afternoon for LSZ263.

Lake Michigan...
Small Craft Advisory from 5 AM early this morning to 8 PM EDT this evening for LMZ221.

Small Craft Advisory from 7 AM this morning to 5 AM EDT Sunday for LMZ248.

Small Craft Advisory from 5 AM early this morning to 5 AM EDT Sunday for LMZ250.

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