Sunrise 5:57 AM   Sunset 9:10 PM Moonrise 3:14 PM   Moonset 2:56 AM

  Print   HELP   Reset   Save   Recall  New

LSZ322 St. Marys River Point Iroquois To E. Potagannissing Bay- 324 Am Edt Sat May 18 2024
.the st marys river system is closed to vessel navigation - .
the st marys river system is closed to vessel navigation due to dense fog. The fog is likely to continue through Sunrise before slowly lifting.
precautionary/preparedness actions - .
dense fog was reducing visibilities to below 1/2 mile. Reduce your speed, and keep a lookout for other vessels, buoys, and breakwaters. Keep your navigation lights on. If not equipped with radar, you should consider seeking safe harbor.
lat - .lon 4653 8413 4624 8411 4606 8396 4606 8390 4612 8382 4612 8364 4591 8386 4592 8396 4612 8417 4624 8436 4628 8430 4643 8436 4637 8452 4648 8466 4652 8463 4646 8456 4645 8448 4651 8438 4649 8427 4654 8420

LSZ300
No data

FXUS63 KAPX 181737 AFDAPX

Area Forecast Discussion National Weather Service Gaylord MI 137 PM EDT Sat May 18 2024

KEY MESSAGES

- Warm today.

- Chance of showers and embedded thunderstorms tonight into Sunday.

- Additional chances for showers and storms Monday through Wednesday with the potential for stronger storms Tuesday night.

UPDATE
Issued at 833 AM EDT Sat May 18 2024

Fog/stratus is eroding in the interior, but near Lk Huron is going to considerably more stubborn. Have extended the dense fog advisory for the coastal counties until 11 am. Also added eastern Mack Co to this, given poor conditions on webcams in the Straits area. Inland counties still expire at 9.

SHORT TERM /THROUGH TONIGHT/
Issued at 232 AM EDT Sat May 18 2024

Pattern Synopsis/Forecast: Broad warm southerly flow anticipated today in advance of low pressure currently centered over southern Manitoba. This low treks northeast to south of Hudson Bay by this evening with a cold front set to cross northern Michigan northwest to southeast tonight into early Sunday morning.

Forecast Details: Late night/early morning stratus and locally dense fog continues to expand across eastern upper and northeast lower. This should be fairly quick to burn off in most spots this morning, but may linger towards midday in eastern Chippewa/Mackinac counties. Otherwise, lots of sunshine and warm temperatures with high temps away from the Great Lakes in the low-mid 80s. Perhaps even a few upper 80s in southwesterly downsloping locations. Mainly 70s at the coasts and in the eastern U.P.

LONG TERM /SUNDAY THROUGH FRIDAY/
Issued at 232 AM EDT Sat May 18 2024

Pattern Synopsis / Forecast: Sporadic unsettled conditions will litter the forecast to close out the weekend as a shortwave races through the upper Great Lakes, leading to a cold front passing through northern Michigan Saturday night into Sunday. This front will become more "strung out" as flow more parallel to the boundary stunts the south and eastward advance of the front. Nonetheless, expectation is that enough instability will be present to force some showers and perhaps some thunder later Saturday night.
Aforementioned front looks to more or less stall / wash out farther downstate, leaving a pool of low level moisture closer to Saginaw Bay that could drum up additional showers and storms in that area on Sunday. Weather next week will be dictated by an ejecting / digging shortwave trough into the central Plains, and associated surface cyclogenesis. There is potential for this system to track into the upper Midwest as a deepening surface low, which, would conceptually draw in rich Gulf moisture on Tuesday, and with the passage of any associated frontal boundaries, presents an additional chance for showers and storms, but there is much uncertainty to be had with the evolution of this potential system. As far as temperatures go, looks like abundant southwest flow aloft will keep things Summer-like into the beginning of next week before a cooler surge of air is set to intrude behind the early week system as we progress past midweek.

Primary Forecast Concerns:

Saturday Night Unsettled-ness: Big show (at least in the Great Lakes) will be across Wisconsin / Western Yoop along the approaching frontal boundary, as a pronounced area of thunderstorms (some severe) erupt during peak heating. As this front approaches, it will be losing steam from a forcing standpoint. Couple in with a more nocturnal passage of the front, this doesn't exactly spell an overly robust outburst of convective development. CAMs seem to point toward some semblance of elevated instability (250-500 J/kg MUCAPE), which would support some shower and perhaps thunder development late Saturday night (maybe into early Sunday morning)... highest PoPs in the eastern Yoop owing to better forcing proximity, best chances across northern lower favor north and west of an HTL to APN line.
Quite the mild night as well... expecting lows in the mid 50s to lower 60s across the board, wouldn't be shocked to see some spots struggle to get much below 65 if more widespread showers do not materialize.

Sunday: Signal for a lack of moisture scouring out in the vicinity of Saginaw Bay remains during this forecast cycle. Owing to strong differential heating between the land and colder Great Lakes (highs in the 70s and 80s over land, water temps in the 40s) suggests lake breezes will not hesitate to get going Sunday. Couple this with a light WNW to NW wind, convergence zone will be maximized along Saginaw Bay. With the development of ~500J/kg of CAPE, should be enough to initiate some showers and thunder south and east of an HTL to APN line. Will maintain PoPs from previous forecaster in that area.

Monday - Tuesday: Digging trough into the Plains will drum up deep moisture return into the Ohio Valley, surging into the Great Lakes with time as well. Focus for this will be south of the dilapidated stationary frontal boundary, which, with the advent of more southerly flow, should be enough to force the front back northward into the upper Great Lakes region through Monday. Progressive WSW to ENE 500mb flow will allow for convectively charged waves to ride the front... guidance seems honed in on a particular wave Monday evening into early Tuesday, which could present the next shot at showers and storms. Attention then turns to a potential surface low passing into the vicinity of western Lake Superior... a noted climatological signal for severe potential across the APX footprint. As guidance stands for now, another nocturnal cold frontal passage looks to be in the cards, but with much better forcing this time around. Still a setup to watch for severe weather across the region, but overall, the better potential for severe (at least more widespread / higher end activity) favors the WI/IL/IA owing to instability coinciding with peak heating. Nonetheless, with as much forcing as guidance is spitting at me via the computer screen, the scenario presented of a linear convective mode surging into portions of the CWA remains a possibility at this juncture. Following the passage of this cold front, more seasonable air is set to build in midweek and beyond, with highs falling from the 70s and 80s to the 50s and 60s after midweek.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
Issued at 137 PM EDT Sat May 18 2024

A weakening cold front will advance into the are tonight.
Sct showers and perhaps an embedded TSRA will accompany this.
Some fog/stratus likely to return late overnight CIU/PLN/APN, though we aren't expecting things to be as soupy as this morning. Otherwise VFR.

Onshore lake breezes this afternoon. Light winds tonight, a bit of a nw breeze Sunday.

APX WATCHES/WARNINGS/ADVISORIES
MI...None.
MARINE...None.

toggle option: (graph/table)

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Gaylord, MI,