Marine Forecasts

    EDIT      (on/off)   Help

---

7 Day Forecast for Marine Location Near St. Clair, MI

   Hourly   EDIT   Help

---

Area Discussion for - Detroit/Pontiac, MI

      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
FXUS63 KDTX 231744 AFDDTX

Area Forecast Discussion National Weather Service Detroit/Pontiac MI 1244 PM EST Sat Jan 23 2021

AVIATION.

High pressure continues to move across the northern Ohio Valley early this afternoon, with northern extent reaching into the airspace and allowing for mainly clear skies with the exception of lingering stratocu at KMBS and KFNT, which has occasionally dipped MVFR at times. Sky attempts to stay mainly clear into the early evening hours before mid/high clouds fill in from the southwest ahead of approaching upper wave that will bring a round of periodic light snow late in the TAF period Sunday after 12z. West/northwest winds 5-10 knots will trend variable overnight for a time before reorienting out of the southeast Sunday.

For DTW . Light snow looks to hold off until after 12z Sunday as southern wing of moisture ascent will take some time to overcome near-surface dry air. Potential will exist for some intervals of MVFR snow towards the end of the period, but confidence not there to include mention at this time.

DTW THRESHOLD PROBABILITIES .

* Low in ceilings below 5000 feet after 12z Sunday.

* High in ptype as snow after 12z Sunday

PREV DISCUSSION. Issued at 358 AM EST Sat Jan 23 2021

DISCUSSION .

Overnight stratus has held on nicely through the early parts of the morning, with rapid erosion of cloud cover now noted via infrared across the Grand Rapids region as mid-level subsidence ahead of surface high pressure currently located over the Midwest. Expecting the continued erosion of stratus to take place (south of the thumb) as high pressure continues to work east into the Ohio Valley by this afternoon. After a very cold start to the morning marked by overnight lows in the teens and wind chills in the single digits, a modest warm up into the mid to upper 20s is expected later today along with some sunshine. As the high pressure tracks east through the evening, low-level flow will back from northwest to southwest. This will usher in low and mid level clouds across the state and will keep overnight lows slightly warmer, holding in the upper teens to lower 20s.

The next chance for light accumulating snowfall will then expand across Michigan throughout Sunday morning (after 6 AM EST) as weak system relative isentropic ascent takes place behind the departing high pressure system. Saturation will initially occur in the mid- levels on the 296-203K surfaces and will have to overcome some initial low level dry air. As the column saturates, expecting light snow to fill on across the state, with slightly better forcing noted across Flint up into the Tri Cities, where likely PoPs hold. Expecting around an inch of accumulation through the early afternoon in and around the Tri Cities, with totals holding under an inch elsewhere (half inch or under for northern Metro region south). Area of best isentropic ascent will then slide into the Thumb during the later part of the afternoon, with snow chances diminishing by the late evening.

Water vapor imagery shows one of the main features of interest for this forecast package, a pv feature just off the coast of California, set to pivot south across Baja California late in the day before ejecting east into TX/OK by early Monday morning. This will result in the development of a low pressure system interacting with a baroclinic zone, set to track north into the Ohio Valley between 00Z Tue - 12Z Tue. Plentiful moisture will eject north across the Ohio Valley and into the Great Lakes ahead of the low pressure system and will bring the likely chance to see accumulating snowfall for portions of SE MI starting late Monday evening into Tuesday morning. Predictability of where the heaviest axis of snowfall (potential for 4+ inches) will fall remains low given it will remain sensitive to both the track of the low and trowal/deformation dynamics. WPC cluster phase space analysis shows the most likely location the axis will fall will be somewhere across southern lower Michigan or south into the northern Ohio Valley. As a result, preliminary forecasted snowfall totals of 3-5 inches will hold over the Metro region down to the Ohio border, with gradually decreasing totals north of this heavier forecasted area. Additional adjustments will be needed as the PV feature comes onshore and is better sampled by the NWS upper-air stations in the coming days.

Last, snow chances are expected to taper off later in the day on Tuesday with high pressure filling in from north to south through the midweek period. This will minimize precipitation chances to end the week while temperature trends remain seasonable.

MARINE .

Northwest winds still gusting up around 25 knots over Lake Huron will gradually diminish today, along with the snow showers. Still, the larger waves over the southern Lake Huron will lag with the unstable near surface profiles. Small craft advisories continue through 11 am for the northern/eastern tip of the Thumb region.

Light and variable winds set up this evening as a ridge of high pressure slides through tonight.

Light southerly flow expected on Sunday as weak low pressure tracks through the northern Great Lakes through Sunday night. A period of light warm advection snow likely in this time frame, but visibility's probably remaining at or above 2 miles.

A much stronger low will lift into the Ohio Valley late Monday, and will lead to increasing east-northeast/onshore flow (up around 25 knots), and small craft advisories may be needed by Monday evening and continued into Tuesday. Snow will likely overspread Lake Erie and Lake St. Clair, and possibly as far north as southern third of lake Huron.

DTX WATCHES/WARNINGS/ADVISORIES. MI . NONE. Lake Huron . NONE. Lake St Clair . NONE. Michigan waters of Lake Erie . NONE.

AVIATION . IRL DISCUSSION . AM MARINE . SC

You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.

---

Weather Reporting Stations

   EDIT       (on/off)   Help   NOTE: Click on distance to see the station location on a map

Stations	Dist	Age	Wind	Air Temp	Water Temp	Waves	Pressure	DewPt
MBRM4 - 9014090 - Mouth of the Black River, MI	11 mi	46 min		25°F			1026.4 hPa
AGCM4	14 mi	46 min		24°F	36°F		1027.5 hPa
CLSM4 - St. Clair Shores, MI	32 mi	76 min	WNW 5.1 G 11	22°F			1029.1 hPa (+1.0)
PSCM4	42 mi	76 min	WNW 8 G 13	21°F			1045.7 hPa (+1.3)

Wind History for Fort Gratiot, MI

(wind in knots)    EDIT      (on/off)   Help

1 PM

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

Last 24hr

NW13 G28

NW9 G18

NW12 G18

NW11 G16

NW8 G14

NW11 G16

NW7 G13

NW6 G17

NW9 G15

NW11 G16

NW11 G14

NW8 G20

NW12 G16

NW10 G17

NW7 G14

NW11 G16

NW9 G13

NW12 G18

NW11 G17

NW5 G13

NW7 G13

NW9 G13

NW6 G11

NW6 G12

1 day ago

W9 G18

W9 G14

W5 G13

W7 G10

W5 G8

W11 G29

W14 G19

W13 G20

NW15 G26

W7 G14

W10 G14

W7 G14

W7 G11

W8 G12

W9 G12

NW9 G19

NW12 G17

NW12 G17

NW12 G16

NW10 G17

NW7 G13

NW9 G21

NW10 G21

NW9 G19

2 days ago

W7 G12

SW8 G14

SW11 G15

SW10 G15

SW14 G18

SW14 G18

SW11 G18

SW15 G21

SW19 G25

SW14 G22

SW12 G22

SW15 G19

SW18 G23

SW11 G22

SW14 G18

SW12 G18

SW11 G22

SW11 G15

SW8 G14

SW9

SW9 G14

SW10 G14

SW10 G13

W11 G15

---

Airport Reports

    EDIT      (on/off)   Help   Click EDIT to display multiple airports. Follow links for more data.

Airport	Dist	Age	Wind kt	Visibility	Sky/Weather	Temp	DewPt	Humidity	Pressure
St Clair County International Airport, MI	8 mi	21 min	WSW 5	10.00 mi	Overcast	23°F	10°F	58%	1027.8 hPa

Link to 5 minute data for KPHN

Wind History from PHN (wind in knots)

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

8 PM

9 PM

10 PM

11 PM

12 AM

1 AM

2 AM

3 AM

4 AM

5 AM

6 AM

7 AM

8 AM

9 AM

10 AM

11 AM

12 PM

1 PM

Last 24hr

NW10 G17

W10 G16

W7

W12 G17

W5

W10 G15

W5

NW10 G14

W8 G17

W10

NW9 G15

W7

W10 G16

NW12 G16

W7

W11

NW8

W5

NW5

W4

W7

NW9

W8

NW8

1 day ago

SW7

SW6

SW5

SW4

SW5

W9 G20

W7 G20

W8 G15

W8

W9 G16

W8

W6

W4

W5

W5

W3

NW9

NW9

NW9

NW9 G15

NW12 G17

NW9 G15

W10 G15

NW10

2 days ago

SW7 G14

SW5

S8 G15

S7

S8 G16

S10 G17

S8

S10 G20

S12 G18

S14 G17

S14 G27

S11 G19

S10 G16

S9 G19

S8 G14

SW6

SW6

SW7

SW6

S6

S5

S6

SW6

S7

---

Tide / Current Tables for

   EDIT   Weekend mode (on/off)   (on/off)   Help

---

Tide / Current Tables for

   EDIT      (on/off)   Help

---

Weather Map

       (on/off)   Help Weather Map

---

GEOS Local Image of    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
Link to Loop

Other links: Northern Pacific     Contential US     Full GOES-East

---

Ground Weather Radar Station

---

Cookie Policy: This website uses cookies to save your settings. No personal information is saved. I do not collect statistics on your visit. You can disable cookies in your browser if you like but it is not recommended for this site. I do not sell cookies. Go to a bakery for that. In fact I do not sell anything. To disable cookies from L-36.com, please refer to the Help button in your browser. Privacy Policy: I do not sell or share any user data or anything else for that matter. The only personal information I save is in the site log which has a line for each page view which includes the IP address your browser sends in the header as well as which page you requested. I use this to block hackers and other bad actors. I do not use this raw data to create profiles on users. I periodically delete the log files. Google supplies the ads on this site. Because I do not track who you are, I cannot customize how these ads are served. They may be personalized to improve the ad experience. If you do not want personalized ads, please adjust the settings on the Google site HERE. NOTE: The best I can determine, this site is not subject to CCPA but I am doing my best to comply anyway. Disclaimer: The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerous of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.