Marine Forecasts

    EDIT      (on/off)   Help

---

7 Day Forecast for Marine Location Near Spring Lake, MI

   Hourly   EDIT   Help

---

Area Discussion for - Grand Rapids, MI

      (on/off)   Help   NOTE: mouseover dotted underlined text for definition
FXUS63 KGRR 252340 AFDGRR

Area Forecast Discussion National Weather Service Grand Rapids MI 740 PM EDT Fri Sep 25 2020

LATEST UPDATE . Aviation

SYNOPSIS. Issued at 323 PM EDT Fri Sep 25 2020

- One more warm dry day

- Sunday transitions to cooler with rain toward evening

- Monday looks cool and wet

- Lake effect showers and cool rest of week

DISCUSSION. (This evening through next Friday) Issued at 323 PM EDT Fri Sep 25 2020

-- One more warm dry day--

The convection to our northwest will lift east northeast of this area tonight as the warm front pushes north. There may be a little fog toward morning as more moist air, at low levels, moves in around sunrise. There is a lot of wind in the boundary layer so maybe we will get a brief stratus cloud deck instead of fog. No matter what, it will quickly mix out by mid morning.

The surge of colder air, resulting from the digging northern stream shortwave, caused the upper low over over Texas to shear out to our southest tonight. That helps to cause mid level ridging over our area, which in turn causes subsidence at mid level, which in turn dries the air. At the same time a lead shortwave, over Minnesota now, on the northern stream jet, is forced farther north. That is why the convection associated with it will stay well north of here tonight.

As that upstream system continues to move inland height rises are expected over the central CONUS and Great Lakes into Saturday. That will cause Saturday to be warmer than today but still considerable sunshine once the morning clouds mix out. Highs should reach the lower to mid 80s inland.

-- Sunday transitions to cooler with rain toward evening--

The surface front will come through dry early on Sunday as the next upstream shortwave tracking through the digging upstream trough will also lift northeast like tonights will. So, once again no rain expected. It is curious that the NAM12 has strong 1000 to 850 moisture transport into Southwest Michigan after midnight Saturday night. Normally that would mean showers but with the mid levels so dry we are still thinking no rain.

Finally the jet entrance region of that second lead wave, with southwest Michigan being into the cold air by Sunday afternoon as that part of the jet comes into our area, results in enough lift for rain finally develop over most of the area. Most of the rain will be Sunday night into Monday.

-- Monday looks cool and wet--

There is some suggestion that a surface wave will form on the front on Monday in the Tennessee Valley. If that happens we may see enhanced rainfall here in Southwest Michigan later Monday or Tuesday. Any thunderstorms would be in the warm air, well south and east of this area. This would just be rain. The ECMWF and GFS have different solutions with each run and given how hard a time the models have with shortwaves moving through digging troughs, it is to early to say how this will really play out. One thing for sure is Monday will be much cooler than the past week has been.

-- Lake effect showers and cool rest of week--

By Tuesday we get on the cyclonic side of the polar jet as a very impressive 160 to 180 knot jet core dives into the western side of that digging trough over the central CONUS. I would expect a period of showers as that secondary front comes through on Tuesday.

It is possible a second surface low will develop on the front as that stronger jet core reaches the cold front. The question is where does that surface low go? It may track north toward Michigan or it may go up the east coast. No matter what we stay in the cold air with lake enhanced rain showers through at least Friday, if not Saturday. The coldest weather will be Thursday and Friday.

AVIATION. (For the 00Z TAFS through 00Z Saturday evening) Issued at 740 PM EDT Fri Sep 25 2020

VFR conditions will continue through Saturday afternoon. Winds will be south tonight AOB 10 knots with some LLWS possible. Southwest winds on Saturday will gust over 20 knots.

MARINE. Issued at 323 PM EDT Fri Sep 25 2020

Expect 15 to 25 knot winds from the south tonight and southwest Saturday. This will build waves to 3 to 6 feet tomorrow and to 6 to 9 feet tomorrow night. So we will continue our Small Craft Advisory into Sunday afternoon. We added a Beach Hazard Statement since it will be warm enough to go to the beach Saturday.

At this point gales look less likely they are not totally out of the question. There is a developing surface low that tracks into Western Upper Michigan tomorrow night. That may deepen enough to cause gales over northern Lake Michigan. We will just have to see how this plays out.

With the front in the area the pressure gradient loosens so I do not expect winds to be all that strong Sunday afternoon into Monday but if that next wave on the front really develops we could yet have gales Tue/Wed. Something else we will have to watch for. It could be just the strength of the cold advection will drive gales Tuesday into Wednesday. Of course water spouts will have to be watched for too.

GRR WATCHES/WARNINGS/ADVISORIES. MI . Beach Hazards Statement from Saturday morning through Sunday afternoon for MIZ037-043-050-056.

LM . Small Craft Advisory until 2 PM EDT Sunday for LMZ847>849.



SYNOPSIS . WDM DISCUSSION . WDM AVIATION . Ostuno MARINE . WDM

---

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
45161	12 mi	50 min	3.9 G 3.9	66°F	65°F	1 ft	1012.7 hPa
45029	13 mi	30 min	SSE 1.9 G 3.9	67°F	66°F	1 ft	1012.4 hPa	60°F
MKGM4 - Muskegon, MI	13 mi	40 min	S 8 G 8	68°F			1012.1 hPa	58°F
HLNM4 - 9087031 - Holland, MI	21 mi	52 min	SSE 1.9 G 1.9	69°F	66°F		1012.3 hPa	58°F
45168	47 mi	30 min	NE 1.9 G 3.9	67°F	69°F	1 ft	1012.7 hPa	59°F
SVNM4 - South Haven, MI	47 mi	40 min	NE 1.9 G 1.9	71°F
LDTM4 - 9087023 - Ludington, MI	62 mi	58 min	S 6 G 12	71°F				53°F

Wind History for Holland, MI

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

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

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

Last 24hr

SE5

E5

E6

SE5

SE9

SE11 G14

SE11 G16

SE7

SE6 G9

S10

SE10

S9 G12

E2 G5

SE5 G8

S8

S7

S10

S10

S5

SW4

S1

S1

S3

SE2

1 day ago

S8

S7

S9

S10

S9

S10

S7

S10

S11

S12

S10

S9

S10

S9

S12

S15

S16

S14

S12

S13

S10

S8

S8

SE5 G8

2 days ago

S6

S6

S8

S8

S9

S8

S9

S9

S9

S7

SW4

S4

S6

S9

S8

S10

S10

S8

S9

S8

S8

S9

S8

S10

---

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
Muskegon, Muskegon County Airport, MI	9 mi	15 min	SSE 5	10.00 mi	Fair	67°F	54°F	63%	1012.4 hPa
Holland - West Michigan Regional Airport, MI	23 mi	17 min	N 0	10.00 mi	Fair	66°F	55°F	70%	1012.9 hPa

Link to 5 minute data for KMKG

Wind History from MKG (wind in knots)

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

2 PM

3 PM

4 PM

5 PM

6 PM

7 PM

Last 24hr

S4

SE5

SE4

SE7

SE5

SE5

Calm

S7

S4

Calm

E3

SE3

Calm

SE3

S5

S7

SW6

S9

S10

SW10

S11 G17

SW8

SW8

SW4

1 day ago

S4

S3

S4

S3

S4

S4

S4

Calm

Calm

Calm

Calm

S3

SW4

S3

S6

S8

S10

SW13

S11

S11

S10

S10

S8

S5

2 days ago

S4

S4

S4

Calm

Calm

S3

SW3

S3

Calm

Calm

Calm

Calm

Calm

Calm

SW5

4

SW6

SW9

SW9

SW8

SW11

SW10

SW9

S6

---

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 Grand Rapids/Muskegon, MI

   (on/off)   Help

---

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.