Thursday, August17, 2017 L-36.com


Marine Weather and Tides
Pentwater, MI

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.

Sunrise 6:52AMSunset 8:45PM Thursday August 17, 2017 7:31 AM EDT (11:31 UTC) Moonrise 1:22AMMoonset 4:31PM Illumination 23% Phase: Waning Crescent; Moon at 25 days in cycle
NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.
Marine Forecasts
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LMZ848 Whitehall To Pentwater Mi- 357 Am Edt Thu Aug 17 2017
.small craft advisory in effect from noon edt today through Friday evening...
Today..South winds 15 to 20 knots. Showers and Thunderstorms likely until midday, then partly Sunny with a chance of showers and Thunderstorms in the afternoon. Waves 3 to 5 feet.
Tonight..West winds 20 to 25 knots. Mostly cloudy with a chance of showers. Waves 5 to 7 feet.
Friday..West winds 15 to 25 knots. Mostly cloudy. A slight chance of showers until midday. Waves 5 to 7 feet.
Friday night..Northwest winds 10 to 15 knots. Partly cloudy. Waves 2 to 4 feet subsiding to 1 to 3 feet after midnight.
LMZ848 Expires:201708171515;;510052 FZUS53 KGRR 170757 NSHGRR Nearshore Marine Forecast National Weather Service Grand Rapids MI 357 AM EDT Thu Aug 17 2017 For waters within five nautical miles of shore on Lake Michigan LMZ848-171515-

7 Day Forecast for Marine Location Near Pentwater, MI
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location: 43.78, -86.43     debug


Area Discussion for - Grand Rapids, MI
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Fxus63 kgrr 170736
afdgrr
area forecast discussion
national weather service grand rapids mi
336 am edt Thu aug 17 2017
latest update...

synopsis short term long term marine

Synopsis
Issued at 336 am edt Thu aug 17 2017
expect humid conditions today with occasional showers and
thunderstorms as a low pressure system tracks through wisconsin.

Friday will be breezy, cooler, and less humid with some lingering
clouds and light showers. A warming trend is forecast over the
weekend into early next week.

Short term (today through Saturday)
issued at 336 am edt Thu aug 17 2017
the primary time frame of concern for severe weather today is
roughly noon to 6 pm and the main area of concern is east of
highway 131, particularly the lan and jxn areas. This is where
favorable instability shear ingredients could come together,
although it is highly contingent on at least a couple hours of sfc
heating in the wake of morning warm advection showers.

The current band of showers crossing the area represents the
leading edge gradient of the higher pwat air. After this passes
through, another more solid area of showers over il, associated
with a 35-40 kt llj, should impact the area between roughly 8 am
and noon.

It is in the wake of the second area of rain where a relatively
brief window will exist to get some heating and sfc based
instability before the increasing southwest low level flow off lk
mi sweeps eastward. This convection, on the leading edge of the
mid level dry slot and convergent lake shadow could become quickly
severe with sfc dew pts in the lower 70s in place by that time
(and a tongue of h8 dew pts near 17c).

Deep layer shear of 35 to 40 kts could lead to an organized
band cluster of storms developing east of highway 131 by 18z,
with even some support of a tornado if where sfc wind remains
backed enough as the 35-40kt southwest low level jet is still
overhead. Low LCL heights may also favor a quick spin up. The main
threat of svr wx (and locally heavy rain) looks to shift east of
our area by 22z.

The best risk of showers on Friday is north of i-96 where deeper
moisture is progged in the commahead of the system and h8 thermal
trough is most pronounced. Still, mainly just light QPF amounts
expected.

Another shortwave traverses the area late Friday night and
Saturday morning with about 500-1000 j kg of mu CAPE advertised by
the gfs. Currently the guidance indicates best probability of
shower isolated tstms with this feature will be south of i-96,
but only worth chc pops at this time.

Long term (Saturday night through Wednesday)
issued at 336 am edt Thu aug 17 2017
the long term period will be book ended by dry weather with pcpn in
the middle. High pressure over the great lakes Saturday night will
drift east by early next week. The weekend looks dry with seasonal
temperatures. The zonal flow aloft will begin to buckle early next
week as a short wave moves toward the great lakes. Chances for rain
will begin to increase Monday afternoon first as a warm front moves
north through the CWA and then as a cold front follows on Tuesday.

Tuesday looks like the best chance of showers storms. Shear values
are progd to ramp up to around 40kts Tuesday afternoon so we'll need
to keep an eye on the severe potential.

Aviation (for the 06z tafs through 06z Thursday night)
issued at 134 am edt Thu aug 17 2017
a couple of rounds of showers and storms expected today. The first
round is moving across the lake and will be mostly showers. MVFR
vsbys are likely with these showers as moisture content is very
high. Another round of showers storms is expected this afternoon.

Strong storms are possible with the afternoon round especially at
lan jxn.

Marine
Issued at 336 am edt Thu aug 17 2017
no change to the existing marine headlines for holland north
today for the south-southwest flow. However will issue a new
small craft advisory for areas south of holland starting tonight
at 10 pm when the flow becomes more westerly. The advisories will
run through Friday.

The beach hazard statement will need to be expanded south later
today to include areas south of holland on Friday.

Hydrology
Issued at 330 pm edt Wed aug 16 2017
multiple rounds of thunderstorms are possible Thursday. This may
lead to localized heavy rainfall where storms more frequently
occur. Early to mid morning showers and storms are expected along
a warm front and afternoon evening showers and storms are possible
especially east of us 131. Pwat values will be quite high,
approaching 2.0 inches, along with surface dew points above 70.

There is some potential for a few training thunderstorms with mbe
velocities occasionally dropping below 10 kts. However, this does
not look like a classic flood setup outside of localized ponding
of roads. We will continue to monitor trends.

Grr watches warnings advisories
Mi... Beach hazards statement from noon edt today through Friday
evening for miz037-043-050-056.

Lm... Small craft advisory from noon today to 9 pm edt Friday for
lmz846>849.

Small craft advisory from 10 pm this evening to 9 pm edt Friday
for lmz844-845.

Synopsis... Meade
short term... Meade
long term... 04
aviation... 04
hydrology... Hoving
marine... Meade


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
LDTM4 - 9087023 - Ludington, MI 12 mi44 min SE 5.1 G 8.9 70°F 67°F
45024 15 mi32 min SSE 16 G 19 70°F 69°F3 ft1008.8 hPa (-1.6)69°F
BSBM4 - Big Sable Point, MI 20 mi52 min SE 11 G 18 70°F 1007.8 hPa
MEEM4 - Manistee Harbor, MI 33 mi52 min SSE 9.9 G 17 69°F 1008.1 hPa
MKGM4 - Muskegon, MI 39 mi32 min S 15 G 19 73°F 1007.6 hPa (-1.5)71°F
45161 42 mi32 min SSE 14 G 18 72°F 71°F1008 hPa (-1.5)

Wind History for Ludington, MI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Ludington, Mason County Airport, MI12 mi37 minSE 710.00 miOvercast69°F66°F93%1007.1 hPa

Wind History from LDM (wind in knots)
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Last 24hrCalmSE4CalmCalmCalmW6W4SW6W6W4CalmCalmCalmCalmE4E6E7SE6SE5SE7SE7SE8SE7SE7
1 day agoCalmCalmCalmN4N7NE4N7NW7N10N9NW6N4N3N3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalm
2 days agoCalmCalmCalmSW3W3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmNE6E3N3CalmCalm

Tide / Current Tables for
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Tide / Current Tables for
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Weather Map and Satellite Images
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Weather Map
wmap_A
IR Satellite Image from GEOS
east_satellite

GOES Local Image of GreatLakes    EDIT
Geos

Wind Forecast for Grand Rapids, MI (7,2,3,4)
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Ground Weather Radar Station Grand Rapids/Muskegon, MI
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weather_mapweather_map weather_map

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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 numerious 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.