Sunday, August20, 2017 L-36.com


Marine Weather and Tides
Grand Ledge, 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 6:50AMSunset 8:33PM Sunday August 20, 2017 5:08 PM EDT (21:08 UTC) Moonrise 4:25AMMoonset 6:58PM Illumination 2% Phase: Waning Crescent; Moon at 28 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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LMZ846 Holland To Grand Haven Mi- 305 Pm Edt Sun Aug 20 2017
Tonight..South winds 5 to 10 knots. Partly cloudy. Waves 1 to 2 feet.
Monday..Southwest winds 5 to 15 knots. Then backing south late in the day. Partly Sunny with a slight chance of showers and Thunderstorms. Waves 1 to 2 feet.
Monday night..South winds 10 to 20 knots veering west toward daybreak. Showers and Thunderstorms. Waves 1 to 2 feet building to 2 to 3 feet toward daybreak.
Tuesday..West winds 15 to 20 knots veering northwest. Showers and Thunderstorms likely until midday, then partly Sunny with a slight chance of showers in the afternoon. Waves 2 to 4 feet.
LMZ846 Expires:201708210315;;685724 FZUS53 KGRR 201905 NSHGRR Nearshore Marine Forecast National Weather Service Grand Rapids MI 305 PM EDT Sun Aug 20 2017 For waters within five nautical miles of shore on Lake Michigan LMZ846-210315-

7 Day Forecast for Marine Location Near Grand Ledge, MI
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location: 42.75, -84.75     debug


Area Discussion for - Grand Rapids, MI
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Fxus63 kgrr 201909
afdgrr
area forecast discussion
national weather service grand rapids mi
312 pm edt Sun aug 20 2017
latest update...

synopsis short term long term marine

Synopsis
Issued at 312 pm edt Sun aug 20 2017
high pressure will continue to bring fair weather this evening. It
will become quite warm and humid Monday and an approaching low
pressure system will bring rain and thunderstorms Monday night
into Tuesday. A much cooler airmass will move in behind that
system for mid to late week.

Short term (this evening through Tuesday night)
issued at 312 pm edt Sun aug 20 2017
fair wx will continue late this afternoon through this evening
with high pressure still in control of the wx pattern. A cold
front approaching from the NW will bring a very small chance of
showers to our far northern fcst area toward daybreak Monday.

Showers in association with a warm front to the W SW of our area
should stay SW of our fcst area overnight.

Dry wx will continue through most of Monday morning and afternoon
though a few showers and isolated thunderstorms may develop in an
increasingly warm and humid and unstable airmass out ahead of the
cold front.

A consensus of 12z shorter range guidance time height rh progs and
latest numerical guidance all suggest that rather extensive cloud
cover will linger through Monday afternoon resulting in unfavorable
viewing conditions for the eclipse in our area. However completely
overcast conditions are not expected so the eclipse may briefly be
viewable from time to time from portions of our fcst area.

The best chance for rain and thunderstorms will come late Monday
evening into early Tuesday morning along and ahead of the
approaching cold front. Severe wx is not anticipated given
unfavorable frontal timing with decreasing instability overnight.

However locally heavy rain is possible late Monday evening into
early Tuesday morning when 1000-850 mb moisture transport will be
strongest in conjunction with precipitable water values
approaching two inches at that time.

Rain and perhaps a few thunderstorms will linger Tuesday morning
and early afternoon prior to fropa. However instability prior to
fropa Tuesday will be very weak given extensive clouds showers in
place Tuesday morning.

Cold frontal timing and a consensus of latest 12z guidance all
suggests that stronger convective redevelopment later Tuesday
afternoon will occur well to the southeast of our fcst area. This
notion is supported by the SPC day 3 convective outlook. Brisk west
to northwest winds will usher in a drier airmass late Tuesday
through Tuesday night when skies will gradually clear.

Long term (Wednesday through Sunday)
issued at 312 pm edt Sun aug 20 2017
the overriding message of this coming weeks weather will be our slow
progression into a more "fall like" weather pattern. As I pointed
out yesterday, the frequency of days with highs at or above 80 falls
below 50 percent, at grr, by mid week. Our afternoon highs from
Wednesday through Friday will surely show this to be true.

As it turns out the last time we had the qbo turn from positive to
negative (2014) during the spring into early summer, like it has
this year, we saw a similar pattern where below normal temperatures
becoming more frequent that warmer than normal temperatures. You may
remember how cold of a winter 2014 2015 was. In any event, this
tendency toward colder temperatures occurs due to a more meridional
upper air pattern, verses zonal being favored when the qbo is
positive. In fact we are now seeing this. When the qbo is negative
there tends to be more blocking in the mid to high latitudes than
when it is positive. That is why we get more meridional flow. Of
course this could also mean an extend period of warmer than normal
temperatures if the upper air pattern blocks us close to the upper
ridge position. My point here is we should whatever patten we get
into to be more persistent that last summer or fall. At this point
we have an upper troughs over eastern north america and that seems
to be favored as we go into the fall. In fact the cfsv2 and the 45
day ECMWF from the last such run do show this through september.

Getting back to our forecast for Wednesday through Sunday, we see
one such upper trough digging into the eastern conus, which puts
southwest michigan under the upper trough. As was pointed out by our
previous shift, this means unstable air due to cold air at mid
levels relative to warmer air near the surface. The sounding over
our area on Wednesday are not so dry at mid levels that convection
is out of the question, so do not be surprise do see showers added
to the Wednesday forecast before to long.

Another upper wave digs into the eastern trough in the Friday time
frame so afternoon showers would again be possible. Over the
weekend a system current over western asia, moves across the pacific
and tries to merge with the gulf of alaska upper low. This sends
another pacific upper wave our way. This will likely result in
another major precipitation event for southwest michigan but i
believe this is beyond our current forecast period, more in the
tue Wed time frame. One other aspect that I am nearly sure of is do
not expect any significantly warm weather in southwest michigan in
the next week or so.

Bottom line below normal precipitation and temperatures are favored
over wetter and warmer than normal Wednesday through Sunday.

Aviation (for the 18z tafs through 18z Monday afternoon)
issued at 1236 pm edt Sun aug 20 2017
expectVFR conditions to prevail through Monday afternoon into
Monday evening at all of our TAF sites. I strongly feel any
convection will miss our TAF sites to the north and south tonight
so we would get residual layered mid and high clouds. Another mcs
(shown by the esrl hrrr and hrrr) head toward SW mi during the mid
morning Monday, however it dissipates before getting here. Once
again we get layered mid and high clouds. Just in case I put vcts
for the mkg, grr and azo TAF sites after 16z but that would be a
low probability event at best. If there were any precipitation
from that complex it would be sprinkles from high based mid
clouds. So, the bottom line isVFR rules at all of our TAF sites.

Marine
Issued at 312 pm edt Sun aug 20 2017
winds and waves will remain relatively light through Monday.

Thunderstorms will pose a hazard to mariners Monday night into
early Tuesday and winds and wave heights will increase Tuesday
through Wednesday.

Hydrology
Issued at 312 pm edt Sun aug 20 2017
area rivers are around normal levels for the time of the year and
well below bankfull. Though we are going to get localized heavy rain
of over an inch late Monday night into early Tuesday, most areas
will not see even minor river flooding. Some water covered roads are
possible.

Grr watches warnings advisories
Mi... None.

Lm... None.

Synopsis... Laurens
short term... Laurens
long term... Wdm
aviation... Wdm
hydrology... 63
marine... Laurens


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
HLNM4 - 9087031 - Holland, MI 78 mi50 min S 1.9 G 1.9 77°F 1016.5 hPa
MKGM4 - Muskegon, MI 90 mi38 min S 7 G 8 75°F 1016.3 hPa67°F
SBLM4 - Saginaw Bay Light #1, MI 91 mi68 min SSW 7 G 8 78°F 1016.6 hPa (-1.3)

Wind History for Holland, MI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Capital Region International Airport, MI8 mi75 minVar 510.00 miFair83°F59°F44%1017.2 hPa
Charlotte, Fitch H Beach Airport, MI13 mi73 minSW 610.00 miPartly Cloudy82°F57°F42%1017.3 hPa
Mason, Mason Jewett Field Airport, MI21 mi75 minWSW 410.00 miPartly Cloudy85°F59°F41%1017.9 hPa
Ionia County Airport, MI21 mi72 minWSW 510.00 miFair82°F56°F42%1017.6 hPa

Wind History from LAN (wind in knots)
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Last 24hrW7W9W7W6W7W5CalmCalmCalmCalmCalmS3CalmCalmCalmS3S6S4W7W7SW6W65Calm
1 day agoW12W11
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W11W5SW5SW6SW7W5SW4W4W4W4SW5W3W3NW6NW7NW9NW10545NW8W9
2 days agoS10SW11
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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
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IR Satellite Image from GEOS
east_satellite

GOES Local Image of GreatLakes    EDIT
Geos

Wind Forecast for Grand Rapids, MI (17,4,5,8)
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Ground Weather Radar Station Detroit, 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.