Thursday, April27, 2017 L-36.com


Marine Weather and Tides
Grosse Pointe Woods, MI

Version 3.4
What's New / NOTES
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.
3/12/2015 - Added section for Gulf current for users in the GMZ marine zones.
This was requested by a user. If you have requests, please let me know.

Sunrise 6:28AMSunset 8:29PM Thursday April 27, 2017 12:55 PM EDT (16:55 UTC) Moonrise 6:40AMMoonset 9:00PM Illumination 3% Phase: Waxing Crescent; Moon at 2 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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LCZ460 Lake St Clair- 349 Am Edt Thu Apr 27 2017
.small craft advisory in effect from 10 am edt this morning through this evening...
Today..South winds 10 to 15 knots increasing to 15 to 20 knots in the late morning and afternoon. Gusts to 25 knots. Partly Sunny. Light showers likely and a chance of Thunderstorms in the afternoon. Waves 1 to 3 feet.
Tonight..Southwest winds 10 to 15 knots becoming west 5 to 10 knots after midnight. Partly cloudy. Waves 2 feet or less.
Friday..Southwest winds 5 to 10 knots becoming south 10 to 15 knots in the late morning and afternoon. Partly Sunny. Waves 2 feet or less.
Friday night..South winds 5 to 10 knots. Mostly cloudy with a chance of light showers. Waves 2 feet or less.
Saturday..North winds 10 to 15 knots. Cloudy with a chance of light showers. Waves 2 feet or less.
Sunday..Southeast winds 10 to 15 knots. Cloudy with showers likely. Waves 2 feet or less.
Monday..Southwest winds 15 to 20 knots. Mostly cloudy with showers likely. Waves 1 to 3 feet.
LCZ460 Expires:201704272015;;333611 FZUS63 KDTX 270749 GLFSC LAKE ST CLAIR FORECAST NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 349 AM EDT THU APR 27 2017 WAVES ARE THE SIGNIFICANT WAVE HEIGHT - THE AVERAGE OF THE HIGHEST 1/3 OF THE WAVE SPECTRUM. OCCASIONAL WAVE HEIGHT IS THE AVERAGE OF THE HIGHEST 1/10 OF THE WAVE SPECTRUM. .SYNOPSIS...LOW PRESSURE OF 29.30 INCHES WILL TRACK ACROSS NORTHERN LAKE MICHIGAN AND THE U.P. DURING THE LATE MORNING AND AFTERNOON. WEAK HIGH PRESSURE WILL BUILD INTO LOWER MICHIGAN TONIGHT BEFORE SURFACE HIGH PRESSURE STRENGTHENS OVER THE NORTHERN GREAT LAKES FOR THIS WEEKEND. OVER THE SOUTHERN GREAT LAKES...A FRONTAL BOUNDARY WILL ORGANIZED BRINGING PERIODS OF SHOWERS AND THUNDERSTORMS LATE SATURDAY THROUGH MONDAY. LCZ460-272015-

7 Day Forecast for Marine Location Near Grosse Pointe Woods, MI
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location: 42.43, -82.9     debug


Area Discussion for - Detroit/Pontiac, MI
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Fxus63 kdtx 271642
afddtx
area forecast discussion
national weather service detroit/pontiac mi
1242 pm edt Thu apr 27 2017

Aviation
Cold front will pretty much clear all terminals at the beginning of
the forecast period with just a brief window 18z-19z where a shower
or storm will remain possible. MVFR/lowerVFR stratus will funnel in
behind the front and persist, at least in a scattered to broken
fashion, into tonight. Wind gusts to 30 knots or more will remain
possible, particularly 18z-21z within strongest surge immediately
behind the front.

//dtw threshold probabilities...

* moderate for ceiling 5000 ft or less this afternoon/evening.

* low for thunderstorms 18z-19z as cold front passes.

Prev discussion
Issued at 931 am edt Thu apr 27 2017
update...

expecting southwest wind gusts in the 40 to 45 mph across southeast
michigan, based off upstream obs and local probablistic SREF weighted
guidance, as low pressure (990-992 mb) and 6 hr rise fall pressure
couplet (18 mb) lifts northeast through northern lower
michigan/central great lakes. Best chance for gusts reaching and
exceeded 45 mph will be tri-cities region where best low level cold
advection will occur (850 mb temps dropping below zero by 00z), but
with strong wind gusts being short lived (around noon and just after)
and due to localized nature of 45+ mph gusts, may hold off on wind
advisory and just handle it with an sps.

Prev discussion...

issued at 342 am edt Thu apr 27 2017
discussion...

active stretch of weather begins today and will take us through the
weekend. We'll start off today with gusts winds through the
afternoon and strong (possibly severe) storms this afternoon as a
cold front lifts through the area. Friday may actually stay dry as
an active warm from remains south of the area but then a low
pressure system will lift through the region this weekend bringing
chances of showers Saturday through Monday with thunderstorms
possible Sunday.

For today the main concerns will be strong gradient flow through the
afternoon and severe potential. First we'll look at winds. The
gradient flow will be strong both ahead of, and behind the cold
front that will traverse the area around 18z. A strong low level jet
will be lifting out of the region as the mixing depths increase so
will likely miss out on strongest winds early. Soundings show a deep
layer of winds around 30 knots but increasing rapidly above the
inversion. Momentum transfer supports capping gusts around 30 knots
this morning in the prefrontal airmass. The front will sweep
through around 18z veering winds from south to southwest. Cold air
advection behind the front will produce a strong inversion through
the evening. The again will cap gust potential around 30-35 knots.

Strong winds should be north of i69 close to the low pressure center
lifting through northern lower, but a broad area of gusts to 30
knots may persist a few hours. Not enough of a signal in the models
to warrant higher gusts or a wind advisory.

Having said that, winds aloft will be strong. In the morning we
could be looking at 60 knots down to around 7kft and 70 knots around
10kft. This strongest core lifts north but we're still left with 60-
80 knots in the mid levels. Afternoon convection will possibly bring
down these stronger winds if we can get some stronger cores along
the front. Convection potential remains but is not overly
impressive. Still looking at a high shear (50 knots), tall skinny
cape (~500 j/kg) environment. The low will be tracking nearly north
through the western great lakes while strong jet energy though the
base of the longwave trough surge the base of the trough axis
further east, creating new area of height falls to our south. Also
noted in the previous discussion the upper level difluent flow will
displace further north bringing confluence over southern mi working
against the potential for widespread organized convective bands.

Best chance for convection will be in the 16-20z window working from
southwest to northeast through that time as the prefrontal trough
lifts through. Any storm that GOES up will have the potential to tap
into the strong winds in the mid levels making winds the primary
threat today. SPC continues to highlight a marginal risk area over
se lower mi which is reasonable.

Friday could see a lull in activity as a warm front redevelops south
of the state and high pressure builds in from the west. This will be
short lived as the next low pressure system will be developing over
the southern plains, which will push the front back north over lower
mi Saturday. Then several waves could eject out of the low into the
region providing more support for periods of showers through the
weekend. The low itself will then lift through the western great
lakes Monday and Tuesday providing additional support for showers
into next week.

Marine...

moderate pre-frontal southeast wind will remain in place through
this morning. Existing higher degree of stability will continue to
limit higher gust potential, with gusts capped at or below 25 knots
during this time. Winds will turn to southwesterly this afternoon
as a cold front slips through the region. The combination of
increasingly gusty conditions and a period of wave heights above 3
feet will lead to a marginal small craft condition today across
saginaw bay, the lake huron nearshore waters, lake st clair and lake
erie. There will be a low probability for thunderstorms with the
cold frontal passage this afternoon. Winds and waves will diminish
this evening as high pressure builds into the region. Lower southwest
winds speeds expected Friday as this high sustains a weaker
gradient.

Dtx watches/warnings/advisories
Mi... None.

Lake huron... Small craft advisory until 10 pm edt this evening for lhz421-422-
441>443.

Lake st clair... Small craft advisory until 10 pm edt this evening for lcz460.

Michigan waters of lake erie... Small craft advisory until 10 pm edt this evening for lez444.

Aviation... ..Dg
update... ... .Sf
discussion... Drk
marine... ... .Cb
you can obtain your latest national weather service forecasts online
at

Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CLSM4 - St. Clair Shores, MI 3 mi55 min S 11 G 15 71°F 999.7 hPa (-0.6)
AGCM4 24 mi37 min 71°F 999.1 hPa
MBRM4 - 9014090 - Mouth of the Black River, MI 45 mi37 min 73°F 999.1 hPa
THLO1 - Toledo Light No. 2 OH 45 mi55 min SW 21 G 25 64°F
FTGM4 - 9014098 - Fort Gratiot, MI 47 mi37 min SSW 18 G 27 73°F 998.7 hPa56°F

Wind History for Fort Gratiot, MI
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Last
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S12
G21
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G25
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S9
G19
SE12
G15
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G26
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S10
G14
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S12
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SE12
G20
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G15
SE13
G16
SE12
G16
SE10
G15
SE9
G12
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G15
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NE9
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N11
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N9
N12
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N5
SE11
SE17
G25
SE17
SE10
G13
SE3
G6
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G11
E4
NE3
SE5
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G12
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G15
SE8
G12
S16
G20
S19
G25
S12
G15

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Detroit, Detroit City Airport, MI6 mi62 minS 910.00 miOvercast69°F55°F61%998.8 hPa
Selfridge Air National Guard Base, MI14 mi57 minS 1310.00 miMostly Cloudy70°F59°F70%998.8 hPa
Troy, Oakland/Troy Airport, MI17 mi61 minS 11 G 1610.00 miOvercast71°F52°F51%999.7 hPa

Wind History from DET (wind in knots)
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Last 24hrS11SE13SE15
G24
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G24
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SE11SE11E5E7SE5SE6S3E6E4SE6SE6S8S7S8S13
G18
S13S10
G15
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G17
S9
1 day agoSE10SE8E8E8
G15
SE9E10E8E11E11E8E9E7E5--E5E6CalmE3SE5SE7--SE10S14
G17
SE9
2 days agoE10
G16
E10E9E13
G19
E13SE13
G17
SE12SE12E11E12E16
G21
SE13SE12SE9E4E5E5E4E6SE9SE11SE10SE6SE7

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 Detroit/Pontiac, MI (12,3,4,5)
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Ground Weather Radar Station Detroit, MI
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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.