Thursday, September20, 2018 L-36.com


Marine Weather and Tides
Harper Woods, MI

Version 3.4
What's New / NOTES
9/17/2018 XTide broke when 1and1 "upgraded" my server. It has been esculated. I am sorry for the problem.

Sunrise 7:16AMSunset 7:33PM Thursday September 20, 2018 5:21 AM EDT (09:21 UTC) Moonrise 4:36PMMoonset 1:43AM Illumination 79% Phase: Waxing Gibbous; Moon at 10 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- 409 Am Edt Thu Sep 20 2018
.small craft advisory in effect from Friday afternoon through Friday evening...
Today..East winds 5 to 10 knots becoming southeast 10 to 15 knots in the afternoon. Partly Sunny. A chance of showers and Thunderstorms until late afternoon...then light showers likely and a chance of Thunderstorms late in the afternoon. Waves 2 feet or less.
Tonight..Southeast winds 15 to 20 knots becoming south 10 to 15 knots after midnight...then increasing to 15 to 20 knots early in the morning. Partly cloudy. Light showers likely and a chance of Thunderstorms early in the evening. Waves 1 to 3 feet.
Friday..Southwest winds 15 to 20 knots increasing to 20 to 25 knots in the late morning and early afternoon...then becoming west 15 to 20 knots late in the afternoon. Waves 1 to 3 feet.
Friday night..Northwest winds 20 to 25 knots becoming north 15 to 20 knots after midnight. Partly cloudy. A chance of light showers early in the evening. Waves 1 to 3 feet.
Saturday..North winds 10 to 15 knots becoming northeast 5 to 10 knots in the afternoon and evening. Partly cloudy until late afternoon then clearing. Waves 2 feet or less.
Sunday..Northeast winds 5 to 10 knots. Clear. Waves 2 feet or less.
Monday..Southeast winds 10 to 15 knots. Mostly clear. A chance of showers. Waves 2 feet or less.
LCZ460 Expires:201809202015;;920621 FZUS63 KDTX 200809 GLFSC Lake St Clair Forecast National Weather Service Detroit/Pontiac MI 409 AM EDT Thu Sep 20 2018 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...High pressure over northern Ontario will build east today as low pressure organizes over the Midwest. This low will deepen to 29.30 inches as it reaches Lake Superior late tonight, pulling a warm front north across Lower Michigan and Lake Huron during that time. The trailing cold front will then sweep southeast across the central Great Lakes Friday as this low races into Quebec. This front will be followed by a large high pressure system which will build into the area this weekend. LCZ460-202015-


7 Day Forecast for Marine Location Near Harper Woods, MI
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location: 42.42, -82.99     debug


Area Discussion for - Detroit/Pontiac, MI
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Fxus63 kdtx 200748
afddtx
area forecast discussion
national weather service detroit pontiac mi
348 am edt Thu sep 20 2018

Discussion
Main concern for this forecast will be the increasing potential for
severe weather this morning and into the afternoon. Upper wave
crossing through the northern us rockies will result in lee
cyclogenesis and eject a cyclone through the central plains today.

Elevated instability within a zone of isentropic ascent is bringing
elevated and scattered showers across central lower michigan. Not
expecting a severe threat with the early morning activity as forcing
is not great and soundings show a fair degree of stability.

Convection within a zone of ascent fgen will keep rain convection
going through the morning hours. Areas along and north of i-69 will
be most likely area to see this activity linger into the afternoon
as activity lifts northward. The severe weather threat with this
activity will be low outside of some lightning and gusty winds.

Greater severe threat comes this afternoon, but it will be
conditional on how morning activity impacts the afternoon
environment. The surface low across the plains will deepen moving
towards southern minnesota helping draw warm air advection through
southeast michigan placing us well into the warm sector. Signals are
that some activity will be kicking up along a trailing frontal
boundary across lower michigan along the i-96 i-94 corridors.

Forecast soundings and hodograph associated with these scattered to
isolated cells suggest good low level directional shear with backed
southeast winds at the surface. This is characterized by 0 to 1 km
srh values exceeding 100 m2 s2 and 0 to 3 km SRH approaching 200
m2 s2, which will aid in supporting some rotating updrafts with
activity. Limiting factor with this convection will be lack of mid
to upper level forcing and strong instability. All that said, the
afternoon environment remains conducive for marginal risk.

There will be a brief lull in activity for much of southeast
michigan during the overnight. The strong low pressure system will
lift through the northern great lakes by Friday morning. Strong
gradient flow associated with this system will result in winds
picking up overnight into tomorrow morning. Strong winds continue
into the afternoon in association with a strong cold front that will
clear the area by the afternoon. There may be a broken line of line
of precipitation that develops along the prefrontal trough, but not
expecting strong convection with this activity. The winds will be
the main story for tomorrow as strong cold advection will drive
isentropic decent resulting in wind gusts reaching 30-40 mph during
the afternoon. High temperatures will be able to reach into the
upper 70s and low 80s before plummeting during the late afternoon
into the evening as 850 mb temperatures drop 10-15 degrees compared
the morning.

High pressure moves in behind the front with much cooler
temperatures and cloudier skies to start the weekend. High
temperatures on Saturday are forecast to be in the low to mid 60s.

High pressure will keep weather conditions mostly dry through the
remainder of the weekend. Gradual warming to finish the weekend into
early next week with high temperatures on Sunday a few degrees
higher, but remaining in the 60s, and Monday will see areas reach
into the low 70s. A warm front lifting north on Monday will help
bring the warmer temperatures, but it may also bring some showers
and thunderstorms along with it. Rain chances look to continue
Monday night into Tuesday as an upper trough swings through the
northern plains, which will increase moist southerly flow and bring
back some potentially gusty winds with an increasing pressure
gradient.

Mid-week cold front will keep rain chances in the forecast, though
exact timing and strength is uncertain at this time. Will be
something to watch in terms of rainfall potential. Temperatures look
to take a dip behind this front for the middle and end of next week.

Marine
The gale watch for the open waters of lake huron have been upgraded
to a gale warning for Friday into Friday night. A gale watch is in
effect for saginaw bay and the tip of the thumb for Friday afternoon
and evening. Small craft advisories also begin late tonight for the
locations in this watch and expand southward with time into Friday
as gusty flow becomes established area-wide by mid to late morning.

A warm front will lift north today as low pressure organizes over
the midwest. This will bring an increased chance of showers and
thunderstorms. Worsening marine conditions will also include
increasing wind and waves as the low strengthens over the northern
great lakes. The system will pull much warmer air across lower
michigan and lake huron. This will increase stability and limit wind
gusts to some extent. The exception could be greater gustiness
through saginaw bay if boundary layer mixing becomes established
over land areas late today. Gusts to 30 knots will even be possible
over the cooler open waters of lake huron through tonight.

Once the low crosses the northern great lakes and continues into
ontario early Friday morning, an associated cold front will push
southeast through the central great lakes. The front will bring
veering winds to the northwest with considerably colder air
reversing the thermal profile to an unstable configuration. The
strength of the low likely supports a wind field capable of gusts
exceeding gale force over the open waters of lake huron. In fact,
wind gusts will likely reach 40 knots or more over northern lake
huron the peak of this event. High pressure will then build in
quickly behind this system by Saturday, bringing improved marine
conditions during the weekend.

Hydrology
Showers and thunderstorms will increase coverage and intensity early
this morning and continue at times through mid afternoon as a warm
front lifts northward through the region in response to low pressure
developing over the midwest. The warmer and more humid air moving
into the area with this front will supply enough moisture for total
rainfall averaging of one third to one half an inch today. Locally
higher totals are more likely across the tri cities and northern
thumb where isolated rainfall amounts of around one inch will be
possible. This activity will become more scattered in nature late in
the day and then focus well north of the area along the warm front
from this evening into the overnight. The potential for flooding is
minimal with this system, limited to ponding of water on roads and
minor flooding of poor drainage areas.

Prev discussion
Issued at 1209 am edt Thu sep 20 2018
aviation...

increasing dynamic forcing for ascent will kick off a period of warm
advection beginning tonight and persist well into the day on
Thursday. Initial midlevel theta E advection appears necessary to
moisten the column before 800mb moisture advection ramps up after
12z Thursday. Still some uncertainty with how cig vsby trends will
play out in the warm advection. Still expecting a fair amount of mid
and high cloud that will limit amount of fog development late. Tafs
still carry some MVFR fog around daybreak which may be overdoing
based on MOS trends. Otherwise, midlevel instability development
along and ahead of the retreating 925-850mb warm front after 14z
will lead to a period of showers and be elevated thunderstorms 14-
18z north of m 59. Organized signal in virtually all of the model
data supports lingering thunderstorms during the afternoon south of
m59. These thunderstorms are expected to occur along the surface
warm front between 20-24z. Some questions remain, particularly where
exactly front placement will be.

For dtw... Persistent boundary layer moisture INVOF stalled front
brings a potential for MVFR fog haze at daybreak. Still expecting
mid-high cloud to limit development. Main forecast concern is
potential for surface based thunderstorm development between 20-24z.

Introduced a prob30 group for possible discrete cells. The
thunderstorm potential will be conditional to placement of the
surface warm front.

Dtw threshold probabilities...

* moderate for ceiling 5000 ft or less redeveloping Thursday
morning.

Dtx watches warnings advisories
Mi... None.

Lake huron... Gale warning from 2 pm Friday to 4 am edt Saturday for lhz462-463.

Gale watch from Friday afternoon through Friday evening for lhz421-
422-441.

Small craft advisory from 4 am to 4 pm edt Friday for lhz421-422-
441.

Small craft advisory from noon Friday to noon edt Saturday for
lhz442-443.

Gale warning from noon Friday to 4 am edt Saturday for lhz361>363.

Lake st clair... Small craft advisory from noon Friday to midnight edt Friday night
for lcz460.

Michigan waters of lake erie... Small craft advisory from noon Friday to midnight edt Friday night
for lez444.

Discussion... Aa
marine... ... .Dg
hydrology... .Dg
aviation... ..Cb
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at

Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CLSM4 - St. Clair Shores, MI 7 mi21 min ESE 6 G 8 68°F 1019 hPa (-0.0)
45147 - Lake St Clair 16 mi21 min E 9.7 G 9.7 67°F 71°F1 ft1017.5 hPa (-0.0)
AGCM4 28 mi33 min 61°F 69°F1018.3 hPa
THLO1 - Toledo Light No. 2 OH 42 mi31 min ESE 8.9 G 8.9 70°F
MBRM4 - 9014090 - Mouth of the Black River, MI 49 mi45 min 62°F 1018.4 hPa

Wind History for Fort Gratiot, MI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Coleman A Young Municipal Airport, MI2 mi28 minN 010.00 miPartly Cloudy64°F59°F84%1018.3 hPa
Troy, Oakland/Troy Airport, MI13 mi26 minN 010.00 miMostly Cloudy65°F57°F78%1019 hPa
Detroit, Detroit Metropolitan Wayne County Airport, MI22 mi28 minE 510.00 miOvercast65°F57°F76%1017.7 hPa
Detroit/Grosse Ile, Grosse Ile Airport, MI24 mi26 minNE 410.00 miFair62°F58°F90%1017.9 hPa

Wind History from DET (wind in knots)
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Last 24hrN5NE4NE5NE53SE6E4E4SE3N3NE6E7E5E6E4NE4NE3NE5CalmSE5NE4SE5CalmCalm
1 day agoCalmN3N4N4CalmCalmCalmS4NW8E8E5E6NE6E5NE7NE9E7E5NE8E4NE5NE4NE4N7
2 days agoSE3CalmCalmE3E5CalmCalmCalmE65E9E6SE6CalmSE3S5S4SW3CalmW4W4CalmCalmCalm

Tide / Current Tables for
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Weather Map and Satellite Images
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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.
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Wind Forecast for Detroit/Pontiac, MI (5,6,7,8)
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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.