Tuesday, September25, 2018 L-36.com

Marine Weather and Tides
Copper Harbor, MI

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9/17/2018 XTide broke when 1and1 "upgraded" my server. It has been esculated. I am sorry for the problem.

Sunrise 7:08AMSunset 7:09PM Tuesday September 25, 2018 9:42 AM EDT (13:42 UTC) Moonrise 7:03PMMoonset 6:32AM Illumination 99% Phase: Full Moon; Moon at 15 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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7 Day Forecast for Marine Location Near Copper Harbor, MI
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location: 63.03, -82.89     debug

Area Discussion for - Marquette, MI
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Fxus63 kmqt 251105
area forecast discussion
national weather service marquette mi
705 am edt Tue sep 25 2018

Short term (today and tonight)
issued at 511 am edt Tue sep 25 2018
wv imagery and rap analysis indicated a mid upper level trough from
saskatchewan into the central rockies western plains resulting in sw
flow from the plains into the upper ms valley and northern great
lakes. Water vapor imagery showed one shortwave lifting NE through
the upper great lakes associated with a frontal boundary now moving
into western upper mi. Another shortwave rounding the base of the
mid-level trough over the central rockies is expected to lift ne
along the frontal boundary later this afternoon into this evening
bringing widespread showers to much of upper mi.

Today and tonight... Narrow band of showers along cold front moving
into western upper mi has rapidly weakened in past hour and should
dissipate in next hour or two with weakening dynamics along the
front due to shortwave exiting through northern ontario. Models
indicate cold front slowly moving east through upper mi today then
stalling out near southeast upper mi as the vigorous shortwave over
the central rockies lifts NE along the frontal boundary into the
upper great lakes. Vigorous fgen in right entrance region of
associated 120 kt jet MAX will be strong enough to support
widespread rain through most of upper michigan late afternoon into
evening with the heaviest pcpn (in excess of one half inch at some
locations) over central upper mi. MUCAPE up to 300 j kg could result
in isolated t-storms over south central and eastern sections. As
shortwave lifts NE of the upper lakes system pcpn will diminish
and or end. However, 850 mb temps lowering to 0c behind the system
and lingering weak q-vector convergence over lake superior will
continue to support NW flow lake effect rain showers downwind of the
lake into Wed morning.

Long term (Wednesday through Monday)
issued at 345 am edt Tue sep 25 2018
ridge positive height anomaly currently over the NE pacific will
strengthen, becoming a huge positive height anomaly (+350 to +400m
at 500mb) over ak this weekend. Downstream, a trof is already
beginning to develop over central N america in response to the ne
pacific ridge. Then, in concert with the building ridge, this trof
will amplify and become quite deep as the week progresses, allowing
for a build up of unseasonably cold air for so early in the season,
centered in central canada. With the height anomaly over ak closing
off a mid-level anticyclone by the weekend, flow will undercut it
into the western conus, and this will work to prevent the
unseasonably cold air building to the NW from fully dumping into the
upper lakes. Even so, temps for the remainder of this week and into
early next week will end up blo normal as the southern edge of the
building cold air to the N brushes the area due to the passage of
several shortwaves. The first shortwave is currently passing thru
the upper lakes. A second will follow quickly late today tonight, a
third late Thu thu night, a fourth weak wave on fri, and a fifth sun
night mon. Each wave will bring some shra to at least parts of the
fcst area. From a standpoint of pcpn amounts, it appears the second
wave will probably produce the greatest rainfall, occurring this
aftn evening. However, the system early next week will probably be a
significant pcpn producer due to the strong temp contrast that will
be present at that time across the CONUS southern canada. Being 5-6
days out, it's uncertain exactly where the corridor of heaviest pcpn
will occur though some part of the great lakes region will certainly
be in the path.

Beginning Wed wed night... A subtle shortwave will pass wed. Forcing
is limited at best, suggesting nothing more than isold
-shra, if that. Recent large wave action on lake superior has
mixed cooled waters with the 3 mid lake buoys showing water temps
already down to 52f, 43f, 45f from W to e, but there are certainly
areas of warmer water. Even with 850mb temps around 0c wed,
conditions really won't be supportive of lake effect -shra given
current water temps. Of course, solar insolation on surrounding land
and the resulting building mixed layer at this time of year is also
a big negative for lake effect processes. Overall, dry weather will
prevail for most locations Wed thru at least Wed evening.

Next more significant shortwave will drop toward the upper lakes on
thu with associated sfc low tracking from southern manitoba wed
evening across northern ontario thru thu. Forcing is a little weaker
than viewed in the models 24hrs ago as 500mb height falls are only
around 50m instead of 70-80m. Still, should see at least sct -shra
accompany the cold front across the fcst area on thu. Behind the
cold front, cyclonic flow and fairly deep moisture with 850mb temps
falling to around -2c will support some lake enhanced -shra for W to
nw flow favored areas Thu night into Fri morning. Approaching subtle
shortwave and associated sfc trof will keep some -shra going thru
fri, including an expansion of at least isold -shra into and across
the interior.

With 850mb temps falling to around -5c Fri night into Sat morning,
would expect lake effect -shra to increase for areas favored by wnw
flow. However, GFS fcst soundings are quite dry with a developing
well-mixed layer look that is hostile for lake effect. -shra
should remain limited in coverage. If clouds scatter out
sufficiently in the interior, a frost freeze will be likely fri
night. If any -shra are occurring, they will probably end during
sat, leaving dry weather into at least Sun morning. Sat night
looks like a better opportunity of a widespread frost freeze with
sfc high pres closer.

Later Sun into mon, shortwave originating in the flow undercutting
the strong mid-level high over ak will streak ene across the conus.

While this wave is still not particularly strong as currently
depicted in medium range guidance due to its progression thru a more
confluent flow regime, the strong thermal contrast across the conus
and southern canada may make this a mdt hvy pcpn producer as it
reaches the great lakes. Track of sfc wave and where exactly the
corridor of heaviest pcpn will occur is uncertain given that we're 5-
6 days out in the fcst, but some part of the great lakes region will
certainly be in the path of the mdt hvy pcpn. Upper mi, at a
minimum, will likely be affected by at least lighter pcpn at some
point late Sun mon. Drier weather will follow on tue.

Aviation (for the 12z tafs through 12z Wednesday morning)
issued at 651 am edt Tue sep 25 2018
expect ifr to MVFR conditions today in moist onshore flow and
with rain moving in late afternoon and evening these conditions
will persist. Conditions will improve late tonight to higher end
MVFR and possibly toVFR at kiwd as drier air advects in from the

Marine (for the 4 am lake superior forecast issuance)
issued at 511 am edt Tue sep 25 2018
with a cold front moving through this morning, winds will shift to
the NW today and increase to 15-25kt tonight and continue at 15 to
25 knots out of the west on wed. The next low pres system moving e
toward northern ontario will result in stronger SW winds of 20-30kt
wed night into Thu that will veer to the NW Thursday night. Would
not be surprised if a gale warning is needed for the west half of
the lake Wed night.

Mqt watches warnings advisories
Upper michigan...


Lake superior...


Lake michigan...


Short term... Voss
long term... Rolfson
aviation... Voss
marine... Voss

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Wind Forecast for Marquette, MI (9,2,3,4)
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Ground Weather Radar Station Marquette, MI
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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.