Thursday, March30, 2017 L-36.com


Marine Weather and Tides
Mackinaw City, 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 7:16AMSunset 8:06PM Thursday March 30, 2017 12:44 PM EDT (16:44 UTC) Moonrise 8:09AMMoonset 10:23PM Illumination 11% Phase: Waxing Crescent; Moon at 3 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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LHZ345 Straits Of Mackinac Within 5 Nm Of Mackinac Bridge Including Mackinac Island- 1049 Am Edt Thu Mar 30 2017
.small craft advisory in effect through Friday afternoon...
Today..East wind 10 to 20 knots with gusts to around 25 knots. Slight chance of snow in the late morning, then chance of snow in the afternoon. Waves 2 to 3 feet.
Tonight..East wind 10 to 20 knots with gusts to around 25 knots. Chance of snow. Waves 2 to 3 feet.
Friday..Northeast wind 10 to 15 knots with gusts to around 20 knots. Chance of rain and snow showers. Waves 2 to 3 feet.
Friday night..Light winds. Partly cloudy. Waves 2 feet or less. SEe the open lakes forecast for days 3 through 5.
LHZ345 Expires:201703302300;;316437 FZUS53 KAPX 301449 NSHAPX NEARSHORE MARINE FORECAST NATIONAL WEATHER SERVICE GAYLORD MI 1049 AM EDT THU MAR 30 2017 FOR WATERS WITHIN FIVE NAUTICAL MILES OF SHORE ON LAKES HURON... MICHIGAN AND SUPERIOR LHZ345-302300-

7 Day Forecast for Marine Location Near Mackinaw City, MI
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location: 45.78, -84.76     debug


Area Discussion for - Gaylord, MI
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Fxus63 kapx 301516
afdapx
area forecast discussion
national weather service gaylord mi
1116 am edt Thu mar 30 2017

Update
Issued at 1116 am edt Thu mar 30 2017
overview: parent stacked/occluding low pressure system analyzed
over the kansas/missouri border this morning with a warm front
stretching eastward through kentucky. Surface high pressure sits
over western quebec down into the northern lakes. Strong upper
jet core stretches through the mid mississippi river valley with a
secondary core across the northern lakes... Placing lower michigan
within a favored upper divergence region of the coupled jet
structure.

Nice "warm conveyor belt" of moisture stretches from the gulf up
into the western great lakes this morning. Precipitation becomes
most expansive across the lower great lakes well north of the
surface warm front... Where a tight low-mid level thermal gradient
and strong deformation exists... Coupled with the aforementioned
upper jet forcing. But northward advancement of precip thus far
this morning has "hit a wall" south of m-55... The result of dry
low level easterly flow across northern michigan around the
canadian high and likely part of the descending branch of the
upper jet circulation.

Rest of today: as mentioned above, regional radar plot tells the
story, at least in the near term. Northward advancement of more
widespread precip has pretty much halted south of m-55... Just
getting into far gladwin/arenac counties. 12z NAM forecast as well
as latest hrr trends now suggesting precip will largely remain out
of this CWA through much of the afternoon... Save for parts of
gladwin/arenac counties. Again, radar trends certainly support
that idea. At this point, my plan is to reduce pops/qpf/accumulations
through at least mid to late afternoon.

Late this afternoon/tonight: guidance trends still support the
idea of another piece of upper jet forcing/enhanced precip
sliding out of illinois and up through the SE part of the CWA late
this afternoon into the evening. One can already see this next
batch of precip blossoming over illinois. So... Will see how that
evolves and will have to play around with precip type for late
afternoon into this evening.

Near term (today through tonight)
issued at 431 am edt Thu mar 30 2017
high impact weather potential: a wintry mix and possible slippery
roads tonight.

Pattern synopsis and forecast:
early this morning, sfc high pressure continues to nose into the
great lakes. However, sprawling low pressure/stacked system in the
south central plains is ejecting shortwave energy along an elevated
warm front across much of SRN lower michigan. Somewhat high based
reflectivities seen on regional radars sneaking into areas south of
m-72 over the past handful of hours (mainly light snow/flurries),
within NRN extent of strongest low to mid level warm advection. The
better/heavier precipitation is still well back to the SW in NRN il
where the strongest forcing resided, consisting of that waa, upper
divergence in double jet structure and stronger dpva ahead of the
stacked low.

Forecast concerns: still some significant disagreement in location
and amounts of qpf, along with sfc temperatures due to wetbulbing
effects. This impacts where and how much snow resides, and what
precip type is expected.

From a synoptic pattern perspective, the stacked low pressure system
will track in an east-northeast manner into indiana by Friday
daybreak. This will bring deepening moisture and stronger forcing
via the waa, upper divergence and dpva into the region. The location
of the strongest forcing ATTM looks to be in the SE CWA along and
south of a line from cadillac to alpena. Again, the issue here is
that there are significant differences in the data sets. The main
two issues are what the sfc temperature will be and whether or not
an fgen band can develop this afternoon across the SE cwa. Hi-res
guidance is dead set on sfc temperatures cooling off through
afternoon via wetbulb effects. Essentially allowing for a longer
period of snow and not a mix which would limit accumulations.

However, we will likely need the stronger precipitation for enough
wetbulbing to reduce that temperature and keep it snow. This is
likely going to be relying on the fgen to be there. Some of the hi-
res snowfall forecasts are insanely high, with double digit totals
being seen. Am certainly not going that direction to full extent, or
nowhere near it since some other data sets suggest much much lower
qpf numbers. This is a really tough scenario, and folks will
definitely want to pay attention to later forecast for updated
information, or just be ready for higher snowfall totals that the 1-
3 inches are forecast.

The stronger forcing departs after early evening, and there are
hints of periods of time where deeper moisture is stripped out enough
for less/no ice activation. This will lead to periods of light rain
and drizzle, with maybe some light freezing precip in the coolest
temperatures in the interior higher terrain of NRN lower.

This whole event doesn't look to impact much of eastern upper, where
far SE sections of chippewa and mackinac counties may receive some
minor snowfall by tonight's end.

Short term (Friday through Saturday)
issued at 431 am edt Thu mar 30 2017

Precip diminishes Friday followed by pleasant weekend weather...

high impact weather potential: minimal. Brief wintry mix
transitions to all rain Friday morning.

Pattern forecast: area of low pressure is progged to be centered
over northern indiana/southern lower mi by Friday morning with
deformation precip plaguing portions of northern michigan through
the midday hours Friday before pulling away toward the east coast.

The patterns becomes much more quiet over the weekend, with little
in the way of sensible weather locally, as high pressure settles
atop the western great lakes.

Primary forecast concerns: the main forecast concerns revolve around
diminishing precipitation trends Friday morning into the early
afternoon. As was previously mentioned, deformation precip on the
northern periphery of low pressure/southern stream wave is expected
to linger across portions of the area Friday morning. With boundary
layer temps continuing to warm through midday, any early
lingering mixed rain/freezing rain, drizzle and snow across the
tip of the mitt and eastern upper is expected to transition to
plain rain/drizzle as we head through the morning. Latest trends
suggest stubborn low-level moisture may allow for a good chunk of
northern michigan to remain stuck under low clouds and patchy
drizzle through at least early afternoon (if not longer across
eastern areas) before a more significant shot of low-level dry air
impedes on the area from northwest to southeast. Expecting breaks
in the clouds to begin to first work their in across eastern
upper/far northwest lower during the mid-late afternoon and
elsewhere throughout the evening. High temperatures near 40 area-
wide... Perhaps a bit warmer across eastern upper/tip of the mitt
with a bit of afternoon sun.

Canadian high pressure begins to settle atop the great lakes Friday
night and more so Saturday-Saturday night. Despite a weak wave
zipping through fairly zonal upper-level flow during the day
Saturday, the forecast will represent little more than a bit of
increased cloud cover Saturday afternoon and night as in-place dry
air should stave off any light shower/sprinkle threat. Widespread
high temps in the mid-40s to low 50s.

Long term (Saturday night through Wednesday)
issued at 431 am edt Thu mar 30 2017
high impact weather potential...

another fairly pleasant day is expected across northern michigan on
Sunday with above normal temperatures, but increasing cloudiness as
the day wears on. Fairly progressive northern stream wave is
expected to be toeing the u.S./canada border near international
falls by Sunday evening, which may spread scattered showers across
the area Sunday night. Next week - a fairly active storm track looks
to be setting up across the CONUS with several waves diving into the
four-corners region before ejecting lee of the rockies. Plenty of
guidance spread in the day 5-8 timeframe to warrant much in the way
of details, but worth monitoring for several wet (perhaps more
wintry late next week?) systems to work their way through the
heart of the country.

Aviation (for the 12z tafs through 12z Friday morning)
issued at 714 am edt Thu mar 30 2017
a strong storm system well to the south will advect deeper
moisture into the region through the day.VFR CIGS will lower to
MVFR through the day while rain and snow gradually expand from sw
to NE impacting mainly mbl/tvc and apn. Precip type will be mainly
just rain at mbl/tvc with definite snows arriving at pln/apn this
afternoon and evening. East winds will remain 10 to 15 mph through
the period with gusts mainly during the daytime to around 20 mph.

Ifr/low end MVFR CIGS more probably tonight with some fog in more
sporadic light precip and periods of drizzle.

Total snows maybe up to 3 inches at apn with less than an inch at
pln... And none for tvc/mbl.

Marine
Issued at 431 am edt Thu mar 30 2017
a low pressure system will track in an east-northeast manner into
indiana by Friday daybreak and then into mid atlantic by Friday
night. A mix of rain and snow will impact the nearshore waters along
with strengthening easterly winds today into Friday morning.

Advisory level winds are expected over this time for all of lake
huron and michigan. Less chance across whitefish bay. Winds back
more out of the NE later Friday and Friday night with NE lower
nearshores seeing the continuation of advisory speeds. Winds weaken
through the latter hours of Friday night.

Apx watches/warnings/advisories
Mi... None.

Lh... Small craft advisory until 5 pm edt Friday for lhz345-347>349.

Lm... Small craft advisory until 5 pm edt Friday for lmz323-342-
344>346.

Small craft advisory until 5 am edt Friday for lmz341.

Ls... None.

Update... Tba
near term... Smd
short term... Mjg
long term... Mjg
aviation... Smd
marine... Smd


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
MACM4 - 9075080 - Mackinaw City, MI 2 mi44 min ESE 18 G 25 34°F 1018.8 hPa (-1.6)27°F
WSLM4 20 mi44 min E 28 34°F 1019.2 hPa (-1.3)28°F
SRLM4 33 mi44 min E 23 34°F 28°F
NABM4 - Naubinway, MI 42 mi35 min 35°F 1018.6 hPa
WNEM4 - 9076027 - West Neebish, MI 45 mi44 min SE 8.9 G 17 37°F 1021 hPa (-1.2)22°F
RCKM4 - 9076024 - Rock Cut, MI 45 mi44 min ESE 9.9 G 18 1021.2 hPa (-1.2)
DTLM4 - 9075099 - De Tour Village, MI 48 mi44 min ENE 12 G 14 35°F 1019.8 hPa (-1.2)28°F
PTIM4 - 9099004 - Point Iroquois, MI 49 mi44 min ESE 15 G 21 35°F 1020.3 hPa (-0.9)26°F

Wind History for Mackinaw City, MI
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Mackinac Island - Mackinac Island Airport, MI8 mi64 minE 13 G 1810.00 miOvercast34°F30°F87%1020 hPa
Pellston, Pellston Regional Airport of Emmet County Airport, MI14 mi50 minE 1010.00 miOvercast38°F26°F62%1019.8 hPa
Cheboygan, Cheboygan County Airport, MI16 mi50 minE 12 G 1610.00 miOvercast36°F28°F77%1019.3 hPa

Wind History from MCD (wind in knots)
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Last 24hrE7SE8E9
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SE3CalmE5SE6E6E7E7E7E7E7E8
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1 day agoNW3CalmSW4SW3SW5SW3W6W4W5W3NW6W5NW6N6N5N7N8NE8N4NE6N5NE3NE7E8
2 days agoNW3SW5W6W6NW4NW6NW4NW4NW3NW4NW4NW5NW5N6N6N3N6N6N5N4N5NE4N3N5

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
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GOES Local Image of GreatLakes    EDIT
Geos

Wind Forecast for Gaylord, MI (12,3,4,5)
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Ground Weather Radar Station Gaylord, 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.