Sunday, April30, 2017 L-36.com


Marine Weather and Tides
Grand Marais, MN

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 6:35AMSunset 9:12PM Sunday April 30, 2017 10:50 AM EDT (14:50 UTC) Moonrise 9:28AMMoonset 12:03AM Illumination 21% Phase: Waxing Crescent; Moon at 5 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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LSZ162 Lake Superior West Of A Line From Saxon Harbor Wi To Grand Portage Mn Beyond 5nm- 1018 Am Edt Sun Apr 30 2017 /918 Am Cdt Sun Apr 30 2017/
.gale warning in effect from 8 pm edt /7 pm cdt/ this evening through Monday afternoon...
Rest of today..Northeast winds 15 to 25 knots increasing to 20 to 30 knots by mid afternoon. Waves 1 to 3 feet building to 4 to 7 feet occasionally to 9 feet.
Tonight..Northeast winds 20 to 30 knots increasing to gales to 40 knots after midnight. Scattered rain showers through midnight...then rain showers. A chance of snow showers. Waves building to 6 to 9 feet occasionally to 11 feet.
Monday..Northeast gales to 40 knots. Scattered snow showers through early afternoon...then snow showers. Rain showers. Waves building to 8 to 11 feet occasionally to 14 feet...then subsiding to 6 to 9 feet occasionally to 11 feet.
Monday night..North winds 20 to 30 knots diminishing to 15 to 25 knots after midnight. Rain showers and snow showers likely through midnight...then scattered rain and snow showers after midnight. Waves subsiding to 3 to 5 feet occasionally to 7 feet.
Tuesday..North winds 15 to 25 knots becoming northwest 10 to 20 knots by mid afternoon. Scattered snow showers through early afternoon. A chance of rain showers. Waves subsiding to 1 to 3 feet.
Tuesday night..Northwest winds 5 to 15 knots backing west after midnight. Waves subsiding to calm to 2 feet.
Wednesday..South winds 5 to 15 knots. Waves calm to 2 feet.
Thursday..Southwest winds 5 to 15 knots veering north. Waves calm to 2 feet.
LSZ162 Expires:201704302230;;506798 FZUS63 KMQT 301418 GLFLS OPEN LAKE FORECAST FOR LAKE SUPERIOR NATIONAL WEATHER SERVICE MARQUETTE MI 1018 AM EDT SUN APR 30 2017 FOR WATERS BEYOND FIVE NAUTICAL MILES OF SHORE ON LAKE SUPERIOR WAVES ARE PROVIDED AS A RANGE OF SIGNIFICANT WAVE HEIGHTS, WHICH IS THE AVERAGE OF THE HIGHEST 1/3 OF THE WAVE, ALONG WITH THE AVERAGE HEIGHT OF THE HIGHEST 10% OF THE WAVES WHICH WILL OCCASIONALLY BE ENCOUNTERED. .SYNOPSIS...HIGH PRESSURE OF 30.4 INCHES CENTERED NEAR JAMES BAY WILL MOVE OVER QUEBEC THIS AFTERNOON AND TONIGHT. MEANWHILE...LOW PRESSURE OF 29.6 INCHES OVER THE SOUTHERN PLAINS WILL DEEPEN TO 29.2 INCHES AS IT LIFTS NORTHEAST...REACHING CENTRAL UPPER MICHIGAN MONDAY EVENING AND QUEBEC TUESDAY AFTERNOON. IN ITS WAKE...A HIGH PRESSURE RIDGE OF 29.9 INCHES DEVELOPING OVER THE UPPER MISSISSIPPI VALLEY TUESDAY AFTERNOON WILL BUILD TO 30.1 INCHES OVER THE GREAT LAKES REGION ON WEDNESDAY. THE RIDGE WILL THEN WEAKEN ON THURSDAY AS A LOW PRESSURE TROUGH OF 29.9 INCHES APPROACHES FROM THE NORTHWEST. LSZ162-302230-

7 Day Forecast for Marine Location Near Grand Marais city, MN
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location: 47.86, -89.87     debug


Area Discussion for - Duluth, MN
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Fxus63 kdlh 301127
afddlh
area forecast discussion
national weather service duluth mn
627 am cdt Sun apr 30 2017

Short term (today through Monday)
issued at 412 am cdt Sun apr 30 2017
the focus remains on the potential for snow tonight and Monday
associated with an area of low pressure that will lift into the
upper midwest. It still appears much of the northeast minnesota
will get accumulating snow, but there is increasing confidence the
snowfall will remain below 6 inches, enough so to warrant dropping
the winter storm watch in favor of a winter weather advisory.

Please read on for more details.

A potent area of low pressure over the southern plains, as of
early this morning, will lift into the central plains today and
become well organized and vertically stacked. Meanwhile, an area
of high pressure near james bay in canada will maintain dry and
cool easterly flow across the northland today. Strong northeast
flow will develop over western lake superior, translating into
gusty and cool flow downwind of the lake across portions of
northwest wisconsin, the twin PORTS area, and into east-central
minnesota. Cirrus will continue to spread into the northland
today because of the upper- level flow from the low, maintaining
scattered to broken cloud cover for much of the day and limiting
our heating potential. There was a general trend in warmer trend
in the latest model runs for today's temperatures compared to the
previous model runs, so increased today's high temperature
forecast a bit, despite leaning with the cooler models. Highs
should range from the upper 30s to low 40s near lake superior, to
the middle 40s farther inland from the lake, and to as high as the
upper 40s to low 50s for areas of central into north-central
minnesota out of the way from the lake superior flow.

The low will move into the central plains this afternoon and will
lift into the upper midwest tonight and Monday, reaching southeast
minnesota and west-central wisconsin by late Monday morning. This
low will spread abundant moisture into the northland tonight and
early Monday, with precipitable water values of about 0.75 inches.

Widespread synoptic lift from the approaching low, as well as from
embedded shortwaves in the flow, will bring increasing chances of
rain from the south late this afternoon into tonight with this
surge of moisture. The latest models slowed down the timing of the
precipitation lifting into the northland. This is not a surprising
trend for well-entrenched dry air across the northland, so leaned
on the slowest models, including the NAM and regional canadian,
for the onset of the precipitation because the rain will more
likely be virga until the moisture can modify the dry air.

The moderate rain will move into central and northeast minnesota
by the wee hours of Monday morning. While temperatures aloft, in
the low and mid-levels, will initially support primarily rain,
there will be a transition to snow overnight into Monday morning
because of dynamic cooling from the falling snow from the
upper/mid-levels, which will cool the low-levels and near the
surface near the surface. While some of that snow may melt at
first, it should not take long for the snow to accumulate given
the decent snowfall rates. Plus, there will likely be a period of
good dendritic growth from good lift and saturation near the -15
degree celsius areas aloft to enhance the snowfall rates. Despite
the favorable environment for snow, there has been some backing
off in the latest model runs in the potential for heavy snow
(greater than 6 inches). The slower trend of the models in
bringing in the precipitation, though, is perhaps one reason the
threat of heavy snow looks less likely than it did yesterday
afternoon, since more of the snow may fall well into the morning
hours, with melting cutting down on total snowfall accumulation.

The previously faster model runs would have brought more of the
snow overnight when temperatures could remain cold and support
snow accumulation. The latest forecast is now for widespread
snowfall of 2 to 5 inches across much of northeast minnesota, but
would not be surprised if isolated locations approach 6 inches.

Some parts of northwest wisconsin, from the superior area into the
bayfield peninsula, could also get up to a couple inches of snow.

Snow or snow, this low will bring widespread rainfall of 0.50 to
1.25 inches across much of the northland, with the heaviest rain
in northwest wisconsin. Many rivers in the northland will likely
respond with significant rises into the middle of the week as the
rain works its way into the rivers.

The snow should transition back to rain or wintry mixture, with
little additional snow accumulation, by Monday afternoon when the
deeper moisture and synoptic lift moves out of the northland.

Cool and gusty north to northeast flow and rain and light snow
will continue through the day. Highs will only range from the
middle 30s to low 40s, with the warmest of those temperatures
limited to the fringes of the far southeast and far northwest
forecast area.

Long term (Monday night through Saturday)
issued at 412 am cdt Sun apr 30 2017
the vertically stacked system moves from northeast wisconsin to
quebec Monday night. Will have highest pops in the evening,
trending downward overnight. Will see a mix of rain and snow in
the evening, becoming all snow in some locations as colder air
allows for a change over. Forecast soundings no longer support any
freezing rain Monday night and have removed. Some light snow
accumulation is possible over the arrowhead. The aforementioned
system no longer affects the region on Tuesday. However, a
positively tilted short wave trof moves over the area. Will carry
pops over the eastern third of the forecast area Tuesday as the
trof passes and where best forcing is found. Will see a transition
from snow early, to a rain/snow mix by mid morning, then all rain
in the afternoon. MAX temps will return to near normal. The
shortwave departs by Tuesday evening. This allows some ridging to
build over the area for Tuesday night late and Wednesday morning.

Precipitation returns Wednesday afternoon through Thursday. There
are differences amongst the models on the handling of a long wave
trof on the region. This includes timing, location, strength and
qpf. Used a blended approach for pops and ptypes. The long wave
trof departs Thursday night. A cold front follows behind and with
just enough moisture, may wring out a few showers over north
central wisconsin in the evening. The cold front falls apart
overnight as upper level and surface ridging build into the
region. This ridging remains over the area through Saturday. Max
temps return to the 50s and 60s during this time.

Aviation (for the 12z tafs through 12z Monday morning)
issued at 627 am cdt Sun apr 30 2017
vfr at the start of the forecast. By mid day, gusty northeasterly
winds will affect all terminals but inl. As the storm moves closer
toward the end of the forecast, look for CIGS to drop into MVFR
range as the rain develops/arrives. Look for the rain to change
over to snow at dlh/hib/brd around 03z and ifr CIGS at hyr by 07z.

Hyr should stay all rain and inl will not be affected by
precipitation during this forecast.

Preliminary point temps/pops
Dlh 44 33 36 32 / 10 100 100 60
inl 54 34 41 33 / 0 30 60 50
brd 50 33 39 33 / 20 100 100 50
hyr 46 35 39 33 / 30 100 80 60
asx 43 34 38 33 / 20 100 90 70

Dlh watches/warnings/advisories
Wi... None.

Mn... Winter weather advisory from midnight tonight to noon cdt Monday
for mnz011-012-018-019-025-026-033>037.

Ls... Small craft advisory until 4 am cdt Tuesday for lsz121-140>148.

Short term... Grochocinski
long term... Gsf
aviation... Gsf


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
KGNA 26 mi54 min ENE 12 G 17 43°F 1023.1 hPa26°F
GD5 - 9099090 - Grand Marais, MN 26 mi50 min 44°F 1021.5 hPa (-2.4)29°F
ROAM4 - Rock of Ages, MI 30 mi50 min NE 18 G 19 41°F 1024.5 hPa (-2.5)
DISW3 - Devils Island, WI 71 mi50 min NE 19 G 21 38°F 1021.7 hPa (-2.9)32°F

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Grand Marais/Cook County Airport, MN27 mi57 minE 710.00 miFair41°F15°F36%1021.7 hPa

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Last 24hrCalmCalmSW4SE6SE8S8S6CalmCalmCalmCalmE3CalmCalmN3N4N6N5NE5N5NE4NE5NE8E9
G16
1 day agoW3W3CalmCalmW4NW3NW3NW3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmN3CalmCalmCalm
2 days agoNW3NW4NW3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmW3W4

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
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Wind Forecast for Duluth, MN (10,2,3,4)
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Ground Weather Radar Station Marquette, 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.