Wednesday, July17, 2019 L-36.com


Marine Weather and Tides
Grand Marais, MN

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Sunrise 6:12AMSunset 9:54PM Wednesday July 17, 2019 12:43 PM EDT (16:43 UTC) Moonrise 9:39PMMoonset 5:50AM Illumination 100% 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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LSZ162 Lake Superior West Of A Line From Saxon Harbor Wi To Grand Portage Mn Beyond 5nm- 355 Am Edt Wed Jul 17 2019 /255 Am Cdt Wed Jul 17 2019/
Early this morning..Northeast winds 5 to 15 knots. Waves calm to 2 feet.
Today..Northeast winds 5 to 15 knots increasing to 10 to 20 knots in the afternoon. Patchy fog through early afternoon. A chance of showers and Thunderstorms late. Waves building to 2 to 4 feet.
Tonight..Northeast winds 10 to 20 knots diminishing to 5 to 15 knots after midnight. A chance of showers through midnight. A chance of Thunderstorms. Showers likely after midnight. Waves subsiding to calm to 2 feet.
Thursday..West winds 5 to 15 knots backing south late. A slight chance of showers and Thunderstorms through early afternoon. Patchy fog. Waves calm to 2 feet.
Thursday night..Southwest winds 5 to 15 knots. Patchy fog through midnight. A slight chance of showers after midnight. Waves calm to 2 feet.
Friday..Southwest winds 5 to 15 knots veering west by mid afternoon. Waves calm to 2 feet.
Friday night..West winds 5 to 15 knots. Waves calm to 2 feet.
Saturday..West winds 5 to 15 knots veering northeast. Waves calm to 2 feet.
Sunday..Northeast winds 5 to 15 knots backing north. A chance of showers. Waves calm to 2 feet.
LSZ162 Expires:201907171500;;768860 FZUS63 KMQT 170755 GLFLS Open Lake Forecast for Lake Superior National Weather Service Marquette MI 355 AM EDT Wed Jul 17 2019 For waters beyond 5 nautical miles of shore on Lake Superior. 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...A 30.0 inches high north of Lake Superior will move eastward by tonight. As the high moves to southern Quebec, low pressure of 29.6 inches will organize over southern Manitoba. This low will deepen to 29.2 inches as it tracks across northern Ontario on Thursday. An associated 29.6 inch trough will sweep across Lake Superior Thursday night, lingering much of Friday despite the main low tracking into Northern Quebec. Predictability is lower Saturday, but a 29.9 inch high pressure ridge looks to build back into Manitoba, expanding over the northern Plains and strengthening to 30.2 inches by Sunday evening. LSZ162-171500-


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 171137
afddlh
area forecast discussion
national weather service duluth mn
637 am cdt Wed jul 17 2019

Short term (today through Thursday)
issued at 401 am cdt Wed jul 17 2019
after a brief respite from showers and thunderstorm activity,
chances of thunderstorms will increase across the region today,
continuing through the overnight hours.

As of 4 am 09z this morning, a large complex of showers and
thunderstorms continue to translate eastward over the dakotas. This
activity is associated with a potent mid-level shortwave that will
arrive after sunrise today on southwest flow aloft, and could lead
to strong to severe thunderstorms today and tonight. Considerable
uncertainty exists regarding how the convection will evolve. There
is a large area of instability over iowa southern minnesota, with
the northern fringes of the instability making its way northward as
an elevated warm front ascends into the region. Mixed-layer cape
values will generally range between 1000 to 2000 j kg, with
increasing southerly flow. Effective bulk shear values could range
between 40 to 50 knots this afternoon and evening, which should
sustain some convective updrafts. The latest runs of the cams show a
complex of thunderstorms diving to the southeast along the cape
gradient, which could limit destabilization for thunderstorms over
our area. However, if the environment over our area remains
unmodified, then there could be some organized clusters of storms.

Due to the favorable shear profiles, it's possible that some
supercells could develop, capable of large hail, damaging winds, and
possibly a tornado - most likely over northeast minnesota.

Temperatures will be cooler along lake superior due to northeasterly
on-shore flow due to large surface high pressure over ontario and
approaching surface low to the southwest over the central great
plains. Due to the gusty northeast flow, there is also the potential
for rip currents near twin PORTS beaches. Thus, we have issued a
beach hazards statement for today.

The severe storm threat will continue into the evening hours
tonight, along with a threat for flash flooding as the nocturnal low-
level jet develops. We did decrease the QPF amounts quite a bit due
to the deterministic models shifting the nose of the low-level jet,
and hence, the more favorable moisture transport, farther south. We
can't rule out some risk of flash flooding, especially for areas
that see multiple rounds of convection, but the risk has diminished.

Pwat values from the 17.00z GFS and NAM models continue to be
between 1.6" to 2.1", which are about 97 to 99 percent of
climatology, per the naefs pwat anomalies. Generally, most areas
across the northland will see anywhere between a quarter of an inch
up to one inch in rainfall amounts. However, some isolated areas
could see amounts closer to 1.50" to 2.00" if hit by repeated rounds
of thunderstorms.

Thursday will be drier overall as the mid-level shortwave kicks out
to the east, and the upper-level flow becomes more zonal. There
could be some thunderstorms lingering over north-central wisconsin
by sunrise Thursday morning, but should diminish pretty quickly.

Another mid-level impulse will sweep through the region Thursday,
and bring another round of showers, and perhaps an isolated
thunderstorm, over northeast minnesota. Thursday looks to be
another hot and muggy day, with highs in the middle to upper 80s,
and dew points in the middle to upper 60s.

Long term (Thursday night through Tuesday)
issued at 355 am cdt Wed jul 17 2019
a fast west southwest flow aloft will start out the period with a
transition to northwest flow on Sunday.

We have low pops Thursday night into Friday as a weak trough crosses
the area during that time. Weak high pressure will move into north
dakota into northwest minnesota on Friday. Instability will decrease
from north to south into Friday but remain high enough over
northwest wisconsin and adjacent areas of east central minnesota for
thunderstorms through Friday. Friday will be warm with highs in the
mid eighties to around ninety in northwest wisconsin to the lower to
mid eighties elsewhere. It will still be muggy over northwest
wisconsin with dewpoints dropping back into the fifties over
northern minnesota.

We have pops over southern portions of the northland Friday night
into Saturday as that area may be close enough to a frontal boundary
stalled south of the region. Temperatures will cool a bit more into
Saturday closer to normal and dewpoints will also drop to 55 to 60.

A stronger shortwave will arrive Saturday night into Sunday. There
remains timing differences among the models but they're getting
closer. A chance for showers and thunderstorms will occur with the
shortwave. Instability will be limited so the threat for severe
storms looks low at this time.

As the upper flow becomes northwest Sunday into much of next
week, a longer stretch of dry weather or at least only low pops
will occur. Temperatures will also be near normal.

Aviation (for the 12z tafs through 12z Thursday morning)
issued at 636 am cdt Wed jul 17 2019
a frontal boundary and area of low pressure will act on an
increasingly unstable airmass today to produce showers and
thunderstorms. Coverage should increase later this afternoon and
through the evening hours. There remains uncertainty in the timing
and the current tafs reflect the best opportunities for
showers storms. Later updates will continue to refine the timing.

Some of the storms could be strong to severe and updates to the
tafs to reflect stronger winds and lower visibility will be a
short term issue. Ceilings will lower tonight to MVFR and ifr for
most areas and there will be areas of fog as well.

Marine
Issued at 355 am cdt Wed jul 17 2019
the gradient will increase today as western lake superior will be
between high pressure off to the northeast and low pressure
approaches the region. Expect easterly winds to increase through
early afternoon then slowly subside this evening. The best
combination of winds from 15 to 20 knots and waves of 3ft+ will be
from silver bay to the twin PORTS to sand island. We will issue a
small craft advisory for that area into this evening. A small
craft advisory may need to be expanded some up the north shore but
confidence is lower there. Thunderstorms will be possible this
afternoon into tonight. Some of the storms could be strong to
severe, producing locally high wind and waves.

The wind will be west to southwest Thursday into Friday, with
speed from 5 to 15 knots.

Preliminary point temps pops
Dlh 74 61 86 66 40 70 10 10
inl 78 62 85 62 60 70 30 30
brd 82 67 87 68 50 60 10 10
hyr 84 67 88 67 30 60 30 20
asx 83 65 88 67 30 70 20 10

Dlh watches warnings advisories
Wi... Beach hazards statement from 10 am cdt this morning through this
evening for wiz001.

Mn... Beach hazards statement from 10 am cdt this morning through this
evening for mnz037.

Ls... Small craft advisory from 10 am this morning to 10 pm cdt this
evening for lsz143>146.

Short term... Jts
long term... Melde
aviation... Melde
marine... Melde


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
KGNA 26 mi47 min ENE 8.9 58°F 1013.7 hPa53°F
GD5 - 9099090 - Grand Marais, MN 26 mi61 min 57°F 48°F1013.7 hPa56°F
ROAM4 - Rock of Ages, MI 30 mi43 min NE 8 G 8 61°F 1016.3 hPa (+0.0)
45006 - W SUPERIOR 48NM North of Ironwood, MI 37 mi53 min NNE 9.7 G 9.7 49°F 50°F1013.8 hPa (+0.0)

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Grand Marais/Cook County Airport, MN27 mi48 minSE 310.00 miFair73°F55°F53%1014.9 hPa

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Last 24hrNW4W4W4W6NW3NW4--CalmCalmCalmN4N3CalmN3N3N3N3CalmNE4NE3SE3SE3E4SE5
1 day agoS9
G16
S9S8S7S3W4CalmCalmCalmCalmS3CalmCalmCalmW3W3W3CalmCalmNW4W3W7W8W8
2 days agoS5S6S7S9S5CalmCalmCalmCalmCalmE4CalmCalmCalmCalmS3CalmCalmCalmCalmS5S5S6S6

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Wind Forecast for Duluth, MN (12,3,4,5)
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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.