Saturday, November18, 2017 L-36.com


Marine Weather and Tides
Myrtle Beach, SC

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
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.

Sunrise 6:49AMSunset 5:11PM Saturday November 18, 2017 9:07 AM EST (14:07 UTC) Moonrise 6:46AMMoonset 5:42PM Illumination 0% Phase: New Moon; Moon at 29 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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AMZ254 Coastal Waters From Little River Inlet To Murrells Inlet Sc Out 20 Nm- 345 Am Est Sat Nov 18 2017
.small craft advisory in effect from this evening through Sunday afternoon...
Today..S winds 10 kt, increasing to 10 to 15 kt with gusts up to 25 kt this afternoon. Seas 2 to 4 ft.
Tonight..SW winds 20 to 25 kt, increasing to 25 to 30 kt after midnight. Seas 4 to 6 ft, building to 5 to 7 ft after midnight. A chance of showers.
Sun..W winds 20 to 25 kt, becoming nw 15 to 20 kt in the afternoon. Gusts up to 35 kt. Seas 5 to 7 ft, subsiding to 3 to 5 ft in the afternoon. A chance of showers.
Sun night..NW winds 15 to 20 kt, becoming N 10 to 15 kt after midnight. Seas 2 to 4 ft, subsiding to 2 to 3 ft after midnight.
Mon..N winds 10 to 15 kt, becoming ne 10 kt in the afternoon. Seas 2 ft in the morning, then 1 to 2 ft.
Mon night..E winds 10 kt. Seas 1 to 2 ft.
Tue..E winds 10 kt. Seas 1 to 2 ft, then 2 ft. A chance of showers through the night.
Wed..NE winds 10 to 15 kt. Seas 2 to 3 ft.
AMZ200 345 Am Est Sat Nov 18 2017
Synopsis for coastal waters from surf city north carolina to south santee river south carolina out to 20 nautical miles.. High pressure will migrate offshore this morning. A strong cold front will move off the coast and across the waters tonight into Sunday. Strong high pressure will follow and build across the local waters through Tuesday. A coastal trough may develop in the vicinity by the middle of next week.

7 Day Forecast for Marine Location Near Myrtle Beach, SC
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location: 33.68, -78.89     debug


Area Discussion for - Wilmington, NC
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Fxus62 kilm 181112
afdilm
area forecast discussion
national weather service wilmington nc
612 am est Sat nov 18 2017

Synopsis
A breezy warmup today will be followed by a strong cold front
late tonight and Sunday morning. The front may be accompanied
by some gusty late night showers. The front will usher in much
colder and drier air with Monday seeing the lowest daytime highs
with the possibility for a freeze or frost late Sunday night
and Monday night. Temperatures will moderate Tuesday and
Wednesday. Forecast uncertainty increases mid to late next week
as another cold front moves into the area. The weather could
turn unsettled and will hinge on the track of developing low
pressure in the gulf of mexico.

Near term through tonight
As of 300 am Saturday... Coldest temperatures of the season so far
ongoing across the area this morning. Many locations have dropped to
35 or less, with a few, marion, lumberton, kingstree, and conway
dropping to 32 or lower. The current 29 at lumberton is the coldest
anywhere in our CWA so far this fall. These numbers are all well
below any available guidance, and while the lav numbers and rap
profiles have tried to "catch up," they remain too warm and this has
made the next few hours a difficult forecast. Temps are lower than
guidance likely due to cloud cover eroding faster than forecast due
to subtle ridging and downward motion aloft, combined with weak
ageostrophic drainage into the area from the surface high centered
just to the north allowing the coldest dry air to bleed southward
into the cwa. Although high level cloud cover is encroaching from
the nw, expect this will have little impact on temps until just
before daybreak when subtle rises may occur, and have expanded the
fr.Y for nearly the entire area. It is possible some counties may
reach freeze warning thresholds before daybreak, but confidence is
low since temps should slowly start to creep upward after 5am, so
have opted not to go with fz.W, especially since it would be such a
late decision.

The aforementioned increased cloud cover is associated with a
shortwave and vort MAX moving through nc this morning, which is also
creating a few sprinkles showers upstream. This feature is progged
to weaken as it lifts ene and do not expect any precip even in the
far NW zones this morning - with moisture manifesting only as cloud
cover instead.

Despite the very cold start, temps will rebound quickly this
morning. A warm front lifting through the southeast ahead of a
strong cold front will push the area into a brief but strong warm
sector beginning this eve. 850mb temps are forecast to climb from
around 7c this morning, to as high as 13c this evening. This will
allow temps to soar into the low 70s most places, despite increasing
clouds both at cirrus level, and some advective stratocu and diurnal
cu in the lower levels of the column. Pushing these temperatures
upward are increasingly strong SW winds typical in the warm sector,
with forecast profiles suggesting speeds reaching 30 kt at the
top of the aftn pbl. This will potentially mix down as wind
gusts to 20-30 mph this evening, and at the same time preclude
much of an inversion after sunset so winds will remain elevated
through the end of the period.

These strong winds will become even more important tonight as a
strong cold front driven by a potent shortwave digs across the
carolinas, moving offshore Sunday morning. Along this front an area
of convection is likely, and the question remains as to how strong
this may be, and how much QPF will occur across the area. Guidance
has slowed the fropa, so any showers are not expected until well
after midnight, and likely won't exit the coast until Sunday
morning. This front will encroach upon a region characterized by
very little CAPE (the most I could find was just 60 j kg of mucape),
but low-level winds of 50-60 kt at 2-3 kft, very strong 0-6km
shear near 60 kt, and strong but weakening 925-700mb fgen.

Parcels lifting along the front will be capped above 700mb, at
which temperatures are too warm for charge separation, and the
weak inversion above this layer will not be overcome due to the
weak instability. For this reason have left out any mention of
thunder for tonight. However, showers occurring within these
very strong low-level wind fields will support strong wind
gusts, possibly reaching 40-50 mph in any stronger echoes as
the line shifts east towards daybreak Sunday. Rainfall will be
limited across the area as showers likely weaken as they
progress quickly to the east.

With the slower fropa, WAA will be ongoing much of tonight, so mins
will be uncharacteristically warm, dropping only to around 60 at the
coast, mid 50s inland, quite a change from the temperatures being
experienced at present!

Short term Sunday through Monday night
As of 300 am Saturday... Models have slowed and the passage of
a strong cold front should take place a few hours later than
previously thought. Current thinking is that the front will be
moving through the inland zones near daybreak Sun and then
offshore mid and late morning. The slower timing requires that
we keep a low risk for showers in the forecast a little longer,
but maintaining the theme of the last several cycles, QPF will
be light and generally a tenth of an inch or less in any one
location. Will end the risk for showers from W to E Sun morning
as quick clearing surges across the eastern carolinas. The
coldest air will move across the area later in the afternoon and
sun eve with 850 mb temps dropping to near zero. The 50 kt low-
level jet (2-3 kft off the surface) will be lifting out
by during Sun morning, but cold and dry air advection will allow
for a well mixed environment and so it should be brisk on sun
with sustained winds in the 15 to 30 mph range. A slower timing,
especially given the quick return to sunshine, should allow
temps to reach within a few degrees of normal given lows sat
night will be well above normal.

Canadian high pressure will build to the coast Sun night and then
overhead Mon and Mon night. The strongest cold air advection
will wane overnight sun, however, radiational cooling will
maximize as winds go light to calm. Precipitable water values
drop to just a tenth of an inch and it does not get drier than
that. Dewpoints will fall into the 20s overnight Sun and so
there will be plenty of room for temps to drop. Much of the
guidance has come in a little warmer for Sun night, but I think
they will trend lower in later runs. Frost seems like a low
risk given the magnitude of dry air, but a freeze is very much
in play for much of our inland communities, with a much lower
risk for freezing temps near the more immediate coast. Later
packages will likely be raising freeze watches and freeze
warnings for portions of the forecast area.

Monday will be the coolest day of the week and after a chilly
start, highs are only expected to recover into the mid to
perhaps upper 50s, even with bright sunshine with afternoon
relative humidity dropping through the 30s. Light winds on mon
will not add a significant sting to the chill. The center of the
high will move offshore later Mon night, but will continue to
ridge back across the eastern carolinas, keeping the column
exceedingly dry. Typically, models will show temps moderating
too quickly in these situations. Thus, the low temp forecast
undercuts model consensus in most locations. We are forecasting
lower to mid 30s with upper 30s to 40 degrees at the immediate
coast. Where the growing season is still ongoing, a widespread
frost may occur with some inland locations dipping to freezing.

The only limitation to frost development would be if dewpoints
can not recover sufficiently to bring dewpoint depressions to
within a degree or two of each other overnight. The risk for
frost will exist as you near the coast as well, but beach
communities should be spared except on an isolated basis.

Long term Tuesday through Friday
As of 300 pm Friday... A split upper pattern will exist next week
across north america. A series of shortwaves moving across
southeastern canada in the northern stream will have relatively
little impact on the carolinas, however a pair of shortwaves in the
southern stream will have impacts on our sensible weather Tuesday
and Thursday night into Friday.

Veering low-level winds and a warm advection pattern developing
Tuesday and Tuesday night should support the development of a
coastal trough as a weak shortwave approaches from the
southwest. There are significant model differences in the track
the shortwave takes (ecmwf from south ga to CAPE fear; GFS from
central ga to near norfolk) which then determine how well-
developed the surface system can become. A compromise solution
should advect enough shallow atlantic moisture back onshore for
a 20-30 percent chance of showers Tuesday night, clearing out by
Wednesday morning as the shortwave moves offshore. Cold air
will sneak south as another canadian high moves across the ohio
valley. This should keep highs on thanksgiving day only in the
upper 50s to around 60, a good 6-8 degrees below normal.

Attention then turns to a much stronger shortwave diving into the
western and central gulf of mexico Wednesday night and Thursday.

Just like yesterday there are still model differences here, with the
ecmwf slower than the GFS with the eastward movement of the trough
across the gulf of mexico Thursday and Friday. A compromise solution
of the operational gfs, ecmwf, and their ensembles brings rain
chances into the area Thursday night through Friday night, but given
all the uncertainty (and to better blend with surrounding nws
offices) i'm capping pops no higher than 30 percent for now.

Aviation 12z Saturday through Wednesday
As of 12z... The big story of the coming 24 hours will be
increasing south to southwest winds ahead of a cold front which
should reach the area just before sunrise Sunday morning. Light
south winds this morning should increase this afternoon to 10-15
kt with gusts over 20 knots developing by 20z. Winds 500-2000
feet above ground level will continue to increase after sunset,
reaching 35-40 knots overnight. Surface winds should remain
only 10-15 knots with gusts 20-25 kt due to poor mixing given
the time of day.

The cold front should reach the flo-lbt corridor around 08-09z
Sunday, shifting winds westerly, and potentially bringing a
short period of MVFR ceilings and light showers. Any measurable
rainfall or low cloudiness will become more spotty as the front
reaches the coast just before sunrise.

Extended outlook...VFR conditions are expected Sunday through
Tuesday morning. There is potential for MVFR ceilings Tuesday
night and Wednesday.

Marine
Near term through tonight ...

as of 300 am Saturday... Placid marine conditions early this morning
will begin to deteriorate quickly this aftn. A warm front will lift
north through the southeast today, ahead of a cold front which will
approach the waters late tonight. This leaves increasing SW winds
across the area, with speeds rising from 10-15 kt late this
morning, to 20-30 kt tonight. Gusts to gale force are also
likely, and may approach 40 kts at times. These strong winds
have necessitated the issuance of an sca, which GOES into effect
at 7pm this evening for all waters. After a period of low-
amplitude seas through this morning, wave heights will grow
steadily, finally peaking at 5-9 ft tonight during the period of
strongest winds. The cold front will likely be positioned just
west of the waters at the end of the period, but scattered
showers with locally higher and erratic winds are possible
tonight anywhere in the local waters.

Short term Sunday through Monday night ...

as of 300 am Saturday... Strong small craft advisory conditions
will slowly wane through the day sun. A strong cold front will
be moving offshore Sun morning, sweeping in a chilly and very
dry airmass. Canadian high pressure will slowly build from the
west Sun afternoon and night and then overhead mon. The center
of the high will move offshore late Mon night.

Sustained wind speeds will be up to 25 to 30 kt Sun morning with
a few lingering gusts to gale force early, decreasing to about
20 kt by late Sun afternoon and 15 to 20 kt overnight sun. A
further reduction in wind speeds is expected mon, from 10 to 15
kt to 10 kt or less and these light winds will hold Mon night.

Seas will be highest Sun morning, up to 6 to 9 ft. The developing
strong offshore flow Sun should knock seas below 6 ft throughout
late in the day. Seas will subside to 3 to 4 ft Sun night and
to 2 ft or less Mon afternoon and night.

The wind direction will be shifting from SW and wsw to NW sun
morning. NW winds will veer to N Sun night. N winds Mon will
veer to NE with easterly winds developing late Mon night.

Long term Tuesday through Wednesday ...

as of 300 pm Friday... Return flow behind the departing high
Tuesday will buckle as a coastal trough develops along the
southeast coast. Winds should turn easterly on Tuesday, then
perhaps southeasterly for a time Tuesday night as the trough
makes its closest approach to shore, but by Wednesday morning
the feature should retreat back offshore as high pressure
advances across the ohio valley and shifts our winds to a more
northerly direction.

Ilm watches warnings advisories
Sc... Frost advisory until 8 am est this morning for scz017-023-024-
032-033-039-053-055.

Nc... Frost advisory until 8 am est this morning for ncz087-096-099-
105>107-109.

Marine... Small craft advisory from 6 pm this evening to 6 pm est Sunday
for amz250-252-254-256.

Synopsis...

near term... Jdw
short term... Rjd
long term... Tra
aviation... Tra


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
41024 - Sunset Nearshore (SUN 2) 24 mi60 min SE 7.8 G 9.7 61°F 62°F1017.8 hPa
NIWS1 - North Inlet-Winyah Bay Reserve, SC 28 mi83 min NW 1 50°F 1018 hPa49°F
41108 46 mi38 min 64°F2 ft

Wind History for Springmaid Pier, SC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Myrtle Beach Air Force Base, SC2 mi72 minN 010.00 miFair48°F45°F89%1018.5 hPa
North Myrtle Beach Grand Strand Airport, SC13 mi75 minVar 39.00 miFair47°F46°F100%1018.1 hPa
Conway Horry County Airport, SC16 mi73 minN 05.00 miFog/Mist37°F37°F100%1018.3 hPa

Wind History from MYR (wind in knots)
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Last 24hrNE12NE9N645SE5SE4SE3CalmCalmCalmW3CalmCalm--CalmCalmCalmCalmCalmN3CalmCalmSE8
1 day agoNW7NW8NW9NW7NW3N8W6W4CalmW3CalmCalmCalmCalmCalmCalmN5N7N9N9N11NE8N11NE8
2 days agoNE9NE11NE5N5N5N6N7N5W4CalmN3N4N3CalmNW7CalmNW3CalmNW3CalmCalmCalmNW6NW6

Tide / Current Tables for Myrtle Beach, South Carolina
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Myrtle Beach
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Sat -- 12:54 AM EST     -0.08 feet Low Tide
Sat -- 06:42 AM EST     New Moon
Sat -- 06:45 AM EST     Moonrise
Sat -- 06:50 AM EST     Sunrise
Sat -- 07:07 AM EST     5.82 feet High Tide
Sat -- 01:25 PM EST     0.07 feet Low Tide
Sat -- 05:10 PM EST     Sunset
Sat -- 05:42 PM EST     Moonset
Sat -- 07:13 PM EST     4.92 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.2-0.10.41.42.94.35.45.85.64.73.420.80.10.212.23.54.54.94.7431.7

Tide / Current Tables for Socastee Bridge, South Carolina
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Socastee Bridge
Click for Map
Sat -- 05:56 AM EST     0.07 feet Low Tide
Sat -- 06:42 AM EST     New Moon
Sat -- 06:46 AM EST     Moonrise
Sat -- 06:50 AM EST     Sunrise
Sat -- 11:04 AM EST     2.56 feet High Tide
Sat -- 05:11 PM EST     Sunset
Sat -- 05:42 PM EST     Moonset
Sat -- 06:33 PM EST     0.15 feet Low Tide
Sat -- 11:09 PM EST     2.21 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
2.11.71.30.90.50.20.10.411.82.32.62.52.21.81.30.80.40.20.20.71.422.2

Weather Map and Satellite Images
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Weather Map
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IR Satellite Image from GEOS
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Wind Forecast for Wilmington, NC (9,2,3,4)
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Ground Weather Radar Station Wilmington, NC
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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.