Friday, August18, 2017 L-36.com


Marine Weather and Tides
Folly 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 6:44AMSunset 8:01PM Friday August 18, 2017 12:25 PM EDT (16:25 UTC) Moonrise 2:19AMMoonset 4:35PM Illumination 14% Phase: Waning Crescent; Moon at 26 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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AMZ330 Charleston Harbor- 1029 Am Edt Fri Aug 18 2017
Rest of today..SW winds 15 kt.
Tonight..SW winds 15 kt.
Sat..SW winds 5 to 10 kt, increasing to 15 kt in the afternoon. A chance of showers and tstms.
Sat night..SW winds 5 to 10 kt. A chance of showers and tstms.
Sun..S winds 5 to 10 kt. A chance of showers and tstms.
Sun night..S winds 5 to 10 kt. A chance of showers and tstms.
Mon..S winds 5 to 10 kt. A chance of showers and tstms.
Mon night..S winds 5 to 10 kt. A slight chance of showers and tstms.
Tue..SW winds 5 to 10 kt. A chance of showers and tstms.
Tue night..SW winds 5 to 10 kt. A slight chance of showers and tstms. Mariners are reminded that winds and waves higher in and near tstms. Unless otherwise noted, waves 1 foot or less. Charleston harbor water temperature 86 degrees.
AMZ300 1029 Am Edt Fri Aug 18 2017
Synopsis for the coastal waters of south coastal south carolina and north coastal georgia.. Atlantic high pressure will remain in control as troughing persists inland through late this week. A cold front will dissipate as it approaches the area this weekend. High pressure will then return early next week before another cold front likely affects the area for mid week.

7 Day Forecast for Marine Location Near Folly Beach, SC
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location: 32.66, -79.92     debug


Area Discussion for - Charleston, SC
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Fxus62 kchs 181453
afdchs
area forecast discussion
national weather service charleston sc
1053 am edt Fri aug 18 2017

Synopsis
Atlantic high pressure will remain in control as troughing
persists inland through late this week. A cold front will
dissipate as it approaches the area this weekend. High pressure
will then return early next week before another cold front
likely affects the area for mid week.

Near term through tonight
Two minor changes to the forecast.

1. Convergence along the southern half of the coastal waters has
allowed showers to develop. Some rumbles of thunder are
certainly possible, mainly along the mcintosh coast. We added
slight chance pops to portions of the coastal waters, extending
up to the immediate mcintosh coastline. These showers should
gradually dissipate over the next few hours as convective
development shifts to the land areas.

2. Adjusted the sky cover
per latest satellite imagery to reflect less clouds over land
and more over waters, then have clouds gradually increasing into
this afternoon.

Otherwise, the temperatures and dew points are fairly close to
the current forecast.

Rest of today: the recent strong ridging atop the area is still
evident, but is flattened as a short wave passes by to the n
this afternoon within the westerly flow that covers a good chunk
of the conus. Further S we find a prominent tutt low heading
w wnw from the bahamas toward the fl keys. Meanwhile at the
surface the local region remains situated between the piedmont
trough inland and the sub-tropical ridge aligned e-w across fl
into the gulf of mexico.

It'll be another abnormally hot day due to the combination of
both 850 mb and 925 mb temps that are at least 2-3 standard
deviations above normal. Throw in some compressional heating
with some downslope off the appalachians and MAX temps will peak
at 94-97f most places. The exceptions will be along the
shoreline where the resultant sea breeze "limits" highs to the
upper 80s and lower 90s.

These temperatures combined with dew points in the mid and upper
70s will yield heat indices approaching 110 degrees near and
east of i-95. The current forecast has a few points touching
this temperatures for an hour, but the areal coverage appears
limited and it's not the minimum two hours to necessitate a
heat advisory. Even with the surge in dew points with the
afternoon sea breeze, the increase in heat index should be brief
enough to keep the coastal counties out of advisory criteria.

Of course, if temperatures and or dew points are 1-2 degrees
warmer than expected, then that will be enough to tip the bucket
in favor of an advisory. Further inland, dew points will mix
out enough with the westerly trajectories and heat indices will
average 105-107 degrees.

Warm mid levels, moisture confined generally to the first 2-3
miles of the troposphere and the only forcing from the sea
breeze and outflow boundaries, our risk for convection is held
down this afternoon. Most of the hi-res models now show limited
convection along the coast starting at about 2 pm and then
transitioning inland into the evening. Drier air shown on water
vapor satellite imagery could limit this potential, but we're
hesitant to go any lower than slight chance pop's given mlcape
over 2,000 j kg. Whatever storms do form have the potential for
locally heavy rains given pwat 120-130% of normal and weak
steering flow. Dcapes as high as 1,200 j kg could produce a
strong wind threat.

Tonight: lingering boundaries and the sea breeze far inland
during the evening will maintain small pop's along the far nw
tier through mid to late evening, before chances drop below 15%
during the post-midnight hours. Moisture convergence will allow
for some nocturnal convection out near the gulf stream, but
nothing onshore. Some of the statistical guidance shows a little
fog closer to daybreak Saturday with condensation pressure
deficits down under 20 mb. But cross-over temps will be hard to
reach, and the ground is so warm. Thus no mention of fog at this
time. It'll be another very warm and muggy night, and record
high minimum temps will be challenged.

Short term Saturday through Monday
Weak troughing Saturday will give way to a building ridge early next
week. This will cause an approaching cold front to stall and weaken
north and west of the area. However, deep moisture and some
convergence from the inland trough and sea breeze should yield
scattered convection each day. A few strong to severe thunderstorms
are possible, but the severe storm threat overall is low as the
storms will primarily be of the pulse variety. Locally heavy
rainfall will be possible too given the abundant moisture and
relatively weak storm motions, and this could pose a risk of
flooding, especially near the coast as tides will be running high.

Temps in the lower mid 90s combined with high humidity will lead to
heat index values peaking over 100 degrees most locales each
afternoon, probably highest across southeast ga on Saturday where
values could near advisory levels (110 degrees).

Long term Monday night through Thursday
Very strong upper ridging will prevail into Tuesday before a trough
and cold front move in for the middle to latter portion of the week.

This will lead to increasingly unsettled weather toward mid week,
especially Thursday as the front moves into the area. Temperatures
should remain above normal through the period, except possibly
Thursday depending on the location of the front.

Aviation 15z Friday through Tuesday
Vfr through 12z Saturday.

Extended aviation outlook: main concern through Tuesday is showers
and thunderstorms, mainly each afternoon early evening.

Marine
Today: the waters will be located in between an inland trough
and strong ridging to the s-se. SW and W winds this morning will
back to s-sw this afternoon with sea breeze circulations
developing. There is actually a fairly tight gradient that
develops and combined with a boost from the sea breeze will bump
winds up as high as 13-18 kt the second part of the day. Seas
will average 2 or 3 ft.

Tonight: a decent packing of the gradient between the inland
trough and sub-tropical ridge, plus nocturnal low level jetting
will support s-sw winds as high as 15 or 20 kt and seas 3-4 ft.

Saturday through Wednesday: the coastal waters will remain
between an inland trough and offshore high pressure through
Saturday night which will keep a tighter than normal pressure
gradient in place. Winds could push 20 knots at times but this
is just below advisory levels. A weakening cold front will then
approach early next week but likely stall out and never make it
through the area with winds generally remaining 15 knots or
less. Seas will mostly be 4 feet or less, highest near the gulf
stream.

Tides coastal flooding
Astronomical influences will lead to a round of elevated tides
into early next week. Only small tidal departures are necessary
and we could approach shallow coastal flooding levels with the
evening high tides, especially along parts of the sc coast,
including downtown charleston.

Climate
Record high minimums for 18 august...

kchs 78 2010
kcxm 82 1998
ksav 78 2010
record high minimums for 19 august...

kchs 79 2010
kcxm 81 2009
ksav 79 1878

Equipment
The temperature and dew point sensors at the downtown charleston
observation site (kcxm) could periodically fail. Technicians
are working to resolve the problem.

Chs watches warnings advisories
Ga... None.

Sc... None.

Marine... None.

Near term...

short term...

long term...

aviation...

marine...

tides coastal flooding...

climate...

equipment...



Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
FBIS1 - Folly Island, SC 2 mi25 min NE 1.9 G 2.9 91°F 1016 hPa (+0.0)74°F
CHTS1 8 mi37 min W 2.9 G 8.9 94°F 87°F1015.6 hPa
41029 - Capers Nearshore (CAP 2) 19 mi17 min S 5.8 G 9.7 86°F 86°F1015.4 hPa
ACXS1 - ACE Basin Reserve, SC 29 mi100 min WNW 1.9 89°F 1016 hPa77°F
41033 37 mi17 min SSE 1.9 G 3.9 89°F 1015.5 hPa
41004 - EDISTO - 41 NM Southeast of Charleston, SC 45 mi25 min SW 12 G 14 84°F 85°F1015.5 hPa (+0.5)81°F

Wind History for Charleston, SC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Charleston Executive Airport, SC5 mi30 minWSW 510.00 miFair93°F77°F59%1015.2 hPa
Mount Pleasant Regional-Faison Field, SC18 mi30 minNNW 49.00 miA Few Clouds91°F77°F63%1015.2 hPa
Charleston, Charleston Air Force Base, SC18 mi89 minNW 710.00 miA Few Clouds90°F75°F63%1015.4 hPa

Wind History from CHS (wind in knots)
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Last 24hrSW7W7SW6SE5SE3CalmSE5SE5S6SW7SW8S6SW5SW4SW4SW5SW6SW5SW5W4W9NW8NW7W5
1 day agoNW7W8W9W6SW5W8SW11SW7S6S8SW5SW5SW5SW6SW5SW6W5SW4CalmW6W4W4SW5W6
2 days ago65SW8W9W8W7W6SW5SW6SW6W5SW6W4W5W6W7W9W7W6W7NW7NW5NW6NW9

Tide / Current Tables for Folly Island (outer coast), South Carolina
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Folly Island (outer coast)
Click for Map
Fri -- 03:19 AM EDT     Moonrise
Fri -- 05:08 AM EDT     5.21 feet High Tide
Fri -- 06:45 AM EDT     Sunrise
Fri -- 11:16 AM EDT     -0.39 feet Low Tide
Fri -- 05:35 PM EDT     Moonset
Fri -- 05:45 PM EDT     6.36 feet High Tide
Fri -- 08:00 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.61.62.94.14.95.254.22.91.50.3-0.4-0.20.92.54.25.56.26.35.94.83.41.90.7

Tide / Current Tables for Charleston Harbor Entrance, South Carolina Current
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Charleston Harbor Entrance
Click for Map
Fri -- 12:01 AM EDT     0.00 knots Slack
Fri -- 02:04 AM EDT     1.47 knots Max Flood
Fri -- 03:19 AM EDT     Moonrise
Fri -- 05:47 AM EDT     -0.00 knots Slack
Fri -- 06:45 AM EDT     Sunrise
Fri -- 09:11 AM EDT     -2.48 knots Max Ebb
Fri -- 12:08 PM EDT     0.00 knots Slack
Fri -- 02:33 PM EDT     1.93 knots Max Flood
Fri -- 05:35 PM EDT     Moonset
Fri -- 06:37 PM EDT     -0.00 knots Slack
Fri -- 08:00 PM EDT     Sunset
Fri -- 09:51 PM EDT     -2.85 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-011.51.310.6-0.2-1.2-2-2.5-2.2-1.3-0.211.81.91.61.30.6-0.4-1.6-2.5-2.8-2.3

Weather Map and Satellite Images
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Weather Map
wmap_A
IR Satellite Image from GEOS
east_satellite

GOES Local Image of Southeast    EDIT
Geos

Wind Forecast for Charleston, SC (12,3,4,5)
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Ground Weather Radar Station Charleston, SC
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weather_mapweather_map weather_map

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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.