Wednesday, May24, 2017 L-36.com


Marine Weather and Tides
Kiawah Island, SC

Version 3.4
What's New / NOTES
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 6:13AMSunset 8:19PM Wednesday May 24, 2017 9:22 AM EDT (13:22 UTC) Moonrise 4:32AMMoonset 6:06PM Illumination 1% Phase: Waning Crescent; Moon at 28 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- 732 Am Edt Wed May 24 2017
.small craft advisory in effect from noon edt today through this evening...
Today..SW winds 15 kt...increasing to 20 to 25 kt this afternoon. Waves 1 to 2 ft. A chance of showers and Thunderstorms this morning...then showers and Thunderstorms this afternoon. Locally heavy rainfall possible this afternoon.
Tonight..SW winds 15 to 20 kt with gusts to 25 kt. Waves 1 to 2 ft. Showers and Thunderstorms...mainly in the evening. Locally heavy rainfall possible in the evening.
Thu..W winds 10 to 15 kt...increasing to 15 to 20 kt in the afternoon. Waves 1 to 2 ft. A chance of showers and Thunderstorms in the morning.
Thu night..W winds 15 kt...diminishing to 5 to 10 kt after midnight.
Fri..W winds 5 to 10 kt.
Fri night..SW winds 5 to 10 kt.
Sat..SW winds 5 to 10 kt.
Sat night..SW winds 10 kt.
Sun..SW winds 10 kt. A slight chance of showers and Thunderstorms.
Sun night..SW winds 5 to 10 kt. A slight chance of showers and Thunderstorms. Mariners are reminded that winds and waves can be higher in and near tstms. Unless otherwise noted...waves 1 foot or less. Charleston harbor water temperature...78 degrees.
AMZ300 732 Am Edt Wed May 24 2017
Synopsis for the coastal waters of south coastal south carolina and north coastal georgia.. Unsettled weather will persist across the southeast through today. A cold front will push offshore tonight into Thursday followed by high pressure prevailing into the weekend.

7 Day Forecast for Marine Location Near Kiawah Island, SC
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location: 32.59, -80.11     debug


Area Discussion for - Charleston, SC
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Fxus62 kchs 241142
afdchs
area forecast discussion
national weather service charleston sc
742 am edt Wed may 24 2017

Synopsis
Unsettled weather will persist across the southeast through
today. A cold front will push offshore tonight into Thursday
followed by high pressure prevailing into the weekend.

Near term through tonight
Today: the forecast scenario is very complex and confidence
isn't very high regarding the timing and exact placement of
convection. A well defined mid upper level low will begin the
day over missouri and is progged to gradually sink south and
eastward to a position near west tennessee by the evening. As
it does, the trough on its southeast periphery will take on a
more neutral negative tilt with notable shortwave impulses
poised to impact the southeast region this afternoon and
evening. As the upper low translates through the day, an area of
low pressure at the surface will develop and steadily deepen as
it lifts into the ohio valley. Overall, the atmosphere today
will be quite similar to Tuesday. The forecast area will be
within an uninhibited warm sector with precipitable water values
approaching 2 inches by the afternoon. The main forecast
question for today will be what areas will be favored for
convection and will this convection be severe. Regarding favored
areas, that is pretty hard to ascertain. The atmosphere is
fairly uniform across the forecast area and a
shower thunderstorm will be capable of developing pretty much
anywhere at any time. The best dynamics and forcing for ascent
will spread in from the southwest in the afternoon, so the pop
scheme shows values increasing in southeast georgia first.

However, 80-90 percent chances are in place everywhere.

Regarding the severe potential, it certainly looks like a good
setup with an uncapped warm moist atmosphere in place,
coincident with increasing deep layer shear and mid upper level
dynamics. As the aforementioned shortwave energy spreads in this
afternoon, a north south oriented 300 mb jet will strengthen to
around 120 knots with a strong divergence signal in its right
entrance region. This upper level forcing should help make up
for any lack of destabilization we experience from widespread
cloud cover and minimal insolation. Model soundings show the
wind field increasing nicely in the afternoon as well and it
appears the best severe threat will come as the 70+ knot 500 mb
jet noses in from the southwest in the mid late afternoon hours.

Around this time, model soundings and plan view feature cape
values of 1500-2000 j kg and 0-6 km shear values around 50
knots. The wind field is essentially unidirectional, but the
combination of the strengthening magnitude and impressive
indices will result in a scenario similar to Tuesday. The near
storm environment should favor multicells and some broken
convective bands, with the potential for some embedded supercell
type structure. Damaging wind gusts are the main threat, but
given the magnitude of the shear we will once again see the
potential for a few isolated tornadoes. Thunderstorms will be
possible at any time, but the main time period for severe
weather will be from roughly 3-9 pm. There are certainly some
caveats regarding the threat, mainly the impact of convective
overturning from Tuesday and the impact of early morning
convection. However, the environment should be able to
sufficiently recover, especially with a solid replenishment of
warm moist air. Locally heavy rain is again expected today, but
we don't think widespread flash flooding will be an issue.

Tonight: convection will likely reach its peak coverage and
intensity in the evening, then become increasingly concentrated
along the coast in the first portion of tonight. Current
thinking for timing is that the by midnight the bulk of the
convection will be off the coast and the severe threat will be
greatly diminished. Pop's steadily decrease from the west
through the night, such that by sunrise Thursday only slight
chance pop's are in place. Temperatures will cool off late and
we could see some low 60s well inland for lows.

Short term Thursday through Saturday
Thursday: the upper level trough axis will cross the forecast
area mid-day as stacked low pressure continues its trek
northeast into the mid-atlantic region. Surface high pressure
will begin to spill back in from the south and gulf of mexico
behind the cold front as weak upper-level ridging slides slowly
east. This should result in primarily dry conditions Thursday,
but a shower or thunderstorm cannot be entirely ruled out. A
tight pressure gradient will exist across the region, leading to
elevated and gusty surface wind speeds. Temperatures look to be
slightly below normal, with highs just under 80 degrees most
locales and low temperatures averaging around 60 inland and
around 65 at the coast.

Friday: surface high pressure will overspread the region under
weak ridging aloft, continuing a period of calm weather with
almost zero probability for precipitation and mostly sunny skies
anticipated. Near-normal temperatures are anticipated with
highs reaching the lower to mid-80s before cooling into the mid
to upper 60s overnight away from the coast.

Saturday: strengthening trough aloft to the west will induce an
area of low pressure at the surface over the central us. The
associated cold front will begin a slow trek southeast towards
the forecast area. High pressure at the surface will persist
locally under a ridge aloft, and another dry day looks highly
probable under this scenario. Temperatures climb back above
normal, aided by subsidence and some compression in advance of
the front. Expect high temperatures to reach the lower 90s away
from the coast and upper 80s at the beaches, with low
temperatures only dropping to around 70.

Long term Saturday night through Tuesday
A ridge over the east coast combined with surface high pressure
will result in mostly dry weather through the remainder of the
weekend. The surface cold front will approach the area through
the first half of the week as the trough aloft slides east,
bringing the potential for another period of unsettled weather
Monday through Wednesday.

Aviation 12z Wednesday through Sunday
Shower and thunderstorm activity is very limited this morning
and it appears that the bulk of development will take place
later this morning and into the afternoon. No change in thinking
regarding late day thunderstorms. The forecast still features a
tempo at both sites for low end MVFR conditions in thunderstorms
for the late afternoon early evening time period. Given that the
environment will support development at almost any time, we
could see impacts outside of the tempo, but that is the most
likely time. Then overnight, any lingering showers and
thunderstorms will push offshore andVFR conditions will return.

Extended aviation outlook: expectVFR conditions to prevail
into the weekend.

Marine
Today and tonight: poor conditions will continue across the
local waters through tonight. As a surface low strengthens
inland across tennessee, the pressure gradient will tighten and
south to southwesterly winds will remain elevated. Most of the
waters will be in the 20-25 knot range through the day thanks to
the gradient. In fact winds look sufficiently strong today to
support expanding the small craft advisory to include charleston
harbor through midnight. Seas will steadily increase thanks to
the persistent winds. By late today, seas will become generally
4-6 feet out to 20 nm and 6-8 feet beyond. By late tonight, seas
could be up to 8 feet near 20 nm and up to 10 feet in the outer
waters. One thing to keep an eye on is this evening there could
be a window of time where gales occur across the charleston
county waters and the outer georgia waters. Confidence is too
low to introduce a gale warning however. Also, another round of
strong thunderstorms are expected to develop and impact the
waters beginning late today. Wind gusts in excess of 35 knots
and waterspouts will be possible. The main time period for
strong thunderstorms will be from around 4 pm through midnight,
however thunderstorm development will be possible at any time.

Thursday through Sunday: tight pressure gradient behind the
surface cold front will lead to elevated and gusty SW to wsw
winds and increasing seas. A small craft advisory has been
hoisted for all zones Thursday, with conditions gradually
improving Friday into Saturday under high pressure.

Rip currents: strong southerly to southwesterly winds combined
with increasing astronomical influences will result in a
moderate risk of rip currents at all beaches.

Tides coastal flooding
Evening high tide levels will trend higher each day as we
approach the new moon and perigee this Friday, though we expect
tides to remain just below coastal flood advisory stage. The
bigger issue is if heavy rainfall occurs around the time of high
tide this evening, in which case more significant street
flooding would be possible due mainly to freshwater.

Chs watches warnings advisories
Ga... None.

Sc... None.

Marine... Small craft advisory from noon today to midnight edt tonight
for amz330.

Small craft advisory until 8 pm edt Thursday for amz352-354.

Small craft advisory until midnight edt Thursday night for
amz350-374.

Near term... Bsh
short term... Jmc
long term... Jmc
aviation... Bsh jmc
marine... Bsh jmc
tides coastal flooding...



Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
FBIS1 - Folly Island, SC 13 mi82 min WSW 9.9 G 13 75°F 1005.9 hPa (+0.3)72°F
CHTS1 16 mi52 min SW 9.9 G 16 78°F 78°F1005.5 hPa
ACXS1 - ACE Basin Reserve, SC 18 mi97 min SW 1.9 74°F 1005 hPa72°F
41033 27 mi74 min WSW 19 G 27 77°F 77°F1004.3 hPa
41029 - Capers Nearshore (CAP 2) 30 mi74 min W 16 G 19 78°F 76°F1004.9 hPa
41004 - EDISTO - 41 NM Southeast of Charleston, SC 54 mi42 min SSW 21 G 25 75°F 76°F1006.3 hPa72°F

Wind History for Charleston, SC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Charleston Executive Airport, SC10 mi27 minSW 6 G 139.00 miMostly Cloudy77°F71°F83%1005.4 hPa
Charleston, Charleston Air Force Base, SC23 mi86 minSW 710.00 miA Few Clouds73°F70°F90%1004.8 hPa

Wind History from JZI (wind in knots)
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Last 24hrCalm6SW8
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1 day agoSW3S6S8S7S7S11S10S10S8S6S4CalmCalmCalmW5CalmW5S8S6S5SW5SW6SW6SW6
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Tide / Current Tables for Kiawah River Bridge, South Carolina
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Kiawah River Bridge
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Wed -- 01:26 AM EDT     -0.24 feet Low Tide
Wed -- 05:32 AM EDT     Moonrise
Wed -- 06:16 AM EDT     Sunrise
Wed -- 07:35 AM EDT     5.91 feet High Tide
Wed -- 01:38 PM EDT     -0.74 feet Low Tide
Wed -- 07:05 PM EDT     Moonset
Wed -- 08:04 PM EDT     7.23 feet High Tide
Wed -- 08:18 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.8-0.1-0.10.92.43.95.15.85.85.13.82.10.6-0.5-0.70.21.93.95.66.87.26.85.63.9

Tide / Current Tables for Charleston Harbor Entrance, South Carolina Current
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Charleston Harbor Entrance
Click for Map
Wed -- 01:53 AM EDT     0.00 knots Slack
Wed -- 04:10 AM EDT     1.89 knots Max Flood
Wed -- 05:30 AM EDT     Moonrise
Wed -- 06:15 AM EDT     Sunrise
Wed -- 07:50 AM EDT     -0.00 knots Slack
Wed -- 11:07 AM EDT     -2.89 knots Max Ebb
Wed -- 02:00 PM EDT     0.01 knots Slack
Wed -- 04:34 PM EDT     2.36 knots Max Flood
Wed -- 07:04 PM EDT     Moonset
Wed -- 08:17 PM EDT     Sunset
Wed -- 08:26 PM EDT     -0.01 knots Slack
Wed -- 11:41 PM EDT     -3.29 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-2.4-1.20.11.31.91.71.30.8-0.2-1.4-2.4-2.9-2.5-1.4-01.32.22.31.91.40.5-0.8-2.1-3.1

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 (9,2,3,4)
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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.