Saturday, August19, 2017 L-36.com


Marine Weather and Tides
Mount Pleasant, 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 6:45AMSunset 8:00PM Saturday August 19, 2017 7:03 AM EDT (11:03 UTC) Moonrise 3:21AMMoonset 5:31PM Illumination 8% Phase: Waning Crescent; Moon at 27 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- 627 Am Edt Sat Aug 19 2017
Today..SW winds 5 to 10 kt, becoming S 15 kt in the afternoon.
Tonight..S winds 10 to 15 kt, becoming sw 5 to 10 kt.
Sun..S winds 5 to 10 kt. A slight chance of showers and tstms.
Sun night..S winds 5 to 10 kt. A slight chance of showers and tstms.
Mon..SE winds around 5 kt, increasing to 5 to 10 kt in the afternoon. A slight chance of showers and tstms.
Mon night..S winds around 5 kt. A slight chance of showers and tstms.
Tue..SE winds 5 to 10 kt. A slight chance of showers and tstms.
Tue night..S winds 5 kt. A slight chance of showers and tstms.
Wed..SW winds 5 to 10 kt. A chance of showers and tstms.
Wed night..SW winds 5 to 10 kt. A 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 627 Am Edt Sat Aug 19 2017
Synopsis for the coastal waters of south coastal south carolina and north coastal georgia.. A weak cold front will linger inland over the se this weekend. Broad low pressure is expected to move nearby from the western atlantic on Monday. High pressure will return Tuesday and Wednesday.

7 Day Forecast for Marine Location Near Mount Pleasant, SC
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location: 32.93, -79.83     debug


Area Discussion for - Charleston, SC
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Fxus62 kchs 191030
afdchs
area forecast discussion
national weather service charleston sc
630 am edt Sat aug 19 2017

Synopsis
A weak cold front is forecast to slowly slide over eastern
south carolina and georgia this weekend, likely becoming
stationary over the region on Sunday. Broad low pressure is
expected to move inland from the western atlantic on Monday.

Summertime weather should result from ridging high pressure
Tuesday and Wednesday. A stronger cold front is timed to pass
over the region on Thursday, likely followed by a slightly
cooler and drier airmass through the rest of the week.

Near term through tonight
Today: an interesting pattern aloft features a tutt low moving
w-nw through the SE gulf, an embedded short wave to pass through
the oh valley within the westerlies just to our n, and
anticyclones in the SW atlantic and over the southern great
plains. At the surface the sub-tropical ridge is suppressed to
the s-se, as the aforementioned short wave bumps a weak cold
front near or just upstream from the NW zones.

While the mid levels remain warm and there is still some
evidence of a subsidence cap, forcing from the nearby front and
most especially the sea breeze will allow for better coverage of
showers and t-storms than yesterday. Isolated activity will form
near the sea breeze, near the us-17 corridor as we reach our
convective temps around 90f by 12-1 pm. Coverage than increases
further into the scattered range during the course of peak
heating during mid afternoon, mainly E of i-95 in sc and areas
just inland from the ga beaches to E of a line from about
springfield to hinesville and ludowici.

Probabilities are capped at 30-40%, but with 15-20 kt of 0-6 km
bulk shear, there is a risk of a few multi-cellular clusters
developing. The overall risk for severe weather is quite low,
but with dcape 800-1200 j kg there is some risk for strong
downbursts of wind where boundary collisions and or mergers
occur. There is also the chance for locally heavy downpours
given pwat of at least 2 inches and weak storm motion.

Low level thickness and both 925 mb and 850 mb temps are similar
to or a bit less than Friday, and that along with more cloud
cover and higher convective rain chances will keep most places
from getting quite as hot as recent days. Still, lower and
middle 90s are forecast, and the hourly temp curve will need
some adjusting later in the day due to rain-cooling storms.

Far interior SE ga and places west of i-95 will experience a
mixing out of dew points this afternoon, but pooling of dew
points in the mid and upper 70s elsewhere will generate maximum
heat indices of 106-108f. This is just shy of the requirement of
a heat advisory, but still at dangerous levels.

Tonight: convection will fade quickly during the early and mid
evening, and the bulk of the night will be rainfree. However, a
light southerly flow from off the ocean and the resulting
convergence could allow for widely scattered late night showers
and t-storms moving onshore from the atlantic. Some of the
guidance suggests late night fog, and with the previous expected
rainfall and some places reaching their cross-over temps this is
possible. But I think there will be just too much cloud cover
and condensation pressure deficits look a little too high. Thus
no mention of fog at this time. Temps will again remain far
above normal, but a little "cooler" than the past few nights
with more of a decoupled atmosphere.

Short term Sunday through Tuesday
Sunday: short term guidance indicated that broad high pressure
centered over bermuda will remain just off the sc ga coast. Weak
flow under the h5 ridge should result in the weak cold front to
become nearly stationary near the coast on Sunday. In fact, llvl
flow is forecast to back, possibly resulting in the weak boundary to
drift inland as a sea breeze during the afternoon hours. This
pattern will likely favor highs in the mid to upper 90s across the
inland counties to the low to near 90 near the beaches. Forecast
soundings show a subsidence inversion around h725, favoring low pops
across the region. I will forecast generally isolated convection on
Sunday, favoring areas along the i-95 corridor.

Monday: both the GFS and ECMWF indicate that the center of the h5
595 dm shifting west just off the nc coast by the afternoon. Short
range guidance shows a band of moisture associated with a tropical
wave rippling west over the forecast area during the daylight hours.

Forecast soundings show pw values rising above 2.2 inches by Monday
afternoon. In addition, soundings indicate multiple layers of clouds
during the afternoon hours, especially during the afternoon hours.

However, sfc flow across the high pressure should support winds from
the se, favoring a sea breeze developing during the mid day.

Forecast soundings for points near the beaches indicate thinner
decks of cloud cover. It appears that areas east of the potential
sea breeze, near the beaches, will see the greatest potential for
viewing the solar eclipse. Sct thunderstorms will likely develop
over the land zones during the afternoon, with isolated coverage
expected over the marine zones. High temperatures are forecast to
range a few degrees below values reached on Sunday.

Tuesday: typical summertime conditions are expected as the h5 ridge
shifts over the deep south and weakens slightly. I will forecast
high temperatures within a degree or two of normals. Thunderstorms
should generally follow a diurnal trend with sct coverage across sc
and ga.

Long term Tuesday night through Friday
Wednesday through Saturday: broad high pressure will gradually
weaken across the region on Wednesday as a cold front slides across
the southern appalachians by the afternoon. A cold front should
push across the forecast area on Thursday, likely supporting a band
of thunderstorms. High pressure sourced from canada will remain
centered well north of the region through the rest of the week.

However, the forecast area should see slightly cooler and drier
conditions Friday night into the weekend. In fact, guidance supports
afternoon dewpoints in the upper 60s inland by Saturday afternoon.

Aviation 11z Saturday through Wednesday
Vfr with no concerns through about 16-18z, before isolated to
scattered shra tsra develops on the sea breeze. This boundary
will be near both kchs and ksav from around 19-23z, and it is
during this time that brief flight restrictions can occur. For
now vcts with CB clouds will suffice at both terminals during
the mid afternoon through early evening.

Extended aviation outlook: thunderstorms may result in short periods
of flight restrictions, greatest potential during the afternoon and
early evening.

Marine
Today: the waters will be sandwiched between a weak cold front
inland over the SE that nudges a little closer and sub-tropical
ridging just to the s-se. Wsw winds will start the morning at 10
or 10-15 kt, continuing that way through midday. Then sea
breeze circulations will back winds around to the S or ssw and
speeds ramp up several knots again. Seas will average 2-3 ft.

Tonight: once sea breeze influences fade this evening, the
pressure gradient slackens as the cold front attempts to nudge a
little closer. S and SW winds will hold at or below 15 kt (quite
a bit lower than recent nights), and seas remain in a steady
state around 2 or 3 ft.

Sunday through Thursday: western atlantic high pressure combined
with a broad inland trough will yield a weak pressure gradient over
the coastal waters through mid week. A cold front should sweep
across the forecast area on Thursday. Sfc winds are forecast to
remain light from the SE through Tuesday, then veering from the
south-southwest Wednesday and Thursday. Wave heights are expected to
generally range between 2-3 feet Sunday through Thursday.

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 through Tuesday along parts of the sc coast.

Climate
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
CHTS1 11 mi46 min WNW 1.9 G 4.1 82°F 87°F1013.9 hPa
41029 - Capers Nearshore (CAP 2) 14 mi56 min SW 12 G 18 82°F 85°F1013.2 hPa
FBIS1 - Folly Island, SC 17 mi64 min SW 8 G 8.9 83°F 1014.1 hPa (-0.5)76°F
ACXS1 - ACE Basin Reserve, SC 42 mi79 min Calm 79°F 1013 hPa76°F
NIWS1 - North Inlet-Winyah Bay Reserve, SC 45 mi79 min WSW 6 82°F 1013 hPa78°F
41004 - EDISTO - 41 NM Southeast of Charleston, SC 49 mi34 min SW 12 G 16 83°F 85°F1013.6 hPa80°F

Wind History for Charleston, SC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Mount Pleasant Regional-Faison Field, SC3 mi69 minN 010.00 miFair81°F75°F84%1013.5 hPa
Charleston, Charleston Air Force Base, SC11 mi68 minSW 310.00 miFair79°F73°F85%1013.4 hPa
Charleston Executive Airport, SC18 mi69 minN 010.00 miFair81°F75°F84%1013.5 hPa
Moncks Corner Berkeley County, SC21 mi69 minWSW 310.00 miFair77°F73°F89%1013.5 hPa

Wind History from CHS (wind in knots)
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Last 24hrSW5W4W9NW8NW7W5SW5SW84S8SW10S14S11S11S7S9SW8S8S6S6S6SW6SW5SW3
1 day agoCalmW6W4W4SW5W6SW7W7SW6SE5SE3CalmSE5SE5S6SW7SW8S6SW5SW4SW4SW5SW6SW5
2 days agoW6W7NW7NW5NW6NW9NW7W8W9W6SW5W8SW11SW7S6S8SW5SW5SW5SW6SW5SW6W5SW4

Tide / Current Tables for Cainhoy, Wando River, South Carolina
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Cainhoy
Click for Map
Sat -- 12:58 AM EDT     0.28 feet Low Tide
Sat -- 04:20 AM EDT     Moonrise
Sat -- 06:45 AM EDT     Sunrise
Sat -- 07:19 AM EDT     6.36 feet High Tide
Sat -- 01:08 PM EDT     -0.35 feet Low Tide
Sat -- 06:30 PM EDT     Moonset
Sat -- 07:50 PM EDT     7.78 feet High Tide
Sat -- 07:59 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.80.30.81.93.34.75.86.36.15.23.61.90.4-0.301.33.14.96.57.57.87.15.73.8

Tide / Current Tables for Charleston Harbor Entrance, South Carolina Current
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Charleston Harbor Entrance
Click for Map
Sat -- 01:00 AM EDT     0.01 knots Slack
Sat -- 03:03 AM EDT     1.51 knots Max Flood
Sat -- 04:21 AM EDT     Moonrise
Sat -- 06:45 AM EDT     Sunrise
Sat -- 06:52 AM EDT     -0.00 knots Slack
Sat -- 10:10 AM EDT     -2.66 knots Max Ebb
Sat -- 01:08 PM EDT     0.00 knots Slack
Sat -- 03:32 PM EDT     1.97 knots Max Flood
Sat -- 06:30 PM EDT     Moonset
Sat -- 07:35 PM EDT     -0.00 knots Slack
Sat -- 07:59 PM EDT     Sunset
Sat -- 10:46 PM EDT     -3.02 knots Max Ebb
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
-1.3-01.11.51.41.10.7-0.1-1.2-2.1-2.6-2.4-1.4-0.21.11.91.91.71.40.7-0.5-1.8-2.7-3

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 (7,2,3,4)
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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.