Sunday, April23, 2017 L-36.com


Marine Weather and Tides
Darien, GA

Version 3.4
What's New / NOTES
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.
3/12/2015 - Added section for Gulf current for users in the GMZ marine zones.
This was requested by a user. If you have requests, please let me know.

Sunrise 6:46AMSunset 8:01PM Sunday April 23, 2017 3:49 PM EDT (19:49 UTC) Moonrise 4:02AMMoonset 4:05PM Illumination 6% 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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AMZ450 Coastal Waters From Altamaha Sound To Fernandina Beach Fl Out 20 Nm- Coastal Waters From Fernandina Beach To St. Augustine Fl Out 20 Nm- Coastal Waters From St. Augustine To Flagler Beach Fl Out 20 Nm- 249 Pm Edt Sun Apr 23 2017
.small craft should exercise caution...
Tonight..South southwest winds 15 to 20 knots becoming west southwest 10 to 15 knots in the morning. Seas 3 to 5 feet with occasional seas up to 6 feet. Dominant period 5 seconds. Inland waters a moderate chop. A chance of showers and a slight chance of Thunderstorms.
Monday..West winds 15 to 20 knots. Seas 3 to 5 feet with occasional seas up to 6 feet. Dominant period 6 seconds. Inland waters a moderate chop. A chance of showers and a slight chance of Thunderstorms in the morning.
Monday night..West winds 10 to 15 knots. Seas 3 to 5 feet with occasional seas up to 6 feet. Dominant period 7 seconds. Inland waters a moderate chop.
Tuesday..West southwest winds 10 to 15 knots. Seas 2 to 4 feet. Dominant period 8 seconds. Inland waters a light chop.
Tuesday night..West southwest winds 10 to 15 knots. Seas 2 to 3 feet. Inland waters a light chop.
Wednesday..Southwest winds 5 to 10 knots becoming southeast 10 to 15 knots in the afternoon. Seas 2 to 3 feet. Inland waters a light chop.
Wednesday night..South southwest winds 10 to 15 knots. Seas 2 to 4 feet. Inland waters a light chop.
Thursday..South southeast winds 10 to 15 knots. Seas 2 to 4 feet. Inland waters a light chop.
Thursday night..South winds 10 to 15 knots. Seas 2 to 4 feet. Inland waters a moderate chop.
Friday..South southeast winds 10 to 15 knots. Seas 2 to 3 feet. Inland waters a light chop.
AMZ400 Synopsis For Altamaha Sound Ga To Flagler Beach Fl Out To 60 Nm- 249 Pm Edt Sun Apr 23 2017
Synopsis.. A cold front will cross area waters tonight into Monday morning. Low pressure is expected to track north of the region Monday...then track northeast away from the local waters Tuesday. High pressure will build across south florida Wednesday and southeast of the region through the end of the week.

7 Day Forecast for Marine Location Near Darien, GA
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location: 31.32, -81.36     debug


Area Discussion for - Charleston, SC
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Fxus62 kchs 231727
afdchs
area forecast discussion
national weather service charleston sc
127 pm edt Sun apr 23 2017

Synopsis
A low pressure system will affect the area today through Tuesday.

High pressure will then build into the area through the weekend.

Near term /through tonight/
Today: the synoptic pattern today will feature a cut-off upper
low digging into the gulf coast states. At the surface, a
low pressure system, currently centered over northern ga, will
shift east in central ga through the day, with a relatively
stationary front positioned just to our north. This will place
the forecast area within the warm sector, allowing for another
warm day with highs mainly in the mid 80s inland of the beaches.

The best large scale forcing appears to remain out of the area
through the daylight hours, so still think afternoon convection
will initiate off of mesoscale boundaries such as the sea
breeze. With the early afternoon update, made minor tweaks to
pops based on latest radar trends and hourly t/td grids.

Tonight: the forecast is expected to become considerably more
interesting after sunset. The upper low is expected to
strengthen as it tracks into central georgia late tonight and
impressive deep forcing for ascent will overspread the forecast
area. The surface low is progged to reach the forecast area
around midnight and linger in the vicinity through the rest of
the overnight. The first item of interest is the potential for
severe thunderstorms beginning in the evening as the low and
associated ongoing convection approach from the west. Wind
profiles will begin to increase and thanks to low level south-
southeasterly flow, decent veering of the flow with height will
be present. The magnitude of shear isn't too impressive (on the
order of 20-25 knots), but storm relative helicity will increase
thanks to the veering with height. As always seems to be the
case, instability will be main factor in question. There are
indications in NAM and rap soundings that CAPE values could be
in the 1000-1500 j/kg range, but it is certainly a
climatologically unfavorable time with the loss of diurnal
heating. So, the atmosphere could be conducive to the
development of supercell structures depending on how the
instability evolves. Given the uncertainties regarding the
instability and whether or not it will be rooted in the surface,
will not introduce a mention to the hwo with this package. The
main area would likely be southeast georgia and along the
savannah river through midnight, with strong wind gusts, hail,
and even a tornado possible if conditions work out just right.

The other forecast concern is the potential for an area of
intense rainfall to develop late. Forcing dynamics are quite
impressive with the models depicting a slot of intense jet
dynamics coincident with vorticity advection as the upper low
draws closer. Model consensus shows precipitable water values
increasing to around 1.5 inches which would be near the daily
observed maximum value. The combination of a deep moisture feed
off the atlantic with high precipitable water values, and
focused forcing creates increased confidence in a zone of high
rainfall rates in the presence of convection. Models show good
agreement that the most likely area to be impacted will be from
around the savannah river up to the tri- county region. This
would likely begin to setup in the early morning hours and
rainfall amounts by sunrise Monday could approach 2 inches in
some areas. The risk for widespread flash flooding appears to be
low however, thanks to well below normal rainfall over the last
couple of months. Likely to categorical pop's are warranted,
and we have also added a mention of locally heavy rainfall.

Short term /Monday through Wednesday/
Now that the models have further slowed the progression of the
storm system, Monday now looks rather interesting. The powerful
closed upper low will move directly over the forecast area
while the associated surface low gradually shifts through
central ga/sc. Deep onshore flow will advect 1.5" pwats into
southern sc which is around the 95th percentile for late april.

Additionally, strong synoptic forcing will exist in this area
until mid to late Monday afternoon. At a minimum we expect
numerous showers with heavy rain at times, especially over the
northeastern portion of the area through early Monday afternoon.

Instability parameters vary between the models, though all
agree on at least -2 to -3c lifted indices in the tri-county
area and capes ranging from 300 to 800 j/kg. The NAM is
considerably more bullish with instability than the rest of the
models. Extensive cloud cover will likely inhibit the
development of significant CAPE though low-level theta-e
advection will yield at least something to work with. 30-40 kt
0-6 km shear values would support some storm organization if
enough buoyancy develops. The best chance for severe weather
would be with a quasi-linear complex that could develop along
and ahead of the cold front Mon afternoon. Damaging winds and
large hail would be the main concerns.

The area has remained fairly dry as of late, so widespread
flooding is not anticipated despite the possibility of a few
inches of rainfall. The flooding potential would be higher in
coastal areas if heavy rain coincides with high tide since tide
levels will be running above normal.

Light showers may persist into Monday night and Tuesday, mainly
across southern sc due to wrap around moisture as the low
pressure system departs.

Cooler temps anticipated Mon into Tuesday though temps quickly
warm back up by Wednesday as upper ridging occurs.

Long term /Wednesday night through Saturday/
Deep layered ridging will result in dry weather and highs in
the mid to upper 80s. A weak upper shortwave will approach early
Friday but is expected to be deflected to the north.

Aviation /17z Sunday through Thursday/
Conditions are expected to deteriorate overnight as a low
pressure system impacts the area. Shower/t'storm coverage is
expected to increase overnight with associated low ceilings and
reduced visibility likely to impact both terminals.

Precipitation will end in the morning at sav, and a bit later at
chs. Sub-vfr CIGS could persist through the end of the valid
taf cycle.

Extended aviation outlook: periods of flight restrictions,
mainly low ceilings, possible Monday morning through Tuesday
morning as a low pressure system moves through. Heavier rains
around kchs are possible Sunday night into Monday resulting in
potential vsbys restrictions at times as well.VFR conditions
will return Tuesday afternoon.

Marine
Today: the local waters will be caught in the region between
the surface low to the west and high pressure to the east. The
pressure gradient and low level jet will steadily increase
through the day and strengthening south to south-southeasterly
flow is expected. Current thinking keeps winds in the 15-20 knot
range, with the strongest winds expected in the tonight period.

However, charleston harbor could see gusts to 25 knots with the
proximity to the land/sea interface. Have kept the forecast
15-20 knots in the charleston harbor for now, but a small craft
advisory may be needed if winds are stronger than expected. Seas
will increase by later in the day, but will generally range 2-4
feet.

Tonight: the low level jet will increase further as the surface
low draws closer and confidence has increased in small craft
advisory conditions for the charleston county waters and the
outer georgia waters. The advisory begins at 02z for both zones.

Elsewhere, conditions will likely be borderline advisory
levels, but confidence isn't as high there. Seas will increase
to become 3-5 feet out to 20 nm and 5-6 feet beyond. Strong
thunderstorms will become more of a concern around and after
midnight, and the strongest storms will be capable of strong
gusts and even a waterspout or two.

Residual 6 ft seas expected to persist over the offshore ga
waters through midday Mon and Mon eve for the charleston
nearshore waters.

Modest offshore winds expected Mon night into Tue behind the
low pressure system with seas over the offshore ga waters
possibly rising back above 6 ft for a brief period.

Southerly winds will return mid to late week as atlantic high
pressure prevails.

Chs watches/warnings/advisories
Ga... None.

Sc... None.

Marine... Small craft advisory from 10 pm this evening to noon edt
Monday for amz374.

Small craft advisory from 10 pm this evening to midnight edt
Monday night for amz350.

Near term... Ect
short term... Jrl
long term... Jrl
aviation... Bsh/jrl
marine... Ect/jrl


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
SAXG1 - Sapelo Island Reserve, GA 8 mi50 min SSE 12 83°F 1009 hPa (-2.0)65°F
41008 - GRAYS REEF - 40 NM Southeast of Savannah, GA 27 mi60 min S 12 G 14 74°F 73°F3 ft1009.8 hPa (-2.0)66°F
41112 - Offshore Fernandina Beach, FL (132) 42 mi50 min 74°F3 ft
FRDF1 - 8720030 - Fernandina Beach, FL 45 mi50 min SE 8.9 G 15 80°F 78°F1010 hPa (-2.3)

Wind History for Fernandina Beach, FL
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Brunswick / Glynco, GA7 mi55 minESE 14 G 1810.00 miFair86°F68°F55%1009.1 hPa
Brunswick, Malcolm McKinnon Airport, GA12 mi57 minSE 1410.00 miFair81°F66°F61%1009.6 hPa

Wind History from BQK (wind in knots)
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2 days agoSE9E6SE9SE6SE5SE4S3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmSW8SW10W7S6W3SE10
G14
SE10

Tide / Current Tables for Jones Creek entrance, Hampton River, Georgia
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Jones Creek entrance
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Sun -- 12:16 AM EDT     0.35 feet Low Tide
Sun -- 05:01 AM EDT     Moonrise
Sun -- 06:48 AM EDT     Sunrise
Sun -- 07:11 AM EDT     7.52 feet High Tide
Sun -- 12:45 PM EDT     -0.14 feet Low Tide
Sun -- 05:05 PM EDT     Moonset
Sun -- 07:35 PM EDT     8.07 feet High Tide
Sun -- 07:59 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.40.61.534.6677.57.25.941.90.3-0.10.62.13.95.77.17.986.952.9

Tide / Current Tables for Old Tower, Sapelo Island, Georgia
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Old Tower
Click for Map
Sun -- 12:17 AM EDT     0.35 feet Low Tide
Sun -- 05:01 AM EDT     Moonrise
Sun -- 06:20 AM EDT     7.14 feet High Tide
Sun -- 06:47 AM EDT     Sunrise
Sun -- 12:47 PM EDT     -0.18 feet Low Tide
Sun -- 05:05 PM EDT     Moonset
Sun -- 06:42 PM EDT     7.61 feet High Tide
Sun -- 07:59 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.40.61.73.45.16.47.176.14.83.11.40.2-0.20.72.44.56.37.47.66.95.63.92.2

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 (15,3,4,5)
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Ground Weather Radar Station Jacksonville, FL
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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.