Monday, March25, 2019

Marine Weather and Tides
Isle of Palms, SC

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 7:15AMSunset 7:35PM Monday March 25, 2019 6:34 PM EDT (22:34 UTC) Moonrise 11:31PMMoonset 9:30AM Illumination 76% Phase: Waning Gibbous; Moon at 20 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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7 Day Forecast for Marine Location Near Isle of Palms, SC
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location: 30.97, -77.7     debug

Area Discussion for - Charleston, SC
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Fxus62 kchs 252207
area forecast discussion
national weather service charleston sc
607 pm edt Mon mar 25 2019

Low pressure will cross the region tonight followed by a strong
cold front Tuesday. High pressure will then build in from the
north and persist into Saturday. A cold front may affect the
area late next weekend.

Near term until 6 am Tuesday morning
It appear that both air quality and visibilities are improving
across the savannah metro area early this evening where a thick
plume of smoke was traversing the city several hours ago. Vsbys
at ksvn dropped as low as 3sm and city webcams were quite hazy
at times. At one point, air quality likely peaked in the orange
category (unhealthy for sensitive groups) across parts of the
metro area. The air quality special weather statement will be
allowed to expire at 7 pm.

Otherwise, upstream convection continues to slowly organize
ahead of an approaching cold front and along the nose of an
approaching 850 hpa jet max. This activity will move across
southeast south carolina and southeast georgia later this
evening, likely clearing the coast shorty after midnight.

Increased pops slightly with the early evening update with
gridded pops capped at 70%. May need to increase pops to the
categorical range later once convective trends become more
apparent in a few hours. The risk for isolated tstms persists,
although instability will be waning as convection from the west
approaches the local forecast area.

Tonight: mid level shortwave energy across the upper gulf coast
and tennessee valley is forecast to shift through ga and the
carolinas overnight. After sunset, 500 mb height falls will
increase while upper difluence builds ahead of the left exit
region of the upper jet along the gulf coast. Across southern
ga, we note that the low level flow becomes west in the 00z-03z
time frame and this should disrupt any transport from the gulf
of mexico in the boundary layer. We have maintained likely pops
during the late evening hours mostly along and north of i-16
where the best combo of upper forcing and moisture bisect. The
12z NAM has a too-slow but otherwise plausible solution with
upstream convection perhaps loosely organizing across the sc
midlands in the early evening and shifting east across the area,
especially north of i-16 over much of southern sc. Since the
timing for the brunt of the convection is generally after dusk,
instability is forecast to quickly wane with ml capes less than
500 j kg and decreasing with time. The mid levels are fairly
impressive with mid level lapse rates greater than -6.5c and
parameters indicating the potential for tstms. We suspect if
storms do tend to cluster upstream, wind potential appears low
with increasing CIN and surface-based inversions. We continue to
mention slight chance thunder this evening in all zones but the
severe weather risk appears generally low.

After midnight: as the short wave aloft moves over the region,
a cold front will pass offshore late with lingering chances
for showers north of the savannah river toward daybreak.

Temps will mainly be in the 50s for the overnight across the
area. We cannot rule out some patchy fog across out northern
zones inland from charleston where a broad frontal trough
exists out ahead of Tuesday's backdoor cold front.

Short term 6 am Tuesday morning through Thursday
A backdoor cold front will drop into the area Tuesday morning from
the north and then continue to push south through the day. Moisture
is confined to the lower levels, so think any rain accompanying the
front will be fairly light. Accumulations should be a few hundredths
of an inch on average. Temperatures will be much cooler than Monday,
remaining in the 60s, except around 70 close to the altamaha. Lows
Tuesday night will range from upper 30s inland to low mid 40s at the
coast. Elevated winds will preclude any frost.

Cool high pressure will build in wake of the front, providing quiet
and dry conditions for Wednesday and Thursday. One forecast concern
is the potential for frost Wednesday night into early Thursday with
lows dropping into the mid upper 30s far inland. Winds will be
fairly light, and these conditions could support some patchy frost.

Long term Thursday night through Monday
Unseasonably warm and mostly dry through the period. A cold
front may move through late Sunday or Sunday night though it is
currently unclear how much precipitation will accompany it.

Aviation 22z Monday through Saturday
Vfr conditions giving way to an approaching line of showers with
isolated tstms by late evening. The line is expected to move
through both terminals in 03-06z timeframe bringing a risk for
MVFR vsbys cigs. The risk for tstms looks to small at this point
to include a mention, but trends will be monitored for a
possible amendment. Winds will turn west and diminish behind the
line. There is a brief window for some fog to potentially impact
kchs between 07-10z as winds diminish and low-level moisture
pools ahead of a backdoor cold front. Best chances look to
remain just west of the terminal so will not include at this
time. Winds will turn north and eventually northeast behind the
front as it drop south through the terminals. Low-end MVFR to
ifr CIGS are likely in the post-frontal airmass, which will
linger for much of the day Tuesday. Will limit CIGS to ovc012
for now.

Extended aviation outlook: sub-vfr ceilings will improve Tuesday
afternoon evening.VFR expected thereafter.

Tonight: winds have really surged in the charleston harbor over
the past few hours with the shutes folly and ft. Sumter weatherflow
sensors reporting winds near 20 kt. Sent an updated forecast to
show 15-20 kt through sunset.

Southwest flow will continue into the evening hours
with stronger flow beyond 20 nm off the charleston county coast.

Speeds will mainly be below 15 kt with seas 2 to 3 ft. A cold
front will move off the coast late tonight with wind directions
veering offshore with
Tuesday through Saturday: marine conditions will deteriorate on
Tuesday behind a back door cold front that will drop through the
area. Small craft advisory conditions will develop across all
coastal waters by late afternoon. The charleston harbor could reach
criteria, however it appears marginal during the daytime hours. A
more sure bet would be late Tuesday night into Wednesday. Will hold
off on an advisory for now and reevaluate with next forecast cycle.

The period of strongest winds will be the 06z-18z Wednesday time
frame as 1000 mb geostrophic flow reaches 45-50 knots. A gale watch
has been hoisted for the outer ga waters where confidence is
highest. This may need to be expanded to at least some of the
nearshore zones eventually. Winds will begin to improve later
Wednesday, however it will take longer for seas to subside,
especially in the outer ga waters.

Rip currents: there will be an enhanced risk for rip currents mid-
week as elevated northeast winds and swell impact the beaches.

Tides coastal flooding
Between strong high pressure building from the north and low
pressure developing off the coast, strong northeast winds will
create elevated tide levels along the coast mid-week. While
astronomical factors do not favor tidal flooding, probabilistic
guidance depicts a low chance for minor salt water flooding,
mainly with the Wednesday morning high tide.

The kclx radar remains out of service until further notice.

Additional parts are on order and the radar will be serviced
again on Tuesday.

Chs watches warnings advisories
Ga... None.

Sc... None.

Marine... Small craft advisory from 2 pm Tuesday to 2 pm edt Thursday
for amz352.

Gale watch from Tuesday evening through Wednesday afternoon
for amz374.

Small craft advisory from 2 pm to 11 pm edt Tuesday for amz374.

Small craft advisory from 11 am Tuesday to 2 pm edt Thursday
for amz350.

Small craft advisory from 5 pm Tuesday to 2 pm edt Thursday
for amz354.

Weather Reporting Stations
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Charleston Executive Airport, SC171 mi39 minSSW 10 G 209.00 miFair70°F59°F69%1013.5 hPa

Wind History from JZI (wind in knots)
Last 24hrSE4S4CalmS5CalmCalmS4CalmCalmCalmSW5S4CalmS3S7S8S11SW11
1 day agoS5CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalmE7E5SE8SE75E7SE6SE7SE5
2 days agoW8CalmCalmSW6W6SW6W6W5W7N4NW4CalmNE4NE8NE11NE9N114

Tide / Current Tables for
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Tide / Current Tables for
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Weather Map and Satellite Images
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GOES Local Image of Southeast    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Wind Forecast for Charleston, SC (18,4,5,8)
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Ground Weather Radar Station Wilmington, NC
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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 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 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.