Monday, May29, 2017

Marine Weather and Tides
Walhalla, 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 6:17AMSunset 8:38PM Monday May 29, 2017 5:05 PM EDT (21:05 UTC) Moonrise 9:25AMMoonset 11:34PM Illumination 19% Phase: Waxing Crescent; Moon at 4 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 Walhalla, SC
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location: 34.77, -83.07     debug

Area Discussion for - Greenville-Spartanburg, SC
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Fxus62 kgsp 292036
area forecast discussion
national weather service greenville-spartanburg sc
436 pm edt Mon may 29 2017

A series of weak cold fronts will cross the area through mid week.

Weak high pressure will make Thursday the drier day of the week.

Expect a stronger cold front to reach our region over the weekend.

Near term through Tuesday
As of 430 pm: surface trough in place across the piedmont with
approaching shortwave moving out of the deep south and a bit of
an upper jetlet are the main forcing mechanisms for convection
this afternoon. Deep upper trough low over lake superior and upper
high just east of the bahamas has led to strong southwesterly fetch
aloft, helping to draw moisture out of the gulf. Given the abundant
deep shear INVOF the jetlet, multicell clusters are expected to
be the main storm mode. Main threat remains gusty damaging winds,
though some low-end hail cannot be ruled out. Severe TSTM watch
in effect for most of NE ga, the upstate, and us 74 corridor
of the nc piedmont, as well as adjacent portions of central ga
and sc. This watch primarily covers the threats associated with
storms developing within the cwfa. However, there is the additional
threat that clusters will organize over ga and move NE into our
area closer to sunset. While not a significant concern, at least
minor hydro threat cannot be ruled out with any training cells.

Convection should wane overnight and we lose most of our deep-layer
forcing as we push into tomorrow, but surface trough remaining
in place and southwest flow aloft continuing will allow for
diurnal convection, possibly enhanced a tad with the proximity
of the trough aloft. Best chances for Tuesday remain across the
piedmont (especially sc ga where the trough will linger) and the
sw mountains. Guidance is trending cooler for tomorrow but we're
warming up more than anticipated today so have erred on the warm
side, but still right at seasonal normals. Lows tonight a handful
or so degrees above.

Short term Tuesday night through Thursday
As of 200 pm Monday: at long last, the axis of the upper trough,
that has been over the central CONUS for what seems like ages, will
finally push to the east coast by the end of the short term. This
will drag a weak cold front through our area on Wednesday. While
this should provide a focus for deep convection Wed afternoon,
coverage may not meet the expectations of a typical late-spring
fropa. Progged mid-level lapse rates are very poor, while forecast
soundings depict a well-mixed relatively dry boundary layer. As a
result, no short term guidance source depicts anything more than
modest levels of CAPE Wed afternoon and pops will be advertised only
in the 20-30% range across much of the area (maybe 40% in the high
elevations near the blue ridge). Deep layer shear will remain
somewhat respectable, so a severe storm or two cannot be ruled out,
but the threat should be limited by the overall lack of robust

By Thursday, guidance suggests weak but relatively dry high pressure
should be building into the area, limiting diurnal destabilization.

In fact, most guidance produces little or no QPF response across our
area Thu afternoon. Pops will be limited to a slight chance across
roughly the southern half of the area (closer to the departing
frontal zone). Temps will generally remain close to normal, perhaps
a degree or two above, through the period.

Long term Thursday night through Monday
As of 210 pm Monday: a deep SW flow out of the gulf will develop
Thursday night and persist into the weekend. The persistent upper
level closed low and trough over eastern canada will rotate and
surge a bit further south during the weekend with axis roughly along
the east coast. A surface cold front will be pushed south with
moderately strong high pressure dropping down from the western great
lakes. This cold front will be the focus of more widespread
convection as it reaches our region late Saturday night and Sunday
morning. If this scenario occurs with front arriving in the cooler
part of the day, this should prevent stronger convection. Of course,
this is nearly a week away and timing of frontal passage could speed
up or slow down. Some strong convection ahead of the cold front may
reach the nc mountains Saturday evening before weakening Saturday
night. Late Saturday is the best chance of severe with prefrontal
forcing and effects of convective generation from diurnal max
heating. Drier air should filter in from the north by late Sunday
night. The front should stall out over florida to start the upcoming
week with drier weather for at least a couple of days.

Max temps are forecast to be near normal and min temps forecast to
be about 5 degrees above normal due to the cloud cover and higher
moisture level preventing radiational cooling.

Aviation 21z Monday through Saturday
At kclt and elsewhere: guidance all still has convection blossoming
across the blue ridge in the next couple of hours and spreading east
across the area through the afternoon evening. Have timed tempo tsra
as close as possible, including vrb gusty winds as that is the main
threat in any strong severe storms. GenerallyVFR through the
evening except in any tsra, but with CIGS becoming bkn-ovc 5-7kft.

Could see some MVFR CIGS vsby in the predawn hours on Tuesday.

Introduced another prob30 at most sites starting 15z Tuesday with
more typical diurnal convection expected.

Outlook: primarily afternoon and evening tsra are possible each day,
bringing periodic restrictions. Areas of morning fog and or low
stratus may potentially develop especially where ra fell the
previous evening. This pattern will continue through at least the
end of the work week.

Confidence table...

20-02z 02-08z 08-14z 14-18z
kclt high 100% high 96% high 83% high 88%
kgsp high 100% high 100% med 78% high 83%
kavl high 98% high 89% high 86% high 91%
khky high 100% high 100% high 80% high 98%
kgmu high 100% high 96% med 76% high 84%
kand high 100% high 97% high 94% high 88%
the percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:

Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CHDS1 - Strom Thurmond Dam, SC 89 mi86 min N 6 G 7 85°F

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Clemson, Clemson-Oconee County Airport, SC12 mi72 minVar 410.00 miMostly Cloudy84°F64°F53%1015 hPa

Wind History from CEU (wind in knots)
Last 24hrW11
1 day agoSW7W7SW53CalmSW3SW6N12
2 days agoSW75SW4SW4SW3SW4SW4W4W3W6SW4SW54CalmW4W8W9SW7W9W13W856W10

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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Weather Map
IR Satellite Image from GEOS

GOES Local Image of Southeast    EDIT

Wind Forecast for Greenville-Spartanburg, SC (17,4,5,8)
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Ground Weather Radar Station Greer, SC
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weather_mapweather_map weather_map

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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.