Thursday, August17, 2017 L-36.com


Marine Weather and Tides
Franklin, NC

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 6:51AMSunset 8:16PM Thursday August 17, 2017 1:37 PM EDT (17:37 UTC) Moonrise 1:31AMMoonset 3:56PM Illumination 21% Phase: Waning Crescent; Moon at 25 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 Franklin, NC
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location: 35.1, -83.39     debug


Area Discussion for - Greenville-Spartanburg, SC
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Fxus62 kgsp 171731
afdgsp
area forecast discussion
national weather service greenville-spartanburg sc
131 pm edt Thu aug 17 2017

Synopsis
High pressure will gradually erode over the next few days, though
warmer than normal conditions will remain. Moist and unsettled
weather will return late week and into the weekend. Some drying
is favored by Sunday with a return to moist conditions to start
the new work week.

Near term through tonight
As of 130 pm edt: convection developing across the area. Have
updated pop trends for current radar and latest cam guidance.

Instability on the 12z raobs was higher today with a slightly better
mid level lapse rate and increased surface dew points. Dcape values
are moderate. 0-6km bulk shear is also higher today, albeit less
than 15 kts. Still expect scattered to likely convective coverage
across the mountains this afternoon with moderate instability,
pre-frontal trough, and differential heating in place. The latest
cam guidance now shows storms dissipating as they move out of the
mountains into the foothills. However, have left low end scattered
pop in place given the instability and potential for the development
of a lee trough. Isolated severe storms will be possible. Pw values
remain above climo, but storms should move along steadily from west
to east to keep any excessive rain flooding problems isolated in
nature. Heat will be an issue this afternoon with many piedmont
temperatures in the low to mid 90s, with dewpoints in the lower 70s.

Have posted an sps today for piedmont heat index values in excess of
100 degrees at times.

The shortwave ridge over the region late today will move east
tonight, with heights falling once again from the west overnight.

Precipitation chances will increase along the spine of the southern
appalachians during the early morning hours as deeper moisture
begins to push back in. Expect continued mild and muggy min temps
early Friday, with mountain valley fog and low stratus redeveloping.

Short term Friday through Saturday night
As of 245 am edt Thursday: the short term fcst period kicks off on
Friday morning amidst a departing shortwave ridge in lee of the
southern appalachians while a region of height falls associated with
a longwave trof approaches from the west. At the surface, a cold
front tied to a surface low will extended southward beneath said
upper trof into the oh tn valleys as a prefrontal lee trof extends
across northeast ga and the western carolinas. Pattern evolution
through the short term will feature the intrusion passage of the
cold front on Friday afternoon evening with modest CAPE in excess of
1.5 2.0k j kg with shear generally maximized along ahead of the
front over western nc in the 25kts range at 0-6km. With that, the
fcst will feature low mid chance pops along south of i85 where shear
will be weakest, while favoring mid high chances with a few areas of
likely pops across the nc high terrain eastward. Given the
abundance of dry air evident in the profiles, wouldn't be shocked if
a few storms became severe with damaging winds and large hail being
the primary threats.

Moving into Saturday, the cold front will sweep through remainder of
the fcst area overnight into the mid morning hours as cooler drier
high pressure spills in from the northwest. Fortunately given the
drier nature of the airmass present over northeast ga and the
western carolinas behind the front, conditions look rather stable
with a dry fcst to prevail across the vast majority of the region
with the only mentionable pops for Saturday afternoon being
along south of i85 in closer proximity to any residual frontal
convection. Temperatures on Friday will top out a few degrees above
normal with heat indices reaching near the century mark across the
far southern zones. By Saturday temperatures will top out near
normal with dewpoints being a few degrees cooler, thus keeping any
excessive heat concerns at bay.

Long term Sunday through Wednesday
As of 300 am edt Thursday: the medium range fcst period initializes
on Sunday morning amidst the passage of a dry upper trof, with
shortwave ridging building back across the southeast states thanks
to a strengthening h5 anticyclone along the gulf coast. At the
surface dry high pressure will be in control once again across
northeast ga and the western carolinas effectively keeping the fcst
dry to round out the weekend amidst slightly above normal
temperatures.

As for Monday (eclipse day), conditions do look to be improving for
our region as guidance still favors the resurgence of a stationary
front, however at a slower rate than previous model runs on both the
gfs and ecmwf. With that, the front slowly surges northward out of
the low country and midlands, yet now not reaching the i85 corridor
until mid late afternoon, most likely after totality. In addition,
low level rh fields have improved as well with values ranging in the
45-55% percent range as opposed to nearly 10% higher in days past.

All in all, think viewing conditions are looking better. That said,
by the late afternoon hours the front is expected to slide into the
region increasing chances for showers and thunderstorms along south
of i85. Thus pops on Monday will be mostly dry, with the exception
of slight chances over the higher peaks given ridgetop convection,
as well adjacent to the approaching front south of i85 with some
chance pops highlighted as well. Tuesday looks to return to more of
a diurnal convective trend as moisture streams into the region from
the south as the front lifts well northward, while another cold
front approaches the region from the west on Wednesday. Pops both
days will be at or slightly above climo levels regionwide.

Temperatures through midweek look hold at near normal levels.

Aviation 18z Thursday through Tuesday
At kclt: lowVFR cumulus and developing convection this afternoon.

Have kept the timing for the tempo as is but added variable gusty
winds with the storms. Winds turn S this evening with ending
convection but lingering lowVFR clouds. Winds become light s
overnight with only a low chance of any fog. Scattered cumulus
develops early Friday with increasing SW wind. Convection may start
early as well, but left out of this TAF period for now.

Elsewhere: cumulus increasing and convection developing across the
area. Have included tempo at kavl khky where convection more likely
and vcts for the sc sites. Convection ends and low clouds scatter
out this evening with fog developing at kavl and khky. Could be
dense but there may be some lingering convective debris limiting
severity. Early cumulus and convection expected Friday but left
convection out for now. S to SW wind this afternoon becomes light
overnight. SW wind picks back up on Friday, NW for kavl.

Outlook: the transition to a more typical late summer pattern
continues through early next week. Expect scattered afternoon
convection and morning low stratus and patchy fog each day,
especially in the mountain valleys and in locations seeing
appreciable rainfall.

Confidence table...

17-23z 23-05z 05-11z 11-12z
kclt high 100% high 100% high 100% high 100%
kgsp high 100% high 100% high 100% high 100%
kavl high 100% high 100% high 83% low 48%
khky high 100% high 100% high 100% high 83%
kgmu high 100% high 100% high 100% high 100%
kand high 100% high 100% high 100% high 100%
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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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure

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Wind Forecast for Greenville-Spartanburg, SC (13,3,4,5)
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Ground Weather Radar Station Greer, SC
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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.