Monday, March27, 2017

Marine Weather and Tides
Lake Norman of Catawba, NC

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 7:13AMSunset 7:42PM Monday March 27, 2017 6:29 PM EDT (22:29 UTC) Moonrise 6:09AMMoonset 6:24PM Illumination 0% Phase: New Moon; Moon at 0 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 Lake Norman of Catawba, NC
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location: 35.6, -80.98     debug

Area Discussion for - Greenville-Spartanburg, SC
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Fxus62 kgsp 271844
area forecast discussion
national weather service greenville-spartanburg sc
244 pm edt Mon mar 27 2017

Moist southerly flow will linger over the southeast through Tuesday,
with several rounds of showers and thunderstorms possible. Drier air
will briefly return by the middle of the week as a cold front
settles south of the area. Rain chances return to end the week as a
low pressure system approaches from the west and interacts with the
stalled front.

Near term /through Tuesday/
As of 240 pm edt: isolated to scattered convection will move east
across the area this afternoon and early evening ahead of a lead
short wave moving ahead of an upper trough. An isolated severe storm
cannot be ruled out given the moderate instability and relatively
steep lapse rates, mainly along and south of i-85. Organization is
not expected this afternoon as the best shear will be over the
mountains and doesn't overlap the best instability.

That may change this evening and early tonight as relatively strong
short wave swings across the area just ahead of the approaching
upper trough. This forcing will combine with good upper jet
divergence and deep layer q vector convergence. Good shear remains
across the area, but elevated instability, while continuing, will be
on the decline. All this means a good chance of convection during
the evening and early overnight across the mountains then spreading
east but diminishing as it moves across the area. Severe storms
cannot be ruled out, especially across the mountains this evening.

The question remains whether organized MCS type convection can get
going across tn. If so, then this may be enough to increase severe
chances if it can hold together as it moves into the mountains. Lows
will be around 15 degrees above normal.

The upper trough swings across the area Tuesday but the surface cold
front moves more slowly. Convective coverage overall will be greater
in the morning as that's when the deepest moisture and forcing will
be over the area. Coverage will be better along and east of the i-77
corridor during the afternoon. The best overlap of instability and
shear will be to our north and east Tuesday. However, there could be
enough overlap during the afternoon along and east of the i-77
corridor for an isolated severe storm. The air mass behind the front
is not very different, and with the slow movement, highs will be 10
to 15 degrees above normal.

Short term /Tuesday night through Thursday/
As of 215 pm edt Monday: in the short term, an upper ridge will
cross the eastern conus, while a deep upper low ejects out of the
four corners region into the southern plains. At the surface, a weak
cold front will slide east, as high pressure builds into the the
great lakes. Low-level CAA will be weak behind the front, so well
above normal temps are expected Tuesday night and Wednesday.

Conditions should be dry under partly cloudy skies.

Wednesday night and Thursday, as a vigorous low pressure system
tracks across the plains, low-level flow will turn out of the south
atop the cwfa, with WAA and upglide supporting the development of
clouds and spotty light showers. With an ~1032 mb surface high
centered over central quebec, hybrid cold air damming should set up
by daybreak Thursday. This will make for a tricky temp forecast, as
precip will be forced mainly by isentropic lift and weak southerly
upslope flow. So mainly drizzle and sprinkles with a few light
showers are expected. Pops still ramp up to likely in the southwest
corner of the cwfa by the end of the day on Thursday. If the models
prove to be overdone on precip, temps may end up being a couple
categories warmer than the going forecast. Both the NAM and GFS show
elevated CAPE above the wedge in the upper savannah valley. So will
keep a chance of thunder mention Thursday afternoon there. But
severe threat should remain well to the west closer to the
approaching cold front.

Long term /Thursday night through Monday/
As of 230 pm edt Monday: the medium range fcst period kicks off
on Thursday evening amidst a highly amplified upper pattern that
is highlighted by a ridge axis along the east coast, as well as
a closed and robust h5 cyclone embedded in a longwave trof atop
the plains and ms valley regions. At the surface, the pattern
is just as complex thanks to an entrenched hybrid cad centered
off the jersey shore, while cyclogenesis dominates the field
across dixie alley, eastward into the southern appalachians by
way of an approaching zone of baroclynicity. With that, the
cold front associated with said surface cyclone will be well to
west by fcst initialization, likely yet to cross the ms river,
however a warm front will have laid out across the i75 corridor
region in ga. Moisture advection tied to this pattern still looks
as if it will lift isentropically atop the wedge airmass leading
to increasing chances for stratiform precipitation into the early
overnight hours. At that point the fcst becomes quite interesting
given the approaching upper wave to provide synoptic scale lift,
as well as cooling the mid levels and thus increasing lapse rates.

Meanwhile, the cad will begin to retreat to the east leading to
intrusion of the warm front, and thus providing focus for llv srh
enhancement given remnant backed surface flow. Eventually the
flow will veer leading to straightening of hodographs, at least in
the 0-1km layer, however improved mid level lapse rates will yield
increasing instability while the primary shortwave passes overhead.

Given the fcst range these details are still a bit uncertain,
yet it still looks as if the pattern could be rather convectively
active Friday morning/afternoon before the cold front sweeps in
Friday evening.

Moving on, remnant northwest flow showers are progged behind the
fropa on Saturday while the remainder of the fcst area tends to dry
out as deep layer ridging builds in for Sunday. This deep ridging
looks dominant through Monday as well, however with sly flow to be
reestablished as the surface ridge shifts over the western atlantic.

Meanwhile another deep upper system will be building across the
plains, before sharply ejecting northeast into the oh/tn valleys
toward periods end, which will lead to another round of wet weather
across northeast ga and the western carolinas into midweek.

As for the fcst itself, pops will ramp up sharply on Thursday night,
holding at widespread high chance to likely levels through much of
the day Friday. Said pops will taper into the overnight of Saturday
morning given the fropa, thus no mentionable pops are featured by
12z regionwide with the exception of the tn line upslope regions.

By midday Saturday, those pops are removed leading to dry conditions
through Sunday and into Monday when pops increase slowly from
the west as the next system ejects from the southern plains.

Temperatures through the period will be a bit variable, however
above normal.

Aviation /19z Monday through Saturday/
At kclt: MVFR CIGS have scattered out. However, lowVFR and the
potential for convection return during the afternoon. Guidance has
backed off on the potential for tsra at the airfield, but chance is
high enough to change the tempo to vcts. Decreasing nocturnal
instability should lead to mainly showers overnight. Guidance has
been consistent bringing in MVFR vsby and ifr CIGS overnight, so
have added these to the taf. Should be a quick vsby recover Tuesday
but a slow cig recovery. Winds will be S to ssw through the period.

Elsewhere: similar conditions to kclt except with an earlier onset
of convection. Wind will shift after daybreak to NW at kavl and will
go more westerly elsewhere.

Outlook: another round of thunderstorms will be possible on Tuesday
afternoon, especially near kclt. Continued low level moisture will
provide a good chances of restrictions throughout. Drier conditions
should briefly return during mid-week before another storm system
begins affecting the region Thursday and Friday.

Confidence table...

18-24z 00-06z 06-12z 12-18z
kclt high 90% high 92% low 59% med 75%
kgsp high 97% high 100% med 60% med 74%
kavl high 100% high 100% high 83% high 84%
khky med 75% med 78% med 62% low 58%
kgmu high 100% high 100% med 64% med 75%
kand high 93% high 100% med 77% med 77%
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
WATS1 - Lake Wateree, SC 89 mi60 min W 1.9 G 7 77°F

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Statesville Municipal Airport, NC11 mi50 minSSW 610.00 miPartly Cloudy77°F58°F53%1014.2 hPa
Lincolnton, Lincolnton-Lincoln County Regional Airport, NC13 mi35 minSW 8 G 1710.00 miPartly Cloudy78°F52°F41%1014.6 hPa
Concord Regional Airport, NC20 mi40 minSSW 810.00 miPartly Cloudy79°F53°F42%1015.6 hPa
Hickory, Hickory Regional Airport, NC24 mi37 minSSW 910.00 miPartly Cloudy76°F54°F47%1012.2 hPa

Wind History from SVH (wind in knots)
Last 24hrCalmCalmCalmCalmE3NW5CalmCalmS3CalmCalmS3S3S5S3SW8SW5S5S5S6S4S7S5SE4
1 day agoS4CalmCalmCalmCalmSE3SW3SW5SW4S3S3CalmCalmCalmCalmS5S8
2 days agoSW3CalmCalmS3CalmCalmCalmS4SW5S5S5SW4SW3SW4SW4SW5SW10

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 Mid-Atlantic    EDIT

Wind Forecast for Greenville-Spartanburg, SC (18,4,5,8)
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Ground Weather Radar Station Greer, SC
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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.