Friday, August18, 2017 L-36.com


Marine Weather and Tides
Stanardsville, VA

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 6:31AMSunset 8:03PM Friday August 18, 2017 2:55 AM EDT (06:55 UTC) Moonrise 2:00AMMoonset 4:42PM Illumination 17% Phase: Waning Crescent; Moon at 26 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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ANZ536 Tidal Potomac From Indian Head To Cobb Island- 131 Am Edt Fri Aug 18 2017
Overnight..S winds 5 kt. Waves less than 1 ft. A slight chance of showers and tstms.
Fri..S winds 5 to 10 kt. Waves 1 ft. Scattered showers and tstms.
Fri night..W winds 5 to 10 kt. Waves 1 ft. Numerous showers and tstms.
Sat..NW winds 5 kt. Waves less than 1 ft.
Sat night..W winds around 5 kt. Waves 1 ft or less.
Sun..NW winds around 5 kt. Waves 1 ft.
Sun night..SE winds around 5 kt. Waves 1 ft.
Mon..S winds around 5 kt. Waves 1 ft.
Tue..SW winds around 5 kt. Waves 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 131 Am Edt Fri Aug 18 2017
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A cold front will approach Friday, then pass through Friday night into early Saturday. High pressure will build to the north and west of the waters while a pressure trough will remain nearby for later Saturday and Sunday. The high pressure will shift offshore early next week.

7 Day Forecast for Marine Location Near Stanardsville, VA
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location: 38.31, -78.4     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 180128
afdlwx
area forecast discussion
national weather service baltimore md washington dc
928 pm edt Thu aug 17 2017

Synopsis
A warm front will exit the area to the northeast tonight. A cold
front will approach from the west Friday before crossing the
region Friday night. Surface high pressure will build in
Saturday, but an upper level disturbance will cross the region
Saturday night. A warm front will advance back north across the
region early next week, followed by a strong cold front in the
middle of the week.

Near term until 6 am Friday morning
Scattered storms exist from cumberland to charlottesville,
advancing northeast. These are likely tied to a theta-e ridge
and developing modest low level jet. Even though hi-res guidance
generally shows a weakening trend over the next several hours,
would not be surprised if showers and storms persist continue to
develop due to the forcing and around 2000 j kg of MUCAPE per
mesoanalysis and 00z iad sounding. Will carry chance pops
through most of the night, as elevated instability will remain
in place. The isolated severe threat should be waning though
due to increasing surface inhibition. Precipitable water values
near 2 inches and deep warm cloud layers suggest heavy rain will
be the biggest threat, though so far storms have been
exhibiting reasonable motion.

Where skies clear, we could get some patchy fog again,
especially in places which saw rain today. Lows will stay very
warm with the high dew points, with 70s common.

Short term 6 am Friday morning through Saturday night
Patchy fog will be a concern early Friday, but not expecting
widespread dense fog, and it should break fairly quickly once
the Sun rises.

Probably the biggest forecast concern is the threat of severe
weather on Friday afternoon. While it is certainly not the best
set up, very high pw's in excess of 2 inches (potentially above
2.25 inches) and surface temps perhaps into the low 90s with
surface dew points into the mid 70s and shear of 25-35 knots,
and the surface cold front moving into it, will likely get some
sort of line of storms going by early afternoon, which will then
slowly push east across the region. Best time in the cities
looks like mid-late afternoon, with storms lingering into the
evening east of i-95 into southern md. Training storms could
easily produce flash flooding as well. SPC has outlooked the
region for marginal severe threat, while wpc has outlooked the
region for slight risk of excessive rainfall.

The hot and humid airmass will result in high heat indices.

Using the best performing model blends results in a heat index
of 100 to locally 105 east of the blue ridge and upper 90s
west. Best chance of reaching criteria will likely be along i-95
corridor which will have the longest heating before storms
arrive. Will allow midnight shift to make the call on an
advisory based on the latest cloud convective trends.

Front slides in later Friday night, with some drying and
cooling. Lows will be a bit cooler than tonight, with some areas
returning to the 60s. Surface high presses into the region
Saturday and Saturday night, but a trough aloft may result in
isolated storms late in the day into the evening. For now have
kept pops mainly NW of the cities, but these may need to be
expanded south and east if confidence in storms grows. Highs
Saturday will be in the 80s. Temps will cool a bit more at
night, with 60s more common.

Long term Sunday through Thursday
High pressure will keep dry conditions on Sunday as it slowly
moves offshore Sunday night into Monday. Southerly flow settles
in advecting moisture into our region Monday and Tuesday. A
pressure trough at the surface could trigger showers and
thunderstorms Monday and Tuesday afternoon and evening. A cold
front will approach from the northwest on Wednesday and move
across on Wednesday night. High pressure returns on Thursday.

High temperatures during this period will be in the mid to upper
80s in northern maryland... To low 90s in central virginia at
times... And 70s at higher elevations.

Aviation 01z Friday through Tuesday
Scattered thunderstorms are a concern at all terminals until at
least late this evening. Some weakening is seen in radar trends,
but will not rule out storms reaching the metros due to modest
low level jet forcing on elevated instability.

Late tonight concern shifts to low clouds and fog potential.

Given variable clouds and uncertainty in storm coverage, it is
still difficult to place exact timing and severity of any
restrictions. 18z guidance suggests the best chance for low
clouds will be along the i-95 corridor. Have generally held tafs
at MVFR for now, but ifr not out of the question.

We should see improvement Friday just in time for the next
round of thunderstorms on Friday afternoon. This activity will
be more organized with the cold front, with a better severe
threat, along with a better chance of low cig and vis with
storms. Generally should improve toVFR by Saturday morning,
with a much lower (though not zero) risk of storms late Saturday
as an upper level trough crosses the region behind the surface
front.

Vfr conditions expected Sunday into Tuesday, with short periods
of sub-vfr conditions mainly Monday and Tuesday afternoon due
to possible showers and thunderstorms.

Marine
Southerly channeling ongoing with occasional gusts to 20 kt.

Expanded the SCA to pooles island on the bay zones due to better
mixing potential of a low level jet on the open waters. Have
carried the northern two zones until 6 am, when the jet should
weaken. However, SCA conditions will still be possible farther
south into Friday, ending Friday night as the cold front slides
southward into the area. Further adjustments to the SCA are
possible.

Otherwise, main concern will be for thunderstorms. Can't rule
out a storm tonight, although the threat for strong storms is
lowering. The strongest storms will likely be Friday afternoon
into evening. Winds diminish and storms end Saturday morning,
but a few isolated storms can't be ruled out late Saturday as an
upper level disturbance moves across the region.

Mainly dry conditions expected Sunday into Tuesday, with
periods of showers and thunderstorms possibly developing Monday
and Tuesday afternoon. Wind gusts are expected to stay below the
small craft advisory threshold.

Tides coastal flooding
Southerly winds will be increasing anomalies up to one foot
above normal. Have gone ahead and issued advisories for straits
point and dc SW waterfront since observations seem to be
exceeding forecasts (advisory already in place for annapolis).

Alexandria will be close, but some time to make that decision
since high tide is around 5:30 am. The following high tide is
lower astronomically, so am not seeing a threat for that one.

With continued south winds, additional advisories may be
needed Friday before the front brings a NW flow and allows
anomalies to drop Saturday.

Lwx watches warnings advisories
Dc... Coastal flood advisory from 3 am to 7 am edt Friday for dcz001.

Md... Coastal flood advisory until 8 am edt Friday for mdz014.

Coastal flood advisory until 1 am edt Friday for mdz017.

Va... None.

Wv... None.

Marine... Small craft advisory until 1 am edt Saturday for anz533-534-
537-541-543.

Small craft advisory until 6 am edt Friday for anz531-532.

Synopsis... Rcm
near term... Ads rcm
short term... Ads rcm
long term... Imr
aviation... Ads imr rcm
marine... Ads imr rcm
tides coastal flooding... Ads rcm


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 83 mi37 min S 6 G 8 79°F 80°F1011.4 hPa
BSLM2 - Chesapeake Bay, MD 95 mi145 min SSE 4.1 68°F 1013 hPa67°F

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Charlottesville-Albemarle Airport, VA12 mi62 minSW 37.00 miFair77°F75°F94%1011.9 hPa
Orange, Orange County Airport, VA19 mi80 minN 010.00 miFair73°F73°F100%1012.5 hPa
Staunton / Shenandoah, VA24 mi60 minN 010.00 miFair71°F70°F98%1014.6 hPa

Wind History from CHO (wind in knots)
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Last 24hrCalmCalmCalmCalmCalmCalmCalmCalmCalm53S66SW3S10S8S9S12
G20
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1 day agoCalmCalmCalmCalmCalmCalmCalmCalm3N4SW4SW4S43NE4E44E4N4N3CalmN3CalmCalm
2 days agoCalmCalmCalmCalmCalmCalmN4N3CalmS3CalmSE33CalmCalmN4NE6N3CalmCalmCalmN3CalmCalm

Tide / Current Tables for Fredericksburg, Rappahannock River, Virginia
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Fredericksburg
Click for Map
Fri -- 02:56 AM EDT     Moonrise
Fri -- 04:26 AM EDT     3.53 feet High Tide
Fri -- 06:27 AM EDT     Sunrise
Fri -- 11:57 AM EDT     0.24 feet Low Tide
Fri -- 05:08 PM EDT     3.07 feet High Tide
Fri -- 05:38 PM EDT     Moonset
Fri -- 07:59 PM EDT     Sunset
Fri -- 11:57 PM EDT     0.24 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.61.42.43.13.53.53.12.51.91.30.80.40.20.61.42.22.83.12.92.41.81.20.70.4

Tide / Current Tables for Massaponax, Rappahannock River, Virginia
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Massaponax
Click for Map
Fri -- 02:56 AM EDT     Moonrise
Fri -- 04:19 AM EDT     3.06 feet High Tide
Fri -- 06:27 AM EDT     Sunrise
Fri -- 12:16 PM EDT     0.23 feet Low Tide
Fri -- 05:01 PM EDT     2.66 feet High Tide
Fri -- 05:37 PM EDT     Moonset
Fri -- 07:58 PM EDT     Sunset
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
0.51.122.7332.72.21.71.20.80.50.20.41.11.92.52.72.52.11.61.10.70.4

Weather Map and Satellite Images
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Weather Map
wmap_A
IR Satellite Image from GEOS
east_satellite

GOES Local Image of Mid-Atlantic    EDIT
Geos

Wind Forecast for Baltimore, MD/Washington (2,6,7,8)
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Ground Weather Radar Station Sterling, VA
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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.