Wednesday, September26, 2018 L-36.com


Marine Weather and Tides
St. James, MD

Version 3.4
What's New / NOTES
9/17/2018 XTide broke when 1and1 "upgraded" my server. It has been esculated. I am sorry for the problem.

Sunrise 7:01AMSunset 7:02PM Wednesday September 26, 2018 1:31 AM EDT (05:31 UTC) Moonrise 7:15PMMoonset 7:20AM Illumination 98% Phase: Waning Gibbous; Moon at 16 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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ANZ535 Tidal Potomac From Key Bridge To Indian Head- 1034 Pm Edt Tue Sep 25 2018
Rest of tonight..S winds 5 kt. Waves less than 1 ft. Patchy fog with vsby 1 to 3 nm.
Wed..SW winds 5 to 10 kt. Waves 1 ft. A chance of showers and tstms. Patchy fog. Vsby 1 to 3 nm.
Wed night..N winds 5 to 10 kt. Waves 1 ft. Showers likely with a chance of tstms.
Thu..NE winds 5 kt. Waves less than 1 ft. Showers likely.
Thu night..NE winds around 5 kt. Waves 1 ft. A chance of showers.
Fri..NW winds around 5 kt. Waves 1 ft. A chance of showers.
Fri night..Light winds. Waves 1 ft.
Sat..N winds around 5 kt. Waves 1 ft.
Sun..SE winds around 5 kt. Waves 1 ft. Winds and waves higher and visibilities lower in and near tstms.
ANZ500 1034 Pm Edt Tue Sep 25 2018
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A warm front will continue lifting north of the waters through tonight. A strong cold front will approach the waters from the ohio valley Wednesday, and will likely stall south of the waters Thursday. Small craft advisories may be needed Wednesday night and Thursday.


7 Day Forecast for Marine Location Near St. James, MD
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location: 39.59, -77.77     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 260149
afdlwx
area forecast discussion
national weather service baltimore md washington dc
949 pm edt Tue sep 25 2018

Synopsis
A warm front will continue to slowly lift north of the area
tonight. A strong cold front will then cross the region late
Wednesday. A wave of low pressure may pass southeast of the
region Thursday into Thursday night. Another, weaker cold front
may cross the region over the weekend.

Near term until 6 am Wednesday morning
For the first time in recent memory, the local radar is not
detecting any precipitation across our cwa. The warm front that
pressed through the area earlier today now resides across
northeastern pa, pegging us in the warm sector with temperatures
in the upper 60s to lower 70s, and dewpoints not far behind in
the middle to upper 60s. Given ample low level moisture, do
expect patchy fog and low level clouds to re-emerge overnight.

Much of the area will remain dry overnight, but cannot rule out
a passing shower or sprinkle. The highest likelihood of this
occurrence would be along the potomac highlands and western
maryland towards daybreak as a cold front and associated trough
nears the ohio valley. As such, will carry slight chance pops
for those areas as daybreak nears. Lows tonight will bottom out
in the lower 60s to near 70 degrees.

Short term 6 am Wednesday morning through Thursday night
Wednesday morning will be dictated by how quickly the low clouds fog
burns off. Aside from that, the morning hours should be quiet dry. A
cold front will be crossing the ohio valley appalachians during the
afternoon, and will be entering the forecast area late in the day.

Ahead of the cold front, sref MLCAPE suggesting 1000-1500 j kg may
develop in peak heating. The better effective shear profiles will
reside across the the potomac highlands, where 30-40 kt possible.

The instability shear lift intersection suggests that there
will be the risk of severe thunderstorms near the end of the day
in the mountains along i-81 approaching the catoctins.

Nocturnal stabilization will play a role as these storms
approach the i-95 corridor, due to the anticipated slightly
later timing vs late september sunset. Nonetheless, will have
likely showers and chance thunderstorms in the forecast, slowly
cutting back as the front crosses and stalls Wednesday night.

Am concerned that the front will not truly clear the area, making
way for more showers Thursday as a shortwave ripples along the
frontal boundary. Have bumped pops up slightly across
virginia southern maryland during the afternoon evening hours.

Long term Friday through Tuesday
On Friday, a relatively weak surface high will be moving across the
northeast in the wake of the aforementioned cold front. This will
bring a period of northerly flow at the surface to the region.

Meanwhile, flow will be out of the southwest aloft, as a trough
slides across the us canada border near the great lakes throughout
the day. This should result in some light rain drizzle for the early
part of the day. At this point, most guidance takes this high
pressure offshore fairly quickly on Friday, switching winds to a
more westerly flow at the surface. Some uncertainty will remain in
regards to how quickly the wedge of cooler air will break down, but
for now, expecting drier conditions Friday afternoon, as surface
flow switches to a more westerly component.

An upper-level ridge looks to build into the southeast through the
weekend, with the jet stream setting up along the us canada border.

This appears to leave us in an area of zonal upper level flow
throughout the weekend. A weak low pressure system will make a close
pass to the north Saturday night into Sunday, but at this point,
expecting this to bring no precipitation to the area. High
temperatures will be seasonable to slightly above average, with
highs in the mid 70s to near 80f by Sunday, with overnight lows in
the mid 50s to low 60s.

On Monday, a 1030mb surface high pressure system builds into
southern quebec, which looks to push cooler air into the region from
the north. Some guidance suggests that this will bring precipitation
to the region, especially along that cold front. Keeping chances
slim at this point, given the westerly to west-northwesterly flow
aloft, which should keep things fairly dry. Could see some clouds
thanks to the overrunning effect, but not sold on seeing a lot of
precipitation at this time, so keeping slight chance pops in the
forecast for now.

Aviation 01z Wednesday through Sunday
The warm front that pressed through the terminals earlier today
now resides well north of the terminals over northeastern pa,
with a light southerly flow prevailing. Given ample low level
moisture residing over the area, low clouds and fog are expected
to re- emerge overnight, producing ifr lifr ceilings and
visibilities for the second half of the night.

Low clouds fog will gradually lift Wed morning. Am hopeful thatVFR
will return in the afternoon prior to the arrival of a cold front.

Local flight restrictions within showers thunderstorms possible...

most likely mid late afternoon. Mrb stands the best chance at these
storms passing before dark, but mrb also stands the best chance at
receiving local strong wind gusts.

Showers may then linger at times through Thursday night, with
associated reductions in cig vis possible.

Some sub-vfr conditions are possible on Friday, especially
early in the day, but drier conditions will return by the
afternoon and through the weekend under building high pressure.

Marine
With a warm front well north of the waters, light southerly flow
is prevailing over the waters, with sub SCA conditions winning
out and expected to persist through the overnight period.

Winds will be pick up again Wednesday as a cold front approaches the
waters. FROPA not likely til Wednesday night, but a few stronger
storms may precede the front. Special marine warnings may be
required Wed afternoon, followed by possible small craft advisories
wed night into thu. The front would have to clear the waters
though... Which is not a certainty. Therefore, am not posting
advisories at this time for Wed night.

Sub-sca conditions should return by the end of the week and through
the weekend after the cold front departs the region.

Tides coastal flooding
A southeast flow continues to cause water levels to run around
1.5 to 2.5 feet above normal. The southeast flow will continue
tonight before turning south to southwest during the day
Wednesday. The southerly component will keep water levels well
above normal. Therefore, will continue with coastal flood
headlines (warnings for sensitive areas such as annapolis,
straits point and washington dc) and advisories elsewhere
through the tide cycle Wednesday morning.

Have issued coastal flood watches for the sensitive areas
Wednesday afternoon and evening, with advisories elsewhere. The
one exception is straits point where the warning continues
through Wednesday afternoon. During this time, elevated water
levels are expected, but the anomalies may come down a but due
to lighter winds and the direction turning west of south.

Therefore, confidence is not as high for moderate
flooding... Which is why a watch has been issued instead of a
warning for annapolis and washington dc alexandria.

A stronger offshore flow will develop behind a cold front late
Wednesday night, and this will cause anomalies to sharply fall.

Lwx watches warnings advisories
Dc... Coastal flood watch from Wednesday afternoon through late
Wednesday night for dcz001.

Coastal flood warning until 4 pm edt Wednesday for dcz001.

Md... Coastal flood advisory until 6 pm edt Wednesday for mdz018.

Coastal flood advisory until 2 pm edt Wednesday for mdz508.

Coastal flood advisory until 11 pm edt Wednesday for mdz011.

Coastal flood warning until 8 am edt Wednesday for mdz014.

Coastal flood watch from 8 am edt Wednesday through Wednesday
evening for mdz014.

Coastal flood advisory until 7 pm edt Wednesday for mdz016.

Coastal flood warning until 6 pm edt Wednesday for mdz017.

Va... Coastal flood advisory until 7 pm edt Wednesday for vaz057.

Coastal flood watch from Wednesday afternoon through late
Wednesday night for vaz054.

Coastal flood advisory until 4 pm edt Wednesday for vaz054.

Wv... None.

Marine... None.

Synopsis... Bkf hts
near term... Bkf
short term... Hts
long term... Cjl
aviation... Bkf hts cjl
marine... Bkf hts cjl
tides coastal flooding... Bjl


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 63 mi31 min SSE 2.9 G 4.1 1018.8 hPa (-0.9)
BLTM2 - 8574680 - Baltimore, MD 67 mi31 min S 1 G 1.9 75°F1018.4 hPa (-0.8)
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 71 mi31 min NNE 1 G 1 72°F 1018.7 hPa (-0.7)

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hagerstown, Washington County Regional Airport, MD9 mi38 minSE 610.00 miFair71°F66°F87%1018.7 hPa
Eastern WV Regional Airport/Shepherd Field, WV17 mi38 minSE 38.00 miFair67°F66°F100%1017.5 hPa

Wind History from HGR (wind in knots)
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Last 24hrN6N6N6N5NW6N4NW3NW4NW4NW4NW6NW4CalmS3SW4W4CalmSE5S6S5CalmSE5SE3SE6
1 day agoNE6NE6NE4N3N5N5NE4NE7E6E6SE5E8SE8E7E5E6E5NE5NE4NE4E3E5NE6E4
2 days agoN4N4NW5CalmNW4NW4CalmCalmNW4NE3NE3N5NW4N3N5N4NE4N3N3NE4N4N3N4NE6

Tide / Current Tables for Chain Bridge, Washington, D.C.
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Tide / Current Tables for Chain Bridge, D.C.
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Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.


Weather Map and Satellite Images
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GOES Local Image of    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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Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Baltimore, MD/Washington (1,6,7,8)
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Ground Weather Radar Station Sterling, VA
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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.