Wednesday, March20, 2019 L-36.com


Marine Weather and Tides
Olney, MD

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 7:10AMSunset 7:21PM Wednesday March 20, 2019 9:41 PM EDT (01:41 UTC) Moonrise 6:02PMMoonset 6:15AM Illumination 100% Phase: Full Moon; Moon at 15 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- 915 Pm Edt Wed Mar 20 2019
.small craft advisory in effect from Thursday evening through late Thursday night...
Rest of tonight..E winds 5 kt. Waves less than 1 ft. A chance of rain late this evening, then rain with vsby 1 to 3 nm.
Thu..N winds 5 to 10 kt. Waves 1 ft. Rain. Vsby 1 to 3 nm.
Thu night..NW winds 10 to 15 kt with gusts to 20 kt. Waves 1 ft. A chance of rain.
Fri..W winds 15 to 20 kt with gusts to 30 kt. Waves 1 to 2 ft. Scattered showers.
Fri night..NW winds 10 to 15 kt. Gusts up to 30 kt...diminishing to 20 kt after midnight. Waves 1 ft.
Sat..NW winds 10 to 15 kt with gusts to 25 kt. Waves 1 ft.
Sat night..NW winds 10 to 15 kt with gusts to 20 kt...diminishing to 5 kt after midnight. Waves 1 ft.
Sun..SW winds around 5 kt. Waves 1 ft.
Mon..N winds around 5 kt. Waves 1 ft. A chance of showers through the day, then rain likely through the night.
ANZ500 915 Pm Edt Wed Mar 20 2019
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Low pressure developing over the carolina coast will move northward near or over the waters Thursday. A cold front approaching from the great lakes will cross the region Friday. High pressure will follow for the weekend. Small craft advisories will likely be needed Friday into Saturday, and gales are possible Friday into Friday night.


7 Day Forecast for Marine Location Near Olney, MD
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location: 39.15, -77.07     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 210056
afdlwx
area forecast discussion
national weather service baltimore md washington dc
856 pm edt Wed mar 20 2019

Synopsis
Coastal low pressure will develop over north carolina tonight
and the low will pass through our area Thursday. The low will
intensify as it moves off to the northeast Thursday night
through Friday and high pressure will return for the weekend.

Low pressure may impact the area early next week with more
unsettled conditions possible.

Near term until 6 am Thursday morning
Clouds continue to gradually lower and thicken tonight ahead of
low pressure developing over the eastern carolinas. Intermittent
light rain already encroaching on southern maryland as of early
this evening, and rain is expected to expand quickly northward
while increasing in intensity after midnight (mainly east of
interstate 81). Some moderately heavy rain is likely by daybreak
between the blue ridge and interstate 95.

Short term 6 am Thursday morning through Friday night
There is a decent chance this system will be an "overperformer"
when it comes to precipitation amounts. Strong height falls with
an approaching negatively-tilled mid upper trough, attendant
mid and upper jet pva, and strong low-level moisture flux all
point to an area of moderately heavy rain from Thursday morning
the mid Thursday afternoon across northern virginia and central
maryland (mainly between the blue ridge and i-95). In addition,
mid-level lapse rates of around 7 c km will contribute to
embedded convective elements heavier rainfall rates (possibly
1 2 inch per hour). A few rumbles of thunder are possible as
well given all the strong forcing in place, despite low cape
values (less than 200 j kg).

The low pressure system will be intensifying NE of our area
Thursday night and the shortwave will phase with additional
northern stream energy on Friday. This will cause some showers
to develop on Friday afternoon. In the meantime, high pressure
will be building west of our region over the central conus. The
gradient from this and the low pressure suggests that gusty nw
winds will develop over our area Friday into Friday night. Gusts
between 30 and 40 mph are possible across most of our cwa, and
gusts up to 50 mph are possible over higher elevations west of
the blue ridge. Snow showers west of the allegheny front are
possible during this time as well, with dry conditions expected
elsewhere.

Long term Saturday through Wednesday
High pressure will gradually build over the region through the day
Saturday as shortwave ridging aloft moves into the ohio valley.

Enough of a pressure gradient will exist between the building area
of high pressure and the departing low over the northeast to
maintain some gusty winds through the day. However, winds are
gradually expected to diminish late Saturday as the low moves
further away and the gradient relaxes. The high will move overhead
Saturday night, then slide offshore on Sunday. This will allow a
southerly return flow to develop, enabling warmer conditions to work
their way back in. High temperatures will run about ten degrees
warmer on Sunday with highs in the low 60s (compared to the
low 50s on Saturday).

On Monday, disturbances in both the northern and southern streams
will start to approach the area. Model guidance differs
substantially with respect to the handling of these disturbances,
casting rather high uncertainty on our sensible weather forecast for
the Monday through Tuesday time frame. In terms of deterministic
solutions, the 12z GFS has a strong northern stream disturbance and
a more diffuse, weak southern stream disturbance. At the surface,
this solution results in a strong area of high pressure developing
over the upper midwest, and a strong, progressive cold front being
driven southward across the area late Monday through Monday night.

This would result in a period of precipitation late Monday afternoon
through Monday night that would clear the area by Tuesday morning.

The 00z euro, on the other hand, showed a slightly weaker,
further northward displaced northern stream disturbance, and a
stronger southern stream disturbance (compared to the gfs
solution). This combination results in the baroclinic zone
stalling out overhead and a more prolonged period of
precipitation Monday through Tuesday. The general notion of a
low predictability forecast is supported by the 00z eps members,
which show more than 30 degrees of spread in the temperature
field through much of the Monday night through Wednesday time
period.

To summarize, the general synoptic pattern appears favorable for us
to see some precipitation at some point during the late Monday
through Tuesday timeframe. However, most of the finer scale
details, including the timing, duration, and character of the
precipitation remain in question. There's plenty of cold air
associated with the northern stream disturbance, so some wintry
precipitation isn't entirely out of the equation, even at lower
elevations. However, given the level of uncertainty it's far too
early to speculate with respect to what will happen with
precipitation type.

Aviation 01z Thursday through Monday
A coastal low pressure system will move near over our area
Thursday and sub-vfr conditions are expected late tonight and
remaining through most of Thursday. Periods of ifr conditions
are expected, mainly 9z-21z Thursday. Periods of heavy rain or
even a thunderstorm are possible. CIGS and vsbys will be
improving Thursday night as the coastal low moves away from us.

Gusty NW winds are expected on Friday as low pressure
intensifies NE of our area. A few showers could develop Friday
afternoon.

Vfr conditions are expected through the weekend. Gusty winds are
possible during the day Saturday before the winds weaken Saturday
night as high pressure builds in.

Marine
A coastal low pressure system will move over the waters on
Thursday bringing rainfall and increasingly gusty easterly winds.

This low pressure system will intensify Thursday night into
Friday as it moves NE and away from us. Breezy conditions are
expected over the waters on Friday into Friday night and
additional small craft advisories or gale warnings may be needed
during this time.

Sca level winds appear likely during the day Saturday. Winds will
weaken Saturday night as high pressure builds in Saturday night.

Hydrology
Strong mid upper height falls PVA jet divergence and low-level
moisture flux as well as elevated instability will contribute to
a widespread soaking moderately heavy rain, generally between
the blue ridge and i-95. Amounts of 1.5-2+ inches are likely
here, with isolated totals of 3 inches possible. Should these
higher totals be realized, especially within a 6-9 hour window,
minor flooding issues of small creeks, streams and urban areas
may result. The heaviest and steadiest rain looks to be between
6 am and 3 pm Thursday. Most recently, the 21z SREF (which had
previously had many members with lower QPF shifted further east)
has trended wetter, in line with the GFS nam ecmwf. Therefore,
had the confidence to hoist a flood watch for the dc baltimore
metro areas for Thursday through Thursday evening. The steadiest
rainfall is expected Thursday morning through mid Thursday
afternoon, but residual runoff issues may persist into the
evening hours Thursday.

Tides coastal flooding
Increasing onshore flow ahead of a developing coastal low
pressure system will cause tidal anomalies to continue to
increase, with minor flooding likely Thursday afternoon and
Thursday evening.

Lwx watches warnings advisories
Dc... Flood watch from 6 am edt Thursday through Thursday evening
for dcz001.

Md... Flood watch from 6 am edt Thursday through Thursday evening
for mdz004>006-011-013-014-503>508.

Va... Flood watch from 6 am edt Thursday through Thursday evening
for vaz052>054-505-506.

Wv... None.

Marine... Small craft advisory from noon Thursday to 6 am edt Friday for
anz532-533-540>542.

Small craft advisory from 6 pm Thursday to 6 am edt Friday for
anz530-531-535-536-538-539.

Small craft advisory from 6 am Thursday to 6 am edt Friday for
anz534-537-543.

Synopsis... Bjl
near term... Imr dhof
short term... Imr dhof
long term... Kjp
aviation... Imr dhof kjp
marine... Imr dhof
hydrology... Dhof
tides coastal flooding... Dhof


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 19 mi59 min ESE 2.9 G 5.1 51°F 51°F1023.7 hPa
BLTM2 - 8574680 - Baltimore, MD 27 mi59 min SSE 7 G 12 47°F 46°F1023.7 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 29 mi53 min ESE 15 G 17 46°F 1023.9 hPa
FSNM2 29 mi59 min ESE 16 G 19 1023.6 hPa
BSLM2 - Chesapeake Bay, MD 32 mi131 min E 4.1 49°F 1024 hPa
APAM2 - 8575512 - Annapolis, MD 33 mi53 min 47°F 1023.5 hPa
CPVM2 38 mi53 min 47°F 36°F
TPLM2 - Thomas Point, MD 38 mi41 min E 14 G 16 47°F 45°F1024.5 hPa (-0.6)36°F
TCBM2 - 8573364 - Tolchester Beach, MD 44 mi53 min ESE 4.1 G 8 45°F 48°F1024.5 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Gaithersburg - Montgomery County Airport, MD5 mi45 minESE 310.00 miFair45°F25°F46%1026.4 hPa
College Park Airport, MD14 mi57 minN 010.00 miPartly Cloudy47°F26°F44%1023.7 hPa
Fort Meade / Tipton, MD16 mi59 minE 510.00 miFair45°F26°F49%1024.7 hPa
Washington/Reagan National Airport, DC, VA20 mi49 minESE 610.00 miOvercast51°F28°F41%1023.6 hPa
Baltimore, Baltimore-Washington International Airport, MD21 mi47 minE 710.00 miMostly Cloudy46°F33°F61%1023.7 hPa
Washington/Dulles International Airport, DC, VA24 mi49 minSE 410.00 miOvercast46°F23°F40%1023 hPa

Wind History from GAI (wind in knots)
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Last 24hrSE6SE5SE4CalmCalmCalmCalmCalmCalmCalmCalmSE3S5S6S9SE7SE7S7E6SE9SE8E6SE7E3
1 day agoCalmN3CalmCalmCalmCalmCalmCalmCalmCalmCalmCalmCalm34Calm43W8CalmNW6CalmCalmCalm
2 days agoCalmCalmCalmCalmCalmCalmCalmCalmW3CalmCalmE544CalmN43W76N5NW6NW3NW3Calm

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
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Wed -- 03:13 AM EDT     -0.12 feet Low Tide
Wed -- 07:12 AM EDT     Sunrise
Wed -- 07:14 AM EDT     Moonset
Wed -- 08:46 AM EDT     3.36 feet High Tide
Wed -- 03:36 PM EDT     -0.23 feet Low Tide
Wed -- 07:02 PM EDT     Moonrise
Wed -- 07:20 PM EDT     Sunset
Wed -- 09:13 PM EDT     3.39 feet High Tide
Wed -- 09:43 PM EDT     Full Moon
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.30.70.2-0.10.10.81.82.73.23.432.31.60.90.3-0.1-0.20.31.32.43.13.43.22.7

Tide / Current Tables for Chain Bridge, one mile below, D.C.
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Chain Bridge
Click for Map
Wed -- 03:08 AM EDT     -0.12 feet Low Tide
Wed -- 07:12 AM EDT     Sunrise
Wed -- 07:14 AM EDT     Moonset
Wed -- 08:41 AM EDT     3.36 feet High Tide
Wed -- 03:31 PM EDT     -0.23 feet Low Tide
Wed -- 07:02 PM EDT     Moonrise
Wed -- 07:20 PM EDT     Sunset
Wed -- 09:08 PM EDT     3.39 feet High Tide
Wed -- 09:43 PM EDT     Full Moon
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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1.30.70.2-0.10.10.91.92.83.33.32.92.21.50.80.3-0.2-0.20.41.42.43.13.43.22.6

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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Wind Forecast for Baltimore, MD/Washington (21,6,7,8)
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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.