Thursday, March21, 2019 L-36.com


Marine Weather and Tides
Upper Marlboro, 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 7:08AMSunset 7:21PM Thursday March 21, 2019 11:59 AM EDT (15:59 UTC) Moonrise 7:14PMMoonset 6:49AM 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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ANZ532 Chesapeake Bay From Sandy Point To North Beach- 1037 Am Edt Thu Mar 21 2019
.small craft advisory in effect through late tonight...
.gale warning in effect from Friday morning through Friday evening...
Rest of today..E winds 5 to 10 kt. Gusts up to 20 kt this afternoon. Waves 1 to 2 ft. Rain. Vsby 1 nm or less.
Tonight..E winds 10 kt...becoming nw in the late evening and overnight. Gusts up to 20 kt. Waves 2 ft. Rain likely.
Fri..W winds 15 to 20 kt. Gusts up to 30 kt... Increasing to 35 kt late. Waves 3 ft. Scattered showers.
Fri night..NW winds 20 to 25 kt with gusts to 40 kt. Waves 5 ft.
Sat..NW winds 15 to 20 kt with gusts to 35 kt. Waves 3 ft.
Sat night..NW winds 10 to 15 kt with gusts to 20 kt. Waves 2 to 3 ft.
Sun..SW winds 5 to 10 kt. Waves 1 ft.
Mon..SW winds 5 kt...becoming n. Waves 1 to 2 ft. A chance of showers through the day, then showers likely through the night.
ANZ500 1037 Am Edt Thu Mar 21 2019
Synopsis for the tidal potomac and md portion of the chesapeake bay.. Low pressure will pass through the waters today and it will strengthen as it moves off to the northeast tonight through Friday night. High pressure will return for the weekend before low pressure and its associated cold front impact the waters early next week. A gale warning may be needed for portions of the waters late Friday night into Saturday morning. A small craft advisory will likely be needed later Saturday into Saturday night.


7 Day Forecast for Marine Location Near Upper Marlboro, MD
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location: 38.8, -76.72     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 211547
afdlwx
area forecast discussion
national weather service baltimore md washington dc
1147 am edt Thu mar 21 2019

Synopsis
Coastal low pressure will pass through the area today. The low
will intensify as it moves off to the northeast tonight through
Friday night and high pressure will return for the weekend. Low
pressure may impact the area early next week with more
unsettled conditions possible.

Near term through tonight
Update... With the freezing level around 6000 ft, heavy
precipitation rates across the terrain of the blue ridge has
resulted in precipitation reaching the ground as snow, with
accumulations noted on webcams at wintergreen and big meadow.

Have updated forecast to reflect snow across the ridgeline. Have
not yet determined whether advisories will be required, but it's
possible.

Previous discussion...

two potent shortwaves associated with the northern stream energy
are phasing over the ohio and tennessee valleys this morning. A
potent ridge upstream over the plains and northern rockies will
allow for the northern stream energy to dig farther south,
increasing the likelihood for phasing. As these systems phase,
the upper-level trough axis will swing toward a negative tilt
and closed upper-level low will develop overhead. The dynamics
and divergence aloft will cause coastal low pressure to
strengthen as it passes through our area today.

The coastal low will strengthen as it moves into the area later
this morning from the south, and at the same time an upper-
level low will be closing off overhead. This will cause rainfall
rates to increase, with moderate to heavy rain expected near
and east of the blue ridge and catoctin mountains. The moderate
to heavy rain will continue through this afternoon, first ahead
of the coastal low and then from wrap around moisture behind the
coastal low toward this evening. Farther west (near and west of
interstate 81), there will be a tight gradient between
significant rainfall and little rainfall. However, latest
guidance does indicate that this system should track far enough
west for rain to occur across these areas as well. Rainfall
amounts will be noticeably lower due to less moisture and less
forcing farther away from the coastal low.

As of mid-morning... Rainfall has already overspread the area,
mainly along east of the blue ridge. Pockets of moderate to
heavy rainfall have been embedded, with a swath of half-inch
rainfall already observed as of 12z from cho to iad-- greater
than model output. Based on that, will be siding with higher
rainfall total amounts for today. Focus will be placed on
several enhanced rainfall bands entering central virginia at
this time.

Guidance continues to be in good agreement with 2-3" of rain
most likely from near the the blue ridge and catoctin mountains
to the bay. Will continue with the flood watch for north-
central maryland as well as the washington and baltimore
metropolitan areas... As already issued. Flash flood guidance is
a bit lower particularly in the urban areas, so this may lead
to creeks and streams rising out of their banks as well as
flooding in low- lying urban areas... Especially due to the
aforementioned enhanced bands. The best chance for flooding
will be this afternoon into this evening. Still recognize that
the watch may need to extend farther south and west for areas
between the blue ridge and interstate 81 corridor as well as the
virginia piedmont. Rainfall amounts may be just as high across
these areas. However, FFG is a bit higher given the recent dry
conditions so confidence was too low at this time to extend.

Will continue to monitor rainfall rates throughout the day.

There may be just enough cold air for snow along the ridge tops
above 3000 feet. However, precipitation rates will not be as
heavy this far west so dynamical cooling may not be quite as
prominent as it would have been if the axis of heavier
precipitation were to occur farther west. Therefore, at this
time latest thinking is that snowfall amounts would be light and
confined to the highest elevations above 3kft in highland and
pendleton county as well as the blue ridge mountains.

The coastal low will continue to strengthen as it moves off to
our north and east this evening. Wrap around moisture will
continue to bring rain, especially across northern and central
areas. A northwest flow will develop on the back side of the
low, and cold advection will increase the chances for snow
showers along and west of the allegheny front. The low will
continue to move off to the northeast overnight and drier air
will gradually work its way into most areas, but again more
upslope snow showers are expected along and west of the
allegheny front.

Short term Friday through Saturday night
The coastal low will continue to intensify over new england
Friday as it phases with more northern stream energy from the
great lakes. The shortwave energy will pass through our area
Friday afternoon, and this will lead to scattered showers across
most areas. A rumble of thunder or small hail cannot be ruled
out due to an abundant amount of cold air aloft that will be
associated with the shortwave energy diving through. For
locations along and west of the allegheny front, snow showers
are expected and accumulation is likely. There is some
uncertainty as to how much accumulation there will be due to the
higher Sun angle this time of year, but it does appear that
there will be times of hazardous conditions due to heavier snow
showers. In fact, a few snow squalls cannot be ruled out given
the unstable atmosphere.

As the low intensifies later Friday afternoon and Friday night,
this will cause a strong pressure gradient overhead in response
to the low over eastern maine and high pressure over the western
great lakes. The strong gradient along with subsidence behind
the departing shortwave energy will lead to gusty northwest
winds. Wind gusts around 50 mph are possible, especially across
the ridges but even in the valleys across eastern west virginia
toward northern virginia and the washington and baltimore
metropolitan areas. Confidence for the strong winds is not quite
as high as the ridges since the best forcing will be somewhat
displaced from daytime heating. However, given the latest
guidance it does appear that the low should strengthen rapidly
enough to overcome that factor. Wind advisories may be needed
during this time.

Winds will subside a little for Saturday and it will be dry
ahead of building high pressure. However, there should be enough
of a gradient for blustery conditions to continue, despite winds
diminishing a little. The high will build overhead Saturday
night and winds will diminish along with dry conditions.

However, it will be chilly.

Long term Sunday through Wednesday
Surface high pressure will be centered over the area early
Sunday and will quickly move offshore. With a ridge axis also
passing by aloft, warm advection will begin and help boost
temperatures above normal... Likely in the 60s for many. It will
be dry, but mid and high level clouds will increase during the
afternoon.

While the 00z runs of the main operational models have converged
a bit on a solution early next week, it's important to point out
the upper level pattern is complex and ensembles continue to
paint a range of solutions. A southern stream shortwave
ejecting eastward from the plains will interact with a northern
stream shortwave (and associated strong cold front) dropping
south from canada. If this happens quickly enough, the
associated surface low will likely pass to our northwest, and
the frontal progression will be quicker.

Some light precipitation may arrive as early as Sunday night as
moisture and ascent increases, but the highest chance of rain
looks to hold off until at least later Monday at this time. In
the more progressive solution, precipitation would exit by
Tuesday morning, with strong canadian high pressure building
southeast from the great lakes. This would result in qpf
amounts on the lighter side and any wintry precipitation more
unlikely, except maybe some brief upslope snow showers. Given
the recent flux of the forecast, won't be entirely removing pops
from Tuesday at this time, but the trend is in that direction.

The surface high should settle into the area Wednesday.

Temperatures will likely remain above normal Monday but then
tumble behind the frontal passage. Highs will only be in the 40s
and 50s for Tuesday and Wednesday, with lows in the 20s and
30s... About 10-15 degrees below normal for late march.

Aviation 16z Thursday through Monday
Coastal low pressure will bring a soaking rain to the terminals.

Rain will be heavy at times along with ifr conditions.

Northwest winds will gradually dry things out tonight with
slowly improving CIGS vsbys. Gusty northwest winds are expected
Friday into Saturday. The strongest winds are most likely Friday
afternoon and Friday night with gusts around 40 knots possible.

Scattered showers are expected Friday afternoon, and some of
those showers may produce small hail and perhaps even a rumble
of thunder.

High pressure will bringVFR conditions for Saturday through
Sunday. Winds will diminish Saturday night.

A frontal system will approach the area on Monday. While there
will be an increasing chance of rain, the forecast remains
uncertain, both in terms of timing and any impacts to aviation.

Marine
Coastal low pressure will pass through the waters today and then
it will move off to our northeast tonight through Friday night
while it strengthens.

The gradient will strengthen today, but it may be suppressed by
the lack of a mixing layer due to rainfall. Therefore, left the
headlines for now, with an SCA this morning for the lower
portion of the bay and lower tidal potomac river, then for the
the middle and lower portions of the bay and lower tidal potomac
river this afternoon. Would not be surprised to see some sca
gusts across northern portions of the waters later this
afternoon, but confidence was too low for a headline at this
time.

As the low strengthens and moves off to the northeast tonight,
northwest winds will increase and an SCA is in effect for all of
the waters. The low will continue to strengthen Friday through
Friday night before finally moving well off the new england
coast Saturday and Saturday night. Gusty northwest winds are
expected during this time. A gale warning is in effect for the
waters Friday through Friday evening. The strongest winds are
most likely late Friday afternoon and evening. The gale warning
may need to be extended overnight Friday into Saturday morning.

Gusty northwest winds will gradually subside later Saturday into
Saturday night as high pressure approaches.

One thing to note is that scattered showers are expected Friday
afternoon. The atmosphere will be unstable enough for the
possibility of a thunderstorm and small hail. Locally gusty
winds outside of the gradient winds are possible in convection
as well.

Light winds will become southerly on Sunday as high pressure
moves offshore. A frontal system will approach the area Monday.

While there will likely be an increase in winds with this
system, the timing and magnitude of the stronger winds remains
uncertain at this time.

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 from near
the blue ridge and catoctin mountains to the bay. Amounts around
2 inches are likely here, with isolated totals around 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 10 am and 6 pm today. However, residual
runoff issues may persist through the evening.

Based on projected qpf, stage forecasts getting mighty close to
flood stage. River flood watches have been issued for
opequon at martinsburg and monocacy at frederick, which come the
closest. Will continue to monitor.

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 possible this afternoon and
evening. Have favored the higher side of the guidance envelope
with support from the stevens ensemble, although will have to
monitor trends closely. Annapolis, straits point, and dc sw
waterfront have the highest probability of reaching minor flood
stage.

Lwx watches warnings advisories
Dc... Flood watch through this evening for dcz001.

Md... Flood watch through this evening for mdz004>006-011-013-014-
503>508.

Va... Flood watch through this evening for vaz052>054-505-506.

Wv... None.

Marine... Small craft advisory until 6 am edt Friday for anz532-533-
540>542.

Gale warning from 6 am Friday to midnight edt Friday night for
anz530>543.

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

Small craft advisory until 6 am edt Friday for anz534-537-543.

Synopsis... Bjl
near term... Bjl hts
short term... Bjl
long term... Ads
aviation... Bjl ads
marine... Bjl ads
hydrology... Hts dfh bjl
tides coastal flooding... Bjl


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BSLM2 - Chesapeake Bay, MD 1 mi149 min NNW 1.9 45°F 1015 hPa45°F
TPLM2 - Thomas Point, MD 17 mi59 min E 7 G 8 48°F 45°F1014.5 hPa (-1.3)48°F
WASD2 - 8594900 - Washington, DC 17 mi59 min N 5.1 G 7 46°F 50°F1014.2 hPa (-1.5)
APAM2 - 8575512 - Annapolis, MD 18 mi59 min 48°F 1013.3 hPa (-1.6)
CPVM2 22 mi59 min 49°F 49°F
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 31 mi59 min NNE 6 G 7 47°F 1014 hPa (-1.6)
FSNM2 31 mi65 min N 7 G 8 46°F 1013.5 hPa
BLTM2 - 8574680 - Baltimore, MD 33 mi59 min NE 6 G 7 47°F 47°F1013.8 hPa (-1.5)
COVM2 - 8577018 - Cove Point LNG Pier, MD 33 mi59 min ENE 8 G 8.9 50°F 1013.2 hPa (-2.0)
SLIM2 - 8577330 - Solomons Island, MD 36 mi59 min NE 8 G 8.9 50°F 46°F1012 hPa (-2.4)
NCDV2 37 mi65 min N 4.1 G 6 47°F 1011.6 hPa
CA2 - 8571892 - Cambridge, MD 38 mi59 min 49°F 48°F1013.1 hPa (-2.0)
TCBM2 - 8573364 - Tolchester Beach, MD 38 mi59 min ESE 4.1 G 6 49°F 47°F1014.1 hPa (-1.6)
PPTM2 - 8578240 - Piney Point, MD 47 mi59 min E 9.9 G 12

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Camp Springs / Andrews Air Force Base, MD8 mi2.1 hrsN 54.00 miRain Fog/Mist45°F44°F99%1014.7 hPa
College Park Airport, MD16 mi75 minN 03.00 miOvercast44°F42°F95%1014.2 hPa
Washington/Reagan National Airport, DC, VA17 mi67 minN 82.00 miHeavy Rain Fog/Mist46°F43°F89%1014.4 hPa
Annapolis, United States Naval Academy, MD18 mi2.1 hrsE 33.00 miRain Fog/Mist50°F46°F89%1014.5 hPa
Fort Meade / Tipton, MD20 mi77 minN 44.00 miOvercast45°F42°F93%1015.2 hPa
Bay Bridge Field, MD24 mi79 minESE 42.50 miRain Fog/Mist48°F0°F%1013.9 hPa

Wind History from ADW (wind in knots)
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SE7SE4E4E7SE7SE8SE7E5E5E5E4E4E6CalmNE6NE7NE5NE6NE7N4N4N5
1 day agoCalmW3CalmN4W8N4CalmE9SE8E4SE4CalmCalmCalmCalmCalmS3CalmCalmCalmCalmCalmCalmS3
2 days agoCalmN6N5E4CalmCalmCalmSE6SE6SE3S3S3CalmW5W4N4CalmN4CalmCalmCalmN3NE4NE7

Tide / Current Tables for Hills Bridge (Route 4), Maryland
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Hills Bridge (Route 4)
Click for Map
Thu -- 01:12 AM EDT     0.08 feet Low Tide
Thu -- 06:20 AM EDT     3.04 feet High Tide
Thu -- 07:09 AM EDT     Sunrise
Thu -- 07:48 AM EDT     Moonset
Thu -- 01:33 PM EDT     -0.47 feet Low Tide
Thu -- 07:01 PM EDT     2.92 feet High Tide
Thu -- 07:19 PM EDT     Sunset
Thu -- 08:14 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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0.30.10.20.81.72.6332.61.91.20.5-0.1-0.4-0.40.10.91.92.62.92.82.31.71.1

Tide / Current Tables for Baltimore Harbor Approach, Maryland Current
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Baltimore Harbor Approach
Click for Map
Thu -- 03:00 AM EDT     0.00 knots Slack
Thu -- 06:07 AM EDT     1.01 knots Max Flood
Thu -- 07:07 AM EDT     Sunrise
Thu -- 07:47 AM EDT     Moonset
Thu -- 09:13 AM EDT     -0.00 knots Slack
Thu -- 12:20 PM EDT     -1.00 knots Max Ebb
Thu -- 03:28 PM EDT     0.00 knots Slack
Thu -- 06:30 PM EDT     0.95 knots Max Flood
Thu -- 07:18 PM EDT     Sunset
Thu -- 08:12 PM EDT     Moonrise
Thu -- 09:31 PM EDT     -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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-1-0.9-0.5-00.50.910.90.60.1-0.4-0.8-1-0.9-0.7-0.20.30.70.90.90.70.3-0.2-0.7

Weather Map and Satellite Images
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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.