Thursday, January24, 2019 L-36.com


Marine Weather and Tides
Halfway, 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 7:23AMSunset 5:22PM Thursday January 24, 2019 2:26 AM EST (07:26 UTC) Moonrise 9:45PMMoonset 9:58AM Illumination 88% Phase: Waning Gibbous; Moon at 18 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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ANZ538 Patapsco River Including Baltimore Harbor- 116 Am Est Thu Jan 24 2019
.gale warning in effect through this afternoon...
.small craft advisory in effect from this evening through late tonight...
Overnight..S winds 15 to 20 kt with gusts to 30 kt. Waves 2 ft. Rain.
Thu..S winds 15 to 20 kt...becoming nw in the afternoon. Gusts up to 30 kt. Waves 2 to 3 ft. Rain. Vsby 1 nm or less.
Thu night..NW winds 15 to 20 kt with gusts to 30 kt...becoming W 10 kt with gusts to 20 kt after midnight. Waves 1 to 2 ft.
Fri..W winds 15 to 20 kt with gusts to 30 kt. Waves 1 to 2 ft.
Fri night..NW winds 10 to 15 kt. Gusts up to 25 kt in the evening. Waves 1 ft.
Sat..NW winds 5 to 10 kt...becoming S in the afternoon. Waves 1 ft or less.
Sat night..S winds 5 to 10 kt. Waves 1 ft.
Sun..W winds 5 to 10 kt. Waves 1 ft.
Mon..S winds 5 kt. Waves less than 1 ft.
ANZ500 116 Am Est Thu Jan 24 2019
Synopsis for the tidal potomac and md portion of the chesapeake bay.. A cold front over the ohio valley will cross the waters this afternoon as low pressure passes through the region. A reinforcing front will push through the waters on Friday, with high pressure transiting the area through the weekend. Small craft advisories are likely Friday and Friday night, and may be required Saturday night and Sunday.


7 Day Forecast for Marine Location Near Halfway, MD
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location: 39.62, -77.79     debug


Area Discussion for - Baltimore, MD/Washington
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Fxus61 klwx 240217 aaa
afdlwx
area forecast discussion... Updated
national weather service baltimore md washington dc
917 pm est Wed jan 23 2019

Synopsis
A cold front approaching from the ohio valley will cross the
mid-atlantic by Thursday afternoon. A disturbance will cross the
region Friday. High pressure will follow for this weekend. Low
pressure may affect the region early next week.

Near term through Thursday
Rain is finally moving into western parts of the fcst area.

Still expected to see around an inch of rain overnight with a
narrow cold frontal rainband expected to cross eastern parts
between 12z-15z. 925 mb winds on the 00z iad sounding were up to
50 kts. Not sure about flooding potential given the short
duration of the rain, but it appears there will be a 3-hr period
of intense rainfall. Rest of the fcst seems on track and will
not make any sig changes.

Previous afd...

a period of damaging wind gusts is possible ahead of the cold
front Thursday morning as hi-res guidance unanimously shows a
strong narrow cold frontal rain band coincident with LLJ of 65+
kts at 2-3kft. Wind advisory in effect to account for hybrid
synoptic convective winds tomorrow morning (right around rush
hour) in the baltimore dc metros and S md.

Temperatures will fall behind the front late Thursday morning and
into the afternoon with northwesterly flow settling in. Rain will
also be moving away, and a possible period of snow is possible west
of the allegheny front into Thursday afternoon.

Short term Thursday night through Friday night
Cold front low pressure and initial upper trough will push east
Thursday night. A stout trailing upper level trough will pivot
across the region Friday. Snow squall parameters light up across
the northern half of the CWA around midday Friday (factors in
instability, moisture and wind; values over 1 indicate snow
squall potential and values up to 5 are forecast over N md). For
this reason, even though models aren't printing out much qpf
explicitly, have a chance of snow showers near and north of
us-50 focused around midday.

Gusty NW winds will usher in a reinforcing shot of arctic air
Friday night.

Long term Saturday through Wednesday
For the weekend, the region remains entrenched underneath the base
of an upper-level trough. At the surface, high pressure will be
stretched along the eastern us. This will result in a dry pattern
overall for much of the cwa. However, a few impulses of shortwave
energy will swing through the area around the base of the primary
upper trough, which could bring a few chances for some precipitation.

The first of those swings through Saturday, with the only
precipitation threat being some upslope snow showers along the
allegheny front. Otherwise, the rest of the region remains dry,
with temperatures in the low to mid 30s. On Sunday, a weak area
of low pressure will track across southern canada, swinging a
cold front through the area by Sunday evening. This front has a
chance to bring some rain or snow showers to the region Sunday
night, with areas west of the blue ridge having the greatest
chance. High temperatures will be a bit milder Sunday when
compared to Saturday.

Monday and Tuesday, things start to get a little more active. A
short wave will slide down into the central CONUS out of southwest
canada, bringing a potent surface low pressure system along with it.

Ahead of this area of low pressure, will get a period of warm
advection on Monday. Keeping slight chance pops in the forecast
for Monday in association with the warm front, but not looking
very likely at this point. The best chance of precipitation
comes on Tuesday, as the cold front approaches, while the
surface low tracks to our northwest at this time, though it
should be noted the upper pattern is highly volatile. Some guidance
has been hinting at two pieces of energy phasing, bringing a
low pressure system up the eastern seaboard during this time.

Aviation 02z Thursday through Monday
Steady and widespread rain is expected to develop late tonight
into early Thursday morning, with locally heavy rain at times.

Strong wind shear is also expected for the rest of today and
into early Thursday morning. Strong low-level wind shear will
persist through tonight with up to 65 kts at 3kft.

Winds will start from the south early on Thursday and will become
northwesterly behind the cold front. Winds could gust up to 30 knots
at times on Thursday, 40 kts near iad dca bwi especially with
heavier convective elements Thu am. Visibilities and CIGS will
be improving through the day Thursday as the front moves away.

MainlyVFR Thu night-fri night, though brief sub-vfr possible in
-shsn for northern terminals associated with disturbance. Gusty
nw winds behind front possible Fri night.

Vfr conditions are likely on Saturday and Sunday, as high pressure
dominates the region. The best chance for any restrictions will come
on Sunday night, if precip can make it east of the mountains.

Marine
Southerly flow over the waters will continue into tonight ahead of a
cold front as a high pressure sits offshore. This cold front is
expected to move across the waters on Thursday morning, with winds
shifting to the northwest behind it. A small craft advisory in
effect through tonight as gradient increases ahead of the front. A
gale warning is in effect over the waters from Thursday morning and
into the afternoon as winds likely gust 35-40 knots along and
ahead a convective line strong front that will move across the
waters Thursday morning. Gusty winds behind the front could also
reach gale warning criteria briefly. A few gusts around 50 kts
can't be ruled out right ahead of the front late Thursday morning.

Sca gusts possible behind reinforcing cold front Friday
afternoon and night.

High pressure will reside over the waters on Saturday with light
winds and sub SCA conditions expected. Winds will increase Saturday
night through Sunday night as the high shifts offshore and return
flow increases ahead of another cold front, bringing the potential
for SCA conditions over portions of the waters.

Hydrology
Overall, not much has changed in the water-related setup for the
overnight Thursday event. Rain of generally around an inch (with
isolated higher amounts, especially in a potential developing line
east of the blue ridge) plus some snowmelt, will promote significant
within-bank rises on most rivers, and some out-of-bank rises on more
susceptible rivers. A flood warning is now in effect for opequon
creek near martinsburg (again). Flood watches are out for the south
branch potomac at franklin wv, and the cacapon river in morgan
county wv. Other small streams have flood potential as well, and the
overall flood watch remains in place for counties cities where the
heaviest rain is currently expected, mostly east of the blue ridge.

Looking further ahead, mainstem river flooding on the potomac is
possible Friday through Saturday, but uncertainty in rain amounts
and snowmelt precludes issuance of watches for these areas at this
time. This will be assessed again on Thursday.

Tides coastal flooding
Tidal anomalies will continue to increase into Thursday as southerly
flow persists over the waters. The potential for minor flooding will
exist as a result, however, given a large spread in guidance and
uncertainty in the strength of surface winds, confidence is low at
this time.

Lwx watches warnings advisories
Dc... Flood watch from 4 am est Thursday through Thursday afternoon
for dcz001.

Wind advisory from 4 am to noon est Thursday for dcz001.

Md... Flood watch from 4 am est Thursday through Thursday afternoon
for mdz004>006-011-013-014-016-503>508.

Wind advisory from 4 am to noon est Thursday for mdz011-013-
014-016>018-503>506.

Va... Flood watch through Thursday morning for vaz025-036-503-504-
508.

Wind advisory until 6 am est Thursday for vaz503-507.

High wind warning until 6 am est Thursday for vaz508.

Flood watch through Thursday afternoon for vaz037>040-050-051-
507.

Flood watch from 4 am est Thursday through Thursday afternoon
for vaz052>056-501-502-505-506.

Wind advisory from 4 am to noon est Thursday for vaz052>057-
502-506.

Wv... Wind advisory until 6 am est Thursday for wvz505.

Marine... Gale warning until 6 pm est Thursday for anz530>543.

Synopsis... Dhof
near term... Lfr
short term... Dhof
long term... Cjl
aviation... Lfr cjl
marine... Lfr cjl
hydrology...

tides coastal flooding... Lwx


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
WASD2 - 8594900 - Washington, DC 66 mi39 min S 13 G 16 56°F 35°F1008.1 hPa
BLTM2 - 8574680 - Baltimore, MD 69 mi45 min S 5.1 G 8.9 46°F 37°F1008.5 hPa
FSKM2 - 8574728 - Francis Scott Key Bridge, MD 72 mi45 min SSE 15 G 17 50°F 1008.6 hPa

Wind History for Washington, DC
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Hagerstown, Washington County Regional Airport, MD7 mi34 minSSE 115.00 miLight Rain Fog/Mist47°F44°F90%1007.4 hPa
Eastern WV Regional Airport/Shepherd Field, WV18 mi34 minN 00.50 miLight Rain Fog41°F41°F100%1006.1 hPa

Wind History from HGR (wind in knots)
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Last 24hrS13S9S7SE9S10W3W4S10S8W3S8S10S10S10S12S8S10S8S8S10S8SE8S10SE11
1 day agoW5CalmSW6SW4CalmS4S4CalmS43SW3CalmCalmSE4S9SE6S7S10S8S9SE8S8S11S9
2 days agoNW18NW15
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NW17NW10SW4W14CalmNW10NW10NW9S4SW4

Tide / Current Tables for Chain Bridge, D.C.
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Chain Bridge
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Thu -- 05:28 AM EST     -0.56 feet Low Tide
Thu -- 07:20 AM EST     Sunrise
Thu -- 09:53 AM EST     Moonset
Thu -- 10:58 AM EST     2.94 feet High Tide
Thu -- 05:20 PM EST     Sunset
Thu -- 05:46 PM EST     -0.51 feet Low Tide
Thu -- 09:42 PM EST     Moonrise
Thu -- 11:21 PM EST     3.06 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

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2.61.91.20.5-0.1-0.5-0.50.11.22.12.72.92.72.11.30.70.1-0.4-0.5-0.10.81.92.73

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.


Weather Map and Satellite Images
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GOES Local Image of Mid-Atlantic    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 (2,6,7,8)
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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.