Thursday, February22, 2018 L-36.com


Marine Weather and Tides
Somerville, MA

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 6:27AMSunset 5:27PM Thursday February 22, 2018 5:52 PM EST (22:52 UTC) Moonrise 11:18AMMoonset 12:32AM Illumination 52% Phase: First Quarter Moon; Moon at 8 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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ANZ230 Boston Harbor- 339 Pm Est Thu Feb 22 2018
Tonight..NE winds 5 to 10 kt. Waves 1 foot or less. A chance of snow and sleet this evening with vsby 1 to 3 nm.
Fri..E winds 5 to 10 kt, becoming se in the afternoon. Waves around 2 ft. A chance of rain.
Fri night..SW winds 5 to 10 kt. Gusts up to 20 kt in the evening. Waves around 2 ft. Rain likely.
Sat..NW winds 5 to 10 kt. Waves 1 foot or less.
Sat night..N winds 5 to 10 kt, becoming ne 10 to 15 kt with gusts up to 20 kt after midnight. Waves around 2 ft. Rain likely.
Sun..E winds 10 to 15 kt with gusts up to 25 kt. Waves 2 to 4 ft. Rain. Vsby 1 to 3 nm.
Sun night..NE winds 5 to 10 kt, becoming nw after midnight. Waves 2 to 4 ft.
Mon..W winds 5 to 10 kt. Waves 1 foot or less, except 2 to 4 ft at the outer harbor entrance.
Mon night..NW winds around 10 kt. Waves around 2 ft.
Tue..NW winds 5 to 10 kt. Waves 1 foot or less.
Tue night..W winds 5 to 10 kt. Waves 1 foot or less. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height.
ANZ200 339 Pm Est Thu Feb 22 2018
Synopsis for massachusetts and rhode island coastal waters.. A wave of low pres tracks south of new england by early evening. High moves east of nova scotia Friday with a series of frontal systems sweeping the waters through the weekend. High pres builds over the waters early next week. For information on possible hazardous weather beyond the 24-36 hour forecast period, please visit www.weather.gov/boston and follow the current hazards link above the map on the left.

7 Day Forecast for Marine Location Near Somerville, MA
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location: 42.37, -71.07     debug


Area Discussion for - Boston, MA
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Fxus61 kbox 222104
afdbox
area forecast discussion
national weather service taunton ma
404 pm est Thu feb 22 2018

Synopsis
A wave of low pressure tracking along a stalled frontal boundary to
the south will bring a period of snow and sleet to much of the
region late this afternoon and early evening, then drying overnight.

Active weather pattern late Friday through the weekend as a series
of frontal boundaries usher wintry weather across the interior. A
near-seasonable, quiet pattern for early next week.

Near term until 6 am Friday morning
400 pm update...

mid level fgen precip continues to stream eastward across the
region. 1040 mb high over quebec continues to advect cold air
southward with surface temperatures tumbling thru the 30s. Shallow
warm layer around 700 mb combined with warm blyr resulting in ptype
of mainly rain over ri and southeast ma. However as this mid level
warm layer erodes and blyr cools from wet bulb process, rain and
sleet changing over to snow across much of northern ma into the city
of boston.

However impacts are limited with surface temps above freezing
yielding just wet roadways. Strongest forcing for ascent occurs
around 21z and then races eastward and offshore by 00z or shortly
thereafter. Meanwhile northerly winds continue to advect shallow
cold air southward. Thus very small window for accumulating snow.

Still thinking main impacts will be the high terrain of western-
central ma where temps will be AOB freezing during most of the event
yielding snow accumulations from a coating to 2 inches with a low
prob of 3 inches along the ma nh border where strongest forcing
occurs in the snow growth region yielding higher slr.

Farther south into the hartford, providence and boston corridor,
already snow and sleet in greater boston area and this trend will
continue into providence and hartford. However with temps likely
remaining AOA freezing most roadways will remain wet, limiting
impacts to the late day commute. Thus have continued the special
weather statement to address this.

As for model guidance, both 3km NAM and href handing ptype
transition very well at the moment and followed this guidance
closely.

Overnight... Later this evening dry weather overspreads the area
however with light winds and subfreezing temps across much of the
region, any standing water or slush will freeze. Thus icy spots
possible overnight.

Short term 6 am Friday morning through Friday night
Friday...

dry and seasonably cool in the morning as 1042 mb high crest over
maine. Could have some leftover icy spots early that may impact the
morning commute. Otherwise fast progressive upper air pattern
results in any breaks of morning sunshine quickly giving way to
increasing clouds as next WAA pattern develops.

Precip overspreads the region during mid to late afternoon from west
east. Cold air is not as deep tomorrow, more shallow and will
support a period of sleet and freezing rain across western-central
ma. Remainder of the region will see a chilly rain.

Friday night...

weak wave crosses the area with evening rain but risk of freezing
rain across western-central ma. Drying trend second half of the
night as post frontal airmass overspreads the region. Not as chilly
as tonight with lows Fri night in the 30s.

Long term Saturday through Thursday
Highlights...

* dry and warm as spring returns on Saturday
* widespread precip on Sunday with wintry mix in the interior
* dry weather trend for early next week
* pattern change for mid to late next week
overview...

12z guidance is in general agreement with the extended forecast.

Just some minor differences related to thermals which provide
different outcomes in p-type for Saturday night into Sunday. Trough
across the western CONUS with southeast ridging deamplifying over the
weekend. Last of the pacific waves will move through Sunday with
surface high pressure to follow into Monday. By early next week the
pattern will begin to change as nao turns negative. Mid-level ridge
across the southeast into the great lakes with cut-off low off the
maritimes. Both the GEFS and eps show anomolous high pressure
building over greenland which will influence the cut-off low to
either retrograde towards sne or remain across the north atlantic.

Depending on where this all stacks up, appears the trend is there
that our pattern could turn more active late next week.

Details...

Saturday... Moderate confidence.

Dry weather day will be on tap as surface high pressure will fill in
behind the offshore front. Still seeing westerly to northwest flow
as 850mb CAA moves into the region. However, appears that surface
temps have the potential to warm into the mid 50s thank to longer
daylight hours and mixing to 925mb which are cooler to cool. Some
guidance even hints as low 60s. Still some uncertainty as how far
south the front will sage will lead to cooler temps or if it slows
down then warm temps are possible. Thus a low confidence forecast
for temps on Saturday, but high confidence on mainly dry weather.

Saturday night into Sunday... Increasing confidence.

Potent wave will eject out of the desert southwest producing a
surface low pressure system up into the northern great lakes.

Stalled front to the south will begin to lift northward as a warm
front. Along the front, triple point low will develop and strengthen
as the system pulls away from the area Sunday night. Before the
secondary low develops, another overrunning precip set-up as
moisture from the south increase as warm front begins to lift
northward. Surface high pressure will be set-up north to northeast
of the region allowing for surface temps to fall thanks to cold air
damming. Models are always to quick at warming temps above
freezing, so trended towards cooler 2m temps and wet-bulb
effects.

P-type will once again be the issue as models are still struggling
with the warm layer. Ec trended to be the coolest of the guidance
which could suggest more snow than freezing rain, whereas the NAM is
the warmest. GFS and the cmc are in the middle of the ground and
thus trended towards the ensembles guidance. Therefore, went a bit
cooler with this forecast resulting in snow at the onset, as cold
air looks to be deep enough north of the pike and ESP route 2. In
fact with good omega in the snow growth region, could see a few
inches of snowfall. Once the mid-level warm front pushes into the
region, a transition to more sleet freezing rain will occur leading
to slick travel across the interior. South of the pike and
especially across ri and SE ma conditions look to warm for any
wintry weather, but still will have to watch as a change in just a
few degrees will impact p-type.

This system looks to the most roust resulting in more widespread
precip, ESP as we continue to tap into that gulf moisture. Thus
increases pops as confidence is high that precip will occur. Lastly,
with the surface warm front trying to push northward, may have a
large gradient in surface temperatures somewhere across southern new
england. While warm fronts tend to struggle to lift northward this
time of year something to watch as we could see low 50s across the
south coast and mid 30s across the interior.

Sunday night into Wednesday... High confidence.

Surface cold front will push through the region resulting in a
drying trend for Sunday night. Strong high pressure over the ohio
valley will begin to strengthen Monday into Tuesday as anomolous ridge
sets-up over the mississippi valley. This high appears to stay in
place into middle of next week before a quick moving wave from the
southwest gets kick into the flow. Thanks to ridging and surface
high, dry weather will prevail as temperatures turn slightly above
average.

Aviation 21z Thursday through Tuesday
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Friday night ... Moderate confidence.

18z TAF update ...

thru 00z... VFR trending toward MVFR 21z-00z in rain changing to
pl sn west to east. Snow accumulations of a coating to two
inches possible western-central ma including korh. Elsewhere
trace to a coating possible.

After 00z... MVFR in pl sn ending 00z-03z from west to east then
trending dry andVFR.

Friday... VFR but trending MVFR late in rain with pl western-
central ma.

Friday night... Low risk of llws with low level wsw jet. MVFR in
evening rain improving toVFR and dry overnight.

Kbos terminal... Moderate confidence taf. Low risk for period of
steady sn pl 22z-00z then improving.

Kbdl terminal... Moderate confidence taf. Low risk for a period
of moderate sn pl 21z-23z.

Outlook Saturday through Tuesday ... Moderate confidence.

Saturday:VFR.

Saturday night: mainlyVFR, with local ifr possible. Breezy. Ra
likely, sn likely, slight chance fzra across the interior.

Sunday: MVFR ifr conditions possible. Windy with gusts to
35 kt. Ra, fzra.

Sunday night: mainlyVFR, with local MVFR possible.

Monday through Tuesday:VFR. Breezy.

Marine
Forecaster confidence levels...

low - less than 30 percent.

Moderate - 30 to 60 percent.

High - greater than 60 percent.

Short term through Friday night ... Moderate confidence.

Tonight...

sca for southern ri waters and south of mvy ack with marginal ne
winds up to 25 kt and seas up to 5 ft, then trending downward later
tonight. Snow, sleet and rain limit vsby this evening but improving
later this evening from west to east.

Friday...

1041 mb high over maine in the morning slides offshore with weak low
pres moving across southern new england. Light NE winds become se.

Vsby lowers late in rain.

Friday night...

weak low pres and attending cold front move offshore with wnw winds
developing along with improving vsby from early rain showers.

Outlook Saturday through Tuesday ...

Saturday: winds less than 25 kt. Seas locally approaching 5 ft.

Saturday night: low risk for small craft advisory winds with
gusts up to 25 kt. Seas locally approaching 5 ft. Chance of
rain.

Sunday: low risk for gale force winds with gusts up to 35 kt.

Areas of rough seas. Rain.

Sunday night: winds less than 25 kt. Areas of rough seas.

Monday: winds less than 25 kt. Seas up to 5 ft.

Monday night: low risk for small craft advisory winds with
gusts up to 25 kt. Seas up to 5 ft.

Tuesday: winds less than 25 kt. Areas of seas approaching 5 ft.

Box watches warnings advisories
Ct... None.

Ma... None.

Ri... None.

Marine... Small craft advisory until 10 pm est this evening for anz255-
256.

Synopsis... Nocera dunten
near term... Nocera
short term... Nocera
long term... Dunten
aviation... Nocera dunten
marine... Nocera dunten


Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
BHBM3 - 8443970 - Boston, MA 1 mi53 min 32°F 1038 hPa (+2.7)
44013 - BOSTON 16 NM East of Boston, MA 22 mi63 min NNE 9.7 G 14 32°F 40°F3 ft1038.1 hPa (+1.8)
44029 - Buoy A0102 - Mass. Bay/Stellwagen 29 mi109 min 9.7 G 12 33°F 40°F3 ft1036.9 hPa
FOXR1 - 8454000 - Providence, RI 43 mi53 min ENE 2.9 G 6 35°F 42°F1038.1 hPa (+2.7)
PVDR1 44 mi53 min NNE 6 G 11 35°F 1038.4 hPa (+2.5)34°F
FRVM3 - 8447386 - Fall River, MA 46 mi53 min 36°F 40°F1038.4 hPa (+2.5)
BLTM3 - 8447387 - Borden Flats Light at Fall River, MA 46 mi53 min NE 11 G 14 36°F 1037.2 hPa (+2.5)
FRXM3 47 mi53 min 36°F 30°F
CPTR1 - 8452944 - Conimicut Light, RI 47 mi53 min N 8.9 G 9.9 36°F 44°F1037.9 hPa (+2.4)
IOSN3 - Isle of Shoals, NH 48 mi53 min NNE 7 G 8 32°F 1038.5 hPa (+1.9)
BGXN3 - Great Bay Reserve, NH 49 mi128 min Calm 33°F 1038 hPa31°F

Wind History for Providence, RI
(wind in knots)    EDIT      (on/off)   Help
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Boston, Logan International Airport, MA2 mi59 minN 50.75 miLight Snow Fog/Mist32°F30°F92%1038.9 hPa
East Milton, MA11 mi57 minENE 6 mi0°F0°F%1037.2 hPa
Norwood, Norwood Memorial Airport, MA14 mi60 minNNE 61.00 miLight Snow Fog/Mist34°F30°F89%1038.8 hPa
Bedford, Hanscom Field, MA14 mi1.9 hrsNE 51.00 miLight Snow Fog/Mist33°F30°F92%1039.2 hPa
Beverly, Beverly Municipal Airport, MA17 mi60 minN 00.50 miSnow Fog33°F32°F96%1038.2 hPa

Wind History from BOS (wind in knots)
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Last 24hrSW12SW14W12NW11
G20
N13N12N13NW15
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NW13NW13N14N10N8N8N6NE10E14NE8NE12NE8NE10NE10NE8N5
1 day agoNE6E6E8NE4E5NE3E7E3CalmSW9SW8SW10S11SW13SW19
G27
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SW18SW18
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SW19S17SW10SW13S11S13
2 days agoS10S8SW12SW16SW13SW15SW16SW14
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SW12SW12SW14SW10SW8SW9SW8SW8SW9W12SW11
G21
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G20
SW14SW10SW9

Tide / Current Tables for Charlestown Bridge, Charles River, Massachusetts
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Charlestown Bridge
Click for Map
Thu -- 03:32 AM EST     10.10 feet High Tide
Thu -- 06:30 AM EST     Sunrise
Thu -- 09:54 AM EST     0.15 feet Low Tide
Thu -- 10:18 AM EST     Moonrise
Thu -- 04:02 PM EST     9.31 feet High Tide
Thu -- 05:25 PM EST     Sunset
Thu -- 10:12 PM EST     0.44 feet Low Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
4.66.88.79.9108.86.74.42.30.70.21.135.27.18.79.38.77.25.13.11.40.50.9

Tide / Current Tables for Boston Harbor, Massachusetts Current
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Boston Harbor
Click for Map
Thu -- 03:05 AM EST     -0.00 knots Slack
Thu -- 06:04 AM EST     -1.16 knots Max Ebb
Thu -- 06:30 AM EST     Sunrise
Thu -- 09:59 AM EST     0.00 knots Slack
Thu -- 10:17 AM EST     Moonrise
Thu -- 12:02 PM EST     1.24 knots Max Flood
Thu -- 03:31 PM EST     -0.00 knots Slack
Thu -- 05:25 PM EST     Sunset
Thu -- 06:24 PM EST     -1.03 knots Max Ebb
Thu -- 10:17 PM EST     0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.
12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm
1.31.10.70.1-0.6-1-1.2-1.1-0.9-0.600.91.21.10.80.4-0.3-0.8-1-1-0.8-0.6-0.20.6

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

GOES Local Image of Northeast    EDIT
Geos

Wind Forecast for Boston, MA (17,4,5,8)
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Ground Weather Radar Station Boston, MA
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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.