Portsmouth, NH Marine Weather and Tide Forecast
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Marine Weather and Tide Forecast for Portsmouth, NH

April 17, 2024 6:25 PM EDT (22:25 UTC) Change Location
Sunrise 5:55 AM   Sunset 7:29 PM
Moonrise 1:17 PM   Moonset 3:37 AM 
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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.

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Marine Forecasts
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ANZ154 Coastal Waters From Cape Elizabeth, Me To Merrimack River, Ma Out 25 Nm- 335 Pm Edt Wed Apr 17 2024

Tonight - S winds 5 to 10 kt, becoming se after midnight, then becoming ne late. Seas 2 to 3 ft.

Thu - E winds 5 to 10 kt. Seas 2 to 3 ft.

Thu night - E winds 5 to 10 kt, diminishing to around 5 kt after midnight. Seas 2 to 3 ft.

Fri - SE winds 5 to 10 kt, increasing to 10 to 15 kt with gusts up to 20 kt in the afternoon. Seas 2 to 3 ft.

Fri night - S winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. A chance of showers.

Sat - SW winds 10 to 15 kt with gusts up to 20 kt. Seas around 3 ft. A chance of showers in the morning.

Sat night - W winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 3 ft.

Sun - W winds 15 to 20 kt, diminishing to 10 to 15 kt in the afternoon. Seas 2 to 3 ft.

Sun night - W winds 5 to 10 kt. Seas 2 to 3 ft.

Mon - W winds 5 to 10 kt, becoming S in the afternoon. Seas 2 to 3 ft.

Mon night - S winds 5 to 10 kt. Seas 2 to 3 ft.

ANZ100 335 Pm Edt Wed Apr 17 2024

Synopsis for stonington me to merrimack river ma out to 25 nm high pressure gradually builds into the waters through Friday, resulting in a general onshore flow and the potential for low clouds and fog a weak cold front associated with canadian low pressure crosses the waters on Saturday. High pressure will then build toward or south of the waters Sunday into early next week and may hold through mid-week as low pressure approaches from both the west and south.


7 Day Forecast for Marine Location Near Portsmouth, NH
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Area Discussion for - Gray/Portland, ME
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FXUS61 KGYX 172003 AFDGYX

Area Forecast Discussion National Weather Service Gray ME 403 PM EDT Wed Apr 17 2024

SYNOPSIS
Clouds will be on the increase tonight into Thursday as a weak disturbance brings a chance for light showers across New Hampshire and far western Maine Thursday into Thursday night. Temperatures will trend cooler as an onshore component to surface flow builds, culminating in the passage of a frontal system with light rain late Friday into Saturday. Quiet, mild, and dry weather, this time with more westerly flow, returns late Saturday through early next week.

NEAR TERM /TONIGHT/
Another quiet night is in store, but clouds will continue to increase from southwest to northwest through the course of the night. Most of this will be across NH and to some extent SW ME, and this should help keep temps milder across the areas. Farther to the east and north, I have blended in some cooler MOS to account for less clouds and light winds. Enough moisture may also allow for a few light showers overnight across SW NH as a shortwave trough approaches, but I think the better potential will hold off closer to daybreak Thurs.

SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/
The approaching shortwave trough will shift the upper ridge ever so slightly to the east Thursday into Thursday night. This shortwave will bring an increase in moisture across the region, particularly over NH and far western ME (near the NH border), and these areas will see more cloud cover along with some showers, again especially over into NH. The farther east one goes, there will be drier air and influence/subsidence from the ridge, which should allow for some sun along with dry conditions. Highs in the cloudiest areas are forecast to be limited to the upper 40s to lower 50s, but farther north and east temps are still forecast to reach the mid 50s.

Showers could stick around over these areas into the early part of Thursday night, but once the wave passes, shortwave ridging will build in, returning dry conditions the rest of the night.
For those that see rain showers, amounts are expected to be light, ranging from a few hundredths to a tenth of an inch.
Worth mentioning, the GFS is more amplified with the shortwave, which is the outlier solution, but should this occur, rain amounts could be slightly higher.

An abundance of cloud cover and light southerly flow will keep temperatures a little more mild than previous nights, ranging from the mid 30s to lower 40s. Will also have to watch for fog overnight as well with light onshore flow returning.

LONG TERM /FRIDAY THROUGH WEDNESDAY/
An upper level ridge of high pressure off the Eastern Seaboard is replaced by a broad upper level trough over the weekend.
While it will bring some unsettled weather, it is expected to be largely unimpactful with light precipitation amounts. If anything, this change in synoptic setup results in a change of gradient flow more favorable for westerly flow... and less favorable for onshore flow, which should make for a pleasant stretch of Spring weather.

Starting Friday... surface high pressure will be centered near the Bay of Fundy while a frontal system approaches from the Great Lakes. Although starting the day dry, onshore flow off the Gulf of Maine will keep conditions cooler and more humid. The bigger question Friday morning will be what the status of the marine layer will be... if it will be supportive of marine stratus, and if so how widespread the stratus will be. Model guidance has been less than impressed with stratus potential, but does hint at this possibility over central and western New Hampshire, which is where deeper moisture supports more cloud cover anyway. Cloud coverage will have a lot of bearing on the high temperature forecast as well, with highs in the 50s, although closer to 50 (or the 40s) where clouds and marine air combine... and closer to 60 where more sunshine and/or mixing can take place. A cold front brings light rain showers, generally less than a quarter inch total across the region later in the day Friday through Friday night with some question as to how quickly the front will move out. Would expect the overnight to be fairly humid with potential for low clouds and fog too, given more onshore flow residency.

Saturday will see the cold front exit with stronger mixing, drier air, and breezier winds up to around 25-30 mph out of the west. This will allow warmer temperatures as well despite a little bit of a dip in t850, with highs generally in the 50s across the north but into the low/mid-60s south of the mountains. There is a chance the front hangs up a bit near our area, which would prolong clouds and lead to a little cooler temperatures.

A cooler airmass briefly settles across the international border Sunday into Monday under a broad upper level trough with clearing skies. Predominantly westerly flow continues in the meantime, which will keep the maritime influence at bay for the most part and allow for a warming (and drying) trend. Highs are forecast to be in the 50s and low-60s, with light flow and interior surface heating likely allowing seabreezes to develop. By Tuesday, high pressure is more likely to be located to our south... setting up a more southerly flow, with further warming over the interior especially west but allowing more maritime influence along the coast and into interior southern Maine.



AVIATION /20Z WEDNESDAY THROUGH MONDAY/
Short Term...Mainly VFR through Thursday night. A weak disturbance will bring some showers to the region early Thursday into Thursday night, mainly across NH and maybe toward PWM.
Potential for MVFR ceilings will also be increasing for the NH terminals during this time, perhaps IFR Thursday night.

Long Term...Restrictions in lowered CIGs possible Fri, especially early in the day when IFR/LIFR is possible at NH terminals. Confidence is low with these restrictions. MVFR to IFR is more likely to develop Fri night into Sat with -SHRA and lowered CIGs . VFR and W winds return late Sat or Sun, lasting through the start of the coming week.

MARINE
Short Term...SCA conditions are not expected through Thursday night. Light S/SW flow will become NE/ENE tonight with high pressure becoming centered north of the waters. The high moves slightly to the east on Thurs/Thurs night veering winds more E/ESE during the day Thursday with more light and variable speeds/direction Thurs night.

Long Term...SE flow increases Fri/Fri night, with an unlikely chance of touching 25 kts while seas similarly increase to 2-4 ft. A cold front crosses Sat with winds turning W to SW AOB 20 kts thru Sun and into Mon with daily sea breezes possible. S to SE flow develops by midweek.

GYX WATCHES/WARNINGS/ADVISORIES
ME...None.
NH...None.
MARINE...None.




Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesinHgDewPt
SEIM1 1 mi55 min 45°F 47°F30.1736°F
BGXN3 - Great Bay Reserve, NH 3 mi100 min SE 5.1 46°F 30.1233°F
IOSN3 - Isle of Shoals, NH 11 mi85 min ESE 15G17 43°F 30.1129°F
44073 13 mi60 min SE 12G14 45°F 44°F
44030 - Buoy B0102 - Western Maine Shelf 19 mi141 min SSE 12G16 44°F 46°F2 ft30.14
WEXM1 - Wells Reserve, ME 21 mi85 min S 5.1 45°F 32°F
44098 - Jeffrey's Ledge, NH (160) 37 mi59 min 45°F2 ft
44029 - Buoy A0102 - Mass. Bay/Stellwagen 40 mi141 min SE 14G16 44°F 46°F3 ft30.15
44007 - PORTLAND 12 NM Southeast of Portland,ME 45 mi45 min S 12G16 44°F 46°F30.1334°F
CASM1 - 8418150 - Portland, ME 49 mi55 min S 8.9G12 46°F 45°F30.11


Wind History for Portland, ME
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Airport Reports
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AirportDistAgeWind ktVisSkyWeatherTempDewPtRHinHg
KPSM PORTSMOUTH INTL AT PEASE,NH 3 sm30 minSE 1210 smOvercast46°F34°F61%30.14
KDAW SKYHAVEN,NH 16 sm34 minESE 0710 smClear48°F34°F57%30.13
KSFM SANFORD SEACOAST RGNL,ME 22 sm29 minS 0410 smClear46°F32°F57%30.14
Link to 5 minute data for KPSM


Wind History from PSM
(wind in knots)
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Tide / Current for Atlantic Heights, Piscataqua River, New Hampshire
   
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Atlantic Heights
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Wed -- 01:22 AM EDT     1.67 feet Low Tide
Wed -- 03:36 AM EDT     Moonset
Wed -- 05:57 AM EDT     Sunrise
Wed -- 07:46 AM EDT     7.05 feet High Tide
Wed -- 01:16 PM EDT     Moonrise
Wed -- 02:08 PM EDT     1.01 feet Low Tide
Wed -- 07:28 PM EDT     Sunset
Wed -- 08:35 PM EDT     6.54 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Atlantic Heights, Piscataqua River, New Hampshire, Tide feet
12
am
2.2
1
am
1.7
2
am
1.8
3
am
2.5
4
am
3.7
5
am
5.1
6
am
6.2
7
am
6.9
8
am
7
9
am
6.5
10
am
5.4
11
am
3.9
12
pm
2.5
1
pm
1.5
2
pm
1
3
pm
1.3
4
pm
2.1
5
pm
3.4
6
pm
4.8
7
pm
5.8
8
pm
6.4
9
pm
6.5
10
pm
5.8
11
pm
4.6



Tide / Current for Portsmouth Harbor Entrance, New Hampshire Current
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Portsmouth Harbor Entrance
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Wed -- 02:55 AM EDT     0.00 knots Slack
Wed -- 03:36 AM EDT     Moonset
Wed -- 04:37 AM EDT     0.65 knots Max Flood
Wed -- 05:56 AM EDT     Sunrise
Wed -- 06:21 AM EDT     0.52 knots Min Flood
Wed -- 06:50 AM EDT     0.53 knots Max Flood
Wed -- 08:34 AM EDT     -0.00 knots Slack
Wed -- 11:40 AM EDT     -1.51 knots Max Ebb
Wed -- 01:16 PM EDT     Moonrise
Wed -- 03:37 PM EDT     0.00 knots Slack
Wed -- 05:28 PM EDT     0.61 knots Max Flood
Wed -- 06:00 PM EDT     0.61 knots Min Flood
Wed -- 07:28 PM EDT     Sunset
Wed -- 07:39 PM EDT     0.72 knots Max Flood
Wed -- 09:24 PM EDT     -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Portsmouth Harbor Entrance, New Hampshire Current, knots
12
am
-1.2
1
am
-1.1
2
am
-0.7
3
am
0
4
am
0.6
5
am
0.6
6
am
0.5
7
am
0.5
8
am
0.3
9
am
-0.3
10
am
-1.1
11
am
-1.5
12
pm
-1.5
1
pm
-1.4
2
pm
-1.2
3
pm
-0.5
4
pm
0.2
5
pm
0.6
6
pm
0.6
7
pm
0.7
8
pm
0.7
9
pm
0.3
10
pm
-0.5
11
pm
-1




Weather Map
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GEOS Local Image of north east   
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Portland, ME,



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