Penobscot Bay Marine Forecast
| Today...Se Winds 5 To 10 Kt With Gusts Up To 20 Kt, Increasing To 15 To 20 Kt With Gusts Up To 30 Kt. Seas 2 To 4 Ft. Wave Detail: S 3 Ft At 4 Seconds. Patchy Fog Until Late Afternoon. Patchy Fog Late. A Chance Of Showers Late This Morning. Showers This Afternoon. Scattered Tstms Late With Vsby 1 To 3 Nm. |
| Tonight...S Winds 15 To 20 Kt With Gusts Up To 30 Kt, Becoming Sw 10 To 15 Kt With Gusts Up To 20 Kt After Midnight. Seas 3 To 5 Ft. Wave Detail: S 5 Ft At 7 Seconds. Showers And Scattered Tstms In The Evening With Vsby 1 Nm Or Less. |
| Fri...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 4 Ft. Wave Detail: S 4 Ft At 8 Seconds. |
| Fri Night...Sw Winds 5 To 10 Kt. Seas 2 To 4 Ft. Wave Detail: S 4 Ft At 7 Seconds. |
| Sat...W Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 4 Ft. Wave Detail: S 3 Ft At 7 Seconds. |
| Sat Night...Nw Winds 5 To 10 Kt. Seas 2 To 3 Ft. Wave Detail: S 3 Ft At 7 Seconds. |
| Sun...W Winds 5 To 10 Kt. Seas 2 To 3 Ft. A Chance Of Showers In The Afternoon. |
| Sun Night...Sw Winds Around 5 Kt. Seas Around 2 Ft. A Chance Of Showers In The Evening. |
| Mon...S Winds Around 5 Kt, Becoming Se In The Afternoon. Seas 1 To 2 Ft. A Chance Of Showers In The Afternoon. |
| Mon Night...Se Winds Around 5 Kt, Becoming Ne After Midnight. Seas 2 To 4 Ft. A Chance Of Showers. Winds And Seas Higher In And Near Tstms. |
| Area Forecast Discussion National Weather Service Gray ME 241am EDT Thu Jun 18 2026 .WHAT HAS CHANGED... A flash flood watch is being issued for the mountains and foothills for today. .KEY MESSAGES... 1. An unseasonably strong storm is forecast to cross the region Thursday, leading to a chance of both severe thunderstorms and heavy rainfall. 2. The weather pattern remains unsettled Friday through the weekend with daily chances for afternoon showers and a few storms. 3. Low pressure could bring more widespread rainfall early next week. KEY MESSAGE 1 DESCRIPTION... An anomalously strong system for this time of year moves into our region from the west today. Chances for widespread rain will increase this morning with the heaviest likely being during the afternoon hours. Have increased forecast rainfall in the mountains due to an anomalously strong low level jet for this time of year coupled with relatively high PWAT (Precipitable Water) values. Have heavily blended in the latest HREF and HRRR (High-Resolution Rapid Refresh) models as they will likely capture mesoscale effects to Quantitative Precipitation Forecast more readily. Given that we have had some flooding problems over the last week or two and that mountain and foothills 1 and 3 hour FFG is relatively low, will go ahead and issue a flash flood watch for them today. In addition there could be a few strong to severe thunderstorms in the afternoon after the larger shield of rain moves out. The issue is that instability should be lacking. However, a few hundred joules of CAPE coupled with unusually strong wind shear for this time of year we can't rule out a few rotating updrafts or some damaging line segments. With the anomalous low level jet in place today winds could gust up to 30 MPH outside of convection. Drier air eventually moves in tonight in the wake of the system with some upslope rain showers possibly remaining in the mountains. KEY MESSAGE 2 DESCRIPTION... Model trends continue to hold steady in regards to broad cyclonic flow prevailing through the extended forecast period and creating unsettled conditions through the weekend. Vertically stacked low pressure moves north of the area on Friday and into the Canadian Maritimes Saturday allowing shortwaves to rotate through the broader trough and provide the forcing for afternoon showers and storms both days (mainly in the mountains and foothills). Forecast soundings suggest freezing levels low enough to support small hail as well as 850 mb winds in the 25 to 30 kt range that could mix down to the surface. Otherwise, seasonable temperatures in the mid to upper 70s south of the mountains (60s to the north where clouds will be stubborn) should make for a pleasant start to the weekend. By Sunday the upper low opens up to a positively tilted trough, with the surface low now well of the northeast. There will still be a chance for afternoon showers and storms, but wind gusts should be noticeably more relaxed. Something else to mention for the weekend timeframe, is the potential for the remnants of what is currently Tropical Cyclone Arthur to re-develop off the Mid-Atlantic coast. If this occurs it won't have a direct impact to New England as model solutions keep it well offshore, but it could result in elevated wave heigheights and rip current risk along the coast. KEY MESSAGE 3 DESCRIPTION... Global models continue to show agreement on another upper low diving into the region early next week, with continued lesser agreement on the surface low out ahead of it (and thusly our next chance for widespread rainfall). Most ensemble solutions are favoring a coastal track, but timing is all over the place with the GFS (Global Forecast System) camp being the fastest by far, with rain starting Sunday night and having the low in and out on Monday. The Euro camp lags the low until Monday night and moves it up the coast during the day Tuesday. The Canadian is more in agreement with the Euro as far as timing, but by far has the weakest low of the three. Certainly a good time window to watch trends as coastal systems usually lend themselves to enhanced rainfall, but as you can see there is much uncertainty at this time. The models then all begin to trend drier toward the middle of the week as they suggest an upper level ridge building in. Marine Southeast winds begin to increase today in response to the strong storm moving out of the Great Lakes. A strong low level jet is forecast to develop in response to this storm, and while mixing will not be strong it does appear that a period of gale force southerly wind gusts is likely ahead of the front. For this reason, a gale warning has been issued outside of Penobscot Bay for this afternoon and evening. Elevated wave heigheights may still be present Friday and Saturday as low pressure slowly departs the area. Will also have to keep an eye on the remnants of what is currently Tropical Cyclone Arthur as some models suggest they may redevelop off the Mid- Atlantic coast in this timeframe. This may result in elevated swell reaching the Gulf of Maine. There should be some window of sub-SCA (Small Craft Advisory) conditions late in the weekend, but will have to monitor early next week for elevated wind gusts and seas with another low pressure system modeled to be in the vicinity of the Gulf of Maine. NOAA Gray/Portland ME Office - Watches - Warnings - Advisories ME...Flood Watch from noon EDT today through this evening for MEZ012-013. NH...Flood Watch from noon EDT today through this evening for NHZ002>006. Marine Gale Warning from noon today to 8pm EDT this evening for ANZ150-152>154-180-182-184. Small Craft Advisory from noon today to 8am EDT Friday for ANZ151. |
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