Marine Weather and Tide Forecast for Bath, ME

NEAR TERM /THROUGH TONIGHT/
A weak shortwave pass through the area this evening bringing a few light rain showers. Mixing layer is very dry, so most rain will be very light due to evaporation drying. A few wind gusts could be possible in any stronger shower due to sub-cloud evaporation, but overall most areas will remain dry. Shower activity should mostly end by midnight tonight. Temperature wise, onshore and southerly return flow has begun. This has allowed a sea-breeze front to push inland this afternoon will cooler temperatures this evening along the coast and a nice warm evening across the interior areas. Temps will remain cool across Maine with lows in the 40s. It will be warmer across southern NH due to cloud cover and not having a onshore flow, with lows around 50.

SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/
Warm front begins to push north tomorrow with a sharp trend upward in dewpoint temperatures as southerly flow becomes established. Temperatures will run well above normal with highs in the 70s and upper 70s for the lower Merrimack River Valley.
Cooler temperatures will remain along the immediate coast.
Instability showers are possible by the afternoon hours, especially across Southern NH as the warm front pivots north through the region. Sounding profiles support around 300 J/Kg of CAPE, so a strike or two can't be ruled out. Rain shower activity will continue to increase through the night across the north.

LONG TERM /SATURDAY THROUGH THURSDAY/
Pattern Overview: A 500mb trough and surface low pressure will swing through the region over the weekend bringing widespread rain Saturday, with shower activity lingering most of Sunday.
The system departs Sunday night with a ridge building in for the first part of the week. Shower chances return midweek as a trough swings through Wednesday along with the passage of a cold front. Thursday looks dry behind the front.

Details: Saturday: Widespread rain will be ongoing Saturday morning as low pressure passes through the region. There is some spread in the ensemble QPF, with the Euro having more widespread values of one inch. The GFS and Canadian keep these amounts more isolated to the mountains and coast where upslope and LLJ enhancement look likely. Outside of these areas ensemble means are still in the range of 0.75" to near an inch, so this will be a beneficial rain for everyone. The previously mentioned LLJ axis looks like it will be mostly offshore, so while the coast may see more rainfall than the interior this should preclude any threat for flooding. Due to runoff the mountains usually have a non-zero minor flood threat, and this fits with the latest thinking from WPC where a Marginal ERO still exists.

Sunday and Monday: Low pressure slides offshore Sunday, but the trend in this progression has been to slow it down, so shower activity may linger through most of Sunday. At the least it will be mostly cloudy with some breaks in the stratus heading toward the evening hours. High temperatures will be limited to the 50s south of the mountains, and mid to upper 40s to the north.
Skies clear overnight Sunday, but likely not quick enough for radiational cooling to be a factor, so low temperatures look to end up in the upper 30s and low 40s. Monday features clear skies and flow turning southwesterly, beginning to usher in a warmer airmass. High temperatures south of the mountains look to get into the upper 60s and low 70s, with low to mid 60s to north.
Low temperatures bottom out in the 40s areawide.

Tuesday-Thursday: Established southwesterly flow makes Tuesday the warmest day as 850mb temps exceed +10C. This translates to mid- to upper 70s across much of the interior. The coast may end up more in the mid 60s as flow turns onshore in the afternoon.
Clouds and shower chances will also be on the increase through the evening ahead of an approaching front. Global models currently keep the front and trough in the region Wednesday and thusly shower chances during the day will stay as well. Shower chances decrease overnight as the front and trough depart. This should put us back in the clear for Thursday with a cooler airmass.

AVIATION /18Z THURSDAY THROUGH TUESDAY/
Short Term...A few light rain showers will move through the area this afternoon and evening with MVFR cigs possible. More showers expected by tomorrow afternoon across southern areas, again no impacts to aviation operations.

Long Term...Widespread rain will bring about some MVFR restrictions, with IFR restrictions possible in areas of heavier rain, Saturday and Sunday. Ceilings trend back to VFR for Monday and Tuesday. Tuesday night is the next chance for low ceilings and showers to bring about restrictions. Thunderstorms are possible at HIE and LEB with the passing of the front Tuesday night.



MARINE
Short Term...High pressure crests over the waters tonight and moves to the east during the day tomorrow. Onshore southerly flow increases through the day but seas and winds will remain below SCA through tomorrow night.

Long Term...SCA conditions are likely Saturday as low pressure slides over the waters ramping up southerly wind gusts and waves to 6-8ft. Winds gusts taper off as winds shift around to northerly for Sunday, but seas will take longer to fall below SCA criteria. By Monday conditions should fall below SCA criteria and stay below through Tuesday.

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