Marine Weather and Tide Forecast for Winterport, ME

NEAR TERM /THROUGH SUNDAY/
Main story in the Near Term period will be a decaying mesoscale convective system (MCS) approaching early Sunday morning.
Skies remain mostly clear late this afternoon, then clouds increase tonight ahead of the system. Most guidance tracks the center over the Crown of Maine. This will bring rain showers to most of the area beginning around sunrise Sunday morning. High-resolution models show the strongest instability remaining southwest of the area. This will likely preclude any severe thunderstorms. However, there will be enough elevated instability for some embedded thunderstorms with the MCS. With PWATS approaching 1.80 inches and a strong low level jet, heavy downpours are a threat with any thunderstorms. Flash flood guidance is lower than average due to recent rainfall.
Thus, isolated flash flooding is possible in heavier thunderstorms. There is still some uncertainty with exact rainfall amounts. This is because convection to the southwest could siphon off moisture from Northern and Eastern Maine.
Showers will become less numerous in the afternoon as the MCC quickly moves off to the east-southeast. However, still expect lingering showers through the afternoon.

High temperatures on Sunday will vary significantly across the area.
With warm air advection and some afternoon clearing, highs will likely reach the lower to mid 80s in the Penobscot and Piscatquis River valleys. Highs will remain in the 70s further north and east due to cloud cover and showers hanging on longer. Coolest highs will be in northeastern Aroostook County, where it will be a struggle to reach 70 degrees. Humidity will increase area-wide Sunday, as dew points climb into the 60s in the afternoon.

SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
High pressure builds across the area Sunday night as a broad upper level ridge also builds northward over the area. Light winds, mostly clear skies, and increasing moisture will favor patchy fog, particularly across the river valleys and near the coast. Low temperatures are expected to be seasonable in the 50s. Heat and humidity begins to build on Monday as dew points climb into the 60s and temperatures into the 80s. An isolated shower or thunderstorm is possible across Northern Maine, but most areas remain dry as rising heights and sinking motion suppresses the majority of convection. Monday night will be unseasonably mild with lows around 70 across the north and in the 60s for most other locations.

Dangerously hot and humid conditions peak on Tuesday as 590dam 500mb heights reach the southwestern portion of the area. A very shallow inversion will quickly mix out with rapid warming during the morning hours. Moisture pooling ahead of a front over Quebec will cause dew points to reach the 70s as temperatures climb into the upper 80s and 90s. An Extreme Heat Watch has been issued for the Penobscot Valley, which is most likely to experience heat indices of 105 or greater. Most other areas will see advisory level heat indices of 95 to 104 degrees Tuesday afternoon. Regardless, this will be much hotter and humid compared to any day so far this year, so there is the potential to not be well acclimated to the heat and underestimate its impacts. There is a moderate to high likelihood of breaking the daily record high temperature of 93 in Bangor, which was set in 1995.

In addition to the heat, strong to severe thunderstorms are possible across the north Tuesday afternoon, particularly if the ridge begins to erode and heights begin to fall before sunset.
An approaching cold front may act as a trigger with the air mass ahead extremely moist, unstable, and moderately sheared. Winds are primarily unidirectional out of the west, so damaging winds and hail would be the primary threats. Models are not particularly bullish on widespread convection, likely due to the ridging supporting sinking motion and marginal mid level lapse rates. However, favorable thermodynamics may overcome these factors.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
Lingering showers and possibly thunderstorms Tuesday night will end with advection of much drier and cooler air providing relief from the heat on Wednesday with mostly clear skies and highs in the 70s across the north and lower 80s across the south. Dew points will also be notably lower in the 40s across the north and low to mid 50s south.

Significant timing differences exist, but in general guidance shows a shortwave trough moving across James Bay into Quebec and clipping the northern part of the forecast area late Thursday into Friday. Increased shower chances are expected during this time. Heat and humidity will likely continue to be suppressed south of the area with this feature, leading to near average temperatures for late June with highs in the lower to mid 70s and lows in the upper 40s to 50s favored.

AVIATION /18Z SATURDAY THROUGH THURSDAY/
NEAR TERM: Northern Terminals: VFR through most of the night tonight.
Conditions quickly deteriorate to IFR early Sunday AM with SHRA to +SHRA. VCTS expected Sunday AM. Improvement to at least MVFR Sunday PM with VCSH. LLWS from around sunrise Sunday through the day. NW winds 5-15 kts, with gusts 20-25 kts late this PM.
Winds light and variable this evening. S winds 5-10 kts with gusts to 20 kts late tonight into Sunday AM. Isolated higher gusts possible in any TS.

Southern Terminals...VFR conditions through most of tonight.
Periods of MVFR or lower possible Sunday AM with -SHRA and VCTS.
Otherwise, VFR through the day Sunday. LLWS Sunday AM. LLWS ending at BGR early PM, continuing through the day Downeast. NW winds 5-15 kts, with gusts to 20 kts late this PM. Winds light and variable this evening. S winds 5-15 kts with gusts to 20 kts late tonight into Sunday AM. Isolated higher gusts possible in any TS.

SHORT TERM: Sunday night to Monday night: VFR during the day. IFR/LIFR possible briefly with patchy fog Sunday night, mainly across coastal and river valley sites such as BHB, PQI, and MLT, shifting more to the coast for Monday night. Light and variable winds Sunday night shifting SSW at 5-15 kts Monday.

Tuesday: VFR. WSW winds 5-10 kts gusting to 20 kts. Scattered TSRA across northern terminals in the afternoon may produce tempo IFR conditions and briefly stronger wind gusts.

Tuesday night to Wednesday night: VFR. NW winds 5-15 kts gusting to 20 kts during the day, becoming light and variable Wednesday night.

Thursday: VFR with scattered SHRA during the afternoon. W winds 5-15 kts.

MARINE
NEAR TERM: Winds and seas will remain below Small Craft Advisory criteria through tonight. Winds and seas build above SCA levels on the outer waters early Sunday morning. A few wind gusts could reach 25 kts on the intra-coastal waters Sunday morning. However, not enough confidence to issue an SCA there at this time. Rain showers could reduce visibility on the waters at times Sunday. Isolated thunderstorms possible over the waters Sunday morning.

SHORT TERM: Winds and seas decrease below advisory criteria Sunday night and remain below criteria through the remainder of the week. Fog will reduce visibility at times Monday night into Tuesday as a very humid air mass settles over the area.

CAR WATCHES/WARNINGS/ADVISORIES
ME...Extreme Heat Watch from Tuesday morning through Tuesday evening for MEZ011-015-016-031.
Beach Hazards Statement until 8 PM EDT this evening for MEZ029- 030.
MARINE...Small Craft Advisory from 7 AM to 8 PM EDT Sunday for ANZ050- 051.