textproduct: Caribou

SYNOPSIS

A weak upper level trough of low pressure will cross the area this morning and begin to swing into the Maritimes this afternoon. High pressure will build over the area tonight into Saturday then slide east of the region Saturday night. A new upper trough will approach Sunday into Monday followed by weak upper ridging on Tuesday.

NEAR TERM /THROUGH SATURDAY/

6:50 AM Update...Extended chances for showers/t-storms just a bit further south based on latest mesoscale model outputs. Otherwise, forecast remains on track.

We will be on the southern edge of a weak upper level trough of low pressure sliding into quebec today. The trough axes will cross the area late this morning then start to lift out to the northeast this afternoon. Cooler air pooled aloft in this trough combined with the days heating will result in some thundershowers building up across the north today. Temperatures will begin to warm aloft this afternoon as the trough begins to lift out. This may offset the risk of intense convection. However, if surface heating can occur a little faster than the warming aloft, a slight net increase in instability should sustain some convection into the afternoon, mainly across eastern areas.

The upper trough will continue to lift out to the east northeast tonight as a large weak area of surface high pressure builds over the area. Calm air and a clearing sky will likely result in some patchy fog forming tonight, mainly in valleys, with fog being most likely anywhere the ground has been moistened by rain.

High pressure and shortwave upper ridging will bring a partly to mostly sunny day on Saturday with the warmest air over the far north where highs will be near 80.

SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/

High pressure begins to slide east of Maine during Saturday night and Sunday as a frontal system slowly approaches from the west. This will allow winds to turn southerly and dew points to rise. Patchy fog and low stratus will be possible late Saturday night into early Sunday morning for Bangor and Downeast. Lows Saturday night will mainly be in the lower 60s, with 50s for Coastal Downeast.

As the front moves closer, showers will become possible by Sunday afternoon. The best chance will be near the Quebec border, but anywhere north and west of Katahdin will see the threat of showers. Some thunder will also be possible, especially near the Quebec border. With southerly flow, the warmest highs Sunday will be in the North. Some spots could approach 80 degrees there. Otherwise, highs will be in the 70s, with 60s at the immediate coast and outer islands. Shower threat increases Sunday night, but will still be limited to areas north of Bangor. Lows once again will be in the lower 60s for most places, with upper 50s Downeast.

LONG TERM /MONDAY THROUGH THURSDAY/

A slow-moving frontal system is forecast to cross the region Monday. This will bring the threat of showers and thunderstorms, with the greatest threat being from the Central Highlands northward. Models show PWAT values between 1.75 and 2.00 inches by Monday afternoon. This means some heavier downpours could occur with any thunderstorms. The front weakens Monday night and Tuesday, reducing the shower and thunderstorm threat. Tuesday looks to be mostly dry, except for an isolated shower or thunderstorm in northeastern Aroostook County. Ridging will bring dry weather Tuesday night and Wednesday. A cold front is expected to approach the region late week, but timing remains uncertain. High temperatures will be close to normal Monday, and above normal Tuesday through Thursday next week.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

NEAR TERM: MVFR to IFR conditions over parts of the north will improve to VFR around midday and remain VFR into this evening with the exception of any thunderstorms today and patchy fog late tonight. VFR conditions are expected on Saturday. IFR to MVFR conditions Downeast will improve to VFR around midday into this evening before dropping back to MVFR or IFR in lower clouds and some fog late tonight. Conditions will return to MVFR late morning Saturday. Winds very light S today through Saturday.

SHORT TERM: Saturday night...IFR/LIFR with any low clouds or FG, mainly BGR & Downeast. Otherwise, VFR/MVFR. S-SE winds 5 to 10 knots.

Sunday...IFR/LIFR early with any low clouds or FG, mainly BGR and Downeast. Otherwise, VFR/MVFR with the slight chance of -SHRA or TS mostly north. S-SE winds 10 to 15 knots.

Sunday night...IFR/LIFR with any low clouds or FG. Otherwise, VFR/MVFR with a chance of SHRA/TS mostly north. S winds 5 to 10 knots.

Monday through Tuesday...Variable conditions with any -SHRA or TS. Also, with any low clouds or FG. Otherwise, generally VFR. S winds 10 to 15 knots Monday. SW-W winds 5 to 10 knots Monday night. Variable winds 5 to 10 knots Tuesday.

MARINE

NEAR TERM: Winds will be light and seas around 3 ft today through Saturday. Some fog and mist is likely over the waters.

SHORT TERM: Winds and seas will remain below Small Craft Advisory criteria Saturday night through the middle of next week. Patchy fog could reduce visibility on the waters Saturday night into Sunday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Beach Hazards Statement through this evening for MEZ029-030. MARINE...None.