textproduct: Caribou

SYNOPSIS

High pressure will slowly build in from the west today and crest over the area Friday into Saturday. Low pressure approaches Sunday then crosses the area Monday.

NEAR TERM /THROUGH TONIGHT/

A large upper level ridge will bring a large surface high pressure system into the region today and tonight. Upper air model soundings indicate ample sunshine for today with light and variable winds. Sunny skies will help boost temps into the mid to upper 20s across the region. For tonight, the main question will be how low the temps will get. The upper air model soundings indicate another shallow inversion, which will help decrease temps with the clear skies and calm winds. River valleys could see a more significant lowering of temps. If this plays out, then river valleys and lower terrain will see patchy fog. With the forecast single digit temps, and possible below zero temps in lower terrain, freezing fog is expected.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/

A deep surface inversion is likely to hang around through the end of the week, leading to a stable near-surface layer under a ridge of high pressure. Skies may remain mostly clear, but there is the chance for freezing fog each night due to radiational cooling under this decoupled layer. Temperatures in valleys may fall into the single digits above zero Friday night, while higher terrain remains in the teens due to this inversion. Cloud cover should return Saturday night as a low approaches from the west.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

A storm will approach the area on Sunday. A weak warm front will likely lift over the forecast area Sunday night followed by an occluded front through the day on Monday. Well- established cold air ahead of this system will create a layer of sub- freezing air near the surface Sunday into Sunday night, while SE winds advect warmer air into the area with the warm front. The warmer air is likely to begin by overrunning this cold layer, and precip may begin as freezing drizzle or freezing rain. As the warm air works into the region, the near surface layer will begin to warm, lifting above freezing and the precip type switching to regular rain. That said, from the Central Highlands north, this SE wind will struggle to efficiently bring the warmer air in rapidly enough to warm the surface layer, and cold air damming could lead to a longer duration of freezing rain, potentially with accumulating ice that could lead to broken tree limbs and weigh down power lines. All areas which see freezing drizzle and/or rain could see slick surfaces by early Monday morning, which could make travel treacherous.

Eventually, the storm may become all plain rain, and combined with warmer temperatures above normal, may erode the snow pack through the end of the calendar year.

AVIATION /08Z THURSDAY THROUGH MONDAY/

NEAR TERM: VFR conditions expected today and tonight. If the inversion sets up in the same way, then possible MVFR at the beginning of tonight, then gradually clearing. Low confidence on patchy freezing fog tonight, mainly for terminals in lower terrain. Winds light and variable.

SHORT TERM: Fri - Sat night: VFR across all terminals each day, mostly VFR each night with a few terminals susceptible to IFR FZFG, such as KFVE, KPQI, and KHUL. BCFG is the most likely, but depending on how much the fog breaches river valleys, it could encroach on the terminals. Winds light and variable.

Sun - Mon: VFR cigs dropping to MVFR/IFR as freezing drizzle, freezing rain, and plain rain move into the area. Greatest chance for extended periods of freezing rain are along a line from KGNR through KHUL and northwards. Increasing SE winds 5 to 15 kts.

MARINE

NEAR TERM: Winds and seas will remain below SCA levels today and tonight.

SHORT TERM: Winds and seas should remain below small craft advisory levels through the weekend. As a storm crosses the waters Sunday night into Monday, winds could gust 25 to 30 kts and seas may reach 5 to 8 ft.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...None.