textproduct: Caribou

WHAT HAS CHANGED

-Dropped Cold Wx Advisory for Central and Northern Piscataquis for tonight. -Dropped Gale Warning from the intracoastal zone down to SCA. -Adjusted time of Gale Warning for the outer waters back by 4 hours. -Adjusted start time of Freezing Spray Advisory up by 5 hours for all waters. -Increasing confidence for a period of light snowfall Tuesday night to Thursday. Accumulations of greater than 1 inch but less than 5 inches are currently favored across most of the area by the majority of deterministic, ensemble, and AI guidance.

KEY MESSAGES

1) Adjusted low temps down over the northwest tonight by 3-5 degrees in the deeper valleys.

2) Periods of light snow and snow showers are likely from Tuesday night through Thursday, producing a light to possibly moderate accumulation. Warmer temperatures approaching freezing are also expected.

DISCUSSION

KEY MESSAGE 1... Adjusted low temps down over the northwest tonight by 3-5 degrees in the deeper valleys.

KEY MESSAGE 1 DESCRIPTION... After temps fell to between minus 5 to minus 10 this morning before clouds backed in from the east have lowered temperature for tonight by a good 3-5 degrees over the northwest. Arctic cold front looks to have made it thru central NH and will be knocking on our door shortly. Though it appears that the bulk of the cold air will squirt west and south of our CWA, enough should be able to bleed over to drop temps below zero tonight once again over the North Woods.

Winds still expected to be strong and gusty late tonight but with an inversion setting up tonight the strongest winds will be over the highest terrain. This will lead to wind chills dropping to between 15 and 25 below over most of the north with the exception of northern Somerset dropping to 25 to 30 below. Have cancelled the Cold Weather Advisory for portions of Piscataquis County for this reason, as widespread 25 below wind chills do not appear likely tonight.

KEY MESSAGE 2... Periods of light snow and snow showers are likely from Tuesday night through Thursday, producing a light to possibly moderate accumulation. Warmer temperatures approaching freezing are also expected.

KEY MESSAGE 2 DESCRIPTION... Vertically stacked low pressure south of the Hudson Bay on Tuesday will move towards the area Tuesday night, bringing an initial surge of warm advection precipitation associated with a warm front and developing occlusion over NH and western ME. Models still differ in the timing and evolution, but generally show a slowing of the upper level low with a weak surface low developing off the coast. There is potential for a weak inverted trough to form as well, but the thermal gradient is not significant which would lower the magnitude of convergence and snowfall rates. Nonetheless, plenty of maritime moisture will be available, first from the Atlantic Tuesday night into Wednesday morning, then from the Canadian Maritimes later Wednesday into Thursday as east flow sets up. Multiple periods of light snow are possible, with a light to moderate accumulation currently favored from the majority of deterministic, ensemble, and AI guidance. The spread of QPF among this guidance suggests between slightly less than a tenth and 4 tenths of an inch of QPF, which would translate to between 1 and 5 inches of snowfall across the area. This is still a significant spread, so check back for future forecast updates to narrow down accumulation potential.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Tonight...VFR with unrestricted -shsn HUL, BGR and BHB this afternoon. NW 5-10kts. LLWS late tonight at Downeast terminals at FL020.

Sunday-Sunday night...VFR. NW 5-15kts with gusts up to 25kts.

Monday...VFR. NW winds 10-15kt with gusts up to 25kt.

Monday Night to Tuesday...VFR. NW winds 5-15kt.

Tuesday night to Wednesday night...VFR becoming MVFR. IFR periods possible due to cigs/vsby. -SN/-SHSN likely. NE winds 5-10kt.

Thursday...MVFR. Tempo IFR possible in -SN/-SHSN. NW winds 5-10kt with gusts to up to 20 kt.

MARINE

SCA level winds increase to gale force over the outer waters after 01z tonight and remain up through Sunday morning. Expect a brief lull back toward strong small craft conditions during the day on Sunday before increasing once again toward gale force over the outer waters Sunday evening. Gales remain through 05z Monday over the outer waters before diminishing to SCA. The intracoastal zone looks to remain at strong small craft levels from this evening through late Sunday night. Seas will range from 4 to 7 feet Sunday before diminishing late Sunday night. As for freezing spray, expect moderate accumulations beginning later this evening over all waters tonight. With winds briefly diminishing on Sunday expect light freezing spray before moderate freezing spray resumes Sunday evening through the overnight hours.

Small Craft Advisory winds and moderate freezing spray are likely to continue into Monday morning, with seas and freezing spray decreasing below advisory levels, but wind gusts persisting around 25 to 30 kt through Monday into Monday night with light freezing spray. Winds fall below advisory levels Tuesday through Wednesday with freezing spray ending.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Cold Weather Advisory from 3 AM to 10 AM EST Sunday for MEZ003. MARINE...Gale Warning from 4 PM this afternoon to midnight EST Sunday night for ANZ050-051. Freezing Spray Advisory from midnight tonight to 10 AM EST Monday for ANZ050>052. Small Craft Advisory from 8 PM this evening to midnight EST Sunday night for ANZ052.