textproduct: Caribou

WHAT HAS CHANGED

- 1:38PM UPDATE for TAFs. See below.

Previous Changes... -Upgraded Winter Storm Watch to Winter Storm Warning for northern and eastern Aroostook county, based on combination of snow, sleet, and freezing rain. -Issued Winter Weather Advisories for southern Aroostook, northern Somerset, Piscataquis, Penobscot, Hancock, and Washington counties. Mixed precipitation is expected, causing some travel impacts.

-Increasing confidence in more impactful mixed wintry precipitation for Northern Maine Saturday night to Sunday morning.

KEY MESSAGES

1) Widespread wintry precipitation late tonight through Friday evening, will greatly impact Thursday evening and Friday morning commutes.

2) Another round of mixed wintry precipitation is expected Saturday night into Sunday morning, impacting travel mainly north of Bangor.

DISCUSSION

KEY MESSAGE 1...Widespread wintry precipitation late tonight through Friday evening, will greatly impact Thursday evening and Friday morning commutes.

KEY MESSAGE 1 DESCRIPTION... Surface high pressure system settles north of Maine, as another low pressure system approaches from the southwest. High pressure system set up helps to cause some cold air damming over the state today. Precipitation begins to fill in from southwest to northeast by tonight, falling mostly as snow. Associated mid- level warm front with aforementioned low pressure system lifts over the region tonight into Friday, bringing some warmer mid- layer temperatures, transitioning snow over to sleet late tonight. Decent moisture column and PWATS around 0.75 to 1 inches moving in associated with this system. Precipitation types are expected to transition all throughout the night into the day. Anticipating a little more sleet than freezing rain for Central Highlands areas northwards, based on a deep cold layer at the surface that develops from cold air damming set up. Temperatures gradually rise as the sun rises, leading to a chance for some freezing rain to follow sleet in the morning, providing a layer on ice on top of already messy conditions. Temperatures rise above freezing after mid-morning, and all precipitation should transition over to rain during the day. Precipitation intensity starts to diminish overnight on Friday, but rain/snow showers persist through the upcoming weekend.

Majority of sleet/ice is expected to fall Thursday night into Friday morning, causing a potential for significant travel impacts for Friday morning commute. Snowfall around 3-5 inches in northern Maine, and 6-8 inches in the St. John Valley. There is a chance for up to an inch of sleet in the Aroostook and Central Highlands region. 0.1 to 0.25 inches of ice possible in northern Maine and Central Highlands/Upper Penobscot Valley regions. T 0.05 inch of ice possible as far down as the Downeast coast. Sleet will be difficult to shovel and result in some nasty clean up processes throughout the north.

KEY MESSAGE 2...Another round of mixed wintry precipitation is expected Saturday night into Sunday morning, impacting travel mainly north of Bangor.

KEY MESSAGE 2 DESCRIPTION... Yet another system with complex precipitation types is on the way. Models are in reasonable agreement this far out, with fairly high confidence in snow to sleet to freezing rain to rain from Saturday night to Sunday morning as a warm front moves through and as the surface low pressure tracks north of us from west to east. At this time, think that areas from Bangor south will be a bit too warm for many travel impacts. The further north you go, the colder it is at the onset and the greater likelihood for hazardous travel early Sunday. High confidence in low-level cold air eroding enough to where everywhere, even the far north, will be above freezing Sunday afternoon, which will lead to much better travel conditions. For the north (where most impacts will be), think that snow will be fairly minor as things quickly transition to sleet, then to freezing rain, then to rain. Most concerned about sleet and freezing rain totals, which could be comparable to the incoming system tonight/Friday. Sleet totals over one half inch or possible, and freezing rain totals approaching one quarter inch are possible.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

18z TAF UPDATE... Rest of Today...VFR all terms except BKN MVFR at BHB (029). Expecting MVFR to SCT or potentially rise to SCT-BKN030 at BHB this PM. Otherwise VFR all other terms... Winds generally trending to become VRB winds around 5kt.

Tonight...IFR/LIFR in snow, sleet, and/or freezing rain. Precip transitions to rain at BHB and BGR by 12z Fri AM. SE winds 5-10kt.

Friday...IFR/LIFR early, with mixed precip changing to RA from south to north through the day. Becoming MVFR/IFR in the afternoon. S/SE winds 5-15kt. Gusts to 25kt at northern terminals possible.

Friday night...IFR north becoming MVFR with MVFR becoming VFR south. VCSH/-SHSN possible at northern terms. Wind shift expected between 05-08Z. Winds SW 5-15kt gusting up to 20kt shifting to the N-NNW 10-15kt.

Saturday...VFR/MVFR. NE winds 5-15kt.

Saturday night...IFR/LIFR with SN/IP/FZRA at northern terms with RA/IP at BGR and RA at BHB. SE winds 10-20kt gusting up to 30kt. LLWS possible.

Sunday...MVFR/IFR with RA likely, except IP/FZRA before 15z from PQI north. S winds 10-15kt gusting up to 30kt. LLWS possible.

Sunday night...MVFR/IFR and RA early becoming VFR late night. Winds shift W 5-15kt.

Monday...VFR. Low chance of MVFR due to SHSN at northern terms. W-NW winds 10-15kt with higher gusts.

MARINE

Small Craft criteria over the outer waters, which will relax later this afternoon. Conditions below criteria, until winds and seas approach Small Craft criteria by Friday and linger through the weekend. Chance of rain Friday. Chance for patchy fog close to the shoreline Friday morning. NE/E winds today, shifting SE by Friday morning. Winds shift S/SW by Friday evening.

Conditions generally small craft from Friday night through early Monday due to winds, seas, or both. There is a 75 percent chance of gale force southeast winds late Saturday night to Sunday morning.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Winter Storm Warning from 11 PM this evening to 5 PM EDT Friday for MEZ001-002. Winter Weather Advisory from 11 PM this evening to 2 PM EDT Friday for MEZ003>006-010-011-031-032. Winter Weather Advisory from 11 PM this evening to 10 AM EDT Friday for MEZ015>017-029-030. MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ050- 051.