textproduct: Caribou

SYNOPSIS

Low pressure develops along the coast tonight, then strengthens as it moves east into the Canadian Maritimes Thursday night. Additional weak disturbances rotate through the area into the weekend.

NEAR TERM /THROUGH THURSDAY NIGHT/

9:50PM UPDATE...Marine weather headline update. See below...

Previous Discussion... Key Messages...

1) Another significant winter storm late impacting New Years travel tonight and Thursday for eastern areas

2) Gusty winds behind system Thursday evening bringing blowing snow

3) Wind chills may drop toward -25 F across the north Thursday night

Key Message 1... Main driver for the coastal low developing overnight is compact s/wv dropping into srn Ontario this afternoon. Sfc low associated with feature is located over Lake Huron and, as disturbance drops south and east tonight, sfc low will intensify near the Adirondacks. Snow develops along the front this evening with steady snow developing over the Downeast coast initially before more widespread snow moves in with the parent low after midnight. H5 trof entering New England by 12z Thursday and will transfer energy to the coast with secondary coastal low fcst to develop in the vicinity of the western Gulf of Maine.

Low will intensify during the day on Thursday, moving toward the Bay of Fundy by afternoon. Upper trof will become negatively tilted over CWA at the same time and will help to capture with a track close to our border with NB. This is important because 1) snow that will be falling Downeast, specifically Washington County, will intensify as low deepens near the entrance to the Bay of Fundy and 2) it may bring a deformation zone to northern and eastern parts of the state in the evening.

Regarding the snow falling over Downeast snowfall rates will approach 1 to 1.5 inches/hr in the morning as sfc low intensifies. Snowfall amnts of 2-5 inches look to be possible along the coast between 12 and 18z, including the Bar Harbor area over toward Vanceboro. Guidance continues to struggle with how quickly sfc low moves inland over NB and snow ends Downeast. The bulk of the snow will fall on New Years Day for Downeast with amnts anywhere from 5-10 inches, highest over far eastern Washington County. However, cannot rule out rain mixing in near the Eastport area depending on how quickly sfc low cuts inland so this may cut down some on snow amounts along the Washington County coast.

Further to the north as low heads thru central NB on Thursday evening, guidance is showing signs of possible fgen forcing with a deformation band setting up. How far west that can extend remains in question but model trends have increased with heavier snow affecting eastern Aroostook County during the evening and overnight hours. For the time being based on latest up-to-date guidance and ensembles have issued a winter weather advisory for eastern Aroostook, and all of Penobscot County including the Bangor Region for snowfall amounts from 3-6 inches. Cannot rule out that portions of the advisory may need to be upgraded to a warning and/or extended in time, especially with impacts from blowing snow which leads to Key Message 2.

Key Message 2... Sfc low heads toward the Maritimes Thursday night with increasing pressure gradient and strengthening low level jet. Temps aloft will drop off quicker than sfc temps with mixing up to H9. Winds around H9 look to range from 30-35kts. West winds will gust to 30-35 mph across the region leading to patchy blowing snow. If snow is currently falling over the northeast, gusty winds may bring widespread blowing snow downwind of open areas and will be able to glean more impacts from further model guidance.

Key Message 3... In addition to blowing snow strong winds when coupled with forecast lows below zero over the north will bring wind chill temps down toward negative 25 degrees. May need to issue a Cold Weather Advisory for the north Thursday night into Friday morning.

SHORT TERM /FRIDAY THROUGH SATURDAY/

Key Message...Well below normal temperatures expected Friday and Saturday.

Low pressure will lift northeast of the region Friday and Friday night. West to northwest flow, both at the surface and aloft, will persist through the period. Some subtle short waves are expected to cross the region later Friday through Saturday in the flow. Although cant totally rule out a few flurries or isolated snow showers, will keep the forecast dry for now. Apparent temperature values may approach cold weather advisory levels across the North Maine Woods Friday night.

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/

Key Message...Continued well below normal temperatures through early next week, then a gradual return to near normal temperature by mid week.

Low pressure will be tracking northeast of the Carolina coast Saturday night and then out into the open waters of the western atlantic through Sunday. Precipitation with this system will stay well to our south and east. But some upper level energy cascading down in the west northwest flow aloft could bring the chance for some light snow, mainly for coastal areas later Saturday night and Sunday. Otherwise, expect dry weather conditions during Sunday. Mainly clear and continued very cold conditions are expected Sunday night as the 500 MB trough axis moves to the east of the region.

West to northwest flow continues Monday through Tuesday. There are some indications that a short wave could bring some light snow to the region Monday night into Tuesday, therefore will maintain slight to low chance pops per the NBM. Another system may approach by mid week with the next chance for snow by Wednesday.

AVIATION /02Z THURSDAY THROUGH MONDAY/

NEAR TERM: Northern Aroostook terminals vary between low VFR and high MVFR cigs this evening before dropping to MVFR toward 08z. IFR snow looks to move into Aroostook terminals around 11z Thursday, likely to remain down during the daytime hours. Depending on storm track may see IFR/LIFR snow and blowing snow impact terminals Thursday night.

Downeast terminals drop to MVFR in light snow between 04-06z tonight and IFR/LIFR toward 10z in moderate snow. Uncertain on how quickly restrictions improve but could see improvement to MVFR by 16z. Still uncertain on how quick improvement to VFR occurs Thursday night.

SHORT TERM:

Fri through Sat...Mainly VFR, although MVFR possible at times vcnty KFVE.

Sat night and Sun...MVFR possible KBHB in -SN, otherwise mainly VFR.

Sun night through Mon...VFR.

MARINE

NEAR TERM: UPDATE...Winds/seas are falling quickly across much of the coastal waters. Have opted to drop the small craft advisory. Looking forward to the Gale Warning that will be coming up Thursday afternoon. Increasing confidence in wind gusts up to 45kt across much of the waters as a low pressure system deepens over the Bay of Fundy and tracks NE into the Maritimes.

Previous Discussion... Seas remain above SCA levels over the outer waters through late this evening. Winds drop below small craft levels this evening before ramping up Thursday afternoon and gale force by the evening hours over all waters. Moderate freezing spray develops Thursday evening and continues through Friday morning.

SHORT TERM: Gale force gusts will persist into Friday evening, then winds/seas will diminish the SCA levels. Winds and seas are then expected diminish below SCA levels over the weekend. Light to moderate freezing spray will be an issue into the upcoming weekend.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Winter Weather Advisory from 3 AM Thursday to midnight EST Thursday night for MEZ002-005-006. Winter Weather Advisory from 4 AM to 7 PM EST Thursday for MEZ011-015. Winter Storm Warning from 1 AM to 7 PM EST Thursday for MEZ016- 017-029-030-032. MARINE...Gale Warning from 2 PM Thursday to 10 AM EST Friday for ANZ050>052. Freezing Spray Advisory from 8 PM Thursday to 1 PM EST Friday for ANZ050>052.