textproduct: Caribou

WHAT HAS CHANGED

Raised pops for Tuesday mainly across the North

Lowered pops Wednesday night given that most of the major forecast models keep the midweek system to our south.

Made mention of potential significant coastal storm late in the weekend.

KEY MESSAGES

1) Light snow is possible across the North from late tonight into Tuesday evening. This may result in some minor travel difficulties over the North.

2) There is a small chance for some snow across southern parts of our area Wednesday night. This could impact travel over southern areas Thursday morning.

3) There is also a small chance for some light snow Friday night into Saturday, which could reduce visibilities across the region.

4) Snow is possible from Sunday night into Monday, possibly impacting the commute next Monday.

DISCUSSION

KEY MESSAGE 1...Light snow is possible across the North from late tonight into Tuesday evening. This may result in some minor travel difficulties over the North.

KEY MESSAGE 1 DESCRIPTION... Northern stream shortwave ridging exits to the east this evening allowing for diffluent flow to set up aloft overnight. This coupled with some weak low level warm advection allows for some light snow to possibly work into the NW 1/3 of the CWA overnight, as a weak surface warm front approaches from the SW.

The region remains under diffluent flow aloft on Tuesday, with a couple of shortwaves passing across mainly Northern Maine embedded in the flow. This should allow for snow to overspread most of the North, mainly north of a Greenville to Houlton line. There is a slight chance of light snow to the south of that line down into the Bangor Region and far northern Downeast Maine.

The snow could linger into Tuesday evening across the North as the main axis of an upper level low swings through and into New Brunswick, before a passing cold front brings an end to the snow from west to east towards midnight.

For now expect snow fall of generally of less than 1/2 an inch with this system, except for around 1" possible across the higher terrain in the North Woods and Saint Johns Valley region.

Upped pops Late Monday night-Tuesday by blending in NAMNest and ConsShort pops with the NBM.

There should be minimal wind with this system, so no expectation of any blowing snow.

KEY MESSAGE 2... Low pressure sliding across Southern New England will bring a chance for some snow across southern parts of our area Wednesday night. This could impact travel over southern areas Thursday morning.

KEY MESSAGE 2 DESCRIPTION... A shallow wave of low pressure sliding under a blocking high in Central Canada will weaken as it approaches Southern New England on Wednesday. From there, the low will be suppressed to our south by the combination of surface high pressure and an upper trough to our north. Forecast models differ considerably on this lows potential to bring us some snow with the ECMWF maintaining a stronger and more rounded low nudging some snow into our area Wednesday night, while the NAM and GFS crush the low to our south keeping our region dry. The NAM, however, is closer with this low indicating that snow may come as far north as the southern tip of Maine, though still south of us. Given the uncertainty, will keep low chance pops for southern parts of our region Wednesday night.

KEY MESSAGE 3... A weak occluded front lifting northeast from low pressure over the Great Lakes will bring a slight chance for some light snow Friday night into Saturday.

KEY MESSAGE 3 DESCRIPTION... As we approach the end of the week, blocking high pressure over East Central Canada will continue to make it difficult for weather systems to reach us with forecast models continuing to struggle with their solutions of when/if a weather system may reach us under this block. A new low will approach from the Great Lakes on Friday supported by a weak upper trough. Both the GFS and ECMWF are indicating that the block will hold this system to the south keeping our region dry so will only carry slight chance pops.

KEY MESSAGE 4... Low pressure developing off the Mid-Atlantic coast late in the weekend may bring snow Sunday night into Monday.

KEY MESSAGE 4 DESCRIPTION... Long range forecast guidance is indicating that a significant low pressure system may develop off the Mid-Atlantic coast late in the weekend supported by a trough digging into the Midwest. From there, the low will track east off the Mid-Atlantic coast. Many major storm systems have been missing us to the south and passing us out to sea during the last few weeks. However, it is climatological that systems will begin tracking back further north as we go into late winter. Both the GFS and ECMWF have a strong storm off the coast Sunday night into Monday with the GFS now tracking it close enough to bring significant snow and wind to our area Sunday night into next Monday. However, the ECMWF is keeping the low south of our area. This is still a week out, but given its potential and the fact that both major long range models are showing a strong system, we are mentioning it now as something that bears watching.

AVIATION /06Z MONDAY THROUGH FRIDAY/

LIFR/VLIFR at KFVE with FZFG, conditions should improve to IFR/LIFR towards sunrise and to MVFR there towards midday. Elsewhere at northern terminals this morning, LIFR ceilings should develop towards sunrise with conditions improving to MVFR towards midday. Conditions improve to VFR at all northern terminals this afternoon. High confidence in VFR conditions at southern terminals through the TAF period.

Light and variable winds could become SE at less than 10kt at some terminals for a period this afternoon, otherwise the winds should remain mainly light and variable through the TAF period.

Late tonight and Tuesday...MVFR or lower probable at all northern terminals in light snow, except for KHUL where there is only a low chance of MVFR or lower. Southern terminals should remain VFR during this time frame. S winds G15kt possible Tuesday morning.

Tuesday night...MVFR to occasionally IFR north. MVFR to VFR south. SW wind less than 5 kt.

Wednesday...VFR except possibly occasionally MVFR over the far north. NW wind 5 to 10 kt.

Wednesday night-Friday...VFR. NW wind 10 kt or less.

MARINE

A relaxed pressure gradient over the waters through Tuesday will limit winds to 10 kt or less and seas to 2 ft or less.

North winds may reach SCA across the offshore waters Wednesday night into Thursday. NE winds may again reach SCA Friday night into early Sunday. Seas will reach 4 to 5 ft, mainly in S swell from an offshore storm, Tuesday night into Wednesday. Otherwise seas should remain below SCA this week into next weekend.

CAR WATCHES/WARNINGS/ADVISORIES

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