textproduct: Caribou

SYNOPSIS

Low pressure moves from west central Quebec this morning to east central Quebec by Friday morning, then into the northern Canadian Maritimes Friday and Friday night. High pressure builds in Saturday and Saturday night, then exits to the east on Sunday,as low pressure approaches from the west. A warm front, then a cold front crosses the area Sunday night. High pressure moves in from the west on Monday.

NEAR TERM /THROUGH FRIDAY/

630 am update... Quick update to mention snow earlier than expected this morning. Already snowing at higher elevations with reflectivity showing showers transitioning over to snow showers across the north. Only minor updates to hrly temps and dwpts.

Prev discussion blo... Triple point located near MDI as of 06z and will track off to the east overnight. Elevated instability has been enough to produce thunder over the Upper Penobscot Region, heading toward the Houlton area but not expecting much more in the way of thunder early this morning. Sfc low along the Ontario/Quebec border has brought occlusion into wrn Maine tonight. Convective showers and thunder likely being forced by the H8 warm front as it lifts northeast thru central CWA as of 06z, in combination with lift associated with H3 jet streak punching into srn New England.

Occlusion and lift will move northeast late tonight with precipitation ending over southwest zones by 12z and northeast zones by 16z. Cold air works into the area between 09-12z this morning with rain showers quickly changing over to snow showers across the north before ending. Any accumulations look to be minor.

Surface temperatures will remain nearly steady this morning or rise another degree or two and with cold temperatures aloft, winds should be able to mix down with mixing depth up toward H8 today. West winds should gust up to 25 mph this afternoon before sunset this afternoon.

With main lift along the front moving into Canada remainder of the daytime hours should see partly cloudy skies today. H5 low remains "stuck" to our northwest leading to dry slot throughout the area. This low will be waiting for a kicker, which appears to be dropping into upr Saskatchewan from the NW Territories late tonight. This will give upr low the nudge it needs to head into the state Friday afternoon. As it does so, it will likely bring snow showers to the region along with very steep lapse rates. Low and mid-level lapse rates are favorable for snow squalls as are CAPE values, which are between 40-100 J/kg. The only element missing are the winds. Pre- frontal trough looks to be present between 18-21z but is not sharp enough to result in snow squalls. Overall thinking is that locally heavy bursts of snow will produce a quick 1-1.5 inches of snow in a short amount of time. Given that road surfaces will likely be below freezing on Friday, especially on bridges, holiday travel may see significant impacts.

SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/

A northern stream closed low exits to the northeast Friday night. Could see some lingering snow showers across the North during the evening, and possibly through most of the night along the western border with Quebec. Elsewhere it should be dry. Lows Friday night should be near to slightly above normal.

A northern stream shortwave crosses the area Saturday morning, followed by northern stream shortwave ridging passing Saturday afternoon. Could see some snow showers along the western border with Quebec in the morning, otherwise it should be dry, with decreasing cloud cover, especially in the afternoon. Highs on Saturday should be around 5 degrees below normal. It should be breezy on Saturday, with widespread wind gusts of 30-35 mph.

Deep layered ridging crests over the area Saturday night, with increasing mid to high level cloud cover as moisture is advected in ahead of the next system. Lows Saturday night should be a few degrees below normal.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

The axis of a deep layered ridge should exit to the east by early Sunday afternoon, allowing for over running precipitation to bloom from W to E mid-late afternoon. This should be mainly in the form of snow along and north of a Greenville to Houlton line, with a mix of rain of snow possible from south of there to roughly a Dexter to Princeton line with mainly rain south of there.

Strong low level warm advection Sunday evening with a 50-60KT low level jet will allow for moderate to locally heavy precipitation at times. In the evening it should be all snow north of a Dover-Foxcroft to Mt Katahdin to Houlton line, with mainly rain to the south. During the overnight hours, there could be enough warming in the low-mid levels across far eastern Aroostook up to around Caribou to change the precipitation to all rain there.

Based on the above, there is the potential for several inches of snow to accumulate north of a Greenville-Milinocket-Haynesville line, with lessor accumulations down to around a Dover-Foxcroft to Danforth line, and little or no accumulations further south.

There is still some uncertainty on the timing of this system (including onset/offset time) and how far north the rain/snow line gets. So expect the ideas for how much snow and where any impacts could be to change with future forecasts.

In addition to the snow and rain, there could be some strong gusty winds Sunday night over mainly Downeast Maine with the low level jet. There is some potential that at least coastal Downeast Maine could end up needing a wind advisory during this time frame.

A northern stream shortwave exits to the east on Monday. Depending on how fast it exits, will determine how much, if any precipitation Eastern Maine will see in the morning. This should be mainly in the form of rain.

The region is under SW flow aloft Monday night, and with no shortwaves progged to be embedded in the flow it should be dry.

A northern stream shortwave approaches Tuesday then exits to the east from Tuesday night into Wednesday. The models have trended a bit farther north with this system, so get pops to chance area wide by Tuesday night. Could see some lingering precipitation into Wednesday morning depending on how fast the system exits. It should be sufficiently cold that it should be mainly snow, except for possibly a snow/rain mix across coastal Downeast.

Temperatures should be near normal Sunday through Monday, then below normal Monday night-Wednesday. Lows Monday night will be the coldest of the season to date, with lows in the single digits probable across most of the North, with mainly 10s elsewhere.

AVIATION /12Z THURSDAY THROUGH MONDAY/

NEAR TERM: BGR seeing VFR conditions with BHB likely to improve to VFR by 13z. Aroostook terminals will see gradually improving conditions this morning as snow showers head out of the area. West winds from 5-15kts with gusts to 20-25kts this afternoon before diminishing with sunset.

For Friday, MVFR/IFR in snow showers, especially at northern terminals. SSW 5-15kts.

SHORT TERM: Friday night-Saturday night...VFR, except for a low chance for periods of MVFR at KFVE. SW-WSW winds G15-20KT possible Friday night W-WNW winds G15-25KT possible Saturday and Saturday evening.

Sunday...MVFR or lower possible. SE winds G20-40KT possible, strongest at KBHB. LLWS likely Sunday afternoon.

Sunday Night...IFR or lower likely. LLWS likely in the evening, WSW winds G20-30KT possible overnight.

Monday...Becoming VFR throughout. W-NW winds G20-30KT possible.

MARINE

NEAR TERM: Small craft continues for all waters today into Friday morning with winds aoa 25kts and seas from 4 to 8ft. Winds increase toward gale force over the outer waters late Friday afternoon as seas remain elevated.

SHORT TERM: Gales probable on the coastal ocean waters Friday night, so have continued the Gale Watch. SCA conditions expected Friday night on the intra-coastal waters so have extended the SCA through then there. Gales possible Saturday on the coastal ocean waters, with SCA conditions likely on the intra-coastal waters. At this time, do not have the confidence to extend the Gale Watch through the day on Saturday over the coastal ocean waters. Saturday night should see SCA conditions throughout in the evening, falling below SCA levels by around midnight. SCA to possibly gale conditions develop on the coastal ocean waters late Sunday and continue into Monday, with SCA conditions likely on the intra-coastal waters.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory until 4 PM EST Friday for ANZ050-051. Gale Watch from Friday afternoon through Saturday morning for ANZ050-051. Small Craft Advisory until 6 AM EST Saturday for ANZ052.