textproduct: Caribou

SYNOPSIS

High pressure over Quebec will build south across the region tonight through Sunday. Low pressure crosses the region Monday then lifts north of the region Monday night into Tuesday, remaining north of the region Wednesday through Friday.

NEAR TERM /THROUGH SUNDAY NIGHT/

1) Cold Tonight, Warmer Sunday as Storm approaches Sun Night

Discussion... Changes with this update: -Lowered temperatures overnight several degrees -Lowered winds and gusts a few to several knots in response to decoupling

Surface high pressure across southern Quebec will drift south over Vermont tonight and remain in control of our weather. The air mass is modifying but with clear skies and snowpack temperatures are expected to fall quickly. In fact, Bangor and Estcourt Station have already fallen below zero, along with a few other sites. Lowered temperatures and winds to be consistent with more decoupling. The lowest low temperatures should be across the western half of the area where the pressure gradient will be weakest.

For the day on Sunday, the surface high will drift south of New England off the Mid Atlantic coast with ridging extending north into southern Quebec. This will set up a light NW breeze at 10-15mph across the area but the airmass spilling over the ridge is warmer. High temperatures tomorrow across the north will range 20-27F with Bangor region reaching 30F and much of the Downeast 28-31F and 30-35F on the islands.

Sunday night temperatures will cool back into the single digits north and teens for most other areas except 20-25F along the shoreline. Calm winds will slowly develop from the E-SE overnight. Mid level warm air advection develops late and expecting temperatures to become anti-diurnal after midnight and slowly warm through the early morning hours. Precipitation will hold off until daybreak and talked about more below...

SHORT TERM /MONDAY THROUGH TUESDAY/

Have issued a Winter Storm Watch for northern/central portions of the forecast area Monday through Monday night. Though individual precipitation types could remain below warning criteria, the combined impacts of snow/sleet/freezing rain could still be significant. Low pressure will track from the Great Lakes toward southwest Quebec province Monday drawing a warm front north across New England, with a triple-point low then starting to develop across western Maine late. Precipitation will expand across the entire forecast area Monday. Across central and Downeast portions of the forecast area, with low level cold air damming and warming temperatures aloft expect an early wintry mix. Warmer air will eventually be drawn northward at low levels helping erode the cold air and allowing a transition to rain across Downeast and possibly east-central areas. Winter Weather Advisories will likely eventually be needed across Downeast areas early Monday due to the wintry mix before the transition to rain. Across northern portions of the forecast area, more uncertainty exists regarding the amount of warming aloft. Precipitation across northern areas should start in the form of snow, then transition to a wintry mix of snow/sleet/freezing rain. How rapidly this transition occurs will be dependent on how rapidly temperatures aloft warm. The triple-point low will lift across the forecast area Monday night, though the track is still uncertain, eventually merging with the remnants of the primary low north of Maine. Track solutions across the forecast area still range from Downeast areas up to northeast Aroostook county. A more southerly track could help limit the extent of warming across northern areas, allowing a greater portion of the precipitation to fall in the form of snow. A more northerly track solution would allow more significant warming across northern areas with a greater portion of the precipitation falling in the form of sleet/freezing rain. A more northerly track would also allow more low level warming and a subsequent northern expansion of where the transition to all rain occurs. Colder air will eventually be drawn across the entire region later Monday night in the wake of the system allowing a transition back to snow. The better snow chances later Monday night will occur across northern areas, with more persistent wrap-around precipitation. Precipitation types and snow amounts with this storm are still uncertain dependent on how the event eventually evolves. The system vertically stacks while the upper low crosses the region Tuesday, lifting to the north Tuesday night. A series of disturbances rotating around this system will cross the region Tuesday through Tuesday night. Expect mostly cloudy skies with snow showers across northern areas Tuesday, with partly sunny/mostly cloudy skies Downeast with a slight chance of snow showers. Skies will remain mostly cloudy with still a slight chance of snow showers across northern areas Tuesday night, with partly cloudy skies Downeast. Temperatures should warm through Monday. High temperatures later Monday should range from the mid to upper 20s north, to the mid to upper 30s interior Downeast with upper 30s to around 40 along the Downeast coast. Temperatures should remain near steady early Monday night then begin to fall late. Low temperatures later Monday night should range from the mid teens to around 20 north, to the lower to mid 20s interior Downeast with mid to upper 20s along the Downeast coast. Near normal, to slightly below normal, level temperatures are expected Tuesday.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

The upper system remains in the vicinity of northern Quebec province Wednesday into Friday with a series of difficult to time disturbances rotating around the system. These disturbances could help support the development of occasional surface lows, though uncertainty with the track/intensity of any surface features still exists. Generally expect partly/mostly cloudy skies across the region Wednesday into Friday with snow shower chances. Any more organized surface features could also help support intervals of steadier snow. High pressure should then build toward the region later Saturday. Temperatures will remain at below normal levels Wednesday through Saturday.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

NEAR TERM: Tonight...VFR. NW winds less than 10 kt. LLWS likely at all terminals through 14z Sunday.

Sunday...VFR. LLWS ends around 14z as surface winds increase. NW winds 5-10kt with gusts to 20 kt at northern terminals.

Sunday Night...VFR north. VFR southern terms turning MVFR due to cigs by 10z. Winds light and variable turning E-SE by 10z.

SHORT TERM:

Monday...VFR/MVFR early, lowering to IFR/LIFR through the afternoon. Snow transitioning to a wintry mix north, with a wintry mix transitioning to rain Downeast. Variable winds 5 to 10 knots, becoming east/southeast 10 to 15 knots with gusts up to around 20 knots.

Monday night...IFR/LIFR. Snow, or a wintry mix transitioning to snow, north. Rain transitioning to snow Downeast. East/southeast winds 10 to 15 knots with gusts up to around 20 knots, becoming west/southwest.

Tuesday...MVFR/IFR north with a chance of snow showers. VFR/MVFR Downeast with a slight chance of snow showers. West/southwest winds 10 to 15 knots with gusts up to 20 to 25 knots.

Tuesday night through Wednesday...VFR/MVFR with a slight chance of snow showers north. VFR Downeast. Southwest winds 10 to 15 knots with gusts up to 20 to 25 knots.

Wednesday night through Thursday...VFR/MVFR, occasional IFR. A chance of light snow or snow showers. South/southwest winds 5 to 10 knots, becoming west/southwest Wednesday night. West/southwest winds 5 to 10 knots, becoming variable Thursday.

MARINE

NEAR TERM: Winds/seas below SCA for the intra-coastal waters through Sunday night. On the coastal waters out 25nm we have a Small Craft Advisory in effect until 2PM EST Sunday. NW winds 15-20kt with gusts up to 30kt. Light freezing spray likely across all the waters through Sunday midday with light ice accretion possible. N winds tonight shift NW tomorrow. Winds fall below SCA tomorrow by sunset. Winds will shift S after midnight Sunday night. Sea surface water temperatures from the Downeast Coast out 25nm range 42-45F including Penobscot and Passamaquoddy Bays.

SHORT TERM: Small craft advisory conditions Monday. Gale conditions Monday night into Wednesday. Rain Monday through early Monday night, chance of a wintry mix late. A slight chance of snow showers Tuesday. Light freezing spray Tuesday night into Wednesday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Winter Storm Watch from Monday morning through late Monday night for MEZ001-002. Winter Storm Watch from Monday morning through late Monday night for MEZ003>006-010-011-031-032. MARINE...Small Craft Advisory until 2 PM EST Sunday for ANZ050-051.