textproduct: Caribou

SYNOPSIS

High pressure builds in tonight and quickly pushes east on Tuesday morning. A coastal low approaches from the southwest Tuesday afternoon, passes offshore Tuesday night, then exits into the southern Canadian Maritimes on Wednesday. An Arctic cold front crosses the region on Thursday with high pressure building in for Friday. Another cold front approaches from the northwest on Saturday.

NEAR TERM /THROUGH TUESDAY NIGHT/

7:09PM UPDATE...Have made Marine Headline changes and updated the aviation forecast for tonight.

Previous Discussion... Key Messages -Noreaster Tuesday and Tuesday night will bring heavy snowfall to Downeast and Bangor

Gusty northwest winds will continue this evening. 1030mb sfc high over NY State will build east toward the region this evening with winds decreasing. Partly cloudy skies are expected tonight before mid-high clouds move in fm the west. Min temps drop into the single digits across the north.

Surface low developing over the northern Gulf as seen on vis imagery as of 19z. S/wv will help deepen low over the southeastern U.S. tonight. By mid-late morning on Tuesday sfc low will eject off of the mid-Atlantic coast and head northeast twd the Gulf of Maine. Snow should move into the CWA around 14z Tuesday. The coastal front will set up late morning/early afternoon leading to mixing with and/or changing to rain along the coast and over the outer islands. Surface temps will rise into the mid-upr 30s in the afternoon along the coast. Inland locations will remain below freezing during the day.

As the coastal low heads northeast toward the Gulf of Maine precipitation overspreads all but far nwrn areas as dry ridge axis remains close to the international border. As precip gets heavier along the coast, evaporational cooling will likely result in snow Tuesday night. The highest snowfall rates will likely be around midnight. SLRs look to be fairly low over Downeast but will likely increase toward morning. This may result in isolated power outages initially but as the pressure gradient tightens, winds increase with gusts upwards of 25-30 mph. Cannot rule out blowing and/or drifting snow late Tuesday night over southern areas.

SHORT TERM /WEDNESDAY THROUGH THURSDAY/

Key Messages -Cool and Dry Clean Up Day Wednesday -Thursday Arctic Cold Front with Snow Squalls

For Wednesday, brief and weak surface ridging should clear out skies and decrease winds. Temps should be in the 20s for northern areas and low 30s south for a good clean up day after the snowstorm. For Wednesday night, a cold front will approach the region from Quebec, increasing clouds and shifting winds from the south. Temps should be in the teens for much of the region with low 20s from Bangor to the shoreline.

For Thursday an arctic cold front will push through the state. Much of the operational and ensemble guidance have a decent handle on timing. Looking at 9-11am timeframe across the NW zones and a Noon-4pm timeframe for SE zones. The concern with this system is the increasing instability along the front. Latest trend in model soundings show enough SBCAPE and elevated CAPE, lapse rates, and negative Theta E to justify snow squalls developing in the afternoon. The question will be if strong enough winds will mix down throughout the day. All the ingredients are there showing modeled BTV snow squall parameters of 2-4 across the region. The winds will determine if short fused SPSs or SQWs will be needed. Temperatures prior to FROPA will be up into the low 30s north and mid to upper 30s south. Messaging will be for potential slick travel and quick visibility drops with snow showers and squalls.

LONG TERM /THURSDAY NIGHT THROUGH MONDAY/

Key Messages -Very Cold Temps Thurs night with wind chills -20F to -15F -Sunny and Cold Friday

Thursday night high pressure will slide south of Maine as low pressure deepens in the Maritimes. Pressure gradient will tighten and then the NW cold air advection will push a large area of -19C to -21C 925mb temps into the area. Surface air temperatures will crash to mainly below zero across the north in the -5F to 0F range. This will be the coldest night so far this season. Temperatures around 0F for the Central Highlands to Bangor Region eastward to Calais area. Generally 5-9F along the Downeast coast and 10-15F on the islands. NW winds will be gusting 15-25mph and some gusts up to 35mph across the higher terrain. This will result in wind chills dropping to around -20F across the North with some places potentially reaching Cold Weather Advisory levels.

Friday will be sunny and cold. -20C to -18C 925mb temps combined with snowpack across much of the CWA will result in cold surface high temps. Highs topping out in the upper single digits to teens across the north, upper teens in the Central Highlands and 20-25F for the Bangor region to Downeast coast. Wind chills across Northern areas will be at zero or slightly below zero but winds will gradually weaken during the day as the pressure gradient weakens.

Beyond for the weekend into Monday the models lose any consistency with another storm possible this weekend. Expect seasonably cool temperatures but warmer than Friday will be.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

NEAR TERM: 00z TAF UPDATE...FEW MVFR cigs possible at northern terms tonight. Otherwise TAFs remain consistent with 18z issuance.

Previous Discussion... VFR this evening, though northern terminals may see brief MVFR cigs or -shsn for the first hour or two of the TAF period. MVFR looks to move in 14z Tuesday with light snow. Conditions then deteriorate to IFR/LIFR Tuesday night. North winds will gust to 20-25kts late Tuesday night, leading to blowing snow.

SHORT TERM: Wednesday...VFR south, MVFR cigs possible north. NW Winds 5-10kt becoming light and variable late day.

Thursday...VFR/MVFR cigs. Brief IFR/LIFR vsby possible due to SNSH in the midday to afternoon hours. SW winds 5-15kt shifting W late afternoon and increasing winds.

Thursday night...VFR south, MVFR cigs north. VCSH/-SHSN for northern terms. W-NW winds 10-15kt with gusts 20-25kt possible.

Friday...VFR. W-NW winds 10-15kt gusting 20-30kt early becoming W-WSW 5-15kt in the afternoon.

Saturday...VFR/MVFR cigs, low end chance of IFR. Chance of snow. S winds 5-10kt.

MARINE

NEAR TERM: UPDATE...Small Craft Advisory in effect through 10PM this evening. A Gale Watch is in effect from Tuesday Evening through Wednesday Morning. No other changes.

Previous Discussion... Gales will continue for the next hour or two before diminishing to small craft levels over the waters this evening. Wind and seas remain below sca levels on Tuesday before approaching gales once again late Tuesday night.

SHORT TERM: Wednesday winds will fall below SCA criteria by midday but waves will remain 5-7ft into the evening hours. W-SW winds will increase to SCA conditions overnight into Thursday AM. Winds will shift W Thursday afternoon and Gales are expected again. Winds will shift NW Thursday night and potentially gusting 45-46kt over the outer portions of the coastal waters. Low end probability of storm conditions, will need to monitor trends. Winds/seas will fall below SCA criteria Friday night. Will need to monitor another storm system nearing the waters this weekend but confidence is too low at this time.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Winter Weather Advisory from noon Tuesday to 4 AM EST Wednesday for MEZ004>006-010-011-031-032. Winter Storm Warning from 11 AM Tuesday to 7 AM EST Wednesday for MEZ015>017-029-030. MARINE...Small Craft Advisory until 10 PM EST this evening for ANZ050>052. Gale Watch from Tuesday evening through Wednesday morning for ANZ050-051.