textproduct: Caribou

SYNOPSIS

A coastal low crosses the Gulf of Maine tonight, 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 into Sunday.

NEAR TERM /THROUGH WEDNESDAY NIGHT/

5:11PM UPDATE...Have changed the Winter Storm Warning to a Winter Weather Advisory for Coastal Hancock and Coastal Washington counties. Latest observations have showed the coastal front pushed into Route 1 between West Ellsworth all the way to Eastport with temperatures 32-36F and 35-40F right at the shoreline. Precipitation has changed to rain in these locations but cold air damming remains in place on the northern end of Penobscot Bay where its 30F in Castine and 27F in Searsport. Given that >50 percent of both zones are now in rain but expecting temperatures to crash later with additional 1-2 inches of snow opted to go with an advisory. These areas will turn back very slick later tonight as temperatures fall, a burst of snow falls and being its nighttime. Expecting slick travel overnight to return in coastal Downeast. The Winter Weather Advisory will match the Winter Storm Warning ending time of 7AM EST.

Lastly dry air is working in fast across the North Woods, St. John Valley and Moosehead Region with precipitation tapering off rapidly. Have adjusted POPs to follow this trend. Lastly, increasing confidence in a burst of snowfall this evening through Midnight as Hi-Res CAMs are showing rapidly increasing FGEN forcing across the Bangor Region into Interior Downeast. Cannot rule out brief 1-3hrs of 1 inch per hour snowfall rates making for tricky travel tonight. Winter Storm Warning remains in effect and Winter Weather Advisory north of that area.

Across far Northern Maine have extended an SPS through 7PM EST to urge caution tonight in Aroostook County where roads are cold and slick with less than 4 inches of snow fell today.

Previous Discussion...

Key Messages -Winter Storm Conditions Continue Tonight, Highest Totals Inland -Snow mixes with Rain on the Downeast Coast, Refreeze Tonight

Discussion... Low pressure is deepening off the Mid Atlantic coast this afternoon with a slug of light precipitation across the CWA. Light snow is falling in most locations with light accumulations already underway making for slick travel. Numerous reports of traffic accidents across the southern 1/2 of the CWA. Will continue the Winter Storm Warning and Winter Weather Advisories as is and an SPS is out through 4PM EST for Northern and Northeast Aroostook County. Latest surface observations show the coastal front slowly working into the Downeast coast with temperatures above freezing on the islands, MDI, Blue Hill area and in Cutler to Eastport. At the same time Jonesport is still 27F, Cherryfield 29F and East Surry 31F. This coastal front will slowly sneak inland to Route 1 and extend close to the Route 9 corridor but expected to remain mainly southeast of Route 9. This will keep much of the Downeast and Bangor Region in the snow with snow being wet and sticky. Rain at the shoreline will improve the driving conditions but expect a lot of slush.

Heaviest precipitation is expected this evening across the southern 1/3rd to 1/2 of the CWA as surface low deepens in the Gulf of Maine as the 500mb trof digs overhead. N-NE winds will increase tonight in response to the increasing pressure gradient. Any locations that experience wet and heavy snow expect potential for isolated power outages with weighted down pine tree limbs. Most inland locations from Bangor northward the SLRs are 10-15:1 or more so fluffy snow will blow and drift in any open areas once winds become gusty above 25mph. Most far northern areas will remain below 20mph so not expecting a lot of blowing snow. Temperatures tonight will cool back below freezing at the shoreline making for slippery conditions once again with refreezing. Inland expecting lows in the teens to low 20s.

Tomorrow the low pressure will depart into the Maritimes and surface ridging builds overhead. NW winds will relax and generally drop below 10mph across the area. Partly to mostly sunny skies will be a good day for cleanup. Highs in the mid to upper 20s north and low 30s for the Highlands and mid 30s for the Downeast coast.

SHORT TERM /THURSDAY THROUGH FRIDAY/

Key Messages -Potential snow squalls on Thursday, reducing visibility -Low temperatures Thursday Night, potentially near ten to twenty below zero

Discussion... Arctic front swings through Maine on Thursday, moving from west to east during the daytime hours. With decent moisture and favorable signals on Theta E, CAPE, potential vorticity, and SNSQ parameter, there is a good chance for some snow squalls to develop as the clouds break up a bit in the afternoon. Mid-level jet associated with the aforementioned low pressure system trough brings high winds aloft, which could mix down to the surface, resulting in gusty winds. If winds are not mixed down though, breezy conditions are still expected, which can reduce visibility and cause dangerous travel conditions. Daytime highs in the low thirties. Heavy burst of snow could result in upwards of an inch in accumulation in some locations.

Thursday night, low pressure to the north moves east, as ridging builds in from the west. Anomalously low mid-level temperatures move in behind this front, with even 850mb temperatures reaching below 10 degrees. Overnight lows just below freezing, with gusty winds from mid-level jet causes sub- advisory level wind chills, around ten to twenty degrees below zero. These winds may also blow around recent snowfall, reducing visibility in flat areas.

Ridging on Friday. Clearing skies, dry conditions and highs in the teens.

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/

Key Messages -High pressure through weekend -Shortwave moves through early next week possibly

Discussion... High pressure Friday night through Saturday. Shortwave moves through Saturday into Sunday, bringing as decent chance for some snowfall in northern and central Maine. High pressure builds in again on Monday. Highs in the twenties over the weekend, and teens early next week. Overnight lows generally in the single digits to teens.

AVIATION /22Z TUESDAY THROUGH SUNDAY/

NEAR TERM: Northern Terms...MVFR cigs with IFR/LIFR vsby this evening becoming MVFR cigs and VFR vsby. -SN ends this evening with VCSH for a few hours. Winds light and variable becoming N-NW 5-10kt. Tomorrow MVFR cigs becoming SCT-BKN low end VFR. NW winds 10-15kt.

Southern Terms...MVFR/IFR cigs and IFR/LIFR vsby with -SN. -SN is going to mix with RA at BHB and shift to RA/RASN with improving vsby. Winds N 5-10kt shifting SE 5-10kt at BHB this evening. Winds turn NW tonight 5-15kt with gusts up to 25kt. Any -SN this evening ends with just VCSH for a few hours. VFR tomorrow with NW winds 10-15kt and gusts up to 25kt.

SHORT TERM:

Thursday...VFR/MVFR cigs. Brief IFR/LIFR vis in afternoon snow showers, particularly across northern terminals. SW winds shifting W 10 to 15 kts with gusts increasing to 20 to 25 kts. Isolated gusts to 30 kts in any heavier snow showers.

Thursday night...VFR south, MVFR cigs north. WNW winds 10 to 15 kts with gusts 20 to 25 kts.

Friday - Friday night...VFR. WSW winds 5 to 10 kts with gusts to 20 kts.

Saturday - Saturday night...VFR/MVFR cigs, low end chance of IFR. Slight chance of SN S winds 5 to 10 kts. Slight chance of SN at eastern terminals Friday night.

Sunday...VFR/MVFR. Winds from the W, 5-10 kts.

MARINE

NEAR TERM: Winds will rapidly increase this evening and shift from the SE to N across the waters. Gale Warning remains in effect from 10PM this evening till 10AM Wednesday for the Coastal Waters out 25nm. Small Craft Advisory for the Intra- Coastal Waters from 10PM this evening till 10AM Wednesday. For the Gale Warning expect N winds 20-30kt and gusts up to 40kt with seas 3-6ft. For the SCA expect N winds 10-20kt with gusts up to 30kt and seas 2-4ft. Moderate to heavy rain at times this evening into early Wednesday AM will reduce vsby below 2nm at times. Tomorrow afternoon N winds will fall below SCA criteria with seas across the outer waters remaining in the 4-6ft range potentially requiring an SCA. Wednesday night a brief break in the winds before winds shift SW and increase to SCA levels again. Sea surface water temperatures range 46-48F across the Coastal Waters from the Downeast coast out 25nm including Penobscot and Passamaquoddy Bays.

SHORT TERM: Small Craft winds and seas expected Thursday, building up to Gale force conditions Thursday night into Friday. Outer-waters see waves up to 10ft on Friday, and up to 6ft over the inter-coastal waters. Rain on Thursday, that transitions over to snow by nighttime. Winds from the WSW Thursday, shifting to the NW by Friday. Gale conditions begin to relax early Friday morning.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Winter Weather Advisory until 4 AM EST Wednesday for MEZ004>006-010-011-031-032. Winter Storm Warning until 7 AM EST Wednesday for MEZ015>017. Winter Weather Advisory until 7 AM EST Wednesday for MEZ029- 030. MARINE...Gale Warning from 10 PM this evening to 10 AM EST Wednesday for ANZ050-051. Small Craft Advisory from 10 PM this evening to 10 AM EST Wednesday for ANZ052.