textproduct: Caribou

WHAT HAS CHANGED

* 5:40AM UPDATE...Update for Marine Weather Headlines. Gale Watch upgraded to a Gale Warning for Coastal Waters and Small Craft Advisory for the Intra-Coastal Waters. See details below...

* 4:15AM UPDATE...Dense Fog Advisory issued for all of the Downeast, Bangor Region, Central Highlands, Upper Penobscot Valley, Baxter SP Region and Eastern Aroostook County till 8AM EST. Numerous areas of Dense Fog developing thanks to the warmer moist air from the rainfall all occurring over the snowpack. Winds remain light to calm which is allowing for areas of dense fog and visibilities less 1/4 mile.

* SPS issued for Northern Maine, Upper Penobscot Valley, Northern Washington County and the Central Highlands including the Moosehead Lake Region till 8AM EST. Areas of black ice this morning will be causing slippery travel conditions on any untreated surfaces.

KEY MESSAGES

1) Rain with fog today (Wintry mix in North Woods and Allagash Region) will result in reduced visibilities at times. Cold surfaces despite the warm temperatures will allow for black ice making travel potentially difficult.

2) Flash freeze likely tonight into Friday morning from NW to SE, with possibly 1-3 inches of snow on top of that across the North. A rapid fall off of temperatures will cause rapid freeze of slush and wet surfaces into ice. This will make for difficult travel for any untreated surfaces, especially those covered by any snowfall across the North.

3) Low potential for a winter storm Sunday night into Monday, but continued significant uncertainty regarding storm track and evolution.

DISCUSSION

KEY MESSAGE 1... Rain with fog today (Wintry mix in North Woods and Allagash Region) will result in reduced visibilities at times. Cold surfaces despite the warm temperatures will allow for black ice making travel potentially difficult.

KEY MESSAGE 1 DESCRIPTION... A mid level warm front is lifting north this morning with temperatures above freezing in most locations above 32F. Except 31-32F currently exists in Oxbow to Ripogenus Dam to Pittston Farm and points northward to include Nine Mile, Allagash and Estcourt Station. It is out here in the North Woods and western St. John Valley where rain and snow will mix and potential exists for a period of wet snow this morning with accumulations. This is mostly existing in areas with dirt/gravel roads and very little paved roads except in the St. John Valley between Fort Kent and Allagash where conditions may become slick this morning. Elsewhere light rain is falling across much of the Central Highlands to Eastern Aroostook County including the Baxter Region. Although air temperatures are above freezing the ground is frozen 8-16 inches deep in much of the Northern 2/3rd of the CWA. Latest observations from MaineDOT RWIS show road temperatures 32-33F which is allowing for black ice to develop given the light precipitation rates. Have issued an SPS that covers all of Northern Maine, Moosehead Region, Upper Penobscot Valley, Central Highlands and Northern Washington County. Expecting to update this for the AM commute where patchy to areas of black ice may continue to be a problem this morning.

Today the surface low will track NE along the Maine/Quebec border as the 500mb shortwave approaches from the west. Expecting precipitation to taper this afternoon from SW to NE across the area as dry air aloft works into the region. However, rain and fog beforehand expected to create some reduced visibilities for several hours this morning. Much of the snowpack will absorb the rainfall with very little run off. Across the North Woods where snow will be falling expecting 2-4 inches of wet snow with isolated amounts to 5 inches possible.

KEY MESSAGE 2... Flash freeze likely tonight into Friday morning from NW to SE, with possibly 1-3 inches of snow on top of that across the North. A rapid fall off of temperatures will cause rapid freeze of slush and wet surfaces into ice. This will make for difficult travel for any untreated surfaces, especially those covered by any snowfall across the North.

KEY MESSAGE 2 DESCRIPTION... As surface low pressure tracks into Northern Maine this evening expecting a surface cold front to be dragged across the state. Temperatures will rapidly fall with FROPA at rates of 2-3 degrees per hour possible. The concern tonight is with very light winds very little drying will occur and a lot of surfaces will have had the salt residue wash away. The potential for a flash freeze is high and untreated surfaces, given the frozen grounds, will rapidly freeze and form black ice. Timeframe for flash freeze is 5-7PM across far Northern Maine in the St. John Valley, 8-11PM for Moosehead Region to Baxter Region to Eastern Aroostook County, 11PM-2AM for I-95 corridor to Interior Downeast Maine and then 1AM-4AM for Coastal Downeast Maine. Temperatures will fall back into the mid to upper teens north by daybreak and 20-25F range for Bangor to Downeast coast.

Additionally, across Northern Maine what may make travel hazardous tonight with the flash freeze is light snow. Surface low pressure will track into Northern Maine this evening into the overnight hours. The potent 500mb trof will be back to the west allowing for an area of upper level divergence aloft which will enhance surface lift. As the column cools rapidly and the DGZ improves rapidly expecting very good snowflake production and light snow will intially be wet snow but quickly become fluffy snow. Snow will taper to snow showers Friday morning. An additional 0.5-2 inch of snow is expected overnight which falling on icy surfaces may make travel difficult in spots and make for a slippery Friday AM commute in Northern Maine. This is expected to be mainly confined from the Moosehead Region to Baxter SP Region northward to the St. John Valley. Any fluffy snow with increasing westerly winds may lead to patchy blowing/drifting snow late tonight into Friday in Northern Maine.

KEY MESSAGE 3... Low potential for a winter storm Sunday night into Monday, but continued significant uncertainty regarding storm track and evolution.

KEY MESSAGE 3 DESCRIPTION... Low pressure will lift northeast across the western atlantic and toward the Canadian Maritimes Sunday night into Monday. Still plenty of uncertainty amongst the various model guidance with regard to the track of this system. Thus, any potential impacts to the forecast area remain highly uncertain at this point in time. There is a much higher degree of certainty that a turn to much colder temperatures can be expected by the middle of next week.

AVIATION /12Z THURSDAY THROUGH MONDAY/

Today...IFR/LIFR cigs. -RA or BR/VCSH reducing vsby. Winds light and variable.

Tonight...IFR/LIFR becoming MVFR/IFR except LIFR possible north due to -SN overnight. VCSH at other terms with the potential of just -RASH becoming -SNSH. Light and variable winds becoming W-SW with FROPA.

Friday...VFR south, MVFR north. -SNSH north. W winds 10-15kt with gusts 20-25kt.

Fri Night...VFR. W wind becoming S around 5 kt.

Sat through Sat night...VFR early, then MVFR possible at times -SN.

Sun through Mon...MVFR or lower possible in snow.

MARINE

5:40AM UPDATE...Gale Watch has been upgraded to a Gale Warning for the Coastal Waters from 5AM-5PM EST Friday. West winds 20-30kt with gusts up to 40kt and seas 7-11ft. The Gale Watch has been upgraded to a Small Craft Advisory for the Intra- Coastal Waters from 7PM EST this evening till 7PM EST Friday. Intially SW winds shifting W 15-25kt with a few gusts up to 35kt. Seas 3-6ft expected. For all the waters Light Freezing Spray possible during the headline time frame.

Previous Discussion... Winds/seas below SCA conditions this morning through midday today. Rain and fog may reduce vsby at times. Seas generally 2-4ft. This afternoon SW winds will increase with gusts up to 25kt and seas building 3-5ft. This evening winds gusting up to 30kt with seas 4-8ft. Overnight Gale Watch is up for wind gusts 35-40kt and seas 5-9ft. Expecting westerly gales to last through Friday afternoon before relaxing back to SCA conditions. Light freezing spray is possible tonight into Friday with rapidly cooling air temperatures. Sea surface water temperatures range from 38-42F from the Downeast Coast out 25nm and east to the Hague Line including Penobscot and Passamaquoddy Bays.

Small Craft Advisory level conditions are expected through the weekend and into early next week.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Dense Fog Advisory until 8 AM EST this morning for MEZ002-005- 006-010-011-015>017-029>032. MARINE...Gale Warning from 5 AM to 5 PM EST Friday for ANZ050-051. Small Craft Advisory from 7 PM this evening to 7 PM EST Friday for ANZ052.