textproduct: Caribou

WHAT HAS CHANGED

No significant changes.

KEY MESSAGES

1) Wet snow is likely Tuesday night for Bangor and Downeast Maine, mainly between 8pm and 6am. Minor travel impacts are possible.

2) Light snow possible Thursday and Friday.

3) Warm, above freezing temperatures expected for the weekend, with potential for mixed precipitation.

DISCUSSION

KEY MESSAGE 1... Wet snow is likely Tuesday night for Bangor and Downeast Maine, mainly between 8pm and 6am. Minor travel impacts are possible.

KEY MESSAGE 1 DESCRIPTION... Weak low pressure will develop Tuesday evening over the western Gulf of Maine and track eastward over Nova Scotia by early Tuesday morning as a northern stream shortwave trough partially phases with the subtropical jet. There is general agreement for about a quarter to third of an inch of QPF across Downeast Maine falling all as snow, except along the coast where some mixing with rain is possible. This will be a heavy, wet snow with snow ratios between 7 and 11 to 1 anticipated, producing roughly 2 to 4 inches of snow. There is some uncertainty with how quickly the low deepens, and there is potential for a stronger low that could bring slightly more QPF northward. HREF and NBM probabilities currently indicate about a 20 to 30 percent chance of at least 4 inches of snow Downeast, so there remains a chance that advisories may be needed if higher QPF scenarios occur. In any case, snow covered and slushy roads are likely for the Wednesday morning commute, especially early on before temperatures warm well above freezing during the day Wednesday.

KEY MESSAGE 2... Light snow possible Thursday and Friday.

KEY MESSAGE 2 DESCRIPTION... Two potential shots at snow Thursday into Friday. The first comes mainly Thursday morning and over Northern Maine. Most models/ensembles have a slow-moving cold front sliding through the north in the pre-dawn hours with sharply cooler air behind it. Then there would be the potential for light overrunning snow on the cold side of the front during the day Thursday. If this occurs, we are looking at an inch or two of snow at most. Not confident that it will occur and went with chance of snow for now, but did go higher for PoPs than the NBM.

Briefly after this, for late Thursday night into Friday morning, a system approaches from the west, perhaps bringing a shot of snow. The best shot of snow is over southern portions of the area, but like the early Thursday system, not quite confident enough to go with likely PoPs. There is a lot of uncertainty with how far north precipitation gets with this system. Some have accumulating snow up to northern Maine, while others keep it south of our area. There is about a 30-40 percent chance of an inch or more of snow Downeast and Bangor region, but if it does snow, totals would very likely stay below 5 inches. Snow appears to be the most likely precipitation chance, unless the storm takes an extreme northerly track, in which case we can't rule out some rain Downeast.

KEY MESSAGE 3... Warm, above freezing temperatures expected for the weekend, with potential for mixed precipitation.

KEY MESSAGE 3 DESCRIPTION... Near certainty that temperatures will top freezing this weekend areawide, and high likelihood (at least 70 percent chance) that they will at least reach 40 even in the north. There could be some light mixed precipitation Friday night and early Saturday as a warm front comes through. While we can't rule out some freezing rain with the transition to warm temperatures, this does not look like a good setup for anything more than brief icing. It's also possible light snow could transition to rain, or there may not be any precipitation at all with the warm front early Saturday, as there is still a lot of uncertainty. Temperatures look quite mild from Saturday afternoon through at least Sunday areawide. Some rain is also possible, but not expecting anything significant. That said, the mild temperatures through the weekend will lead to significant snowpack compaction, with some places mainly in southern portions of the area possibly losing all or nearly all of their snowpack. The potential for river, lake/pond ice decay/rot is also there, especially Downeast. We don't expect river ice to flush out Downeast though, and in the north, the river ice should hold completely through the weekend.

AVIATION /18Z MONDAY THROUGH SATURDAY/

VFR through Tuesday. Light SW winds this evening, increasing to 10 to 15 kts with gusts between 20 and 30 kts during the day Tuesday. LLWS likely late tonight with an inversion around 2kft AGL, before mixing begins and surface winds increase by midday Tuesday.

Tuesday Night: VFR at northern Aroostook terminals, IFR/LIFR at BGR and Downeast terminals with a period of SN developing. MVFR with -SN possible at HUL and MLT. S winds 5 to 10 kts.

Wednesday...Mainly VFR. W winds 5-15kt.

Wednesday night...VFR south. VFR north, low chance of SCT-BKN MVFR cigs. Variable wind less than 10kt.

Thursday...VFR Downeast terminals, and probably MVFR northern terminals. N-NE winds 5-15kt.

Thursday Night and Friday...Possible MVFR/IFR cigs with -SN, but low confidence. NE winds 5-10kt.

Friday Night and Saturday...Possible mixed precipitation with mainly MVFR/IFR. S wind 5-15kt.

MARINE

Winds and seas initially below advisory levels tonight will increase Tuesday morning, with SW wind gusts to 25 to 30 kts and seas increasing to 4 to 7 feet. Winds and seas decrease below advisory levels again Tuesday night. Light freezing spray is expected through tonight, ending by Tuesday morning as temperatures warm.

Likely E/NE small craft winds, with possible gales, Thursday night to Friday evening. Seas 4-7 ft. Winds then becoming S/SW for the weekend generally at small craft levels.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory from 7 AM Tuesday to 1 AM EST Wednesday for ANZ050>052.