textproduct: Caribou

WHAT HAS CHANGED

- All Winter Weather Headlines for this afternoon were cancelled. Issued an SPS for isolated remaining slick conditions.

- Increased chances of snow showers tonight across Northern Maine with cold frontal passage expected.

- Issued Winter Weather Advisory for Saturday night into Sunday morning across northern Maine.

- Gale Watch issued for the outer coastal waters Saturday night into Sunday.

KEY MESSAGES

1) Weak low pressure and cold frontal passage tonight changing precip back to light snow across Northern Maine and Moosehead Region may lead to potentially icy roadways.

2) Mixed precipitation across northern Maine late Saturday night into Sunday morning will cause impacts to travel for the Easter holiday.

DISCUSSION

KEY MESSAGE 1...Weak low pressure and cold frontal passage tonight changing precip back to light snow across Northern Maine and Moosehead Region may lead to potentially icy roadways.

KEY MESSAGE 1 DESCRIPTION... Low pressure tracking across Quebec towards Northern Maine this evening will drag a cold front across the state overnight. As colder air works back into the region expecting scattered rain showers changing to scattered or numerous snow showers especially from the Moosehead to Baxter Region and points north. Models have significantly changed and showing low pressure tracking overhead versus to our north. This will lead to additional cooling aloft in the DGZ and enhance lift. Additional dusting of snow to potentially a inch is possible with these snow showers or brief light snow especially in the St. John Valley. Temperatures will crash with the frontal passage back below freezing. Models continue to be in decent agreement of FROPA occurring between 9PM-1AM in Northern Areas then 10PM-2AM for the rest of the CWA. Temperatures are not expected to turn icy in southern and central zones. The greatest concern is the Moosehead Region to Baxter Region to Southern Aroostook and points northward. A flash freeze may cause any wet roadways and untreated surfaces to freeze back up and form black ice. Use caution overnight heading out traveling.

KEY MESSAGE 2...Mixed precipitation across northern Maine late Saturday night into Sunday morning will cause impacts to travel for the Easter holiday.

KEY MESSAGE 2 DESCRIPTION... A similar setup to the most recent system will unfold again Saturday night into Sunday with slightly warmer temperatures expected as the surface low strengthens earlier and passes much farther to the northwest by comparison. All rain is most likely for Bangor and Downeast Maine, with a brief period of snow changing to a wintry mix of sleet and freezing rain, then rain across the north from southwest to northeast. NBM sleet probabilities were increased again and freezing rain probabilities decreased to account for systematic biases in the ECMWF/EPS precipitation types. Snow ratios were also reduced slightly to account for riming and poor snow growth conditions.

TIMING: The initial warm frontal band of precipitation will reach far northwest areas of the North Woods late Saturday evening, with steadier precipitation overspreading far northern Maine around or just after midnight. Onset timing may be slightly later if the low tracks farther to the northwest. More intermittent precipitation is anticipated across central and southern areas where there will be plenty of moisture but less forcing further away from the parent low and shortwave trough across southern and central Quebec. A brief period of snow is expected for northern areas, with central areas potentially starting as sleet. Central areas will transition to rain early to mid Sunday morning, with northern areas transitioning to rain shortly after by midday. Rain tapers off later Sunday with potential for lingering snow showers behind a cold front Sunday night into Monday, mainly across the north.

AMOUNTS: Significant uncertainty remains with QPF, especially across the far north where solutions range from just under half an inch to around one inch. NBM QPF was preferred as a middle ground given the uncertainty. This still yielded over a half to one inch of sleet across far northern areas, with amounts tapering to around a tenth of an inch for areas just north of Bangor. A light glaze of freezing rain is possible, with the greatest ice accretion to around a tenth of an inch possible across the Central Highlands. An inch or two of snow is possible across far northern areas ahead of the sleet, but snow is expected to be less of a percentage of the total precipitation compared to the previous storm.

IMPACTS: Primarily travel impacts are expected, including slippery roads and reduced visibility late Saturday night to Sunday morning. This will impact travel for the Easter holiday during the morning. Snow removal will be more difficult than usual for the amount due to the weight and density of sleet for areas with the most sleet accumulations across the far north.

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

Rest of Today...IFR/LIFR conditions with -RA, BR, SHRA. SE winds 5-15kt with gusts up to 25kt.

Tonight...IFR/LIFR expected. TEMPO for -SHSN at northern terms. TEMPO for BR/FG at southern terms. Wind shifts expected. SE winds shifting N-NW overnight. LLWS likely. Conditions rapidly improve with FROPA with MVFR/VFR by 12z.

Saturday...Any MVFR cigs early becoming VFR. N winds 10-15kt gusting up to 25kt in the AM shifting NE in the afternoon 5-15kt.

Saturday night to Sunday: VFR early, becoming MVFR, then IFR. -RA expected for BGR and Downeast terminals. A light wintry mix is expected for central terminals, with a heavier wintry mix and more significant accumulation of PL possible for northern Aroostook terminals. Precipitation transitions to -RA Sunday morning from southwest to northeast at all terminals. LLWS possible. SE winds increasing to 10 to 15 kts with gusts to 30 kts.

Sunday night: MVFR possible at northern terminals, otherwise VFR. W winds 5 to 10 kts gusting to 20 kts.

Monday: Low VFR ceilings, with a chance of MVFR at northern terminals. WNW winds around 15 kts with gusts to 25 to 30 kts.

Monday night: VFR. NW winds 5 to 15 kts.

Tuesday night: Periods of MVFR or IFR possible, especially south, with -SN or SHSN. NW winds around 10 kts with gusts to 20 kts.

Wednesday: VFR strongly favored with a slight chance of MVFR at northern terminals. W winds around 10 kts with gusts to 20 kts.

MARINE

A Small Craft Advisory remains in effect through 2PM EDT Saturday for the Coastal Waters out 25nm. Southwest winds tonight, shifting north Saturday morning then northeast. Winds 15 to 25 kt with gusts up to 30 kt and seas 3 to 6 ft. For the Intra-Coastal Waters a Small Craft Advisory remains in effect until 8AM EDT Saturday. Southwest winds tonight, shifting north Saturday morning. Winds 10 to 20 kt with gusts up to 25 kt.

Winds increase to Gale force over the outer waters (75 percent chance) and possibly over the intracoastal waters (40 percent chance) Saturday night into Sunday, with seas possibly reaching 10 feet over the outer waters as well. A Gale Watch has been issued for this period. Advisory level winds and seas will continue into Monday evening, before conditions improve to sub advisory levels later Monday night through Tuesday. Winds increase again Tuesday night with a frontal passage. At least advisory level winds are likely, with gales also possible.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Winter Weather Advisory from midnight Saturday night to noon EDT Sunday for MEZ001-002. Winter Weather Advisory from midnight Saturday night to 10 AM EDT Sunday for MEZ003>006-010-011-031-032. MARINE...Small Craft Advisory until 2 PM EDT Saturday for ANZ050-051. Gale Watch from late Saturday night through Sunday evening for ANZ050-051. Small Craft Advisory until 8 AM EDT Saturday for ANZ052.