textproduct: Caribou

WHAT HAS CHANGED

Adjusted timing for snow showers today as front has been slow to move south and east across eastern Maine.

Increased precipitation chances late week as Maine will enter an active pattern. However, there remains greater uncertainty how far north in New England this precipitation progresses.

KEY MESSAGES

1. Light snow and snow showers progress south and east through the evening hours. These may heavy at times, reducing visibility and deteriorating travel conditions across the north and central locations.

2. There is the potential for snowfall, mainly across the North and along the eastern US/CAN border Tuesday and Tuesday night, with possible impacts to the afternoon commute.

3. Northern New England remains in an active pattern through mid to late week. There is increased uncertainty how much high pressure and resident dry air may suppress precipitation south of the region.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION... Low pressure slides just east of the forecast area through this afternoon and early evening. An associated cold front will be drawn through Maine at the same time with snow showers.

Morning trends have delayed the arrival of this front, and broad light snow showers are now expected to push through the North Woods and into central/southern Aroostook and the Highlands in the early afternoon. Satellite presentation has been on the weaker side, with stratus and cirrus developing in bands slowly overtaking dry air to the east. This will lead to some breaks early, but expect more showery snow to arrive later.

Sufficient moisture and forcing pivots south this evening, with a hint of low level instability. This combination alone can produce some organized mod to hvy snow showers through the evening as it pivots across the CWA. These would bring brief bouts of reduced visibility and minor accumulations on cool surfaces. Gusts may increase around stronger showers, but low level winds are not to the tune (less than 20 kts generally) of reaching snow squall criteria for this disturbance. Additionally, low level instability wanes into mid evening as daytime heating wears off and lapse rates slacken.

Fresh northerly winds will keep some moisture stream into the north, resulting in possibly another push of snow after midnight. This will eventually exit east as parent low pushes towards Nova Scotia Sunday morning.

KEY MESSAGE 2 DESCRIPTION... Low pressure crossing James Bay Tuesday morning will draw moisture toward northern Maine resulting in light snow. GFS and Canadian guidance has been more widespread with precipitation for the entire forecast area, but ECMWF trends have been to hold most of the QPF across the north. At this time, this paints greater confidence in the north seeing snow for the day and into the evening, with lesser chances to the south.

QPF is light across the board is light, thus minimal travel impacts are expected unless forcing can sharpen up.

KEY MESSAGE 3 DESCRIPTION... Precip chances remain into late week as zonal flow carries a number of weak disturbances towards northern New England. At the same time, broad high pressure across Hudson Bay will have some influence via drier continental air across the Canadian Maritimes and eastern Maine.

One time period to watch for snow is Friday into Saturday. It is here where a cross-CONUS jet pushes far enough north to put the exit region into the Gulf of Maine. This region of better lift, if combined with a passing disturbance, can aid in continued cyclogenesis/strengthening. Timing and exact track components are still uncertain, but most guidance sources do show a quick moving low pres pressing east across the Northeast towards the Gulf of Maine into the early/mid weekend.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Today-tonight: Cigs lower as a cold front passes north to south across eastern Maine this evening and overnight. Northern terminals will see the most continuous SHSN and SN, with MVFR cigs and IFR vis at times. Conditions should improve shortly before 12z Sun. SHSN will be lesser towards BGR and BHB also with lesser cig reduction/coverage.

Sunday and Monday: MVFR cigs remain for most northern terminals and HUL in AM. VFR BGR/BHB.

Monday night and Tuesday: Ceilings thicken and lower areawide with SN. MVFR with IFR cigs possible, IFR vis in SN...mostly across the north.

Wednesday and Thursday: Active pattern will likely keep skies mixed with on and off restrictions through ceilings and SN. There remains uncertainty at this range of exact timing and impacts.

MARINE

SCA conditions arrive late this evening and overnight as a cold front passes over the waters from the north. Winds slacken below SCA criteria Sunday afternoon. Through mid and late week, there will be a series of weak but fast low pressure systems that enter the region. There is uncertainty at this time of exact impacts and timing. One feature to track will be low pressure nearing the Gulf of Maine around Friday/Saturday that could bring increased winds and wave heights to the coastal waters.

EQUIPMENT

The KCBW WSR-88D radar and NWR transmitters in the CAR CWA are unable to transmit at this time due to a communications outage. There is currently no estimated restoration time.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory from 1 AM to 4 PM EST Sunday for ANZ050- 051. Small Craft Advisory from 4 AM to 1 PM EST Sunday for ANZ052.