textproduct: Caribou

WHAT HAS CHANGED

*6:30PM Update: Issued 0z TAFs and updated aviation section of discussion.

*5:20PM Update: Issued Winter Weather Advisories for southern Aroostook, Central Penobscot, and Northern Washington counties. Southerly flow and strengthening low pressure system are indicating higher snowfall totals than in the last update. Potential for roughly 2-4 inches in these areas, with a chance for slick travel. Continue to monitor the forecast as we monitor this system.

*Ended Winter Weather Advisory in northern Maine, due to improving conditions. Continue to exercise caution in areas of local blowing snow.

*Increased the probability for snow Downeast Sunday evening.

KEY MESSAGES

1) Another shot of light snow incoming on Saturday.

2) Models trending with a more south track for the winter system later Sunday into early Monday, which could result in locally hazardous travel for Downeast.

3) Increasing confidence in colder temperatures by midweek, with wind chills possibly reaching around 20 below zero.

DISCUSSION

KEY MESSAGE 1...Another shot of light snow incoming on Saturday.

KEY MESSAGE 1 DESCRIPTION... High pressure builds over Maine briefly early Saturday morning, as an occluding low pressure system begin to move into the region form the west. Potential for some heavier snow bands setting up Downeast and/or around the Central Highlands region. Current models are indicating a strengthening low pressure system, and alongside southerly winds, which could help advect in some more moisture, increasing snowfall totals. Will be a decent mid-to-upper level jet moving through the areas during this time frame, with an areas of divergence and moisture developing into the area. Thinking there is a chance for roughly 2-4 inches to fall in these heavier snow areas, and around 2 inches possible elsewhere. Warm air will be advecting in ahead of warm front, and the immediate coastline has a chance of seeing only rain as temperatures are expected to raise above freezing during the day. Rain/snow transition line along portions of the southern interior Downeast. Snow begins to taper off Saturday evening.

KEY MESSAGE 2... Models trending with a more south track for the winter system later Sunday into early Monday, which could result in locally hazardous travel for Downeast.

KEY MESSAGE 2 DESCRIPTION... Upper level models show a positively tilts trof moving from the Great Lakes towards New England on Sunday. Surface models show a low pressure system developing off the coast of Florida and moving along the Atlantic coast throughout Sunday. By Sunday night, the system should track over the Gulf of Maine. Ensemble models show a more southerly track of the system, which would bring less moisture to Downeast. However, the cooler temps and higher snow ratios could bring snow accumulations up to 3 inches. If the ensembles still show a south track, then these amounts will be less.

KEY MESSAGE 3... Increasing confidence in colder temperatures by midweek, with wind chills possibly reaching around 20 below zero.

KEY MESSAGE 3 DESCRIPTION... Upper and mid level models show the jet stream mover the state as the upper level trof begins to move across the CONUS. 850 to 925mb model temps show a digging trof of very cold air from Canada moving across the country into mid week. If the deterministic models are correct, then expect temps in the single digits for high temps and negatives for low temps. If winds become breezy, then winds chills could drop into the 20s below zero. Confidence is low but increasing with closer model trends.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

Tonight...Conditions have improved areawide, with VFR and diminishing winds. Winds less than 10 kts everywhere by 2z, and remaining light tonight with VFR persisting as well.

Saturday...Starting out VFR, but snow moves in from SW to NE, beginning roughly 14z BGR/BHB and roughly 17z FVE/CAR/PQI/HUL. Initially with the snow, MVFR is expected, but IFR is likely at all sites beginning around 19-22z as the precipitation continues. Areas north of BGR will stay all snow, but BGR may mix with rain from about 19z onward, and BHB is likely to mix with or change to rain after 17z. Perhaps some borderline LLWS especially BGR after 19z. Winds E/SE up to about 10 kts on Saturday.

Saturday Night...Starting out mainly IFR with light snow north of BGR and rain or rain/snow BHB/BGR. Precipitation ends from west to east by about 4z. Low confidence is what happens after the precipitation ends, but think it will stay MVFR/IFR rather than clear out. Light winds.

Sunday...MVFR/IFR in chance of snow. Light SW winds.

Sunday night...MVFR/IFR in chance of snow, improving late. Light NW winds.

Monday...MVFR or lower possible early, then VFR. WSW winds 5-10 kts.

Monday night...VFR. WSW winds 5-15 kts.

Tuesday...VFR. W winds 10-15 kts gusts to 30 kts.

Wednesday...VFR. WSW winds 5-10 kts.

MARINE

Small craft criteria for outer waters through Saturday. Light freezing spray over all waters tonight. Rain Saturday. Winds NW tonight, and becoming S on Saturday,

SCA conditions Sunday to Sunday night with seas 4-6 ft. Winds increase Monday to gale force by Monday afternoon. This should remain through Wednesday morning, then decrease to SCA wind through the rest of the week.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Winter Weather Advisory from 10 AM Saturday to 1 AM EST Sunday for MEZ006-011-032. MARINE...Small Craft Advisory until 7 PM EST Saturday for ANZ050-051.