textproduct: Caribou

WHAT HAS CHANGED

-Overcast skies are likely to hold in place through the night tonight, and temperatures will remain relatively stable in the teens through the night across the north due to lack of surface decoupling and efficient radiational cooling.

-Confidence is increasing in measurable snowfall Thursday through Friday, especially over Northern Maine

KEY MESSAGES

1) Turning much colder Thursday into Friday, with likely snow especially for Northern Maine.

2) Brief period of light snow expected Tuesday night, mainly from the Bangor region and points north.

3) Potential for another weather system around Sunday.

DISCUSSION

KEY MESSAGE 1... Turning much colder Thursday into Friday, with likely snow especially for Northern Maine.

KEY MESSAGE 1 DESCRIPTION... Very difficult forecast from Thursday into Friday with a good amount of uncertainty. Bottom line is colder air will be moving in, potentially with moderate to heavy snow with the best chance of this occurring over Northern Maine. A strong Arctic front will be slowly creeping southeast through the area, but the timing of this front is pretty uncertain. Meanwhile, a cutoff upper level low pressure system will be approaching from the west with moist southwest flow aloft ahead of the low. The forward progress of this upper level low is also quite uncertain. The interaction of this approaching upper level low and the Arctic front could be rather volatile, with the main concern being moderate to possibly heavy snow just on the north side of the Arctic front where the mild, moist air aloft from the southwest will be overrunning the cold air at low levels.

Recent model trends have been to slow down the southeast progression of the Arctic front. The front appears to progress through the north from midday Thursday to Thursday evening, and make it to Downeast anywhere from Thursday afternoon to the pre- dawn hours Friday. The airmass ahead of the Arctic front will be mild and warm enough for rain or perhaps a rain/snow mix in the north, with it easily being cold enough for snow behind the Arctic front. The heavier precipitation would likely be behind the Arctic front and not ahead of it. For Friday, depending on the speed of the cutoff low progressing through the region, we could see enhanced/continued snow into Friday if a surface low can form and ride northeast along the front. Over the Thursday/Friday period, there is roughly a 25-40 percent chance of more than 6 inches of snow, with the higher chances north of Bangor. Most areas should see at least an inch of snow during this time. Significant rain is very unlikely, because most of the precipitation would be in the colder airmass where it would fall as snow. Temperatures Friday will be much colder with readings anywhere from 5-15F above in the north and 15-25F above Downeast.

KEY MESSAGE 2... Brief period of light snow expected Tuesday night, mainly from the Bangor region and points north.

KEY MESSAGE 2 DESCRIPTION... Low pressure tracks to our northwest through Quebec Province Tuesday night with a warm front lifting across the area. Confidence is high that we will see a period of light snow with this feature overnight Tuesday, mainly from the Bangor region and points north. Confidence is also high that any snow accumulations will be light, generally an inch or two.

KEY MESSAGE 3... Potential for another weather system around Sunday.

KEY MESSAGE 3 DESCRIPTION... Although model agreement is poor, many models/ensembles do indicate an active weather pattern persisting with potentially a Nor'easter around the Sunday timeframe. If this system were to pan out, snow would be favored in the north, and Downeast could get rain or snow. Right now, roughly half of models/ensembles have at least a moderately strong system passing somewhere through our area around Sunday.

AVIATION /02Z TUESDAY THROUGH SATURDAY/

VFR is expected at the terminals tonight through Tuesday, but with a lower than average forecast confidence, as some forecast soundings are showing the potential for lower ceilings developing later tonight, mainly at the Aroostook Terminals. MVFR cigs are once again possible from KPQI northwards through Tuesday afternoon. SW wind 5 to 10 kt tonight and Tuesday.

Tuesday night...Trending towards MVFR/IFR in -SN BR. S to SE wind around 10 kt.

Wednesday and Wednesday Night...MVFR/IFR. S wind 5-10 kts.

Thursday through Friday...Generally MVFR/IFR. Snow likely in the north Thursday/Thursday night, perhaps into Friday. For BGR/BHB, possibly rain Thursday, then possibly snow Thursday night/Friday. S winds switching to the NW Thursday afternoon and evening, and becoming 10-15 kts with gusts to 25 kts, persisting into Friday.

Friday Night and Saturday...Mainly VFR. SW wind 5-10 kts.

MARINE

Small Craft Advisory conditions will continue into tonight. Conditions should remain below advisory levels Tuesday, and then increase to small craft advisory levels Tuesday night.

Small craft SW winds and seas Wednesday diminish below small craft levels by late Wednesday night. NW gales are likely late Thursday night into Friday, with seas building to around 9 ft. Gradual improvement Friday night/Saturday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory until 5 AM EST Tuesday for ANZ050-051. Small Craft Advisory until midnight EST tonight for ANZ052.