textproduct: Caribou

WHAT HAS CHANGED

- Increasing confidence in the timing and track of the low pressure through the middle of the week, as well some increased confidence in precip type across the north with this system

KEY MESSAGES

1) Unseasonably cold temperatures continue through the weekend.

2) A mix of precipitations types are possible late Tuesday into Wednesday, potentially creating slick travel conditions for the Tuesday night and Wednesday morning commutes.

3) Rapidly dropping temperatures could quickly freeze wet surfaces late on Wednesday behind a cold front, potentially creating slick travel conditions for the Wednesday evening commute.

DISCUSSION

KEY MESSAGE 1... Unseasonably cold temperatures continue through the weekend.

KEY MESSAGE 1 DESCRIPTION... Afternoon high temperatures today will continue a good 10 to 15 degrees below normal for the date. Expect highs today to range from the low to mid 20s across the north and upper 20s to around 30 for the Bangor region and Downeast.

Expect low temperatures tonight to range from 5 to 10 above across the north and mid teens for the Bangor region and Downeast. A stray snow shower not totally out of the question tonight, as a weak disturbance crosses the region.

Sunday will see a continuation of below normal afternoon high temperatures. But it will not be quite as cold, with highs expected range from the low to mid 30s north and upper 30s to around 40 for the Bangor region and Downeast. A stray snow shower will be possible across the north by afternoon.

KEY MESSAGE 2... A mix of precipitations types are possible late Tuesday into Wednesday, potentially creating slick travel conditions for the Tuesday night and Wednesday morning commutes.

KEY MESSAGE 2 DESCRIPTION... An open wave low pressure system will approach from the west early this week, crossing New England through the middle of the week. A warm front will likely lift northwards through our forecast area through the day on Tuesday, bringing warmer temperatures through the day and the first round of precipitation.

There remain a few different solutions for how the low will evolve late Tuesday into the day on Wednesday:

- The first solution is that the low tracks north of the state, as seen on the deterministic ECMWF. In this scenario, the warm front completely clears through the region, with the entire CWA sitting in the warm sector of the low. As surface temperatures warm above freezing, precip type will quickly change to all rain, with any ice between snow and rain being brief as the FROPA lifts through.

- Another solution exists where the low crosses the northern half of the CWA, through around the central portion of the forecast area. This is the solution that most guidance has been trending towards, most notably the GEFS and EC AI models. The NBM blend also captures this solutions well, and in general is what was used with this forecast. With this solution, the Downeast region will quickly warm and become all warm rain, while the northern portion of the FA could get caught in the warm nose of the warm front, while the low tracks eastward along this boundary. This solution could result in a longer duration of mixed precip and/or freezing rain in the north, and would have a larger impact to the Wednesday morning commute than the first solution as ice would have time to develop a glaze on elevated and untreated surfaces.

- A final solution would include the low center tracking over the Gulf of Maine. Though this solution has existed more in past model runs, such as the deterministic CMC, trends have moved northwards from this solution, settling now on a solution with the low track closer to the center of the CWA.

KEY MESSAGE 3... Rapidly dropping temperatures could quickly freeze wet surfaces late on Wednesday behind a cold front, potentially creating slick travel conditions for the Wednesday evening commute.

KEY MESSAGE 3 DESCRIPTION... A cold front will close out this low pressure system by Wednesday night, with temperatures in the mid 40s to upper 50s crashing to the teens to mid 20s overnight Wednesday night. Some guidance, such as the GFS and NBM, points towards temperatures dropping at a rate of at least 3 degrees F per hour, particularly around Bangor and the Interior Downeast regions. Current guidance points towards a lack of tightened pressure gradient with this FROPA, so wet surfaces from the rain of the day could rapidly freeze, creating a glaze of ice on elevated and untreated surface late Wednesday into Wednesday night.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

VFR conditions are expected through tonight. An isolated snowshower could be in the vicinity of the terminals tonight. VFR expected Sunday but MVFR is possible late afternoon across the north in scattered snow showers. N to NW wind 5 to 10 kt early, becoming light S this afternoon. Light S wind tonight. S wind 5 to 10 kt on Sunday.

Sun night...VFR, with SCT-BKN MVFR possible at northern terminals. S/SW winds around 5 kts.

Mon...VFR at BGR/southern terminals, MVFR/IFR at northern terminals in showers. SW winds 5 to 10 kts with gusts to 20 kts.

Mon night...MVFR/IFR cigs at northern terminals, VFR trending towards MVFR at southern terminals. Winds light and variable.

Tues...IFR/LIFR. Rain at southern terminals, possible snow changing to freezing rain at northern terminals. E/SE winds 5 to 10 kts.

Tues night...IFR/LIFR. Rain at southern terminals, possible freezing rain at northern terminals before changing over to rain. SE winds 5 to 10 kts at northern terminals, S winds 5 to 10 kts at southern terminals.

Wed...IFR/LIFR with rain early, with quick drop in temperature with cold front late and rapid improvement to VFR. Southern winds with rapid shift E with afternoon cold front 10 to 15 kts gusting 20 to 25 kts.

MARINE

Winds/seas will remain below SCA levels through tonight. Winds/seas will then begin to increase to SCA levels by later Sunday afternoon.

Wind gusts 25 to 30 kts across the waters Sunday night through Monday, with winds decreasing into Monday night. Seas 6 to 8 ft decreasing to around 5 ft by Monday night. Winds will increase once more with the next storm system Tuesday into Wednesday, with gales likely by Wednesday on the coastal waters, and seas 7 to 13 ft across the waters.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...None.