textproduct: Caribou

WHAT HAS CHANGED

- Raised snow to liquid ratios for Tuesday night into Wednesday AM for the light snow event.

- Increased snow totals across Bangor Region to Downeast Maine for Tuesday Night into Wednesday AM.

KEY MESSAGES

1) Frigid Arctic air will remain over the area today with bitter cold wind chills, especially this morning. This will bring the risk of hypothermia and frostbite.

2) Light Wet Snow for the Bangor Region and Downeast Maine Tuesday Night into Wednesday AM. Minor travel impacts to the Wednesday AM commute.

3) Progressive pattern with the potential for a significant warm up late week into next week. This will result in mixed precipitation events and potential of snowpack loss.

DISCUSSION

KEY MESSAGE 1...Frigid Arctic air will remain over the area today with bitter cold wind chills, especially this morning. This will bring the risk of hypothermia and frostbite.

KEY MESSAGE 1 DESCRIPTION... Bitter cold Arctic air will remain over the region today. Lows this morning will range from the mid teens below zero in the northwest to around ten below in the northeast and zero Downeast. Combined with a northwesterly breeze, this will result in wind chills from the mid 20s below north to the low teens below Downeast to start the day. If you are venturing out early this Monday morning, it is strongly advised that you dress in layers and protect hands and face from the bitter cold. Prolonged exposure will bring the risk of hypothermia and frostbite.

Today will remain bitter cold in spite of bright sunshine. Highs from the low teens north to around 20 Downeast will be just over 15 degrees below normal for early March. This will be followed by another cold night tonight, but not as cold as this morning with lows from near zero north to ten Downeast. This will be followed by a big rebound in temperatures on Tuesday as highs make a run for the 30s across the area.

KEY MESSAGE 2...Light Wet Snow for the Bangor Region and Downeast Maine Tuesday Night into Wednesday AM. Minor travel impacts to the Wednesday AM commute.

KEY MESSAGE 2 DESCRIPTION... A weak surface low pressure will develop in the Gulf of Maine Tuesday evening and track northeast towards Nova Scotia into Wednesday AM associated with a weak open 500mb shortwave. Decent agreement with operational GFS, ECMWF, Canadian, NAM models along with the ECMWF AIFS and AIGFS. There remains some slight differences of 50 miles or so on track but significantly improved timing agreements and keeping the low offshore. This is the important part as it will allow much of the precipitation to fall as snow versus rain. Much of the precipitation is happening at night so that means we can expect decent cooling despite the light southerly winds. So we start the precipitation with temperatures well above freezing but quickly loss of diurnal heating we fall back below freezing. Temperatures will be just below freezing along the coastline, so there is a chance for a rain/snow mix along the immediate coastline but most areas <31F Downeast with 26-30F for Bangor to interior Downeast.

The Column looks good to support higher SLRs than what NBM 4.3 and 5.0 suggest so opted to raise the SLRs. Opted to go with a 9.5-11:1 ratio at the shoreline and 10-12:1 ratio for interior Downeast, Bangor Region up into Northern Maine. QPF has trended up a little bit so combining SLRs and QPF have raised snow totals since previous forecast package. Now expecting 1-3 inches for the Bangor Region, Upper Penobscot Valley into Northern Washington County. Totals of 3-4 inches for the Downeast Coast including eastern half of The Airline (Route 9) in Washington County. Cannot rule out an isolated 5 inches in places like MDI, Sedgwick area, Milbridge to Jonesboro. Expect this snow to be heavy and wet which will likely result in slippery morning commute for Route 1 and 9 regional corridors with slightly fluffier snow for the Route 6 region and this include I-95 in Penobscot County. Precipitation will quickly end in the AM and temperatures quickly warm above freezing so expect any snow to quickly become slush.

KEY MESSAGE 3...Progressive pattern with the potential for a significant warm up late week into next week. This will result in mixed precipitation events and potential of snowpack loss.

KEY MESSAGE 3 DESCRIPTION... Later this week a large 500mb ridge develops over the Southeastern United States as a large surface Bermuda High develops. This forces the northern jet stream over New England or north of New England into Canada. There is a ton of uncertainty on weak dips in the jet that may result in weak systems traversing the area. First potential system is Thursday night into Friday but significant differences in the global operational models and very weak signatures in the ensemble means. Latest NBM leans towards a colder solution given the recent GFS/ECMWF operational trends with a system tracking south of Maine and nighttime precipitation favors snow. However, kept POPs in the chance category because of too much uncertainty.

Despite a lot of uncertainty in the operational guidance strong agreement in the ensembles of 500mb ridge taking hold to the eastern United States with PNA turning negative. 500mb heights turn +1 to +2SD over the entire east which means temperatures will likely be above normal. Saturday and Sunday another potential dip in the jet may result in a storm system but with much warmer temperatures a decent chance this may be more wet than white if precipitation falls during the daylight hours.

Overall the concern turns to the potential for significant snowpack compaction and potential loss with temperatures well above freezing. Additionally, we begin to look at potential for river, lake/pond ice decay/rot with a significant warm up.

AVIATION /06Z MONDAY THROUGH FRIDAY/

Today and tonight...VFR conditions are expected all sites. Winds W 5 to 10 kt today and SW around around 5 kt tonight.

Tuesday...VFR all sites, possibly dropping to MVFR across the south late in the day. Winds SW around 10 kt.

Tuesday night...Northern terms VFR with potential of MVFR cigs due to VCSH/-SHSN. S winds around 5kt. Southern terms MVFR/IFR cigs with IFR/LIFR vsby due to -SN at BGR and -RASN becoming -SN at BHB. S-SW winds around 5kt.

Wednesday...Becoming VFR in the AM. W winds 5-15kt.

Wednesday night...VFR south. VFR north, low chance of SCT-BKN MVFR cigs. NW winds 5-10kt shifting N around 5kt.

Thursday...VFR. N-NE winds 5-15kt. Slight chance of RA late day at southern terms.

Thursday Night...Possible MVFR/IFR cigs with -SN. NE winds 5-10kt.

Friday...Possible MVFR/IFR cigs with -SN. E winds 5-10kt.

MARINE

A SCA will be up early this morning for NW winds gusting up to 25 kt and a freezing spray advisory for moderate freezing spray will be up through late morning. Winds will be below SCA late today into this evening, then increase to SCA late tonight and possibly a low end gale over the offshore waters on Tuesday for SW winds gusting up to 30 kt with a few gusts to 35 kt. Seas down to 3 ft today and early tonight, increasing to 5 ft late tonight then 7 to 8 ft in SW winds on Tuesday.

Tuesday night rain or rain/snow mix will reduce vsby less than 1nm at times. S-SW SCA wind gusts will fall below SCA criteria overnight. Winds will shift NW overnight and seas fall below 5ft into Wednesday AM. Winds/seas below SCA through early Thursday evening. Next chance of SCA conditions with low end Gales possible Thursday night into Friday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Cold Weather Advisory until 7 AM EST this morning for MEZ001>006-010. MARINE...Small Craft Advisory until 7 AM EST this morning for ANZ050>052. Freezing Spray Advisory until 1 PM EST this afternoon for ANZ050>052.