textproduct: Caribou

WHAT HAS CHANGED

Expanded Winter Weather Advisory into northern Somerset and northern Piscataquis Counties.

Increased snow amounts slightly for Central Highlands, Bangor Region and Downeast today and tonight.

Gale Watch issued 12z Mon through 00z Tuesday.

KEY MESSAGES

1) Snow moving into southern and central areas this morning and continues throughout the day. Snowfall rates between 1/2 to 1 inch per hours expected late this morning into the afternoon. This will bring reduced visibilities and slippery road conditions to the Central Highlands, Bangor Region and Downeast today.

2) An Arctic cold front may bring snow showers on Wednesday, mostly across northern and central areas. The snow could briefly coat the roads resulting in slippery conditions.

3) Snow north and snow changing rain south is likely, beginning Thursday and lasting through Thursday night. This may impact the Thursday evening and Friday morning commutes, especially across the north.

DISCUSSION

KEY MESSAGE 1...Snow moving into southern and central areas this morning and continues throughout the day. Snowfall rates between 1/2 to 1 inch per hours expected late this morning into the afternoon. This will bring reduced visibilities and slippery road conditions to the Central Highlands, Bangor Region and Downeast today.

KEY MESSAGE 1 DESCRIPTION... Low pressure sitting over the Midwest with a warm front draped into lower MI and into eastern PA has allowed overrunning to develop north of the front. This low will move to the east this morning with snow spreading into the Central Highlands and Bangor Region early-mid morning. Snow will overspread the remainder of Downeast throughout the morning hours. Snowfall rates of between 1/2 to 1 inch per hour will be possible between 15- 20z today over southern areas. These rates will likely result in slippery road conditions at times, especially on untreated roads. The caveat to that will be lighter snowfall rates and the strong March sun limiting accums on roadways.

Have continued Winter Weather Advisory for the Central Highlands and Downeast, including the Bangor Region up into the Penobscot Valley. Total snow accums will range between 3-6 inches in these areas. Six inch amounts do not appear to be widespread enough to warrant upgrading to winter storm warning but this will be something for the next shift to keep an eye on. Have also expanded the advisory north to include northern Somerset and northern Piscataquis counties as widespread 3 to 5 inch amounts appear likely. Toyed with the idea of expanding it further east into nrn Penobscot County but most of the 4 inch amounts are west of the Rte 11 corridor and confidence was too low.

Further to the north expect that dry air moving in from Canada will bring a tight gradient of snowfall over Aroostook County. It is not out of the realm of possibility that the St. John Valley receives only a dusting while areas around Molunkus receive between 3-4 inches of snow.

KEY MESSAGE 2...An Arctic cold front may bring snow showers on Wednesday, mostly across northern and central areas. The snow could briefly coat the roads resulting in slippery conditions.

KEY MESSAGE 2 DESCRIPTION... An Arctic cold front will approach on Wednesday. A weak trough out ahead of this front may bring some light snow early Wednesday morning. The cold front will then cross the area around mid-morning Wednesday possibly bringing a brief moderate snow shower over northern and central areas. The snow showers will be supported by surface convergence along the front and some dynamic lifts from an upper trough crossing the area. Any snow showers directly ahead of the Arctic front may briefly coat roads resulting in slippery conditions Wednesday morning. However, any travel difficulties will likely be brief with any snow on the roads quickly melting and evaporating in the late March sunshine. Keep in mind, any snow can hide dangerous patches of ice that linger on some driveways.

KEY MESSAGE 3...Snow north and snow changing rain south is likely, beginning Thursday and lasting through Thursday night. This may impact the Thursday evening and Friday morning commutes, especially across the north.

KEY MESSAGE 3 DESCRIPTION... A large clipper type low will quickly approach from the Great Lakes on Thursday spreading snow across the area Thursday afternoon or early evening. The snow will quickly change to a mix then rain Downeast with the rain/snow line progressing north Thursday evening. Models are in good agreement on this storms development but disagree considerably on the timing and the track with the GFS bringing the system in quickly by midday Thursday but the ECMWF delaying the storms arrival until Thursday evening. The GFS is also quicker to pull warmer air north changing snow to rain over most of the area Thursday night while the ECMWF is colder with mostly snow over the region. The greatest chance for impacts will be during the Thursday evening commute across the with slushy and slippery conditions most likely after dark, and a chance of snow covered or slushy roads over the north for the Friday morning commute.

AVIATION /07Z SUNDAY THROUGH THURSDAY/

Today...VFR this morning will diminish to IFR/LIFR over Downeast terminals around 14z in snow with vsbys around 1/2SM. HUL diminishes to IFR around 18z in 3/4SM in snow with northern Aroostook terminals remaining MVFR in light snow. NW 5-10 kts this morning becoming easterly by afternoon.

Tonight...MVFR continues at northern Aroostook terminals tonight. HUL, BGR and BHB should remain IFR during the evening, possibly improving to MVFR late. ENE winds continue 5-10kts.

Monday...MVFR/IFR early, improving to MVFR/VFR in the afternoon. Chance of snow showers. NE 5-15kts.

Monday night...VFR north. MVFR becoming VFR south. N wind around 5 kt.

Tuesday...VFR. NW wind around 5 kt becoming W.

Tuesday night...VFR lowering to MVFR north. VFR south, possibly lowering to MVFR late. SW wind around 5 kt.

Wednesday...MVFR, possibly briefly IFR in any snow showers north. MVFR becoming VFR south. W wind around 10 kt becoming NW.

Wednesday night...VFR. NW wind around 5 kt.

Thursday...MVFR dropping to IFR. Light and variable wind becoming SE around 10 kt late.

MARINE

Winds and seas remain below SCA levels into this afternoon. Winds increase over the outer waters to aoa 25kts in the afternoon with gale conditions Monday morning in northeast winds. Expect that gales will continue through the day on Monday. SCA issued for intracoastal from 00z tonight through 00z Tuesday with seas and winds above small craft levels.

A SCA, and possibly a gale for the offshore waters, will be needed Monday evening, dropping below SCA early Tuesday morning. A SCA will be needed Tuesday night into Wednesday evening. Winds will be below SCA Thursday morning then increase to SCA Thursday afternoon. A gale will likely be needed Thursday night. Seas up to 7 ft Monday evening, dropping to 4 ft late Tuesday. Seas will build back up to 9 ft late Wednesday then drop back to 4 ft Thursday. Seas will rapidly build Thursday night reaching around 12 ft by late at night in response to a gale south wind.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Winter Weather Advisory from 10 AM this morning to midnight EDT tonight for MEZ003-004. Winter Weather Advisory from 8 AM this morning to 4 AM EDT Monday for MEZ010-011-015>017-029>032. MARINE...Gale Watch from Monday morning through Monday evening for ANZ050-051. Small Craft Advisory from 8 PM this evening to 8 PM EDT Monday for ANZ052.