Black Friday Winter Storm Update One

8:24 PM AST Friday 26 November 2021

Special weather statement in effect for:

Fredericton and Southern York County

Significant snowfall tonight and Saturday.

Total 24-hour snowfall forecast: 10 to 15 cm, possibly 20 over higher terrain.

Locations: western and central New Brunswick, including the City of Fredericton.

Remarks: A mixture of wet snow and rain will quickly transition to snow this evening, with widespread amounts of 10 to 15 cm. The snowfall will be heavy at times and may make travel difficult. The precipitation will taper off Saturday evening.

Be prepared to adjust your driving with changing winter road conditions. When clearing snow from your property, remember to take frequent breaks.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to NBstorm@ec.gc.ca or tweet reports using #NBStorm.

000

FXUS61 KCAR 270307

AFDCAR

Area Forecast Discussion

National Weather Service Caribou ME

1007 PM EST Fri Nov 26 2021

.SYNOPSIS...

Intensifying low pressure will lift across the Maritimes

overnight through Sunday. Another low crosses the Gulf of

Maine and exits across the Maritimes by Monday evening. High

pressure will ridge across the region on Tuesday, while another

low moves across northern Maine on Wednesday.

&&

.NEAR TERM /THROUGH SATURDAY/...

1000 PM Update: Latest radar imagery shows the dynamic snow band

across the N gradually diminishing in size and intensity with a

break ovr Cntrl an Downeast areas. However, new deformation

banding is beginning to form and intensify ovr SW coastal ME,

and this area will begin to move into Downeast areas late tngt

as Nrn areas get a brief break in snfl. So far, highest reported

snfl amts range upwards to 4 to 6 inches across the N where

precip at the start msly began as sn with sn ratios since late

aftn were upwards to 16 to 17:1 despite sn falling between 31 to

33 deg F. Sn ratios have come down some to 10 to 13:1 for now.

Otherwise, fcst hrly temps/dwpts were updated into the erly morn

hrs Sat to unchgd ovrngt lows. With little temp fall

experienced across the FA since late aftn, the fall of temps

will be delayed to msly after mdngt when more sig llvl cold

advcn begins.

Prev Disc: No changes were made to the Winter Storm

Warning/Winter Weather Advisory headlines. An intensifying

surface low located along the Maine coast early tonight, will

lift north across New Brunswick overnight along with a closed

upper low. However, whether the track is closer to the Maine/New

Brunswick border, or more across central New Brunswick, is

still uncertain. A more western track would favor heavier

precipitation across eastern portions of the forecast area

tonight. Models indicate an area of focused lift and Q-vector

convergence lifting north across the forecast area tonight with

a developing deformation zone which will help support

precipitation. The location and movement of the deformation zone

will also impact snow accumulations. Precipitation will remain

in the form of snow across northern areas tonight. Based on

critical thicknesses, a rain/snow mix will occur across central

areas early tonight with mostly rain Downeast. Cold air

advection with the deepening low will then allow a transition to

snow southward across the forecast area through the evening.

The vertically stacked system tracks north to the Gaspe

Peninsula Saturday. The most persistent snows Saturday will

occur across northern and central areas with the deformation

zone lifting north. Across Downeast areas, early snow will taper

to snow showers during the afternoon. Additional snow

accumulations are expected Saturday, with the greater amounts

across the north and mountains. Storm total snow accumulations

through Saturday are expected to range from 5 to 10 inches

across northern areas, with 4 to 7 inches across central areas

and 3 to 6 inches Downeast. Gusty winds could support patchy

blowing snow across northern areas Saturday. Low temperatures

tonight will range through the 20s north, to the upper 20s to

around 30 Downeast. High temperatures Saturday will range from

the upper 20s to around 30 north, to the lower to mid 30s

Downeast.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...

The nrn 1/2 of the region will still be feeling some effects of

that low lifting across the Gulf of the St. Lawrence on

Saturday night w/some snow showers and breezy conditions.

Additional accumulations of around an inch are possible in the

St. John Valley and back into the N Woods. The central areas

will see less clouds but it will be turning colder as the latest

mdl guidance, such as the GFS and the ECMWF, show some of the

coldest air of the season pouring into the region right into

Monday. Temps on Sunday will be lucky to bust 30F across the nrn

1/2 of the region, while central and downeast areas should

sees/low mid 30s w/a good deal of sunshine and less wind. Weak

high pres building in later Sunday into Sunday night. Clearing,

lighter winds and the cold airmass in place along w/snow cover,

will lead to some pretty cold overnight lows for late November.

We are talking upper single number up across the nrn border and

to the w.

Monday could turn out to be an interesting day. The 12Z mdl

guidance continued to follow its previous runs w/a cutoff low

in the upper levels apchg from the w Sunday night w/increasing

clouds by the early morning hrs on Monday. A sfc low is forecast

to develop just off the srn New England coast and lift nne on

Monday. There are still some discrepancies in regards to

placement and timing of the precip, which looks to be in the

form of snow all the way into the Downeast region. As stated by

the midnight crew, the ECWMF and its ensembles are further w

w/some measurable snowfall, and the 12Z run has stayed the

course. The 12Z Canadian has shifted w as have some of the GEPS

members. The GFS has continued w/an eastwards track, but a light

to the w. We`ll have to see how the latest mdl guidance trends

w/the newer runs over the day or so. For now, decided to trend

to the w, but not as far as the ECMWF and Canadian, as the

latest NBM is more neutral w/its track. So, leaned w/pops up to

60% across the eastern 3rd of the region for Monday and went

w/just snow. If the westward trend does continue, we could be

seeing some more measurable snow w/in the 4 inch range by

Monday evening.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...

As stated by the midnight crew, we appear to get into

a more progressive pattern w/a series of systems affecting the

region, albeit fairly weak.

After the low pulls through the Maritimes Monday night, high

pres is expected for Tuesday w/lighter winds, some possible

sun, but still rather cold for the last day of November. Another

fast moving system is shown by the longer range guidance is

forecast to move across northern Maine w/some more snow by

Wednesday. Although, this system looks to deliver light snow

w/minor accumulations. High pres to move in for Thursday w/sun

and drier conditions. For Friday, there is potential for yet

another storm system which could a significant snow as it moves

up along the Maine coast. Still plenty of time to see how this

system takes shape. At any rate, temps through this term are

expected to be near or slightly below normal for the 1st couple

of days of December.......