Christmas Week Weather Bomb Update One

12:23 AM AST Tuesday 21 December 2021

Special weather statement in effect for:

Halifax Metro and Halifax County West

Significant rainfall is expected.

Total rainfall: 25 to 40 mm. Locally higher amounts possible.

Maximum wind gusts: possibly greater than 80 km/h.

Locations: Nova Scotia.

Time span: Wednesday ending Thursday morning.

Remarks: Rain is expected to spread from west to east across the province Wednesday. Precipitation may begin as a brief period of snow or freezing rain before changing to rain Wednesday evening over parts of the northern mainland and Cape Breton. Rain may switch to a period of heavy wet snow for a time before ending Thursday morning in some areas making travel difficult. At this time the highest rainfall totals and strongest winds are expected near the Atlantic coast.

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

12:23 AM AST Tuesday 21 December 2021

Special weather statement in effect for:

Queens County P.E.I.

Significant snow, rain and wind is expected.

Total snowfall: Possibly exceeding 15 cm.

Total rainfall: 15 to 25 mm. Locally higher amounts possible.

Maximum wind gusts: possibly exceeding 80 km/h.

Locations: Prince Edward Island

Time span: Wednesday afternoon through Thursday morning.

Remarks: Snow is expected to begin Wednesday afternoon and may mix with freezing rain before changing to rain Wednesday evening. Rain will likely change back to a period of heavy wet snow Thursday morning in strong west to northwest winds. At this time the highest snowfall totals are expected up west, with the greatest rainfall totals down east. The mixture of precipitation types and strong winds will likely lead to poor travel conditions.

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

000

FXUS61 KCAR 210229

AFDCAR

Area Forecast Discussion

National Weather Service Caribou ME

929 PM EST Mon Dec 20 2021

.SYNOPSIS...

High pressure will exit to the southeast overnight. A cold

front will cross the area Tuesday morning followed by high

pressure Tuesday night. Low pressure will strengthen southeast

of the area Wednesday and lift across the Maritimes Wednesday

night. High pressure will build over the area Thursday into

Friday. A warm front will approach the area this weekend.

&&.....

........SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...

High pressure overhead early Tuesday night will move eastward

after midnight. Expect high temperatures to occur around or

prior to 6z, followed by steady or rising temperatures through

sunrise Wednesday as clouds and winds aloft increase. With fresh

snowpack, some of the cooler valleys of northern Maine should

drop to near or below 0 prior to clouds moving in.

Guidance has trended towards a more amplified northern stream

shortwave trough for Wednesday, which has caused earlier phasing

with the southern stream shortwave along the Eastern Seaboard

and significant increases in snow and QPF amounts among the GFS,

NAM, and European models. This is associated with a stronger

surface low tracking further northwest compared to previous

runs. While not all guidance agrees, confidence is increasing in

at least a moderate impact snowfall across northern Maine.

Based on the 12z GFS ensemble, all but 1 of the 30 members have

at least 4 inches of snow in Caribou, and nearly 70 percent have

warning criteria of 7 inches. The 12z European ensemble was

unavailable at the time of writing, but has trended up steadily

over the past few cycles. The last minute phasing favors heavier

snow amounts across northeastern portions of the area, where a

Winter Storm Watch has been issued for northern Penobscot County

and all of Aroostook County. The watch includes northwestern

Aroostook County mainly for the eastern portions of the zone

where most of the zones population resides. If phasing occurs

even slightly sooner, a stronger low would result in snow

amounts well above warning criteria over portions of the watch

area and require an expansion of the watch. Likewise, if phasing

occurs even slightly slower snow amounts may be below warning

criteria. At this time some 0z guidance and the Canadian was

blended in to soften the sharp trend upwards and not go all in

with very heavy snow amounts as shown on the GFS/European

models. The 25th percentile of snow ratios was also preferred

given the potential for stronger winds lowering ratios in the

case of a strong system. However, locally higher snow ratios are

possible in any heavier snow bands across the far north

wherever, depending on the low track, the strongest band of 700h

frontogenesis lines up with the dendritic growth zone. The

heaviest precipitation will occur Wednesday afternoon and into

the evening. Mainly rain is expected along the coast. Depending

on the low track, significant mixed precipitation or a

transition to rain could occur across Interior Downeast,

including the Bangor area, so lower amounts are forecast over

these areas.

Precipitation will taper to flurries and end Wednesday night. As

high pressure builds in, expect winds to increase, particularly

by morning with weak surface heating beginning. Patchy blowing

snow is expected across areas that receive all snow during the

day Thursday. Otherwise, temperatures will be cold with highs in

the upper teens to low 20s and wind chills near or below zero.

&&.....

URGENT - WINTER WEATHER MESSAGE

National Weather Service Caribou ME

817 PM EST Mon Dec 20 2021

MEZ001-002-005-006-211200-

/O.CON.KCAR.WS.A.0007.211222T1400Z-211223T0500Z/

Northwest Aroostook-Northeast Aroostook-Northern Penobscot-

Southeast Aroostook-

Including the cities of Mars Hill, Sherman, Houlton, Fort Kent,

Frenchville, East Millinocket, Millinocket, Clayton Lake, Van

Buren, Madawaska, Presque Isle, Smyrna Mills, Medway, Ashland,

Patten, Hodgdon, Caribou, and Allagash

817 PM EST Mon Dec 20 2021

...WINTER STORM WATCH REMAINS IN EFFECT FROM WEDNESDAY MORNING

THROUGH WEDNESDAY EVENING...

* WHAT...Heavy snow possible. Total snow accumulations greater than

  7 inches possible.

* WHERE...Northern Penobscot, Southeast Aroostook, Northeast

  Aroostook and Northwest Aroostook Counties.

* WHEN...From Wednesday morning through Wednesday evening.

* IMPACTS...Travel could be very difficult. The hazardous conditions

  could impact the Wednesday evening commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Watch means there is potential for significant snow,

sleet or ice accumulations that may impact travel. Continue to

monitor the latest forecasts.

&&

$$

Nouhan