Saturday, December 09, 2023

Early December Wind & Rain Storm Update One






































10:22 PM AST Saturday 9 December 2023
Rain and strong winds are expected on Monday. 

Maximum wind gusts: southerly 70 to 80 km/h except 100 km/h over exposed areas.

Location: Nova Scotia

Time span: Monday morning until late Monday evening.

Remarks: The strongest winds will occur over the western parts of the province from Monday morning until late Monday afternoon. Over eastern Nova Scotia, the strongest winds are expected from mid-afternoon Monday until late Monday evening. 

At this time, total rainfall amounts are not expected to be significant. However, a period of heavy rain is possible during the strongest winds.

In addition, elevated water levels and large waves are expected along 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.


10:09 PM AST Saturday 9 December 2023
Significant rainfall and strong winds are expected. The frozen ground has reduced ability to absorb this rainfall. 

Total rainfall: 30 to 50 mm. Locally higher amounts possible.

Maximum wind gusts: southerly 60 to 70 km/h except 90 to 100 km/h over exposed areas. (Mainly over the southern and eastern parts of the province).

Location: southern and northeastern New Brunswick.

Time span: Sunday evening until late Monday.

Remarks: The heaviest rainfall is most likely to occur over the central and western parts of the province. The strongest winds are most likely to occur in the southern and eastern parts of the province.

In addition, very mild temperatures and rapid snowmelt are expected, contributing to water runoff.

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.


10:06 PM AST Saturday 9 December 2023
Rain, heavy at times is expected. The frozen ground has a reduced ability to absorb this rainfall.

Total rainfall: 30 to 40 mm by Monday morning. Possibly exceeding 80 by Monday night.

Location: northwestern New Brunswick

Time span: beginning Sunday evening and continuing until Monday evening.

Remarks: Strong winds and mild temperatures will accompany the rain, leading significant snowmelt and run-off. The rain is likely to change to snow over parts of the northwest before ending Monday night.

Localized flooding in low-lying areas is possible.

If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop.

Rainfall warnings are issued when significant rainfall is expected.

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.


10:06 PM AST Saturday 9 December 2023
Strong winds are expected on Monday. 

Maximum wind gusts: southerly 70 to 80 km/h except 100 km/h over exposed areas.

Location: Prince Edward Island.

Time span: near noon Monday through Monday evening.

Remarks: The strongest winds will likely occur from late Monday afternoon until early Monday evening.

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.


Flood Watch
National Weather Service Caribou ME
944 PM EST Sat Dec 9 2023

MEZ002-004>006-010-011-015>017-029>032-101100-
/O.CON.KCAR.FA.A.0009.231211T0600Z-231212T1200Z/
/00000.0.RS.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Northeast Aroostook-Northern Piscataquis-Northern Penobscot-
Southeast Aroostook-Central Piscataquis-Central Penobscot-
Southern Penobscot-Interior Hancock-Central Washington-Coastal
Hancock-Coastal Washington-Southern Piscataquis-Northern
Washington-
Including the cities of Eastbrook, Bar Harbor, Smyrna Mills,
Cherryfield, Great Pond, Topsfield, Dedham, Princeton, Castine,
Orono, Danforth, Houlton, Baxter St Park, Bangor, Ellsworth,
Hodgdon, Vanceboro, Chamberlain Lake, Springfield, Machias,
Eastport, Greenville, Van Buren, Presque Isle, Medway, Blanchard,
Mount Katahdin, Amherst, Calais, Wesley, Milo, Grand Lake Stream,
Howland, Aurora, Caribou, Churchill Dam, Old Town, Guilford, East
Millinocket, Mars Hill, Ashland, Bucksport, Dover-Foxcroft,
Orland, Millinocket, Monson, Lincoln, Patten, Brewer, Perry, and
Sherman
944 PM EST Sat Dec 9 2023

...FLOOD WATCH REMAINS IN EFFECT FROM LATE SUNDAY NIGHT THROUGH
TUESDAY MORNING...

* WHAT...Flooding caused by rain and snowmelt continues to be
  possible.

* WHERE...Portions of Central Highlands, Coastal DownEast, Far
  Eastern, Far Northern, Interior DownEast, North Woods, and
  Penobscot Valley Maine, including the following areas, in Central
  Highlands Maine, Central Piscataquis, Northern Penobscot and
  Southern Piscataquis. In Coastal DownEast Maine, Coastal Hancock
  and Coastal Washington. In Far Eastern Maine, Northern Washington
  and Southeast Aroostook. In Far Northern Maine, Northeast
  Aroostook. In Interior DownEast Maine, Central Washington and
  Interior Hancock. In North Woods Maine, Northern Piscataquis. In
  Penobscot Valley Maine, Central Penobscot and Southern Penobscot.

* WHEN...From late Sunday night through Tuesday morning.

* IMPACTS...Excessive runoff may result in flooding of rivers,
  creeks, streams, and other low-lying and flood-prone locations.
  Creeks and streams may rise out of their banks. Flooding may occur
  in poor drainage and urban areas. The Piscataquis River is
  expected to reach minor flood stage with a rapid response to
  snowmelt plus rainfall in complex terrain.

* ADDITIONAL DETAILS...
  - Flooding caused by a combination of rain and snow melt
    continues to be possible.  Heavy rainfall combined with warm
    temperatures will melt most, if not all snow. The heavy rain,
    snowmelt, and high rainfall rates over a partially frozen
    ground will create a scenario promoting small stream, creek
    and river flooding.
  - http://www.weather.gov/safety/flood

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood
Warnings. Those living in areas prone to flooding should be prepared
to take action should flooding develop.

&&
$$

CB


URGENT - WEATHER MESSAGE
National Weather Service Caribou ME
906 PM EST Sat Dec 9 2023

MEZ029-030-101015-
/O.CON.KCAR.HW.W.0004.231211T0600Z-231212T0000Z/
Coastal Hancock-Coastal Washington-
Including the cities of Ellsworth, Bar Harbor, Bucksport, Orland,
Castine, Eastport, Perry, Machias, and Cherryfield
906 PM EST Sat Dec 9 2023

...HIGH WIND WARNING REMAINS IN EFFECT FROM 1 AM TO 7 PM EST
MONDAY...

* WHAT...South winds 30 to 50 mph with gusts up to 70 mph
  expected.

* WHERE...Coastal Hancock and Coastal Washington Counties.

* WHEN...From 1 AM to 7 PM EST Monday.

* IMPACTS...Damaging winds will blow down trees and powerlines.
  Numerous to widespread power outages are likely. Travel will
  be difficult, especially for high profile vehicles.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People should avoid being outside in forested areas and around
trees and branches. If possible, remain in the lower levels of
your home during the windstorm, and avoid windows. Use caution if
you must drive.

&&
$$


Special Weather Statement
National Weather Service Caribou ME
829 PM EST Sat Dec 9 2023

MEZ001>006-010-011-015>017-031-032-100900-
Northwest Aroostook-Northeast Aroostook-Northern Somerset-
Northern Piscataquis-Northern Penobscot-Southeast Aroostook-
Central Piscataquis-Central Penobscot-Southern Penobscot-
Interior Hancock-Central Washington-Southern Piscataquis-
Northern Washington-
Including the cities of Allagash, Clayton Lake, Madawaska,
Fort Kent, Frenchville, Presque Isle, Caribou, Van Buren,
Mars Hill, Ashland, Baker Lake, Billy-Jack Depot, Baxter St Park,
Chamberlain Lake, Churchill Dam, Mount Katahdin, Millinocket,
East Millinocket, Patten, Medway, Houlton, Hodgdon, Sherman,
Smyrna Mills, Greenville, Monson, Blanchard, Lincoln, Howland,
Springfield, Bangor, Brewer, Orono, Old Town, Amherst, Aurora,
Dedham, Eastbrook, Great Pond, Calais, Grand Lake Stream, Wesley,
Princeton, Dover-Foxcroft, Milo, Guilford, Danforth, Vanceboro,
and Topsfield
829 PM EST Sat Dec 9 2023

...Areas of Fog and Patchy Freezing Drizzle Tonight...

Areas of fog are expected across the region tonight with locally
poor visibility. Motorists should use caution and be prepared for
areas of reduced visibility. In addition to the fog, patchy
freezing drizzle is expected. The freezing drizzle will cause
patches of ice on any untreated surfaces. If you have travel plans
tonight, please use caution and be aware that travel conditions
may change rapidly over short distances.

$$

CB


000
FXUS61 KCAR 100200
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
900 PM EST Sat Dec 9 2023

.SYNOPSIS...
A warm front crosses the region overnight into Sunday.
Intensifying low pressure tracks across Maine Monday and will
draw a cold front across the region Monday evening. High
pressure builds Monday night into Tuesday. A cold front moves
through Wednesday. High pressure builds to the south of the
region Thursday.

&&

.NEAR TERM /THROUGH SUNDAY/...
9 PM Update: Low clouds along with fog/freezing fog and patchy
drizzle along the coast and freezing drizzle inland the
remainder of tonight. Temperatures will slowly moderate
overnight with the freezing drizzle to transition to drizzle by
Sunday morning for all areas. A special weather statement was
issued for both the fog and freezing drizzle through early
Sunday morning for all inland areas. No significant changes
planned at this time.

Previous discussion:
A warm front will slowly lift through the area tonight into
early Sunday. While there is strong warm advection and decent
thermal gradients, there is little lift and no precip outside of
drizzle or freezing drizzle. Not expecting measurable
precipitation, so will continue to handle with Special Weather
Statements. Nonetheless, the freezing drizzle has caused traffic
troubles this afternoon and can be expected to continue
delivering locally treacherous conditions tonight. The warm
advection will cause temperatures to slowly rise overnight.
Along with rising temperatures from south to north, the freezing
drizzle will progress northward and exit the entire forecast
area by daybreak. The drizzle is very low level and will not
show up on radar.

The frontal inversion will persist tonight through Sunday. The
strong warm temperature and moisture advection will produce
increasing coverage of fog tonight into Sunday. It is possible
that a Dense Fog Advisory will become a consideration as dew
points well into the 40s surge northward over the cold, snow-
covered ground. With south winds, upslope effect will accentuate
fog and drizzle in Piscataquis and northern Penobscot counties.
Winds aloft will increase Sunday, but with the steep inversion,
expect minimal mixing.

A weak cold sags southeast into the forecast area from the
northwest on Sunday afternoon. The cold front will cause
steadier rain to develop in the afternoon except Downeast where
the fog and drizzle regime will linger.

With the warm advection, highs will creep into the mid 40s north
and low to mid 50s towards Bangor and Downeast. These highs will
not be achieved until late day.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
Significant Storm to Impact Maine Sun Night into Monday...

Setup...A boundary will be in place across the St. John Valley
southward to around the Moosehead Region. 12z operational runs
have shifted this boundary slightly more east which complicates
the forecast. If this trend continues we will need a shift in
wind, rain and snow axes. Opted to take a blend of the NBM, 12z
GFS and NAM shifting this boundary from Van Buren to Moosehead.
Extremely potent energy will be diving around the base of the
trof over the Ohio Valley and will tilt the trof negatively
quickly Sun night. At the same time strengthening jet stream
will set up upper level divergence over the NYC area where
surface cyclogenesis will rapidly take shape. At the same time
strengthening low-level jet will develop and push north towards
Maine increasing into Monday. Surface low pressure as it track
towards Boston by Mon AM and Maine by Mon midday will be
"bombing" out with extremely rapid deepening. This low will
track through Maine during the and into New Brunswick by mid to
late afternoon and into the Maritimes by early Tuesday AM.

Precip...Given deepening surface convergence along the front
over Maine combined with the potent shortwave and low pressure
expecting moderate to heavy rain to develop Sun night into Mon
midday. Southerly winds will favor increased upslope along the
Longfellow Mtns in the Central Highlands to Baxter region.
Widespread rainfall totals by Mon afternoon expected to be 2-2.5
inches with 1.5-2.0 inches along the immediate coast and
2.5-3.25 inches in the upslope areas of the Central Highlands.
Rain will be falling on the snowpack causing significant runoff
into the area rivers, creeks and streams causing significant
rises, see the hydrology section below. Across the North Woods
west of the front the low pressure tracks on will have increased
low-level cold air advection. This will result in a much colder
sounding, based on the latest operational runs. This will
result intially rain changing to wet snow late Sun night into
Mon AM with light to moderate snow expected into Monday before
tapering late day. This is a complex part of the forecast with
models trending east with the boundary which could cause more
snow east to the Route 11 corridor north of Patten. Rain will
change briefly to snow across much of the northern zones late in
the day Monday as temperatures crash to freezing. This will
likely result in refreeze on untreated surfaces. At this point
given the uncertainty will not hoist winter headlines for now.
Given the increasing confidence in heavy rainfall + snowmelt and
rapid river responses opted to expand the Flood Watch to
include everyone except the far North Woods and western St. John
Valley.

Winds...Late Sun Night the 925mb low-level jet will increase
80-95kt over the Gulf of Maine waters and work into Downeast
Maine. The majority of this low-level jet will be below the
inversion and decent mixing suggests large chunk of these winds
will make it to the coastal areas of the Downeast. Friction will
cut this jet down as it penetrates inland over Maine but still
expecting some winds to mix down. The caveat to this will be
the exact track of the low pressure. With a slight shift today
combined with uncertainty on the strongest winds have opted to
keep High Wind Watches up for Southern Aroostook into interior
Downeast including Bangor region. Confidence is high for
southerly wind gusts reaching 60-70mph at the Downeast coast
opted to upgrade to a High Wind Warning. Significant to
widespread power outages from tree damage is likely in these
areas. Inland for the watches will give it another model cycle
before deciding if we upgrade to advisories or warnings. Winds
after the shift in the wake of the storm Monday night will be
gusty from the W-NW gusting up to 30-35mph all night.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Looking out into the long term ensembles have the NAO turning
positive around +1SD and also the PNA turning positive +1SD as
well. This within a positive ENSO pattern will keep much of the
area with more progressive systems with less precipitation and
temperatures generally around normal. A few isolated snow
showers on Wednesday with a weak clipper-like boundary sliding
through the area with a 500mb shortwave transitioning over the
area. Thursday into Friday we have generally 500mb ridging
moving overhead but significant timing differences between the
global operational runs. Thursday AM lows might be the coldest
with high pressure overhead and full decoupling. Opted to keep
near the NBM blend for now but cannot rule out negative single
digit lows across the northern 1/3rd of the CWA......

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