Early December Wind & Rain Storm

URGENT - WEATHER MESSAGE

National Weather Service Caribou ME

918 PM EST Fri Dec 8 2023

MEZ006-011-015>017-029-030-032-091100-

/O.CON.KCAR.HW.A.0003.231211T0600Z-231212T0000Z/

Southeast Aroostook-Central Penobscot-Southern Penobscot-

Interior Hancock-Central Washington-Coastal Hancock-

Coastal Washington-Northern Washington-

Including the cities of Houlton, Hodgdon, Sherman, Smyrna Mills,

Lincoln, Howland, Springfield, Bangor, Brewer, Orono, Old Town,

Amherst, Aurora, Dedham, Eastbrook, Great Pond, Calais,

Grand Lake Stream, Wesley, Princeton, Ellsworth, Bar Harbor,

Bucksport, Orland, Castine, Eastport, Perry, Machias,

Cherryfield, Danforth, Vanceboro, and Topsfield

918 PM EST Fri Dec 8 2023

...HIGH WIND WATCH REMAINS IN EFFECT FROM LATE SUNDAY NIGHT

THROUGH MONDAY EVENING...

* WHAT...South winds 35 to 45 mph with gusts up to 70 mph

  possible. The higher gusts will be on the coast.

* WHERE...Southeast Aroostook, Central Penobscot, Southern

  Penobscot, Interior Hancock, Central Washington, Coastal

  Hancock, Coastal Washington and Northern Washington Counties.

* WHEN...From late Sunday night through Monday evening.

* IMPACTS...Damaging winds could blow down trees and power

  lines. Widespread power outages are possible. Travel could be

  difficult, especially for high profile vehicles.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecasts and warnings for updates on this

situation. Fasten loose objects or shelter objects in a safe

location prior to the onset of winds.

&&

$$

000

FXUS61 KCAR 090214

AFDCAR

Area Forecast Discussion

National Weather Service Caribou ME

914 PM EST Fri Dec 8 2023

.SYNOPSIS...

High pressure will cross the area overnight. A warm front will

approach Saturday then cross the region Saturday night.

Intensifying low pressure will track across Maine Monday and

will draw a cold front across the region Monday evening. High

pressure builds Monday night into Tuesday.

&&

.NEAR TERM /THROUGH SATURDAY/...

9:14 PM Update: Satellite pictures show a clear sky across the

FA. There will be an increase in high and mid level clouds from

the west late tonight. The 00z Caribou sounding showed the

development of a low level inversion, and temperatures overnight

will be the lowest in the sheltered valleys. Even in Bangor and

Downeast it will another cold night with light/calm wind and

snow cover. Made minor adjustments to the forecast elements for

the remainder of the night, but overall the changes were minor

as the forecast remains on track. Did make some adjustments for

Saturday morning to slow the arrival of the patchy freezing

drizzle across the central highlands.

Previous discussion:

The upper level ridge will move across the state tonight and

Saturday. For tonight, guidance shows the winds calming with the

surface ridge moving over the region. This coupled with

snowpack and clear skies, ample radiational cooling is expected.

The current forecast has temps bottoming out at single digits

below zero in the north and single digits above zero in the

south. RH models show the approaching cloud deck after midnight

with the shortwave energy moving over the crest of the mid level

ridge. In addition, winds will shift to the S with the warm

front moving to the north. This will help keep temps from

falling further during the night.

By Friday, the ridge will move E out over the waters as the warm

front settles in to the north. Clouds will increase across the

region as the system moves in. Low level moisture and up slope

flow will produce light precip across the Central Highlands and

into Southern Aroostook. Upper air model soundings show a warm

nose ahead of the warm advection, making for freezing drizzle

along the moisture band, starting in the morning, then expanding

NE in the afternoon. Though ice accumulations will be trace at

best, any freezing drizzle can make travel difficult. Any

accumulation is expected to be in the up slope areas in the

Central Highlands mainly southern Piscatiquis and some areas in

northern Penobscot. Temps expected to reach into the low 30s in

the north and upper 30s in the south.

&&

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

Warm advection and increasing cloudiness will the story for the

rest of the weekend. The concern for Saturday night will be

freezing drizzle...most notably in upslope locations such as

Piscataquis County and northern Penobscot County. Critical

thicknesses will be far too high for snow. The cold air

remaining will be a shallow wedge under the frontal inversion. Low

temperatures will occur in the evening and then tend to rise

slowly for the remainder of the night.

Strong low level moisture advection and warming temperatures

over existing snow pack will likely result in fog formation

Saturday night into Sunday morning for much of the area.

Any frozen precip exits the area early Sunday morning. Low

clouds will remain entrenched over the area all day, but warm

advection will lift temperatures towards the mid-upper 40s to

lower 50s for Bangor and the coast. Fog will linger through the

morning, and may end up staying all day given the temp/moisture

advection and in spite of increasing south winds later in the

day.  Light rain and drizzle can be expected Sunday, but the

heavier precip will remain west until Sunday night.

The big event starts Sunday night. The first question will be

the location of a weak northern stream cold front. The location

of this front sets the stage for events later in the night and

Monday. This cold front stalls over the area Sunday night and

then deep moisture rides northward along the boundary. Where the

boundary sets up will determine where the heaviest rains occur

and where damaging winds occur.

Thermal gradients along the boundary tighten significantly

Sunday night into Monday. The upper flow become parallel to the

boundary and anomalous PWs climb to near record numbers. The

northward moisture transport will be accelerated by a 100 kt low

level jet. Instability aloft is also showing in forecast

soundings. This all points to an axis of heavy rainfall that

will total to 2 to 3 inches where the boundary sets up. The area

remains in a marginal risk from the WPC ERO Sunday night into

Monday.

Guidance varies on the boundary position. 12Z model runs vary

from a more south and east placement from ECMWF and GEMS while

NAM and GFS are further west. Have taken a compromise position

that places the heaviest rain from southern Piscataquis County

towards northern Aroostook County. This axis is also favored by

orography.

Explosive cyclogenesis takes place along the boundary Sunday

night into Monday. Numerous models are showing a rapidly

deepening bomb moving along the boundary across Maine on Monday

as the upper trough develops negative tilt and then closes off

late Monday.

The potential for damaging winds exists on the south side of the

boundary. For the second day in a row, we leaned toward NBM

winds which have worked well during Sou`easters in recent years.

We have issued a High Wind Watch where confidence was highest.

If NAM and GFS verify, we may need to expand northward.

Confidence in winds meeting warning criteria is highest for

Hancock and Washington counties. Even ensemble means are

pointing towards gusts to 70 mph on the coast. The potential for

gusts over 60 mph may extend across all of eastern Maine if the

inversion breaks as suggest by recent GFS runs. These winds and

the expected ground state adds up the potential for widespread

power outages.

Depending on the low track, snow is a possibility for the far

northwestern border of Aroostook and Somerset counties. Do not

foresee any advisories at this point, but it is possible if the

low track shifts east.

&&

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

Winds shift to the west and cold air advection occurs behind the

departing low. There will be a brief period of snow...mostly in

Aroostook County with an inch or two possible Monday evening.

The west winds will gust over 30 mph throughout the night. Not

too concerned about any flash freeze. The biggest travel threat

will be those snow accumulations on the backside of the low.

Temperatures will drop off into the 20s...which will certainly

be unpleasant for those without power. Highs on Tuesday do not

recover that much...upper 20s north and low-mid 30s for Bangor

and Downeast. Winds die off during the day to help with power

restorations.

The remainder of the period features quiet weather with the risk

of moisture-starved northern stream clippers. No significant

replenishment of snowpack is likely. Temperatures will be

mostly seasonable without any Arctic outbreaks.

Hazardous Weather Outlook

National Weather Service Caribou ME

338 PM EST Fri Dec 8 2023

MEZ001>005-092045-

Northwest Aroostook-Northeast Aroostook-Northern Somerset-

Northern Piscataquis-Northern Penobscot-

338 PM EST Fri Dec 8 2023

This Hazardous Weather Outlook is for Central Highlands Maine, Far

Northern Maine and North Woods Maine.

.DAY ONE...This afternoon and tonight.

Hazardous weather is not expected at this time.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Strong gusty south winds are possible Sunday night into early

Monday. Moderate to heavy rainfall is likely Sunday night into

Monday, and could lead to localized flooding.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather

conditions according to Standard Operating Procedures.

$$

Flood Watch

National Weather Service Gray ME

259 PM EST Fri Dec 8 2023

...Heavy Rain and Snowmelt Flooding Sunday into Monday...

A powerful storm system will bring the widespread heavy rainfall to

western Maine and New Hampshire Sunday Night into Monday. Rainfall

of 1 to 3 inches with some locally higher amounts are possible. This

will combine with melting snow and partially frozen ground to cause

flooding. Flooding along mainstem rivers is also possible. The

widespread rainfall will likely cause travel disruptions from

flooded roads, and possibly property damage near rivers.

MEZ007>009-012>014-018>028-033-NHZ001>015-090800-

/O.NEW.KGYX.FA.A.0024.231210T2000Z-231212T0000Z/

/00000.0.RS.000000T0000Z.000000T0000Z.000000T0000Z.OO/

Northern Oxford-Northern Franklin-Central Somerset-Southern

Oxford-Southern Franklin-Southern Somerset-Interior York-Central

Interior Cumberland-Androscoggin-Kennebec-Interior Waldo-Coastal

York-Coastal Cumberland-Sagadahoc-Lincoln-Knox-Coastal Waldo-

Interior Cumberland Highlands-Northern Coos-Southern Coos-

Northern Grafton-Northern Carroll-Southern Grafton-Southern

Carroll-Sullivan-Merrimack-Belknap-Strafford-Cheshire-Eastern

Hillsborough-Interior Rockingham-Coastal Rockingham-Western And

Central Hillsborough-

Including the cities of Rollinsford, North Hampton, Amherst,

Loudon, Ellsworth, Littleton, Claremont, Croydon, Rumford,

Hooksett, Boscawen, Palmyra, Alna, Lebanon, Milan, Wiscasset,

Sugar Hill, Hanover, Jay, Bryant Pond, Roxbury, Montville,

Woodstock, Arrowsic, Bowdoinham, Bremen, Buxton, Livermore Falls,

Windsor, Waterville, Waldoboro, Camden, Kingfield, Millsfield,

Newport, Brunswick, Locke Mills, Cape Elizabeth, Durham,

Somersworth, Chesterville, Brassua, Coburn Gore, Thomaston,

Plymouth, Seabrook, Limington, Laconia, Keene, Berlin, Topsham,

Wakefield, Wolfeboro, Canterbury, Newcastle, Charlestown,

Gilford, Waterville Valley, Grantham, Newton, Goshen, Hope,

Dummer, Goffstown, Morrill, Long Pond, Pelham, Bowdoin, Embden,

Gray, Bethel, Yarmouth, Sabattus, Milford, Unity, Brooks,

Portsmouth, Hollis, Lancaster, Middle Dam, Brookfield, Conway,

Weare, Greenland, Augusta, Whitefield, Manchester, North Conway,

New Vineyard, Rockport, Damariscotta, Bridgton, Lewiston, Saco,

Pittston Farm, China, Rye, Boothbay Harbor, New Sharon, Cornish,

Waldo, Bristol, Temple, Bingham, Sanford, Knox, Avon, Oquossoc,

Moosehead, Wales, Hampstead, Rangeley, Gorham, York Pond,

Bridgewater, Nashua, Naples, Northport, Madison, Moultonborough,

Jaffrey, Exeter, Kittery, Byron, Portland, Pittsfield,

Lincolnville, Belfast, Dresden, Berwick, Appleton, Dover,

Colebrook, Dunbarton, Madbury, Wilsons Mills, Goodwins Mills,

Barrington, Gilsum, Liberty, Owls Head, Searsmont, Newry,

Winterport, Skowhegan, Alfred, Bath, Chester, Derry, Vassalboro,

North Windham, Westbrook, Phippsburg, Old Orchard Beach, Sharon,

Marlow, Lempster, Lincoln, Seboomook, New Gloucester, Biddeford,

Palermo, Atkinson, South Portland, Ashland, Meredith, Mont

Vernon, Rumney, Greene, Sidney, Lyme, Harrison, Albany, South

Arm, Plaistow, Jackson, Cornville, Davis, Surry, Sullivan,

Rockland, Turner, Peterborough, Ossipee, Hampton, Jackman,

Milton, Thornton, Athens, Norway, Minot, Rochester, New Portland,

Chatham, Crawford Notch, Salem, Upton, Fryeburg, Tuftonboro,

Farmington, Bethlehem, Phillips, Andover, Auburn, Concord,

Holderness, Hampton Falls, Oxford, Errol, and Wilton

259 PM EST Fri Dec 8 2023

...FLOOD WATCH IN EFFECT FROM SUNDAY AFTERNOON THROUGH MONDAY

EVENING...

* WHAT...Flooding caused by rain and snowmelt is possible. Heavy

  rainfall of 1 to 3 inches with isolated amounts up to 4 inches is

  possible across New Hampshire and western Maine.

* WHERE...Portions of Maine, including the following areas,

  Androscoggin, Central Interior Cumberland, Central Somerset,

  Coastal Cumberland, Coastal Waldo, Coastal York, Interior

  Cumberland Highlands, Interior Waldo, Interior York, Kennebec,

  Knox, Lincoln, Northern Franklin, Northern Oxford, Sagadahoc,

  Southern Franklin, Southern Oxford and Southern Somerset and New

  Hampshire, including the following areas, Belknap, Cheshire,

  Coastal Rockingham, Eastern Hillsborough, Interior Rockingham,

  Merrimack, Northern Carroll, Northern Coos, Northern Grafton,

  Southern Carroll, Southern Coos, Southern Grafton, Strafford,

  Sullivan and Western And Central Hillsborough.

* WHEN...From Sunday afternoon through Monday evening.

* IMPACTS...River and stream flooding as well as low lying and urban

  flooding is likely. Unprotected property near river banks may be

  inundated by flood waters.

* ADDITIONAL DETAILS...

  - Heavy rainfall along with warm temperatures will cause

    melting of the snow pack from the foothills southward. This

    will increase the runoff into streams and rivers. Moderate to

    heavy rainfall over partially frozen ground will support the

    potential for flash flooding as well as river flooding.

    Disruptions to travel is likely on Monday.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor the latest forecast and be alert for possible

Flood Warnings. Those living in areas prone to flooding should be

prepared to take action should flooding develop.

&&

$$

Legro