Destructive Subtropical System Update Two

000

FXUS61 KCAR 180317

AFDCAR

Area Forecast Discussion

National Weather Service Caribou ME

1017 PM EST Sun Dec 17 2023

.SYNOPSIS...

Strong low pressure will track up the East Coast on Monday then

pass to our west and continue north into Canada Monday night

into Tuesday. High pressure will slowly build into the area from

the northwest Wednesday into Friday.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...

1015pm update...Rain is overspreading the area at this time and

will pick up in intensity later tonight. Low level moisture

spreading north is causing some areas of fog...most notably in

higher terrain. Temperatures will continue to rise all night.

The ongoing forecast for the Sou`easter looks good and no

substantive changes were made. The three major threats remain in

place for Monday: winds, flooding rains, and coastal flooding.

Our initial 00Z analysis and review of guidance indicates the

forecast remains on track.

The High Wind Warning for Downeast and the Bangor area continues

to look like an unfortunate reality. The highest winds will be

in the afternoon and early evening. Guidance continues to

advertise a 925mb low level jet with a strength between 80 and

100 kt depending on the model. The max speeds will be on the

coast, but magnitudes of over 60 kt will reach Aroostook County.

Guidance has been consistent on the LLJ for many days now and

confidence is high. We are not dealing with the caveat of a

shifting low track like a week ago. Surface gusts along the

coast around 70 mph are likely to cause widespread power outages

Downeast. Gusts of 55 to 65 mph further inland are a

significant threat to produce scattered to widespread power

outages across the entire forecast area. The previous discussion

below reiterates the concerns and uncertainties.

In terms of rainfall, this is a warm core low with origins deep

in the Gulf of Mexico. Deep moisture is moving north along the

Atlantic Seaboard from the Caribbean and the system has been

producing flooding from Florida northward into North Carolina.

Flood Watches are in place from North Carolina to Maine as the

system moves north tonight and tomorrow. PWs will likely be at

or above record daily readings on Monday along with record high

temperatures. The current Flood Watch looks good with the

heaviest rain moving across the area from mid-morning into late

afternoon Monday. The heaviest rain continues to show up in the

upslope terrain of Piscataquis County north towards the Katahdin

region. Higher terrain locations could see nearly 4 inches of

rain...which is about the threshold associated with road

washouts last week. Did notice a slight uptick in PWs and

overall QPF in recent guidance, but not enough to make changes

in ongoing headlines. The previous discussion below provides

more pertinent details.

The third concern is the coastal flooding. The coastal flooding

section below succinctly lays out the issues for tomorrow

afternoon`s high tide between 230pm and 3pm and the latest

guidance is consistent with our previous forecasts.

Previous discussion...

Have been some glazed roads from freezing drizzle in the Central

Highlands early this afternoon, but generally, temps have risen

above freezing and will continue to rise, and any icy roads

will be ending fast.

Tonight will feature increasing light rain and rising

temperatures to downright balmy levels...with mid 40s to low 50s

around dawn. No flooding concerns through the night as the

heavier rain won`t have arrived yet. Also, winds tonight will be

increasing some, but not impactful yet through the night.

Monday into Monday evening looks very rough. Models are locked

in on the rain and winds, and confidence is quite high on our

forecast rain totals and wind gusts. A strong low pressure will

be tracking north, passing just west of us late Monday. This

puts us under a very anomalously moist, warm, and windy airmass.

Big concerns for heavy rain and strong winds. For the winds,

have converted the high wind watch to a warning and raised gusts

just a little to a max of 70 mph on the coast and 60 mph inland

toward Bangor. Very concerned about numerous to widespread power

outages resulting. Have compared the parameters to similar

storms in the past, and this setup is about as bad as it gets

for downing a lot of trees. Went with a wind advisory north of

Bangor for gusts to 55 mph. Looks pretty significant by Northern

Maine standards as well, and can`t rule out needing a high wind

warning but went with a high end wind advisory for now. At the

least, expect isolated to scattered power outages in the north,

and can`t rule out more. The highest winds come Monday afternoon

and evening before a cold front moves through from SW to NE and

shuts off the winds pretty fast.

For the rain, we aren`t looking at quite as much as parts of

Downeast saw with last week`s event. However, still expecting

2-3 inches over the southern 2/3 of the area, with a little less

in the far north which is left out of the flood watch but could

still have localized issues. Could be locally up to 4 inches in

the Central Highlands. Soil moisture is already extremely high

and creeks and rivers and running high. The heaviest rain rates

will during the day Monday and into early evening with up to

about a half inch an hour. Expanded the flood watch north to

Northern Penobscot due to forecast precip amounts being just as

high there as areas further SW that were already in the watch.

Rain tapers off from SW to NE early Monday evening, though the

flood threat lingers through the night. Will not be at all

surprised if there are quite a few roads closures and even some

damaged/destroyed roads like some areas Downeast saw last week.

Temperatures will be very mild in the 50s on Monday, and only

cool off a bit Monday night behind the cold front. No flash

freeze of roads expected on the back side of the system.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...

A cold front will begin to cross the region during the day

Tuesday. Ahead of the front, it will still be another

unseasonably mild day with highs in the 40s. There will the

chance of showers with the front. As the colder air moves in

later Tuesday afternoon, there is a chance that any rain ends

in the form of a few snow showers across northern areas. Winds

shift to west/northwest in the wake of the front Tuesday night

ushering in much cooler air. This will allow Tuesday nights lows

to fall into the 20s under partly cloudy skies. High pressure

builds in for Wednesday with mainly dry conditions. Afternoon

highs will be just a few degrees above normal for this time of

year.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...

High pressure remains in control through much of the period. This

brings generally fair weather through the weekend. A large

storm system will remain to the south of Nova Scotia through mid

week. Not totally out of the question that Downeast areas get

clipped with a few snow showers if the storm tracks far enough

west, but it appears that the system will remain far enough

east to have much of an impact on the region. It will be cooler

both Wednesday and Thursday with highs near seasonal levels both

days. There will also be a stiff north to northeast breeze on

Thursday, as the pressure gradient tightens up between high

pressure to our north and the strong low to the east. Fair

weather will persist Thursday night through next weekend as high

pressure remains in control. Expect mainly clear to partly

cloudy skies through the period. Afternoon high temperatures

will also be near normal through the period.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...

NEAR TERM: MVFR through the rest of the day, with IFR beginning

to develop around or a little before 0z. High confidence in IFR

or worse areawide tonight, with rain developing as well. LLWS

at all sites, all times, generally increasing. For Monday,

generally IFR or low MVFR, and windy from the S with heavy rain.

Wind gusts 40-50 kts inland, and 50-60 kts near the coast. Winds

rapidly diminishing Monday night, with improvement to MVFR or

possibly VFR.

SHORT TERM: Tue...VFR/MVFR expected with scattered showers.

SW wind 10 to 15 kt becoming W to NW during the afternoon.

Tue Night through Saturday...Mainly VFR.

&&

.MARINE...

NEAR TERM: Seas and winds will ramp up through Monday, with

south winds storm force and seas building to near 30 ft late

Monday into Monday evening with a long period southerly swell.

Winds/seas beginning to ease late Monday night.

SHORT TERM: SCA conditions will persist through much of the mid

to late week period.

&&

.HYDROLOGY...

Another round of significantly warmer temperatures and heavy

rainfall poses another threat for small river, stream, creek and

urban flooding. Groundwater levels across Downeast and the

Central Highlands are in excess of the 95th percentile for this

time of year. Much of the partial frost that existed Downeast

has thawed along with the Central Highlands resulting in the

grounds being prone to additional water releases and very

little absorption. Much of the rivers across the Central

Highlands and Downeast are open and free of ice but some

isolated areas of ice do exist but expected to play a minimal

role in this event. Ice is present on portions of the northern

river basins, however the only significant ice is on the St.

John River. River ice is expected to break up and move in spots

on the Aroostook & St. John Rivers due to heavy rainfall and

very warm temperatures. Localized ice jams are possible on the

St. John River but expected to cause minimal impacts. Across the

Central Highlands and Downeast with excessive rainfall of 2-3

inches and very soaked thawed grounds poses the greatest risk of

flooding. Have opted to expand the flood watch to include all

of Downeast and Central Highlands including the Bangor region.

Larger rivers across portions of Central and Downeast Maine will

respond to the excessive runoff. Much of the rivers across

Central and Downeast Maine are running in the 76th-95th

percentile for daily flows while northern rivers are near

normal. Latest river ensembles (GEFS, HEFS & NAEFS) have a

35-50% chance the Piscataquis River at Dover-Foxcroft reaches

minor flood stage. The ensembles have the Mattawamkeag at

Mattawamkeag in a 25-50% chance of reaching minor flood stage.

Lastly, the Penobscot at Bangor will need to be monitored on

Monday at the time of high tide for potential flooding as noted

below in the tides and coastal flooding section.

&&

.TIDES/COASTAL FLOODING...

Confidence has increased in coastal flooding and wave runup

issues on Monday at the high tide near 245pm. While not a

particularly high astronomical tide, maximum storm surge and

large waves corresponds with the high tide. Surge is now

expected to be over 2 feet with potential to be close to 2.5

feet. Combined with seas 10 to 15 ft, minor to moderate coastal

flooding is likely...with wave runup being more of a concern

than raw water levels. At this time, the combined tide and

surge looks sufficient to cause minor issues on the Deer Isle

Causeway and in Machias along with other vulnerable locations.

With the strong southerly push, will also have to look for a 2

to 3 foot surge up the Penobscot River to Bangor at high tide.

The magnitude of the waves and the total water level at high

tide brings strong potential for significant splashover on

coastal roads such as Seawall Road and along the Schoodic

Peninsula. A Coastal Flood Warning has been hoisted for the

Downeast Coast from 1PM-5PM on Monday.

&&

.CLIMATE...

Record high temperatures are possible on Monday Dec 18th.

The current forecast high at Caribou is 55F. The record high is

54F in 2000.

The current forecast high at Bangor is 56F. The record high is

53F in 2000.

Record warm low temperatures are also possible on Monday at

these locations.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...

ME...Wind Advisory from 7 AM Monday to 1 AM EST Tuesday for

     MEZ001>006-010-011-031-032.

     Flood Watch from 7 AM EST Monday through Tuesday morning for

     MEZ005-010-011-015>017-029>032.

     High Wind Warning from 7 AM Monday to 1 AM EST Tuesday for

     MEZ015>017-029-030.

     Coastal Flood Warning from 1 PM to 5 PM EST Monday for MEZ029-

     030.

MARINE...Storm Warning from 7 AM Monday to 1 AM EST Tuesday for

     ANZ050>052.

&&

$$

Near Term...Foisy/MCW

Short Term...Bloomer

Long Term...Bloomer

Aviation...Foisy/MCW/Bloomer

Marine...Foisy/MCW/Bloomer

Hydrology...

Tides/Coastal Flooding...

Climate...

10:28 PM AST Sunday 17 December 2023

High Storm Surge levels and very large waves are expected to impact the coast.

Impacts from storm surge are expected, including coastal flooding, beach erosion, minor infrastructure damage, spread of coastal debris, and localized coastal road washouts.

Locations: Atlantic coast of Nova Scotia, especially south-facing shorelines near Halifax and Eastern shore.

Maximum Water Levels: exceeding high astronomical tide, with water inundating vulnerable sections of coastline.

Maximum wave heights: 6 to 8 metres, breaking upon approach to shore.

Time span: Monday evening and Tuesday morning. Worst near high tide.

Remarks: Be sure to follow any instructions issued by local authorities.

High waves combined with the surge may cause damage along the coast. Coastal flooding is possible along the shoreline.

Storm surge warnings are issued when water levels pose a threat to coastal regions.

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.

10:27 PM AST Sunday 17 December 2023

Heavy rain is expected.

Locations: parts of mainland Nova Scotia.

Rainfall amounts: 50 to 70 mm, with potentially higher amounts locally.

Time span: Monday and ending Tuesday morning, except continuing for areas east of Halifax into mid-week.

Remarks:  A large area of rain will accompany the strong winds and will spread across the province Sunday night and Monday morning. Rainfall rates will likely peak Monday night. For eastern areas rain will continue well into Tuesday bringing additional amounts.

Localized flooding in low-lying areas is possible.

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 NSstorm@ec.gc.ca or tweet reports using #NSStorm.

10:26 PM AST Sunday 17 December 2023

Strong winds that may cause damage are expected or occurring.

Maximum wind gusts: southerly near 90 km/h.

Time span: beginning Monday afternoon and persisting into early Tuesday.

Locations: P.E.I.

High winds may toss loose objects or cause tree branches to break. Utility outages may occur.

Wind warnings are issued when there is a significant risk of damaging winds.

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.

10:25 PM AST Sunday 17 December 2023

Very strong wind gusts that may cause damage are expected or occurring.

Maximum gusts: southerly 100 km/h.

Locations: Nova Scotia.

Time span: intensifying Monday morning and continuing Monday night.

Exterior seasonal decorations should be secured.

High winds may toss loose objects or cause tree branches to break. Utility outages may occur.

Wind warnings are issued when there is a significant risk of damaging winds.

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.

8:38 PM AST Sunday 17 December 2023

Rainfall amounts: 30 to 50 mm, except locally near 80 mm in areas of heaviest rain.

Time span: Monday morning tapering to showers overnight Monday.

Locations: western, central, and southern New Brunswick.

Similar storms in the past have caused:

- localized flooding, especially in poor drainage areas

- the overflowing of creeks and rivers

- road shoulder erosion and washouts

Remarks: Rainfall rates will likely peak Monday evening. Highest rainfall totals will occur in areas of higher terrain.

Watch for possible washouts near rivers, creeks and culverts.

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.

8:06 PM AST Sunday 17 December 2023

Very strong wind gusts that may cause damage are expected or occurring.

Maximum gusts: southerly 90 - 100 km/h.

Locations: south-central New Brunswick.

Time span: Monday near noon ending overnight Monday.

Exterior seasonal decorations should be secured.

High winds may toss loose objects or cause tree branches to break. Utility outages may occur.

Wind warnings are issued when there is a significant risk of damaging winds.

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.

Coastal Hazard Message

National Weather Service Caribou ME

250 PM EST Sun Dec 17 2023

MEZ029-030-181400-

/O.UPG.KCAR.CF.A.0002.231218T1800Z-231218T2300Z/

/O.NEW.KCAR.CF.W.0002.231218T1800Z-231218T2200Z/

Coastal Hancock-Coastal Washington-

250 PM EST Sun Dec 17 2023

...COASTAL FLOOD WARNING IN EFFECT FROM 1 PM TO 5 PM EST MONDAY...

* WHAT...Up to 2 feet of inundation above ground level expected in

  low-lying areas near shorelines. A powerful storm system will

  track west of Maine Monday and Monday night. Strong south to

  southeast winds and very large offshore seas will push a

  significant amount of water to the shoreline.

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

* WHEN...From 1 PM to 5 PM EST Monday.

* IMPACTS...Large breaking waves will cause overtopping of

  exposed coastal roadways, allowing large rocks to cause

  significant damage to vehicles. In addition, road debris and

  minor road damage could close some roadways. Major beach erosion

  with overtopping to dune structures is expected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If travel is required, allow extra time as some roads may be

closed. Do not drive around barricades or through water of

unknown depth. Take the necessary actions to protect flood-prone

property.

&&

$$

URGENT - WEATHER MESSAGE

National Weather Service Caribou ME

242 PM EST Sun Dec 17 2023

MEZ001>006-010-011-031-032-181345-

/O.NEW.KCAR.WI.Y.0011.231218T1200Z-231219T0600Z/

Northwest Aroostook-Northeast Aroostook-Northern Somerset-

Northern Piscataquis-Northern Penobscot-Southeast Aroostook-

Central Piscataquis-Central Penobscot-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, Dover-Foxcroft, Milo, Guilford, Danforth, Vanceboro,

and Topsfield

242 PM EST Sun Dec 17 2023

...WIND ADVISORY IN EFFECT FROM 7 AM MONDAY TO 1 AM EST TUESDAY...

* WHAT...Southeast winds 20 to 35 mph with gusts up to 55 mph

  expected.

* WHERE...Northwest Aroostook, Northeast Aroostook, Northern

  Somerset, Northern Piscataquis, Northern Penobscot, Southeast

  Aroostook, Central Piscataquis, Central Penobscot, Southern

  Piscataquis and Northern Washington Counties.

* WHEN...From 7 AM Monday to 1 AM EST Tuesday. Period of maximum

  winds is Monday afternoon and early evening.

* IMPACTS...Strong winds may blow down limbs, trees, and

  powerlines. Isolated to scattered power outages may result.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use extra caution when driving, especially if operating a high

profile vehicle. Secure outdoor objects.

&&

$$

URGENT - WEATHER MESSAGE

National Weather Service Caribou ME

242 PM EST Sun Dec 17 2023

MEZ015>017-029-030-181345-

/O.UPG.KCAR.HW.A.0004.231218T1200Z-231219T0600Z/

/O.NEW.KCAR.HW.W.0005.231218T1200Z-231219T0600Z/

Southern Penobscot-Interior Hancock-Central Washington-

Coastal Hancock-Coastal Washington-

Including the cities of 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, and Cherryfield

242 PM EST Sun Dec 17 2023

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

TUESDAY...

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

  the coast...and to 60 mph inland...expected.

* WHERE...Southern Penobscot, Interior Hancock, Central

  Washington, Coastal Hancock and Coastal Washington Counties.

* WHEN...From 7 AM Monday to 1 AM EST Tuesday. Period of maximum

  winds is Monday afternoon and early evening.

* 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.

&&

$$