Mid-November Subtropical Storm

000

FXUS61 KCAR 160133

AFDCAR

Area Forecast Discussion

National Weather Service Caribou ME

833 PM EST Wed Nov 15 2023

.SYNOPSIS...

A weak cold front crosses the area overnight. High pressure

will build across the region Thursday. A warm front approaches

from the southwest Thursday night, then lifts to the northeast

on Friday. A cold front crosses the area Friday night and

Saturday morning as an area of low pressure tracks well offshore

through Saturday. This low then tracks into the Canadian

Maritimes Saturday night, followed by a trough of low pressure

crossing the area on Sunday. High pressure then builds in from

the west Sunday night and Monday.

&&

.NEAR TERM /THROUGH THURSDAY/...

830 PM Update: Based on latest radar ref trends, we did increase

snow shwr cvrg a little to sct across far Nrn areas for the

remainder of the Eve. From the standpoint of QPF/snfl, it

matters little with any accumulation of snfl related to far Nrn

higher trrn lctns. With cld cvr and llvl warm advcn ahead of

the cold front going into the Ovrngt hrs, temps should be steady

to slowly rising during this tm frame with no chgs to fcst

ovrngt lows attm.

Prev Disc: In a fast zonal flow, surface and upper level

ridging move eastward offshore this evening. Warm advection and

a subsidence inversion is causing stratocumulus clouds in

northern Aroostook County that will finally dissolve by this

evening. A weakening northern stream shortwave with minimal

moisture crosses the area later tonight with a weak surface cold

front. There is very little lift with this feature...maybe just

enough to graze the Saint John Valley with a few snow showers

late evening. QPF of a hundredth of an inch or so is as much as

we can reasonably anticipate. Further south, no QPF is forecast.

Cloud cover and warm advection will limit low temperatures to

the lower 30s tonight. There is nominal cold air advection

behind the cold front as measured at 850 and 925mb, but sunshine

and deeper mixing are expected to generate warmer temperatures

on Thursday. Mid 40s are expected towards Presque Isle while

readings near 50F are forecast for Bangor, Brewer and eastward

towards Ellsworth and Machias. While always vary of persistent

thin stratocu fields, strong surface/upper ridging and PWs

dropping below a quarter inch helped influence the decision to

go with sunny skies on Thursday.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...

Northern stream ridging crosses the area Thursday night then

exits to the east on Friday. A combination of subsidence under

the ridge, followed by negative vorticity advection in SW flow

on its backside will keep things dry Thursday night and Friday

morning and quite likely through most if not all of Friday

afternoon. Thursday night and Friday morning should see minimal

cloud cover, then there should be increasing mainly high and

mid clouds Friday afternoon from SW to NE. Some isolated to

possibly scattered showers are possibly across mainly far NW

zones late Friday afternoon ahead of the next system.

Lows Thursday night should be near normal and highs on Friday

10-15 degrees above normal.

A full latitude trough develops over the eastern US Friday

night. The models differ over its exact timing and orientation,

the placement and strength of shortwaves embedded in its flow,

and the extent to which it interacts with a southern stream

system located off the east coast of Florida. What they do agree

on is precipitation should start a little later than previously

forecast, with a steady rain developing, except possibly mixed

with snow over the higher elevations over far NW Aroostook. It

could be quite breezy Friday night, with gusts of 25-35 mph

possible. Lows Friday night should be around 15 degrees above

normal.

The models then split into roughly two camps for Saturday, with

high resolution models and the CMC-Global and some ensemble

members with a more progressive, positively tilted trough,

allowing for the associated surface cold front exits offshore

by Saturday evening, with the coastal low being farther to the

east as a result. This would bring precipitation to the end over

most areas Saturday morning. The other camp has the GFS, ECMWF

and a majority of the ensemble members, with a slower more

neutral tilted trough. As a result the surface cold front makes

slower progress through the state and the coastal low comes

closer towards SW Nova Scotia. This allows for overrunning flow

to set up on the cold side of the front, and rain through

afternoon, mixing with or changing to snow across the north.

Both camps solutions are plausible, so for now went with a

blended approach - lingering precipitation, especially across

the north through the afternoon, but with only chance vice

likely pops. Highs on Saturday will be in the morning across

most areas, except for across Downeast Maine where an afternoon

high is possible. Temperatures on Saturday should be around 10

degrees above normal.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...

All models agree that the axis of the full latitude trough

pushes through Saturday night. Models do agree that

precipitation will end sooner than previously forecast,

including the GFS/ECMWF camp, so taper off precip after

midnight. If the GFS/ECMWF camp is right there is the potential

for a flash freeze Saturday evening along with a period of

accumulating snow across the north before the precipitation

tapers. If the CMC- Global camp is correct, Saturday night

should be dry, with NW winds likely drying most road surfaces

before a flash freeze can occur. Given this spread in solutions,

do not have the confidence to mention anything in the HWO at

this time.

A northern stream trough axis crosses the area on Sunday, with

some flurries possible (though not quite confident enough to

reflect this in the forecast).

Deep layered ridging builds in Sunday night through Monday

night, then slides to the east Tuesday. It should be dry from

Sunday night into Tuesday as a result, and possibly all day

Tuesday depending on how quickly the ridge axis actually slides

to the east. For now, have slight chance pops over far W and S

portions of the region for late day showers.

Another full latitude trough approaches Tuesday night and

Wednesday. This warrants increasing pops to chance for a period

of overrunning precipitation. This should be mainly snow across

the North Tuesday night, mixing with or changing to rain on

Wednesday with mainly rain elsewhere.

Temperatures should be near normal Saturday night, then below

normal Sunday-Monday night. Temperatures should be above normal

Tuesday-Wednesday.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...

NEAR TERM: MVFR cigs remain north of HUL this afternoon. These

clouds will move out later this afternoon, but MVFR cigs return

again tonight as a warm front lifts north this

evening...followed by a cold front late tonight. A brief snow

shower late this evening could produce IFR vis at FVE, but not

concerned about reductions in vis elsewhere. There is also a

small chance of IFR cigs at HUL tonight with the warm front, but

confidence is insufficient to include in TAF.

For BGR and BHB, the predominant condition tonight will be VFR.

There is a small risk of MVFR cigs this evening as clouds in

the Gulf of Maine lift northward for a brief period.

For Thursday, went with VFR at all sites except FVE where MVFR

remains. It is possible that thin stratocumulus could still

generate MVFR cigs for HUL/PQI/CAR too, but opted to bet on

scattered skies or at least cigs above 3000 ft.

SHORT TERM:

Thursday night-Friday...VFR, with exception of MVFR possible

over far NW Maine late Friday. LLWS possible.

Friday night-Saturday...IFR or lower developing Friday night.

Conditions could improve to VFR from NW to SE on Saturday. LLWS

possible Friday night. N-NW winds G15-25KT possible Saturday.

Saturday night...A chance of MVFR or lower in the evening, with

rain changing to snow, otherwise VFR. NW winds G15-25KT

possible.

Sunday-Monday...VFR. NW winds G15-20KT possible Monday.

&&

.MARINE...

NEAR TERM: 830 PM Update...Southwest winds will pick up this

evening with gusts over 25 kt based on expected mixing. As a

result, the current Small Craft Advisory til 5am EST has been

extended in areal coverage to include the inner bay/harbor

waters. The winds will cont into the late night hours then

diminish by daybreak, becoming west to northwesterly at 10 to 20

kt.

SHORT TERM: Sub-SCA conditions are expected on all waters

Thursday night and Friday morning. SCA conditions develop on

all waters Friday afternoon. Gales are possible on the coastal

ocean waters Friday night-Saturday night, this threat will be

highlighted in the HWO. Conditions should be just below SCA levels

on the intra-coastal waters during this time frame, with a very

low chance of gale gusts (to low to reflect in the HWO). SCA

conditions are forecast on all waters on Sunday, with these

possibly lingering into Monday on the coastal ocean waters.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...

ME...None.

MARINE...Small Craft Advisory until 5 AM EST Thursday for ANZ050>052.

&&

$$

Near Term...VJN

Short Term...Maloit

Long Term...Maloit

Aviation...VJN/Maloit

Marine...VJN/Maloit

ZCZC MIATWOAT ALL

TTAA00 KNHC DDHHMM

Tropical Weather Outlook

NWS National Hurricane Center Miami FL

700 PM EST Wed Nov 15 2023

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Southwestern Caribbean Sea (AL98):

A broad area of low pressure over the southwestern Caribbean Sea is 

producing a large area of disorganized showers and thunderstorms.

Environmental conditions appear marginally conducive for 

development of this system over the next couple of days, and a 

tropical depression could form by this weekend as the system  

moves northeastward across the western and central part of the 

Caribbean Sea.  An Air Force Reserve reconnaissance aircraft is 

scheduled to investigate the system tomorrow. 

1. Regardless of development, this system is expected to produce heavy 

rains that could result in flash flooding and mudslides over 

portions of the Caribbean coast of Central America and the Greater 

Antilles through this weekend. Interests in Jamaica, Cuba, Haiti, 

the Dominican Republic, the southeastern Bahamas, and the Turks and 

Caicos Islands should continue to monitor the progress of this 

system. 

* Formation chance through 48 hours...medium...40 percent.

* Formation chance through 7 days...medium...50 percent.

2. Offshore Southeast Coast of United States:

A non-tropical area of low pressure appears to be forming near 

southern Florida along a frontal boundary.  This system is forecast 

to move quickly northeastward across the Bahamas and offshore of the 

east coast of the U.S. through the weekend.  Although development 

into a tropical cyclone appears unlikely, this system is expected to 

produce gusty winds and heavy rains across portions of southern 

Florida, the Florida Keys, and the Bahamas during the next couple of 

days.  For more information on this system, including gale warnings, 

see High Seas Forecasts issued by the National Weather Service.

* Formation chance through 48 hours...low...10 percent.

* Formation chance through 7 days...low...10 percent.

High Seas Forecasts issued by the National Weather Service

can be found under AWIPS header NFDHSFAT1, WMO header FZNT01 

KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php

Forecaster Cangialosi