546
FXUS61 KCAR 141033
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
633 AM EDT Sun Jul 14 2024

.SYNOPSIS...
High pressure will build across the region today. Several weak
troughs will cross the area Monday through Tuesday. A more
robust cold front will move into the region on Wednesday and
exit on Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
6:30 a.m. update...No change to the forecast this morning as
early morning fog starts to burn off. Sunrise is also showing
some smoke in the upper levels on satellite. Although this may
make the sky seem hazy, it is not anticipated to significantly
affect daytime temperatures. Forecast remains on track.

Previous discussion...

High pressure moves over the area today and skies have already
mostly cleared from last night`s showers. The atmosphere has
decoupled and some fog is visible on satellite, however it is
not as widespread as previous nights. The marine fog has mostly
pushed offshore with very weak northwesterly flow in the wake of
yesterday`s upper level trough. Today is expected to be the
first in a series of hot, humid days as abundant sunshine
increases daytime highs. As the axis of the ridge shifts
eastward, return flow around the high will also increase
dewpoints. Decided to split the difference on guidance with the
forecast, bumping Tds up slightly from the previous forecast but
not raising them as high as the NAM. This will keep heat
indices at 90 and below, which is below advisory criteria but
still muggy.

Another area of uncertainty in the forecast is the chance for
showers this afternoon. Some CAMs have shown some afternoon
convection across the forecast area. There will certainly be
enough surface moisture, and afternoon heating will increase the
instability. The question is whether there will be a weak
shortwave aloft to trigger anything. Think there`s enough of a
possibility to keep isolated showers in the forecast, but these
should be short lived and will not carry much in the way of
QPF.

Not much of a change in the overnight forecast, with the humid
airmass keeping overnight lows in the mid-60s. Chance of
overnight fog prevails, perhaps slightly more widespread than
this morning due to the increase in dewpoint with southwesterly
flow.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
A series of shortwave troughs will push through the forecast
area through the first half of this week, bringing several
rounds of showers and storms to the region. Decent CAPE and
shear will exist both Monday and Tuesday afternoons, thanks in
part to diurnal heating but also with the 500 mb shortwaves
transversing the area. MLCAPE may surpass 1000 J/kg and bulk
shear may sit around 30 to 40 kts, as suggested by 00z runs of
the CAMs. Given this setup, there could be a few stronger storms
both Monday and Tuesday afternoons, but storms will be fairly
isolated as the region will also be situated under the
subsidence sector that is the right exit region of a weak 100 kt
jet streak.

Though storms will be sparse, heat will be another area of
concern through the first half of the week. Temperatures will
lift into the mid to upper 80s, with a chance to push into the
lower 90s in the Central Highlands down through the Bangor area.
As there will be very little change in air mass to what has been
seen over the last week, relative humidity levels will remain
high, with dewpoints lifting into the lower 70s by Tuesday
afternoon. This will lead to heat indices (or what it feels
like) potentially lifting into the mid 90s, and may approach
heat advisory criteria.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A deepening upper level trough will dig into the New England
area through the day on Wednesday, leading to a cold front
dropping across the forecast area by late Wednesday night. At
this time, there is still some model disagreement with the
timing of this front, as the CMC pulls the front through nearly
12 hours earlier than any other global model. This large,
positively tilted trough will have connections into air from the
Gulf of Mexico region, and this added moisture could help
support locally heavy rainfall Wednesday afternoon through
Wednesday night.

Behind the low pressure system crossing into early Thursday
morning, the forecast area may see drier conditions as a robust
area of high pressure establishes itself over the Great Lakes.
Dewpoints may fall into the 50s across the north and lower 60s
Downeast, and precipitations chances may be lower.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: Fog is starting to return with a bit of a "sunrise
surprise" so have kept it in the TAFs for now. Once this burns
off, VFR conditions and light winds expected through the day
today. Returning possibility of IFR in fog overnight tonight.


SHORT TERM:
Monday: VFR across all terminals, with a brief period of
MVFR/IFR possible in any heavy showers or thunderstorms. SW
winds 5 to 10 kts.

Monday night: Generally VFR across all terminals, though
IFR/LIFR more likely at BHB and any terminals which see rainfall
during the day. Winds light and variable.

Tuesday: VFR across all terminals, with a brief period of
MVFR/IFR possible in any heavy showers or thunderstorms. SW
winds 5 to 10 kts.

Tuesday night: Generally VFR across all terminals, though
IFR/LIFR more likely at BHB and any terminals which see rainfall
during the day. Winds light and variable.

Wednesday: Beginning VFR across all terminals, with a possible
lowering towards MVFR late in the day as rain moves into the
area from the west. SW winds 5 to 10 kts.

Wednesday night: MVFR/IFR in rain showers and thunderstorms.
Light SW winds shifting NW behind a frontal passage.

Thursday: Conditions improving to VFR across all terminals. Winds
W to NW at 5 to 10 kts.

&&

.MARINE...
NEAR TERM: Winds/seas below small craft advisory levels
overnight through tonight. Areas of fog overnight through the
day, pushed slightly offshore this morning then returning
through the day.


SHORT TERM: Winds and seas should remain below small craft
advisory levels through the middle of the week. Fog will remain
a concern through most of the week, with patchy dense fog
routinely causing visibility to drop below 1 SM.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Beach Hazards Statement through this evening for MEZ029-030.
MARINE...None.

&&

$$


Near Term...LF
Short Term...AStrauser
Long Term...AStrauser
Aviation...LF/AStrauser
Marine...LF/AStrauser