888
FXUS61 KCAR 041900
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
300 PM EDT Tue Jun 4 2024

.SYNOPSIS...
Weak high pressure drifts south of the Gulf of Maine tonight.
A weak disturbance rotates north to south over Maine on
Wednesday. A flattening ridge works overhead into Wednesday
night. An upper level low then slowly approaches from the west
Thursday into Friday and moves across the area this weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Tonight, surface high pressure drifts south of the Gulf of Maine
waters tonight with flow turning W-WNW tonight aloft with
increasing moisture spilling over the ridge. Partly cloudy
skies expected tonight and remaining dry as temperatures fall
back into the low to mid 50s with light and variable winds.
Tomorrow morning expecting the large cutoff low over the
Maritimes to remain locked in place thanks to the -NAO blocking
in the North Atlantic. A piece of vorticity will rotate
southward out of Northern Quebec between the low and the 500mb
ridging over the Eastern Great Lakes. Warm, increasingly moist
air and partly sunny skies will allow for a convective
situation in the afternoon. High temperatures top out in the
low to perhaps mid 80s for much of the CWA with the exception
along the Downeast coast where an afternoon sea breeze develops.
Tomorrow, dew points will increase with Td`s into the low 60s
so a touch of humid weather for the Central Highlands and
Interior Downeast with mid to upper 50s dew points north.

Hi-res cams continues to depict a variety of solutions on the
development of convection tomorrow. Based on the latest modeled
soundings the likelihood of reaching the convective temperatures
looks really good. Modeled soundings showing steep low level
lapse rates 9-9.5C/km given steep inverted "v" look. Tomorrow,
mid level lapse rates are "okay" with 6-6.5C/km across the area.
SBCAPE looks to develop in the 1000-1500j/kg range but
relatively dryer low levels depending on where you are in the
state. Freezing levels are going to be on the 10.5kft to 11.5kft
range tomorrow. While the low levels are dry the mid level RHs
look to be in the 75-85% range. PWATs tomorrow do increase close
to the 90th percentile so if any convection can develop brief
heavy rain is possible as storm motion NNW to SSE will be slow.
Lastly, confidence in stronger storms is low given the drier low
levels but with storm motion NW-SE cannot rule out a "surprise"
stronger system as it has happened before in similar setups.
Overall, isolated to scattered showers and some thunderstorms is
possible. Given the thermodynamics and overall upper level
dynamics lacking in some aspect expecting mainly garden variety
showers and storms. SPC continues to paint the area in "general
thunder" and will keep any enhanced wording out of the grids for
now. Any rain will be welcomed given the long term deficits...

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
Shortwave ridging will continue but slowly break down as Maine
remains between upper level lows over the Great Lakes and Gulf
of Saint Lawrence. Any convective showers and thunderstorms
Wednesday afternoon will dissipate with loss of daytime heating
Wednesday evening. Clearing skies are expected across much of
the area Wednesday night, especially north of Baxter State Park.
Most areas will remain dry on Thursday with just a slight chance
of showers over most of the area. Greater shower chances, more
cloud cover, and slightly cooler temperatures are expected
across southern and western portions of the forecast area, while
far northern Maine is expected to remain warm and partly to
mostly sunny. Patchy fog is possible each night into the morning
along the coast and extending inland.

There is more uncertainty by Friday regarding the timing of the
initial push of positive vorticity advection (PVA) on the
eastern edge of the upper level low. However, the greater
chances for rain and cooler temperatures will again be across
southern and western portions of the area, with greater chances
for breaks of sunshine and slightly warmer temperatures across
far northern Maine. A majority of guidance keeps the 500mb PVA
west of the area through Friday evening, so it is possible some
areas may stay dry into the evening. Forecast soundings indicate
warmer and drier air aloft, especially from 500mb and above both
Thursday and Friday, leading to poor lapse rates. For this
reason, PoPs were lowered compared to the NBM and thunderstorm
chances should remain low (less than 10% chance within 25mi)
both days.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The leading edge of PVA along the eastern edge of the upper
level low will move across the area Friday night into Saturday
night, although precise timing remains uncertain. This will
bring a batch of more widespread, slow moving showers and a
period of steadier rain to the area. Moisture aloft and
steepening lapse rates will bring back the chance of thunder,
especially by Sunday. However, extensive cloud cover and limited
surface heating should preclude more widespread and stronger
thunderstorm activity. Fog could also occur, particularly along
the coast or over areas where skies clear, but confidence was
too low to include in the long range forecast. Temperatures are
expected to remain seasonable with highs generally in the upper
60s to lower 70s and lows in the upper 40s to lower 50s.

Guidance disagrees on the progress of the upper level low by
early next week, but there is good agreement among ensemble
guidance that large scale upper level troughing will continue
across the Northeastern United States through the middle of next
week regardless. This will result in continued unsettled weather
with near normal temperatures and chances for showers and
possibly thunderstorms.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: VFR tonight with SCT-BKN cigs becoming FEW-SCT. VRB
winds becoming nearly calm tonight. Tomorrow, light and variable
winds for northern terms, turning S around 5-10kt at BGR & BHB
in the afternoon. VCSH at northern terms, VCSH southern terms in
the afternoon cannot rule out VCTS at BGR in the afternoon.

SHORT TERM:
Wednesday night: VFR, except IFR or lower possible
mainly at southern airports due to patchy fog. Light winds.

Thursday: VFR. Southeast winds 5-15 kts.

Thursday night to Friday night: VFR at Aroostook County
airports. MVFR/IFR possible at southern airports extending into
GNR with showers and patchy fog at night into the early morning.
Southeast winds 5-15kts.

Saturday to Sunday: Predominantly MVFR/IFR with showers.
Southeast winds 5-15 kts.

&&

.MARINE...
NEAR TERM: Winds/seas below SCA conditions through tomorrow. W
winds less than 15kt tonight becoming S tomorrow. Seas 1ft or
less tonight becoming 1-2ft tomorrow. Patchy fog may reduce vsby
tonight into tomorrow.

SHORT TERM: Winds will remain below advisory levels and
generally below 20 kts through the period. Seas will also remain
around 2 feet or less. Fog is expected at times, particularly
Wednesday night into Friday morning.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.

&&

$$


Near Term...Sinko
Short Term...MStrauser
Long Term...MStrauser
Aviation...Sinko/MStrauser
Marine...Sinko/MStrauser