-- Discussion containing changed information from previous version are highlighted. --
475
FXUS61 KCAR 172233
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
633 PM EDT Mon Jun 17 2024

.SYNOPSIS...
High pressure will stall south of the region and remain in
place through Wednesday. A cold front will cross the area
Thursday and stall south of the area by Friday. Another area of
low pressure approaches this weekend.

&&

.NEAR TERM /THROUGH TUESDAY/...
-- Changed Discussion --
634PM Update...No mjaor changes to the forecast for this
update.

Previous Discussion...
Tonight the mid level warm front over the area continues to
drift Northeast into New Brunswick which will allow for some
clearing. 1027mb surface high pressure drifts south of Nova
Scotia as a strengthening 500mb high to around 593-594dam
drifts NE into the Mid Atlantic states. Temperatures tonight
will be much warmer than the last few nights as 925-850mb
temperatures begin to warm as the ridge advects warmer air
northeastward. Expect temps to fall back into the mid to upper
50s across the North Woods, St. John Valley, Moosehead Region
south to Bangor and the Hancock County coast. To the east a
little cooler in Washington County with low to mid 50s for the
morning lows. Partly to mostly cloudy tonight with perhaps a few
showers especially closer to the coastline near Eastport.
Additionally, with the increasing moisture in the boundary layer
and warming air expect a few areas of patchy fog in the river
valleys by daybreak.

Tomorrow, dew points will be rapidly increasing in the morning
hours approaching very humid to oppressive conditions by midday
and be very noticeable. Light south-southwest winds develop in
the morning and generally be less than 10mph. Tomorrow will turn
hot, hazy and humid with 850mb temps increasing to +18.5C to
+19.C across the CWA. This will result with partly to mostly
sunny skies with air temperatures reaching the upper 80s to low
90s across much of Northern Maine, Central Highlands into
interior Downeast. The hot spots look to be the Greater Bangor
area, Millinocket area to Houlton to Caribou to eastern St. John
Valley. A weak seabreeze develops along the Downeast coast with
upper 60s to mid 70s at the shoreline with low to mid 80s along
the Route 1 corridor just inland from the coast with upper 80s
along Route 9. Dew points will top out in the upper 60s to low
70s across the entire area by afternoon. This will result in
heat index values climbing into the mid 90s to perhaps upper
90s. Confidence has increased that this will impact areas along
the I-95 corridor from Newport to Bangor northeastward to
Houlton then north along Route 1 into NE Aroostook County. Given
this increased confidence have hoisted a Heat Advisory and it
is a slam dunk heat indices will be hot on Wednesday have opted
to run the advisory through 00z Thu. Heat indices will be
higher on Wednesday and noted below in the Short Term. Tomorrow
it will be important for those outside to drink plenty of
fluids, wear light colors and fitting clothes, sunscreen and
take frequent breaks. Additionally, its good idea to check on
your neighbors without AC and the elderly. For more heat & heat
safety information visit www.weather.gov/car/heat.

Additionally, thunderstorms will be possible tomorrow especially
across the Moosehead Region northward to eastern St. John
Valley. Uncertainty exists on just how many storms can fire so
kept POPs confined to isolated and scattered. Interesting setup
for tomorrow given there is still some weak relatively flat
shortwave riding the edge of the ridge that will pass through
Maine in the afternoon. 500mb heights gradually increase but
across northern areas still a little bit of a cool pocket aloft.
SBCAPE will increase with several models suggesting
2000-3000j/kg especially in northern areas. PWATs will rapidly
increase to between 1.7 and 1.9 inches which is above the 90th
percentile. There isn`t a lot of shear tomorrow with Sfc-6km
shear generally less than 30kts. Lapse rates if well mixed will
be steep in the low levels and modest in the mid levels. This
appears to be a high cape, low shear with weak forcing setup to
feature potentially a few stronger robust storms. Uncertainty
does exist but if any storms do develop they could produce gusty
winds (DCAPE 800-900) and heavy rainfall...Hail will be limited
with the warmer air aloft and much higher 0C and -20C levels.
Opted to added enhanced wording for mainly northern and
northeast Aroostook County tomorrow.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Heat will continue to increase on Wednesday as heights continue
to rise and the center of the 500mb high moves from the Mid-
Atlantic into southern New England. Model 925mb temperatures
around 26-27C will yield potential for surface temperatures near
all time records in the middle to upper 90s. The most
significant uncertainty is with dew points, which could drop
during the day with mixing of slightly drier air aloft. Areas
that are heavily forested and near moisture sources will see
less dew point decreases, and thus a higher max heat index. Max
heat indices could exceed 105 on Wednesday afternoon,
particularly across the Penobscot Valley and an upgrade to
Excessive Heat Warning may be required for some zones as
confidence increases. Expansion of the existing heat advisory to
most of the rest of the area is also anticipated with future forecaster
updates. There is a small (10 percent) chance of a thunderstorm
during the day Wednesday as a weak shortwave moves over the
northern edge of the ridge. Subsidence and warm air aloft should
limit most of this activity, but trends will need to be
monitored. Fog is possible along the coast both Tuesday night
and Wednesday night, with lowering chances by Thursday as winds
shift offshore.

By Thursday high to mid level clouds from convection to the west
will move across northern Maine. This will help to steepen mid
level lapse rates and facilitate development of scattered
showers and thunderstorms ahead of a cold front during the
afternoon. Slightly cooler temperatures in the upper 80s to
lower 90s are anticipated across the north, while southern
portions of the forecast area see temperatures similar to
Wednesday. Along the coast, winds shifting west to west-
northwest should repel the sea breeze closer to the coast,
allowing very hot heat indices to extend closer to the coast
compared to Tuesday and Wednesday. Thunderstorms across northern
and central areas could bring very heavy rainfall and gusty
winds. West to east oriented boundaries, such as the cold front
and pre-frontal trough, could produce localized flooding given
the Corfidi vectors, relatively skinny CAPE, and very high
precipitable water (PWAT) values near 1.8 to 2 inches.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
A cold front will move across the area Thursday night, bringing
additional showers and thunderstorms overnight. Friday will be
much cooler but still above normal with the cold front slowing
just south of the area. A few showers or thunderstorms will
remain possible across the southern part of the area along the
boundary. High pressure builds towards the area for Saturday
with highs in the upper 70s to low 80s and mainly dry
conditions. The stalled front south of the area will begin to
lift back north as a warm front late Saturday into Sunday. There
are differences in guidance on the timing, but chances of
showers and thunderstorms steadily increase by Sunday and
maximize on Monday.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: BKN-OVC VFR cigs tonight as winds become light and
variable. BCFG possible at PQI but confidence low for the TAFs.
Tomorrow, northern sites VFR with potential VCSH/VCTS especially
for PQI, CAR and FVE. FEW-SCT MVFR tonight at BHB with possible
BR. Otherwise, dry tomorrow at BHB & BGR. Areawide winds shift
S-SSW at 10-15kt tomorrow.

SHORT TERM: Tuesday night to Friday...VFR. MVFR/IFR possible at
coastal airports with fog Tuesday night and Wednesday night.
Brief MVFR/IFR and gusty winds are also possible in scattered
showers and thunderstorms Thursday afternoon and evening. Light
SW winds Tuesday night to Wednesday night, shifting W Thursday
and NW Thursday night into Friday.

Saturday: VFR.  Light NW winds.

Sunday: VFR with MVFR also possible in showers and isolated
thunderstorms. Light S winds.

&&

.MARINE...
NEAR TERM: Winds/seas below SCA conditions through tomorrow
afternoon. Winds may approach briefly 25kt this evening in
eastern areas near the Hague Line. Seas generally 2-4ft through
tomorrow. Patchy fog bank will develop late tonight across the
waters and last into the day tomorrow that may reduce vsby.

SHORT TERM: Winds and seas will remain below advisory thresholds
through the period. Mist and fog are possible at times,
particularly Tuesday night through Thursday night.

&&

.CLIMATE...
Temperatures will soar under an anomalously upper level high
pressure system, challenging record high temperatures
and record max minimum temperatures. Multiple days of record
breaking temperatures will lead to dangerous heat without a
chance for reprieve overnight.

June 19th High Temperature Records:
(Forecast)

Caribou (97)96 in 2020
Bangor (96)95 in 1995
Millinocket (97)95 in 2020
Houlton (96)95 in 2020

June 20th Max Minimum Temperature Records:
(Forecast)

Caribou (69)68 in 1970
Bangor (72)72 in 1931
Millinocket (73)69 in 1923
Houlton (70)67 in 1976

June 20th High Temperature Records:
(Forecast)

Caribou (89)            93 in 2020
Bangor (96)             95 in 2020
Millinocket (94)        96 in 2020
Houlton (92)            94 in 2020

All-time Record Highs:
(Forecast, Day)

Caribou (97 June 19)96  June 2020
Bangor (96 June 19/20)104 August 1935
Millinocket(97 June 19) 101 June 1907
Houlton (96 June 19)99  August 1975

All-time Record Max Minimum Temperature Records:
(Forecast, Day)

Caribou (70 June 19)71 in July 2018
Bangor (74 June 19) 77 in August 1949
Millinocket(73 June 20) 80 in July 1912
Houlton (69 June 20) 72 in August 2009

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Heat Advisory from noon Tuesday to 8 PM EDT Wednesday for
     MEZ002-005-006-011-015-031.
MARINE...None.

&&

$$


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