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264
FXUS61 KCAR 190007
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
807 PM EDT Tue Jun 18 2024

.SYNOPSIS...
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High pressure will remain south of the region through Wednesday
night. A cold front will cross the area Thursday followed by
high pressure building in through Saturday, then sliding to the
east Saturday night. A warm front will lift over the area on
Sunday.
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&&

.NEAR TERM /THROUGH WEDNESDAY/...
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730pm Update...Atmosphere is well capped, expect storms over N
Somerset to dissipate as they move east due to the strong
subsidence under the anomalous upper level ridge. The forecast
appears on track.

Previous Discussion...
Near record to record heat and humidity will continue to build
through Wednesday as a ridge of high pressure extends north of
Bermuda, bringing very warm humid air and broad southwest flow
at all levels. Guidance remains consistent in showing 925mb
temperatures around 27C, suggesting surface temperatures in the
mid 90s even without full sunshine. Projections of mid level
moisture have increased over the last 24 hours, leading to less
transfer of drier air aloft towards the surface than previously
anticipated. As a result, forecast dew points were increased by
a couple degrees into the 72-74F range. This, combined with the
air temperatures, will lead to areas around the Bangor Region
and Penobscot Valley exceeding 105 degree Excessive Heat Warning
criteria for a few hours Wednesday afternoon. For the first
time in the history of our weather forecast office, an Excessive
Heat Warning has been issued, valid for southern Piscataquis
and central/southern Penobscot Counties from late Wednesday
morning through Wednesday evening.

Despite ample instability, convection chances remain limited
over the next 24 hours due to large scale subsidence and warm
temperatures aloft. Any activity this evening and again on
Wednesday will remain isolated (20 percent chance or less). If a
storm does form, it would be capable of producing gusty winds
and briefly torrential rain.

A strong seabreeze will extend across all of coastal Downeast
Maine and into portions of Interior Downeast Maine tonight
through Wednesday. The stability will lead to poor air quality
across portions of the area, especially coastal Hancock County
where the Maine Department of Environment Protection has issued
an Air Quality Alert. Patchy fog is also possible over these
areas later tonight into early Wednesday morning.
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&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
Wednesday Night...
Extraordinarily warm temperatures Wednesday night thanks to the
very warm airmass and limited decoupling/good mixing. Went on
the warm side of guidance, with lows in the low to mid 70s,
except 60s along the coast. The warmest low temperatures will
likely be in the north. Can`t totally rule out an isolated storm
through the evening, but can`t pinpoint where the isolated
storm would be, so went with broadbrushed 15-20 PoPs.

Thursday...
Upper level ridge begins to flatten and a surface cold front enters
Northern Maine. Some uncertainty in exact timing of the cold
front, and the timing of the front would determine where storms
are the most abundant, and how far north the 90s make it. Right
now, think the best shot at storms, which could be
strong/severe, will be from Houlton and Greenville south. Also
the low to mid 90s should be along and south/east of I-95, with
heat advisory criteria being met again easily in these areas. In
fact, Thursday should be the warmest day for immediate coastal
Downeast thanks to shore-parallel or slight offshore flow. The
far north will see drier, cooler air beginning to move in behind
the front mid/late afternoon. Again, some uncertainty on the
speed of the front, and the north/south position of the storms
and the 90s could vary some.

Thursday Night and Friday...
Some storms Thursday evening Downeast just ahead of the cold front,
then the cold front moves offshore, with at last some drier and
cooler air working in from the north areawide Thursday night
into Friday. The push of drier/cooler air will be stronger in
the north, but all areas will have welcome relief. Highs on
Friday will be in the upper 70s in the north and low 80s
Downeast. Dewpoints will be in the mid to upper 40s north and
low to mid 50s Downeast. Compare this to the low 70s dewpoints
ahead of the cold front. Plus, there will be a decent NW breeze
on Friday. No precipitation expected Friday. Models have trended
stronger with the push of cooler/drier air for Thu night/Fri,
and went along with this trend.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
High pressure builds in Friday night but is short-lived, as it
moves east late Saturday as the next system approaches from the
west. Rain chances begin to increase late Saturday afternoon
into evening, but the best rain chances appear to be late
Saturday night through Monday. Most models/ensembles have low
pressure tracking to our north, which would bring a warm front
early Sunday, eventually followed by a cold front sometime
roughly Monday afternoon. Thunderstorms will be possible from
Sunday into Monday. The airmass looks somewhat warm/humid in
between the warm front and cold front, but not remotely as
warm/humid as what we are seeing now. Quieter weather for
Tuesday.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: Predominantly VFR through Wednesday with brief
MVFR/IFR possible in low stratus and fog at coastal airports
such as KBHB and KEPO tonight into Wednesday morning. An
isolated thunderstorm is also possible Wednesday afternoon. SSW
winds 5 to 15 kts expected.

SHORT TERM:
Wed Night...Mainly VFR, except possible local IFR near the
coast, including BHB. SW wind around 5 kts.

Thu...Generally VFR, but scattered to numerous showers and
storms which would bring brief MVFR conditions and gustier
winds. Outside of storms, W wind 10 kts with gusts to 20 kts.

Thu Night through Sat...Other than a few storms Thu evening
Downeast, looking VFR Thu night through Sat. Variable winds
around 5 kts.

Sat Night and Sun...MVFR/IFR possible late Sat/early Sun in rain
and low clouds. Thunderstorms also possible. S wind increasing
to 10 kts.

&&

.MARINE...
NEAR TERM: Winds and seas will remain below advisory levels
through Wednesday. Seas will generally range around 2 to 3 feet,
with winds around 10 to 15 kts.

SHORT TERM: Winds/seas could get near small craft levels
Wednesday night/Thursday morning, but likely stay just below.
Conditions then likely below small craft until Sunday
night/Monday, when there is a reasonable shot at small craft
conditions from winds/seas.

&&

.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 (96)96 in 2020
Bangor (95)95 in 1995
Millinocket (96)95 in 2020
Houlton (95)95 in 2020

June 20th Max Minimum Temperature Records:
(Forecast)

Caribou (67)68 in 1970
Bangor (72)72 in 1931
Millinocket (71)69 in 1923
Houlton (65)67 in 1976

June 20th High Temperature Records:
(Forecast)

Caribou (89)            93 in 2020
Bangor (95)             95 in 2020
Millinocket (93)        96 in 2020
Houlton (91)            94 in 2020

All-time Record Highs:
(Forecast, Day)

Caribou (96 June 19)96  June 2020
Bangor (95 June 19/20)104 August 1935
Millinocket(96 June 19) 101 June 1907
Houlton (95 June 19)99  August 1975

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

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

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
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ME...Heat Advisory until 8 PM EDT Wednesday for MEZ001>006-010.
     Heat Advisory until 10 AM EDT Wednesday for MEZ011-015-031.
     Excessive Heat Warning from 10 AM to 8 PM EDT Wednesday for
     MEZ011-015-031.
     Heat Advisory from 10 AM to 8 PM EDT Wednesday for MEZ016-017-
     032.
     Air Quality Alert from 11 AM to 11 PM EDT Wednesday for MEZ029.
MARINE...None.
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&&

$$


Near Term...Maloit/MStrauser
Short Term...Foisy
Long Term...Foisy
Aviation...Maloit/MStrauser/Foisy
Marine...Maloit/MStrauser/Foisy
Climate...