280
FXUS61 KCAR 200029
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
829 PM EDT Wed Jun 19 2024

.SYNOPSIS...
High pressure will remain to our south tonight. A cold front
will cross the area Thursday followed by high pressure on
Friday. Low pressure will approach on Saturday and track north
of our area Sunday.

&&

.NEAR TERM /THROUGH THURSDAY/...
815 PM Update: A few showers and storms have moved through the
Downeast region early this evening, leading to a rapid reduction
in temperatures in this area. For northern areas which missed
out on any rainfall, temperatures are on a more subtle decline
into the evening hours. Dewpoints remain high, around 70 across
most of the forecast area, and these humid conditions will limit
how far temperatures fall tonight. Into the day on Thursday,
current CAMs trends indicate a slightly slower FROPA, so the
decrease in dewpoints, and subsequently heat indices, is delayed
by about an hour from the previous forecast. Heat advisories and
Excessive Heat warnings are now out for the day on Thursday as
the dangerously hot temperatures continue.

Previous Discussion:
Anomalously strong upper level high pressure slowly retreats
southward tonight into Thursday while a cold front sags
southward from Quebec.

The strong warming with the high has been responsible for
numerous daily high temperatures records being tied today,
including a 96F reading at Caribou which also ties the all-time
high temperature record. Millinocket did break the daily record
with 96F so far. The heat index at Caribou did set an
unofficial all- time record at 106F, besting the old mark of
100.7F. However, these figures are not part of the official
climate record and not available for other climate sites in the
CWA.

A weak upper level disturbance and unusually high SBCAPE values
will result in isolated thunderstorms this evening moving into
northern Somerset County, Piscataquis and Penobscot counties and
into eastern Aroostook. While these pulse storms will be short-
lived given the lack of shear, they could produce heavy
downpours and gusty winds. Storm movement will be very slow and
allow storms to dump quite a bit of rainfall. Have mentioned
heavy thunderstorms in the forecast. SPC has placed the area in
a marginal risk in the convective outlook.

The thunderstorms will diminish this evening with the loss of
heating. High clouds and warm advection ahead of the cold front
will make tonight will be among the warmest nights in memory.
Lows will be in the mid 70s for much of the area. Temperatures
may still be near 80F as late as midnight for many locations.
Based on this expectation, an all-time max minimum temperature
record of 71F at Caribou will be tied tonight. That will also be
a daily and monthly record. The coast will be cooler with the
sea breeze developing this afternoon into the evening.

For Thursday, another hot day will be on tap with more heat
advisories expected for the southern half of the forecast area.
We will maintain the existing advisories and warnings through
expiration and issue any headlines for tomorrow later this
evening. Thursday is forecast to be even hotter than today for
Downeast due to offshore winds.

The convective outlook for the cold front shares many of
environmental characteristics we see today. Once again, PWs will
be nearing 2 inches and SBCAPE may reach the 2000 to 3000 J/kg
range. Storms may reach towards the trop at 40 to 45k ft and
Corfidi vectors remain generally 10 kt or less. Upper level
support and shear looks weak.  Thus, heavy localized rainfall
will be a threat again. Storms reaching the trop will also bring
the risk of gusty winds. Since the front will be moving through
northern zones in the morning, the bigger threat for
thunderstorms will be in the southern half of the area where the
front will be the trigger.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
Showers and thunderstorms will linger Downeast on Thursday
night as the front slowly makes its way offshore. Most
importantly, the hottest portion of the air mass will be pushed
southward and temperatures will return to more seasonable levels
for the northern portion of the forecast area. Lows Thursday
night will rand in the mid-60s to upper 50s, and highs will be
closer to 80 for both Friday and Saturday. With dewpoints
falling back into the 40s to 50s, there will be a noticeable
difference in how the temperature feels for the end of the week
and the beginning of the weekend.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
For the second half of the weekend, a strengthening low
pressure system will move from the midwest into southern
Ontario, bringing a series of fronts across Maine. Sunday day,
the warm front will approach from the south and stratiform
precipitation will spread across the area. Maine will remain
under the warm sector through Monday afternoon, when the cold
front will finally cross as the upper level trough shifts
eastward, taking the main low with it. PWATs during this time
will be above 1.5 inches, and with some upper level instability
and the slow movement of the main front, there is the potential
for some heavier periods of rainfall. Current forecast is too
far out for specifics on amounts, but this bears watching as the
system approaches.

A shortwave ridge will follow on Tuesday, bringing mostly quiet
weather, then the potential of another cold front approaching on
Wednesday. The air mass ahead of the cold front on Wednesday
will bring warmer temperatures to the region, but these should
be more on the order of low to mid 80s vs the 90+ degree
temperatures seen this week. There is an increasing potential
for showers and thunderstorms on Wednesday, but with uncertainty
on timing of the front, nothing more than chance PoPs in the
forecast at the moment.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
NEAR TERM: VFR conditions to continue tonight into the day on
Thursday. Breezy SW winds over most of the area will decrease
and become light overnight. Brief LLWS possible at northern
terminals late tonight. A returned threat for showers and
thunderstorms late Thursday morning into Thursday afternoon with
a front moving from north to south. Winds will shift NW at 5 to
15 kts on Thursday.

SHORT TERM: 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 through Mon...MVFR/IFR developing from the south late
Sat/early Sun in rain and low clouds, continuing through
Monday. Thunderstorms also possible. S wind increasing to 10
kts.

&&

.MARINE...
NEAR TERM: Quiet conditions continue with light SW generally 10
kt or less. South swell at around 2 to 3 feet is anticipated
into Thursday. Patchy fog is expected to reappear tonight with
the warm, humid air moving over the cold waters.


SHORT TERM: Winds and seas will remain below small craft
criteria Thursday through Saturday night. The next reasonable
potential for winds greater than 25kts occurs for a brief period
Sunday afternoon and Sunday night. During this period, seas
will also build to 6 feet, so a possibility exists for the
necessity of a small craft advisory due to seas.

&&

.CLIMATE...
Preliminary daily record high temperatures have been tied at
Caribou, Bangor, and Houlton, with a preliminary new daily
record high temperature being set at Millinocket of 97. This
also means that, preliminarily, Caribou tied their all time
record high temperature today.

Temperatures will soar under an anomalously upper level high
pressure system, challenging record high temperatures
and record max minimum temperatures thru Thu.

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 (65 June 19) 72 in August 2009

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Heat Advisory from 11 AM to 8 PM EDT Thursday for MEZ002-005-
     006-011-030>032.
     Excessive Heat Warning from 11 AM to 8 PM EDT Thursday for
     MEZ015>017-029.
     Air Quality Alert until 11 PM EDT this evening for MEZ029.
MARINE...None.

&&

$$


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