838
FXUS61 KGYX 152250
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
650 PM EDT Sat Jun 15 2024

.SYNOPSIS...
Behind a departed cold front an area of high pressure will
settle over the region through Sunday, bringing mild and less
humid conditions for the weekend. A warm front will move into
the region Monday followed by a stretch of very hot and humid
conditions through the week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
650 PM Update...Little change to the going forecast as a clear
evening with diminishing winds are expected.

Previously...

High pressure centered over Ontario will gradually build in
tonight and will crest over the area Sunday morning. Breezy NNW
winds will relax later this evening and will go close to calm
tonight, especially in valley locations. The combination of
clear skies and calm winds will allow for efficient radiational
cooling. The forecast challenge for tonight will be how cold do
northern valleys get and the potential for patchy frost.
Currently dewpoints in northern valleys are near 40F and 32F on
Mt Washington suggesting this is the floor for lows. Have
utilized MOS guidance for lows which does bring lows into the
mid to upper 30s across northern zones and into the 40s south of
the mountains. Have included patchy front is the forecast in
Coos County, while areal coverage too limited for a Frost
Advisory, although will watch trends if temperatures trend
cooler.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
High pressure centered over the area Sunday morning will slide
southeast offshore Sunday afternoon. Skies will start off mostly
clear with some cirrus moving in from the west Sunday afternoon.
Highs will generally be in the mid to upper 70s across the
interior with low 70s across the north and near the coast where
winds turn onshore.

Mid to high level clouds increase Sunday night ahead of an
approaching warm front. Showers associated with the front will
likely hold off until Monday morning. Lows will not be as cold
as tonight and will generally be in the 50s.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
*** The heat is on as potentially record breaking temperatures
 arrive for the start of summer ***

Here are the records...

RECORD HIGHS FOR JUNE 19:
Concord-98, 1995
Augusta-98, 1995
Portland-94, 1995

RECORD HIGHS FOR JUNE 20:
Concord-98, 1993
Augusta-95, 1953
Portland-93, 2020

We begin the extended with a tale of two climates on Monday. A
strong warm front will be draped over the region. East of this
front, chilly conditions will continue across much of the
Midcoast region of Maine with highs only in the 60s. The
remainder of the state will be seasonably warm with highs in the
70s. Across western York County and much of New Hampshire, the
warm front is expected to pass through with temperatures
reaching the lower to mid 80s.

This strong warm front with rapid height rises and the
possibility of a short wave rounding the top periphery of the
ridge may trigger a few showers and storms on Monday. In fact,
this type of set up has the potential for a fast moving MCS to
round the ridge. While this is not a likely scenario, it should
be considered.

In any case, remarkable height rises continue on Tuesday across
the Northeast. This is rare for June and with height rises
approaching 600 dm at 500 mb over New York City, this anomaly
is particularly significant as we are still in the middle of the
month. The Euro ensemble suggests a 45 to 50 percent chance of
heights greater than 597 DM at WFO GYX. The highest 500 mb
height ever measure at GYX (by our balloon launch sounding) was
598 DM set on July 5th in 2018.

In any case, widespread 90s can be expected across the region
with the highest readings over southern New Hampshire.

It is important to note that along and near the coastline a
cooling sea breeze will form. In fact, temperatures may hold in
the 70s to lower 80s for highs along the beaches and
peninsulas as a south to southeast onshore breeze develops.

Surface dew points will be on the increase as well. Expect this
moisture to climb and reach the mid to upper 60s. There remains
some drier air aloft to mix down per latest Bufkit soundings.
Mixing levels may reach 7K feet. This moisture will allow for
patchy overnight fog to develop across portions of the region.

The large dome, an upper level ridge will be parked over the
Northeast again on Wednesday. Guidance has trended warmer for
this day including the coastline where temperatures will climb
rapidly through the 80s despite a sea breeze. Across the
interior, widespread 90s expected with a few communities over
southern New Hampshire flirting with 100 degrees.

PWATS will be increasing with surface dew points remaining
between 65 and 70. This will allow for maritime fog to likely
form over the cold Gulf of Maine water temperatures. However,
with a west to southwesterly flow aloft, this fog should remain
offshore. This flow will be weak however with the forecast 18Z
winds at MWN expected to be 260 degrees at 16 knots. A warm
night will follow with 60s and lower 70s for overnight lows.

Thursday will be a repeat day with hazy, hot and humid
conditions. Compressional warming ahead of an approaching cold
front may balance out increasing clouds to determine the
expected forecast highs. Nevertheless, widespread 90s and
possibly low 100s remain plausible. A few late afternoon
showers and thunderstorms may develop along the front, mainly
over central and northern areas.

It will be slight less hot on Friday. Never the less, hazy, hot
and humid conditions will end out the work week and into
Saturday.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Short Term...VFR will prevail tonight through Sunday night. NNW
winds will relax this evening becoming light and variable
tonight. A sea breeze likely develops Sunday bringing onshore
winds into coastal TAF sites.

Long Term...IFR conditions developing in scattered showers and
thunderstorms on Monday. Otherwise, mainly VFR conditions
through Wednesday followed by more showers and thunderstorms
with a cold frontal passage on Thursday. Areas of IFR conditions
as well during the night time period with patchy valley fog.

&&

.MARINE...
Short Term...High pressure builds in from west tonight and
crosses over the waters Sunday into Sunday night. NW to N winds
will prevail into tonight and then shift onshore Sunday. Winds
and seas will remain below SCA thresholds while waves may
approach 4-5 at the outer fridge of offshore zones.

Long Term...Winds and seas will primarily be out of the south
during the extended portion of the forecast and below SCA
thresholds. Highest wind gusts likely will be during the
afternoon hours as the sea breeze attempts to form.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$


NEAR TERM...Ekster
SHORT TERM...Schroeter
LONG TERM...Cannon