292
FXUS61 KGYX 160743
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
343 AM EDT Sun Jun 16 2024

.SYNOPSIS...
High pressure will build over southeastern New England today,
allowing for continued mild temperatures and low humidity. A
warm front will move into the region Monday followed by a
stretch of very hot and humid conditions through the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Nighttime microphysics satellite imagery early this morning
shows clear skies over the region with surface based weather
stations indicating light and variable winds. These conditions
have allowed for strong radiational cooling with widespread
readings across the north into the 30s. This could continue to
result in the formation of frost for a few more hours. Further
south readings are primarily into the 40s and lower 50s. A few
additional degrees of cooling can be expected through sunrise.

Surface high pressure will build over southeastern New England
today with increasing WAA aloft helping to push h850
temperatures up to around +8C. This will allow highs to reach
the lower to middle 70s in most spots, possibly near 80 in the
Merrimack River Valley. Light winds will allow for developing
onshore flow, which will keep coastal locations a little cooler.
It will otherwise be a partly to mostly sunny day.

Clouds will begin to increase tonight with lows into the 40s
across the normally colder spots and middle 50s elsewhere. Some
patchy fog could develop overnight as well.

&&

.SHORT TERM /MONDAY/...
A surface warm front will lift northward over our area on Monday
with increasing southerly flow. Mainly cloudy skies during the
morning will become mostly sunny by the afternoon. A few widely
scattered showers and perhaps rumble of thunder will be possible
through late morning but most locations will likely remain dry.
High temperatures will range from the 60s across the Mid-Coast
due to the onshore wind with 70s across interior western ME and
middle 80s in south-central NH.

&&

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

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 into the upper
60s to lower 70s. 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.

An Excessive Heat Watch has been issued for interior southern NH
from Tuesday afternoon through Thursday. This is where the
greatest confidence is for afternoon heat indices to approach
105 degrees. Additional heat headlines will be needed for much
of the area away from the coast as forecast confidence
increases.

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 /07Z SUNDAY THROUGH THURSDAY/...
Short Term...VFR conditions will persist today through the
foreseeable future. Light and variable winds early today will
become southerly at 5-10 kts at KPSM, KPWM, and KRKD due to a
sea breeze. There is a low-end chance for patchy fog tonight but
this is of low forecast confidence. Southerly winds can be
expected on Monday at 10-15 kts along with widely scattered
-SHRA. No LLWS is expected through the period.

Long Term...Mainly VFR conditions through Wednesday followed by
more showers and thunderstorms with a cold frontal passage on
Thursday. Areas of IFR conditions are possible as well during
the night time period with patchy valley fog.

&&

.MARINE...
Short Term...High pressure will build over the waters today
through Monday with winds and seas remaining below SCA
thresholds.

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.

&&

.CLIMATE...
Record breaking high temperatures and warm overnight low
temperatures are likely Tuesday through Friday of next week.

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

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Beach Hazards Statement from 8 AM EDT this morning through
     this evening for MEZ024>028.
NH...Excessive Heat Watch from Tuesday afternoon through Thursday
     evening for NHZ008-012-013-015.
MARINE...None.

&&

$$

NEAR/SHORT TERM...Tubbs
LONG TERM...Cannon
CLIMATE...Tubbs