825
FXUS61 KGYX 191038
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
638 AM EDT Wed Jun 19 2024

.SYNOPSIS...
High pressure will remain east of New England through much of
this week, continuing our period of hot and humid conditions
through Thursday. Record high temperatures and potentially
dangerous heat index values are likely. A cold front will
slowly cross through the region on Thursday and Friday with an
increasing chance for scattered strong thunderstorms and cooler
temperatures starting on Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
645 AM Update... Minor changes to reflect latest observational
trends. Still expecting hazy, hot, and humid conditions today
with perhaps a few interior spots approaching the 100 degree
mark.

Previously...
Nighttime microphysics satellite imagery early this morning
shows some passing cirrus overhead along with some valley and
coastal marine fog that is beginning to develop. Current
temperatures are into the 60s and 70s and they will likely drop
another degree or so prior to sunrise. It will otherwise
continue to be a warm and humid morning.

Surface high pressure will remain anchored east of New England
today, allowing for southwesterly flow over our region. Warm
temperatures aloft combined with afternoon mixing will result in
high temperatures into the middle 90s across most interior
locations with 70s/80s along the coast and in the mtns. Surface
dew points will be into the upper 60s and lower 70s, which will
push heat indices into the middle 90s across areas covered under
the heat advisory with readings up to around 105F within the
excessive heat warning.

Latest CAMS continue to show the potential for a few afternoon
and evening thunderstorms to develop as a s/wv crosses southern
Quebec. Forecast soundings indicate a high CAPE and low shear
environment with bulk shear of only around 15 kts. Despite this,
inverted-v soundings combined with precip loading and high DCAPE
introduces a locally strong wind threat within any stronger
storms. Coverage is expected to be spotty though due to fairly
weak forcing and a mid-level CAP. The Storm Prediction Center
has placed much of our area under a MRGL risk for severe storms
this afternoon.

Any remaining showers and thunderstorms will diminish this
evening, leaving behind another warm and muggy night. Lows will
primarily be into the 70s. Fog may develop overnight, especially
across the valleys.

&&

.SHORT TERM /THURSDAY/...
Clouds will increase from north to south on Thursday ahead of a
sfc cold front that will cross during the afternoon and evening
hours. Ahead of this front, it will be another hot and humid
day with high temperatures into the lower to middle 90s away
from the coast with 80s in the mtns and the coast. Heat indices
will climb up to around 100 degrees for a few hours, which will
likely necessitate additional heat advisories.

This strong sfc heating will allow for steep low-level lapse
rates with MLCAPE increasing to around 2000 J/KG. This combined
with 20-30 kts of 0-6km bulk shear and PWATs nearing 2.00" once
again introduces the potential for scattered strong to severe
thunderstorms. The primary hazard will be locally damaging winds
with precip loading but the added shear could also allow for
some hail as well. Coverage is likely to be greater than today
due to the additional forcing from the passing cold front. The
storm Prediction Center has placed much of the CWA into a MRGL
risk with a SLGT risk in southwestern NH.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The cold front will clear the coast Thursday night, bringing an
end to the showers and thunderstorms. Lows will range from
around 60 across the north to the 70s south.

It will be still be warm on Friday, especially over southern
NH, but will be much more manageable than the temps today-
Thursday with the post-frontal air coming in. Highs are forecast
to be in the mid- upper 80s for southern NH and the low-mid 80s
for the rest of the area. There will also be a tight moisture
gradient with the higher moisture across NH and this area has
30-50% chances for showers while chances decrease to the north
and east.

Although still running above normal for this time of year,
temperatures will follow a cooling trend over the upcoming
weekend as heights lower, flow aloft becomes more zonal, and
more in the way of clouds are expected. In addition to this,
dewpoints will also come down into the 50s for most of the area
on Saturday (except lower 60s in southern NH) before creeping
back upward into the 60s on Sunday. Highs on Saturday are
forecast to be in the upper 70s to lower 80s, and these may
increase by another couple of degrees by Sunday as southerly
flow starts increasing ahead of a cold front. This is certainly
good news after the hot weather this week. There is another
chance for shower late Saturday into Saturday night as energy
aloft moves overhead, but due to confidence have stuck with NBM
of 40-50% at this time.

A better chance for more widespread precip and possibly a few
storms arrives late Sunday and into Monday as a more potent
upper trough pushes a cold front through New England. Assuming
the front pushes through as advertised (decent agreement in the
models this far), we should see drying conditions by next
Tuesday or so.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Patchy FG and low ceilings will continue to result
in the potential for IFR to LIFR restrictions through around
12Z, mainly at KLEB. Otherwise, VFR conditions will prevail
today with southwesterly winds at 10-15 kts. Scattered TSRA are
possible this afternoon and any storm may contain locally
strong winds and restrictions. Patchy FG will once again be
possible tonight, which will result in IFR to LIFR restrictions
through early Thursday morning. VFR conditions early Thursday
will be followed by a greater chance for scattered TSRA in the
afternoon and evening. Some LLWS is possible late tonight into
early Thursday.

Long Term...For Friday and Saturday, precip chances look lower
overall, but the better chances will be across the NH terminals.
A cold front approaches Sunday into Monday with chances for
widespread precip and restrictions.

&&

.MARINE...
Short Term...Southwesterly winds will prevail today through
Thursday with gusts between 15-20 kts. A few gusts to around 25
kts are possible across the outer waters. Seas will be at 3-4 ft
and marine fog will be possible, especially at night.

Long Term...Broad high pressure remains over the waters Friday
and Saturday before southerly flow potentially exceeds SCA
levels Sunday into Monday as a cold front approaches.

&&

.CLIMATE...
RECORD HIGHS FOR JUNE 19: Concord-98 in 1995; Augusta-98 in 1995
Portland-94 in 1995

RECORD WARM LOWS FOR JUNE 19: Concord-69 in 2017,1876;
Augusta-72 in 1995; Portland: 72 in 1995

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

RECORD WARM LOWS FOR June 20: Concord-73 in 1931; Augusta-67 in
1974; Portland-69 in 2020

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Heat Advisory from noon today to 8 PM EDT this evening for
     MEZ007>009-022>028.
     Excessive Heat Warning from noon today to 8 PM EDT this
     evening for MEZ012>014-018>021-033.
NH...Heat Advisory from noon today to 8 PM EDT this evening for
     NHZ001>003-005-007-011-014.
     Excessive Heat Warning from noon today to 8 PM EDT this
     evening for NHZ004-006-008>010-012-013-015.
MARINE...None.

&&

$$

NEAR TERM...Tubbs
SHORT TERM...Tubbs
LONG TERM...Combs