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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KGYX 091348
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
948 AM EDT Sun Aug 9 2020

.SYNOPSIS...
Warmer and increasingly humid air will spread across the area
through the first half of the new work week. Along with the
building humidity will come the chance of a few showers and
thunderstorms from time to time. A cold front will cross the
area early Thursday...with a bit less heat and humidity to
follow for Friday and the start of next weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
945 AM Update...Have updated the forecast mainly for minor
adjustments to sky cover and temperatures based on latest
observations. Any remaining fog or low clouds will burn off
shortly. Still expecting isolated to widely scattered
convection this afternoon as a short wave trough approaches from
the west. Last few runs of the HRRR are pretty dry so will
continue with very low PoPs, but at least a mention of thunder.

Previously...


645 AM...Minor ESTF update to reflect the current mesonet and
satellite trends in near term grids.

Prev Disc...
At 06z...a 1021 millibar high was centered over southeast New
England. A weak surface trough extended from the Ottawa Valley
through western New England. GOES water vapor showed a weak
impulse vicinity of the Ottawa Valley and a second trailing
impulse over the upper Great Lakes. NWS Doppler Radar mosaic
showed a lone shower over northern New Hampshire likely
associated with the weak trough and approaching impulse.
Otherwise...some high and mid cloud was spilling into the area
ahead of the approaching impulses. Some patchy valley fog and
stratus had also developed over western New Hampshire. For
today...the lead impulse will swing across northern sections
today. CAMS and the remainder of the 00z model suite show
scattered convection mainly across northern and western sections
through early evening. Modified soundings show CAPE AOB 1000
j/kg and limited potential for strong convection. Highs today
will be in the 80s...with a few upper 70s along the immediate
coastline.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
For tonight...the trailing impulse will cross the area with
widely scattered showers and isolated thunderstorms possible.
Otherwise...a partly cloudy and humid night with patchy fog
developing. Lows will be in the 60s. On Monday...the impulse
will finally slide offshore by afternoon. Partly sunny skies
along with the building heat and humidity should produce at least
widely scattered convection...especially across inland sections.
Highs will range from the mid 80s to lower 90s. Apparent
temperatures will fall short of advisory criteria in southern
New Hampshire...likely peaking in the lower 90s.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
No significant changes to model guidance or the forecast package
with this latest update. Heat and humidity will continue to be a
factor through the midweek period.

00Z model suite continues to show a large scale upper level low
pressure system crossing central, then eastern Canada for much
of this upcoming work week. Western Maine and New Hampshire will
remain on the periphery of this system, with very high upper
level heights. A southwesterly flow at all levels will allow for
increasingly deep moisture and heat to enter the region. Warm
air advection will allow for H8 temperatures in the +18C to +20C
range by Tuesday. With the increased moisture and surface
temperatures likely to top out in the upper 80s to mid 90s over
interior locations, max apparent temperatures will soar well
into the 90s in some areas. Heat advisories may be required for
portions of southern New Hampshire and interior southwest Maine.
Along the coastal areas, temperatures will be slightly cooler
thanks to onshore winds of the Gulf of Maine.

A short wave trough and accompanying weak frontal system will
attempt to approach northern areas Tuesday afternoon and Tuesday
night. This may allow for showers and with increased
instability, a few thunderstorms.

The heat continues on Wednesday as an upper level trough passes
by to our north. There may be a few showers or thunderstorms
once again with temperatures in the upper 80s to lower 90s in
the south and central areas. The coastline will be warmer this
day than Tuesday as the gradient becomes more out of the
southwest.

Thursday is the big question. Some of the models hint at the
passage of a backdoor cold front during this time frame. The
Euro brings the front through, but late in the day after the
heat has already hit the region, while other models are more
faster with the any cold air advection. In any case, moisture,
heat and instability could pool over far southern areas of Maine
and New Hampshire, fueling showers and thunderstorms during the
day.

High pressure will likely build over the Canadian Maritimes
Friday and into next weekend. This will set up a cooler onshore
flow and the chance for moisture arriving off the Gulf of Maine
and beyond.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
Short Term /through Monday/...VFR with isold MVFR psb in
-SHRA/-TSRA today through Monday. Lcl IFR possible once again
tonight and early Monday in patchy stratus and fog.

Long Term...Scattered showers and possibly a few thunderstorms
expected through midweek, mainly during the afternoon and early
evening hours and mainly away from the coast. Locally IFR
conditions in patchy fog through midweek as well, mainly at
KLEB, KCON and KHIE.

&&

.MARINE...
Short Term /Through Monday/...Gradient remains light across the
waters through Monday with winds and seas remaining below SCA.


Long Term...Winds and seas will remain mainly below SCA levels.
However, southwesterly winds may gust as high as 25 knots along
and near a frontal system Tuesday night. Pockets of fog possible
from time to time.

&&

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

&&

$$

NEAR TERM UPDATE...Ekster
SHORT TERM...Schwibs
LONG TERM...Ekster