NWS Gray, Maine Area Forecast Discussion



000
FXUS61 KGYX 182233
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
633 PM EDT Thu Aug 18 2022

.SYNOPSIS...
The low pressure system responsible for rain across the area
will lift northeast tonight allowing high pressure to build in
for Friday. This will result in much warmer and drier
conditions. A warm and somewhat humid weekend is expected under
partly sunny skies. Conditions look to turn somewhat more
unsettled as we move into next week with chances for showers and
thunderstorms returning to the forecast with temperatures
returning back toward seasonal norms.

&&

.NEAR TERM /THROUGH FRIDAY/...

630PM Update...Despite there being a few echoes showing up on
radar across southern NH, the low levels look to have dried
enough to where only a brief sprinkle or two may reach the
ground at this point. So, have cut back PoPs across this area
with the majority of the shower activity remaining confined to
the mountains, foothills, and those slightly downstream.


Previous discussion...

High Impact Weather Potential: Minimal.

Pattern: Large upper low dominates early afternoon water vapor
imagery with a vertically stacked low pressure system over
northern Maine slowly beginning to lift north and east away
from northern New England. The weakening/departing low has
yielded gradually improving conditions with shower activity
slowly weakening. This improving trend will continue through
tonight as high pressure begins to build towards the region from
the south and west. Primary forecast focus will be on lingering
showers and any potential for fog given moist surface
conditions.

Through this evening: Showers continue to pinwheel around decaying
surface low...but have weakened and decreased in coverage since this
morning.  Still...scattered to numerous showers will continue into
the evening hours given moist...cyclonic boundary layer flow.
Temperatures at 8pm will range from 60 over the mountains to the
mid/upper 60s to the south.

Tonight: Mid level height rises continue across the region under
northwest flow aloft as low level cyclonic flow slowly releases it/s
grip. Scattered showers will be ongoing this evening...but will
gradually become increasingly confined to the upslope regimes before
ending.  Overnight...skies will partially clear with light westerly
winds continuing.  Lows should fall into the 50s for most spots.
Given the recent rainfall and partial clearing...some valley fog
will be possible...with overnight lows near crossover values.
Have included patchy fog mention across the north and down the
CT Valley.

&&

.SHORT TERM /FRIDAY NIGHT/...
High Impact Weather Potential: Minimal.

Pattern: Flow aloft will back and heights will build as trough and
associated surface low continue to lift north and east away from the
region. High pressure will build towards the region from the south
and west through Friday night with a quiet period of weather
expected.

Friday: Lingering cyclonic flow may be enough to allow for a morning
sprinkle in the upslope regime but otherwise...the drying
llevel airmass suggests a partly to mostly sunny day as high
pressure builds in from the west. Review of model sounding and
plan view progs suggest dewpoints will fall into the
50s...though the core of the driest air looks to reside over
southern New England which saw much less in the way of rainfall
over the past 36 hours. T8s will be pretty warm...around +14C
which should allow SE NH and SW ME to rise into the upper 80s
with middle 80s elsewhere south of the mountains...and
temperatures in the 70s in the mountains where temps aloft will
be cooler and there will likely be a few more clouds.

Friday Night: Quiet and comfortable night as high pressure ridge
axis will be overhead in the presence of a reasonably dry boundary
layer airmass.  This should allow for mostly clear skies...light
winds and temperatures to fall into the 50s for most locations...
closer to 50 in the northern valleys...and closer to 60 for ASH-MHT-
PSM-PWM...which is closer to the statistical guidance and a bit
below the National Blend of Models.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
High pressure over the Atlantic will spread to the northwest
Saturday bringing warm temperatures for the weekend.  Clear skies
Saturday will allow temperatures to rise into the mid to upper 80s
south of the mountains with some southern/valley locations reaching
near 90 degrees.  Humidity will gradually increase over the weekend
as well with dewpoints in the low 60s expected Saturday, rising into
mid 60s Sunday and Monday.  Clouds will start increasing over the
day Sunday as low pressure starts drawing nearby.

Unsettled conditions move in for the start of next week with a few
shortwaves creating some chances for precipitation by midweek.  Low
pressure, currently over the southern US, will slowly make its way
up the east coast over the weekend bringing cloudier and more humid
conditions to the north. At the same time, an upper level low will
slowly make its way east across the Great Lakes with both systems
making their way into New England on Monday.  The combination of
these two systems will bring unsettled conditions to the area for
the first part of next week.  Ensemble cluster analysis is showing
better agreement on showers moving in from the southern system
Monday afternoon before filling in to the west and north as the
system from the Great Lakes moves in overnight.  QPF amounts and
timing of heavier showers/precip is still uncertain.  Cluster
analysis is still a mixed bag for Tuesday with roughly equal chances
for wetter and drier solution.  Generally the GFS and CMC are in
better agreement on a wetter/more northern solution than the ECMWF
and have been more consistent on the dynamics.  Ensemble members
aren`t picking up on a main organized low developing over these few
days of unsettled conditions, however that could easily change with
future model runs. The general model trend is making me lean
towards the GFS/CMC solutions which would bring a 48 hour period
of wetting rains to the area but I am still keeping precip at a
chance until areas of heavier rainfall are more certain.

Winds turn to the northwest Thursday with some upslope showers
lingering through the day before another chance of precipitation
moves up the east coast to New England for the end of the week.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Short Term...

Summary: Low pressure just east of the region will lift away from
the area tonight with gradually improving conditions as high
pressure arrives from the south and west.

Restrictions: Variable conditions across the terminals at the moment
with MVFR continuing over much of western ME but improvement to VFR
having occurred over southern NH. Scattered showers will
continue into this evening before coming to an end with overall
improving conditions expected. Expect all sites to be VFR by
00Z Friday with some overnight fog bringing IFR/LIFR at HIE-LEB.
VFR conditions expected Friday with valley fog potentially
impacting both HIE/LEB again Friday night.

Winds: Northwesterly winds 10g18kts will diminish to less than
10kts overnight...returning back to around 10kts for the day on
Friday. Winds will go calm/light-variable Friday night.

LLWS:  No LLWS is expected through Friday night.

Lightning: No lightning is expected through Friday night.

Long Term...VFR conditions prevail through the weekend with
southwesterly winds before unsettled conditions move in for next
week. Overcast and lower ceilings will linger through midweek
with MVFR/IFR restrictions possible within showers.

&&

.MARINE...
Short Term...With low pressure pulling away from the
region...westerly winds and waves will continue to subside
through the short term period with no additional headlines
expected.

Long Term...Winds and seas will continue to be below SCA
thresholds through the weekend and into next week as high
pressure sets in and winds turn from the southwest. Unsettled
conditions move in for the first part of next week with a chance
of showers Mon-Wed.

&&

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

&&

$$

UPDATE...Combs
SYNOPSIS...Arnott
NEAR TERM...Arnott
SHORT TERM...Arnott
LONG TERM...Thunberg
AVIATION...Arnott/Thunberg
MARINE...Arnott/Thunberg

NWS GYX Office Area Forecast Discussion