Area Forecast Discussion
Issued by NWS Portland, ME

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837
FXUS61 KGYX 041035
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
635 AM EDT Thu Jul 4 2024

.SYNOPSIS...
A brief shower or two will remain possible today as a weak
frontal system decays over the region, but the vast majority of
the day will be dry. Higher temperatures and humidity begin to
build as well today with this trend continuing through the end
of the week. The next chance for more widespread showers and
thunderstorms is expected this weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Update...
Have updated the forecast to allow for scattered showers
exiting the coastline early this morning and into the Gulf of
Maine. Highest pops for showers during the day today will
continue to be northern areas.

Models are continuing to hint for some stratus and fog for the
overnight hours tonight which is supported by the latest HREF
solution. May introduce some fog with this package update.

Prev Disc...
A weak frontal system will decay over the region today. There
will be some increase in moisture and a slight chance for a
shower will remain possible, but overall forcing for
precipitation will be minimal. Some increase in sunshine will
occur over the northern mountains later today.

Surface dew points and PWATs will be on the increase with the
atmosphere becoming more muggy with time. Temperatures will top
out in the 75 to 85 degree range. The exception will be the
coastline where onshore winds off the chilly Gulf of Maine will
keep readings in the upper 60s to mid 70s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Most of the cloud cover will remain over southern areas tonight.
This cloud cover will insulate the atmosphere and keep
temperatures from dropping much. Most areas will remain in the
60s by morning.

Friday will feature partly sunny conditions. It will be warmer
with high temperatures mainly in the 80s. There could be a few
widely scattered showers and with increased destabilization a
couple thunderstorms as well. This will mainly be in northern
areas as a weak trough crosses the region.

Surface dew points will continue to increase as well. The latest
HRRR brings dew points through the lower 70s over southern areas
on Friday.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Overview: An active weather pattern taking shape late this week
into the weekend. Low pressure is forecast to track from the
Great Lakes into eastern Quebec Saturday. This will bring the
chance for showers Saturday with the added potential for
thunderstorms and heavy rain. Some uncertainty how quickly this
system pulls east for drying Sunday, but high pressure following
the system should be overhead by Monday. Another period of
unsettled weather may be in the region by the middle of next
week, perhaps with more potential to linger than this weekends
system.

Details: High pressure to the north will continue moving NE as
low pressure moves across the Great Lakes and into Quebec
through Saturday. Warm sector moisture keeps Saturday humid and
damp. Saturday likely sees the best chance for rain during the
day, with some thunder potential. Some guidance is robust with
warm layer aloft and CAPE suffers especially surface based
instability. The window for instability may be open a bit more
towards western NH, where a stronger storm cant be ruled out
given the strong shear and moist environment. At this point
however, the risk for heavy rain may be a larger but still muted
aspect. CWA PWATs push 2 inches Saturday with much of the
column saturated between early morning and early afternoon.
Additionally, the aforementioned warm air aloft keeps warm cloud
layers deep, around 13-14kft. So precip efficiency is there,
but the setup lacks favorable storm motion and features dry
antecedent conditions. Wed really need training storms Sat
(possible were CAPE to improve) and impactful shower activity on
Friday to increase odds of flooding Sat. One possibility is if
the following cold front slows, focusing rainfall along its axis
overnight into early Sunday morning, but best push of
efficiency parameters may be pulling east by then.

Sunday features less in the way of rainfall, but cant rule out
a few showers for the first half of the day. High pressure
nears the Northeast into early next week, providing a break of
the dreary weather Monday. This high will play a key role as it
exits the East Coast into Tuesday and Wednesday. Restrengthening
high pressure in the open Atlantic could allow for a focus of
unsettled weather to remain in the region mid week through late
week. A channel of moisture appears to get blocked and may align
with a good portion of New England and the East Coast as a
whole.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Short Term...VFR conditions are expected today. A few patches
of valley fog possible tonight but coverage would be sparse. A
few widely scattered showers today and Friday could bring a
period of lowered conditions but overall, VFR conditions are
expected through Friday.

Long Term...Mainly VFR Friday, but ceilings will begin to lower
in the evening and overnight hours. Many terminals will likely
see IFR to LIFR ceilings along with some reduced vis due to fog.
IFR lingers for mostly western ME terminals Saturday as SHRA and
some TS develop. A return to VFR may not be likely until Sunday
when high pressure moves towards the region.

&&

.MARINE...
Short Term...A few southerly gusts may approach 20 kt this
afternoon but sub SCA conditions are expected through Friday.

Long Term...The waters will spend much of the weekend within a
warm sector of passing low pressure to the west. This will
result in periods of fog or low stratus over the coastal waters.
Conditions may improve Sunday into Monday as a cold front slowly
moves over the waters. Onshore winds are expected through
Saturday, becoming SW Sunday and then W Monday.

&&

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

&&

$$
NEAR/SHORT TERM...Cannon
LONG TERM...Cornwell