Area Forecast Discussion
Issued by NWS Portland, ME-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KGYX 290301
Area Forecast Discussion
National Weather Service Gray ME
1101 PM EDT THU JUL 28 2016
A weak frontal boundary dropping out of Canada will continue showers
and thunderstorms into the evening. The front slowly slips
offshore on Friday as low pressure track east along the front
offshore of Cape Cod. This will bring another chance of showers
Friday into Friday night. Cooler, more seasonable temperatures
return for the weekend with dry conditions Saturday and another
chance for showers on Sunday into Monday.
.NEAR TERM /THROUGH FRIDAY/...
-- Changed Discussion --11pm.. Just a minor update for current conditions. shower
activity remains to the south of our area.
8pm update... The front has pushed through the region. Remaining
shower activity has pushed off shore with the front. Overnight
look for the front to remain stalled to our south. Dewpoints
remain in the mid 60s. The combination of a humid airmass and
cloud cover will keep overnight temperatures up in the 60s and
allow patchy fog to form.
Prev disc... A weak front will move south across the region
tonight. Scattered showers and thunderstorms will accompany the
front. Some storms may be be strong but dynamics are not favorable
for a sever weather outbreak. By later in the evening most of the
stronger convection will diminish to just showers. Temperatures
will be warm and muggy tonight as per model guidance.
-- End Changed Discussion --
.SHORT TERM /FRIDAY NIGHT THROUGH 6 PM FRIDAY/...
8pm update... Looking ahead to tomorrow still expecting a low to
develop around delmarva and move northwards passing between the
benchmark and Cape Cod. Deterministic guidance has come into good
agreement on the low track however there is still some spread in
the northward extent of the precipitation shield. While this low
will be strong for the time of year /around 1 to 2 standard
deviations below normal/ and has a strong jet maxima aloft, it is
lacking the mid level dynamics /low level jet or frontogenesis/
that typically drive the heavier precipitation patterns northwest
of a low center in winter. Without these dynamics, expect the
precipitation to be more convectively driven and thus remain south
of the sagging front... keeping most of the precipitation in
Massachusetts. Have thus pulled the northward extend of the PoP
back southward a bit. At the same time the juicier summer
airmass does have the potential to create heavy rain in localized
areas in convective downpours as PWAT climbs to near 1.75 inches.
Have thus added heavy rain wording to the extreme southern New
Hampshire and Maine seacoast.
Prev disc.... On Friday the front becomes stationary to the south
with a low/mid level wave of low pressure developing along the
front over the southern new england coast and moves rapidly east
by Friday evening. Heavy qpf will be associated with this wave to
our south but our forecast area will be far enough north and
spared to only receive .25-.50 inches Friday with the heaviest
amounts over southeast NH. Temperatures will be cooler Friday and
Friday night as cooler air from the north slowly spreads south.
Used a blend of models for pops and temperatures and RFCQPF.
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
With active wx across the forecast area this afternoon the
extended forecast will stay close to the previous forecast. Used a
multi-model consensus blend with the previous forecast. Little
change is seen with the latest model guidance...with another round
of showers possible Sun night or Mon...and gradually warming temps
and scattered afternoon showers for the remainder of the week.
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Short Term...MVFR and possible brief ifr conditions tonight
through Friday in scattered showers and even a few possible
thunderstorms. Conditions will improve to vfr Friday night.
Long Term...A period of MVFR conditions is possible in SHRA Sun
night and Mon. Confidence is low on how far N those SHRA
extend...so much of the forecast area may remain dry and VFR.
Short Term...Conditions to remain below SCA thresholds through
Long Term...Winds and seas are expected to remain below SCA