Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 280425

Area Forecast Discussion
National Weather Service Gray ME
1225 AM EDT THU JUL 28 2016

A weak frontal boundary will drop south out of Canada and into
northern New England Thursday, bringing a chance for showers and
thunderstorms as it does so. The front slowly slips offshore on
Friday as low pressure track easts 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.


Have updated the grids based on current conditions. Lowered min
temperatures overnight by a degree or two outside southern NH.
Otherwise, very little change to the forecast package. Convection
will be slow to cross the forecast area tomorrow afternoon and

Prev Disc...
6pm update...just a minor update for current conditions.
Decreased the areal coverage of overnight fog to focus on the
favored valley locations as the dewpoints have generally mixed out
a bit more through most of the area.

High pressure will continue over the region tonight allowing
another warm humid night with fair weather. With calm winds and
generally mostly clear conditions some patchy fog will develop
after midnight. generally used a blend of models which were in
general agreement for overnight min temperatures.


On Thursday scattered showers and thunderstorms will develop first
over northern and western areas of Maine and New Hampshire and
then will gradually spread southward to the coastline by evening.
By Thursday night, the front will become quasi-stationary along
the coastal waters with showers and thunderstorms continuing along
and north of the front. The best chance for any thunderstorms will
be primarily early in the evening. We are not expecting any of the
storms to become severe due to poor dynamics with the system.

Temperatures will be hot once again over southern areas Thursday
reaching the upper 80s to lower 90s. Further north in the
mountains temperatures will be cooler ranging from the upper 70s
to lower 80s due to the developing cloud cover and convection.
Another warm muggy night is also expected Thursday night due to
the lack of any ventilation of cooler or drier air.


On Fri we will be dealing with a s/wv trof lifting out of the TN
Valley and towards the Srn New England coast. There is strong
model consensus on coastal low pres developing and moving very
close to the elbow of Cape Cod. With that in mind I will increase
PoP for much of the Srn half of the forecast area during the day
Fri. Another thing to keep an eye out for will be the heavy rnfl
potential. On the NW side of the low pres model guidance has a
strong frontogenesis signal...especially for this time of year.
With warm cloud depths on the order of 12,000 feet or more...rnfl
could be quite efficient in places. I have added heavy rnfl
wording to the grids for Fri. At this time the best potential will
be over Srn zones...which may actually be welcomed for relief
from the dry wx.

After Fri the pattern looks to be dominated by an Ern CONUS trof.
With the Wrn CONUS ridging also being flattened...the Nrn stream
could be more active and lead to more unsettled wx. It was hard to
find a day where PoP could be completely removed from the
forecast...and so most days have a chance for showers/t-storms.


Short Term...VFR conditions are expected tonight, except for
perhaps a few hours of patchy areas of fog 06z-11z. VFR conditions
Thursday become MVFR in developing scattered showers and
thunderstorms in the afternoon and evening.

Long Term...Fri may see an extended period of MVFR conditions as a
coastal low pres system brings an area of rnfl to Srn zones. This
would be most likely to affect MHT...PSM...PWM...and RKD. Even CON
and AUG may be too far N to get into the heaviest precip. There is
a low chance that some heavier rnfl moves into the Srn most
terminals and brings local IFR conditions. VFR conditions return
Fri night. Another round of MVFR showers is possible Sun night
into Mon.


Short Term...Conditions are expected to remain below small craft
thresholds through Thursday night.

Long Term...Winds and seas look to remain below SCA thresholds
thru the end of the period.




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