Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
1132 PM EDT Tuesday Sep 2 2014
a cold front will cross the region tonight...bringing some showers
and thunderstorms. High pressure will build in from the south
Wednesday and Thursday...bringing fair weather and less humid
conditions. The shifts offshore on Friday allowing more humid air
back into the region through Saturday. A cold front crosses the
area Saturday night into Sunday. High pressure builds in early
Near term /tonight/...
1130pm update... have updated to adjust pop to reflect high
confidence in rain tonight in northern areas and much of New
Hampshire. Showers and embedded storms may begin to break up as
they move across the area tonight... but still a good chance of
rain for most of the area.
7 PM...updated probability of precipitation to keep the first part of the evening dry and
mainly clear...except along the middle- coast where marine fog and
low clouds are already moving in. Rain showers/thunderstorms and rain just ahead of the
cold front...currently across upstate New York...will work their way eastward
and should arrive in the CT valley 01-02z...earliest in the far north.
Latest mesoscale models are trending for bulk of this precipitation to
shift across mountains and foothills...where best dynamics will move
through. Have limited the likely/Cat probability of precipitation overnight to this area and
just went with chance probability of precipitation closer to the coast.
Previously...weak pre-frontal trough currently kicking off line
of convection across southern New Hampshire early this afternoon
and expect this area to weaken as it moves into marine layer in
southeast New Hampshire and southwest Maine. Expect scattered
convection to continue popping up in hot and humid airmass as
heating continues this afternoon. Not a lot of shear at the moment
and freezing levels are quite high so not looking for any
widespread severe but some isolated cells may produce brief gusty
winds approaching severe limits.
Main event will come later this evening ahead of the front
generally after 00z. Although loss of heating will tend to weaken
convection as it moves through this evening...increasing shear may
contribute to some bowing line segments which may produce damaging
winds. Main area of concern would be southern New Hampshire and
the Connecticut valley. Will likely be getting towards midnight
before convection moves into western and central Maine. Will see
areas of fog developing behind the front before northwest
gradient tightens...clearing out most areas around daybreak. Will
be a mild night with lows ranging through the 60s.
Short term /6 am Wednesday morning through Wednesday night/...
high pressure will build in from the west through Wednesday.
Looking for a breezy and warm day with highs from the middle 70s to
the middle 80s. Upslope clouds in the mountains will gradually clear
during the day and the remainder of the area should see mostly
Clear and cool Wednesday night as high pressure crests over the
area. Colder mountain valleys will dip into the middle to upper 40s
while the remainder of the forecast area dips into the lower to
Long term /Thursday through Tuesday/...
high pressure settles over the region Thursday but moves east on Friday. Cooler
and drier with be associated with the high until late Friday. On Friday
night and Sat a return warmer southwesterly flow develops once again with
scattered showers/thunderstorms to develop well in advance of an approaching cold
front that will move across the region and then off the coast by Sat
night. Canadian high pressure builds across northern New England
early next week with cooler and drier air. Overall stayed close to
the superblend model for pops, weather and temperatures.
Aviation /04z Wednesday through Sunday/...
short term...IFR/LIFR ceilings and visibility developing this evening in
coastal and southern interior sections of Maine. Areas of valley
fog elsewhere after midnight. VFR Wednesday and Wednesday night.
Long term...VFR Thursday and Friday. Becoming MVFR in scattered showers/thunderstorms Friday
night through early Sat night. Conds return to VFR sun.
short term...no flags. Sca's may be needed on Wednesday.
Long term...a Small Craft Advisory may be needed Sat ahead of the approaching cold
front Saturday as winds increase from S-SW.