Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Gray ME
916 am EDT sun Jul 24 2016

Synopsis...
a narrow ridge of high pressure will build in from the west today
and will shift offshore tonight. This will bring sunny skies,
with less humid conditions today. A cold front will approach from
the west on Monday and will cross the region Monday night,
providing another round of showers and thunderstorms. High
pressure will build in from the west Tuesday through Wednesday. A
weak frontal boundary will settle south from Canada Wednesday
night and will stall over the region on Thursday. High pressure
building in from the north will suppress the stalled frontal
boundary south of New England Thursday night. Several weak waves
of low pressure will track east along the stalled frontal boundary
Friday and Saturday.

&&

Near term /until 6 PM this evening/...
9am.. no major changes as high pressure builds in for the day.

640 am...just a quick update to adjust grids based on current T/TD
and sky. Clouds in the mountains will diminish in the next few
hours as upslope flow weakens and atmosphere mixes out. Otherwise
and warm for today with lower humidity.

Previously...a tranquil day is expected compared to the last two,
with mainly sunny skies, lower humidity and seasonably warm temps
from around 80 in the mountains to the upper 80s in southern New Hampshire.
This is thanks to a ridge moving in aloft and sfc high pressure
sliding in from the west beneath it. Initially northwest flow aloft will
provide a sfc flow W-NE...but as the gradient weakens may see a
weak sea breeze develop mid-late afternoon.

&&

Short term /6 PM this evening through 6 PM Monday/...
the sfc ridge move across the County Warning Area tonight, and it is expected to
remain dry. SW flow will begin to develop behind the ridge and
this will allow the humidity to start creeping in late tonight.
Will also see some cirrus moving overnight. Overnight lows will
range from the mid-upper 50s in the north...to the low 60s in srn
New Hampshire and along the ME coast.

Tds will go from tolerable Monday morning to steamy by afternoon
as flow shifts around to south. Inland areas will be able to tap
into 850 temps around 18-19c, but more of an onshore will be
prevalent through a large part of the day...especially east of
Portland. Highs will reach into the low 90s in southern New Hampshire...and
mid to upper 80s most everywhere else. The coast, from Casco Bay
east will generally be limited to the 70s to around 80.

Equatorward end of 500 mb wave will approach from the west
Monday, and will see cold front approach from the west. Will see
showers and storms develop, mainly in the afternoon. Still lots of
questions as to intensity of storms, but there is some potential
for strong to severe storms, although extent of cloud cover, and
timing of beast instability vs best shear still in question, so
will hold off introducing any enhanced wording at this point.
Still coverage of convection should increase from west to east as
the afternoon progresses.

&&

Long term /Monday night through Saturday/...
cold front will cross the region Monday night sweeping showers
and thunderstorms east of the region by midnight or shortly after.
Low temperatures will range through the 60s to near 70.

Drier and somewhat cooler air will ride into the region Tuesday
on an increasing northwest flow ahead of high pressure building
in from the west. Should see a mix of sun and clouds with highs
ranging through the 80s.

High pressure will continue building in from the west Tuesday
night and Wednesday. Lows Tuesday night will range from the mid
50s to lower 60s north and mid to upper 60s south. Highs on
Wednesday will range through the 80s to near 90. Could see a late
day shower or thunderstorm in far northern zones as a very weak
frontal boundary drops into southern Quebec.

Weak frontal boundary will sag south into the region Wednesday
night and will stall over the area on Thursday. Expect variable
cloudiness Wednesday night with just a chance of a shower. Low
temps will bottom in the lower to mid 60s.

Showers and thunderstorms will develop on Thursday as stalled
frontal boundary remains draped across region. Very little in
the way of shear is expected so looking at pulse type...very
slow moving convection and with pwat's approaching 1.5 inches
could see some very heavy downpours with these storms and
possible flood problems. Best chance for storms will be inland as
weak gradient will allow for a strong sea breeze to develop
shielding coastal areas from these storms. Highs will range
through the 80s to near 90.

Frontal boundary will gradually sag south of New England
Thursday night as high pressure noses in from the north.
Looking for variable clouds overnight with just a chance of a
shower.

Very broad shallow shortwave approaching from the west will keep
skies fairly cloudy on Friday. Good instability in the afternoon
will once again lead to showers and thunderstorms. Should see
cooler temps with highs ranging from the mid 70s to mid 80s.

&&

Aviation /13z Sunday through Thursday/...
short term...mainly VFR through Monday. Some valley fog possible
this morning but boundary lyr flow is increasing thru the morning,
and clouds over northern New Hampshire will limit it yo some degree at
khie/kleb. Also, thunderstorms possible Monday afternoon.

Long term...VFR Monday night through Thursday. Areas of MVFR
ceilings and vsby in scattered showers and thunderstorms
Thursday.

&&

Marine...
short term...all quiet on the waters through Monday. Only issue
will be thunderstorms late Monday afternoon.

Long term...no problems noted.

&&

Gyx watches/warnings/advisories...
ME...none.
New Hampshire...none.
Marine...none.

&&

$$
Synopsis...
near term...Curtis
short term...
long term...
aviation...
marine...

National Weather Service Glossary of Abbreviations