Scientific Forecaster Discussion
fxus61 kgyx 230752
Area forecast discussion
National Weather Service Gray ME
352 am EDT Wed may 23 2018
a cold front will drop south across the area today producing
scattered showers and thunderstorms across northern and
eastern portions of the forecast area. High pressure will build
into the region Thursday and Friday with very warm weather
expected. A backdoor cold front drops into the region this
weekend and will likely provide for some unsettled weather.
Near term /until 6 PM this evening/...
one short wave trough passing through northern New England early
this morning will bring an end to the shower activity early on.
In the wake of this short wave trough downsloping flow will
allow temperatures to rise well into the 70s and even lower 80s
across central and southern zones. However, another short wave
trough will graze northern and eastern zones today. Scattered
showers and thunderstorms will likely be the result
today...especially over mid coast zones. The most likely time
period for this will be during the afternoon hours.
Forecast thermodynamic profiles will be favorable for gusty
winds and small hail in any thunderstorms. Have included this
enhanced wording in the forecast for today.
Short term /6 PM this evening through 6 PM Thursday/...
fair weather is expected tonight through Thursday with high
pressure moving into the region. Temperatures on Thursday will
be in the 65-75 degree range depending on location...warmest
Long term /Thursday night through Tuesday/...
the week will culminate with the warming trend we've seen since mid
week pushing high temperatures on Friday well into the 80s across
Overall looking like a hot, dry, and windy day on Friday. With
forecast soundings supporting mixing to nearly 750mb (~7000 ft)
have trended the entire forecast towards this concept and
increased high temperatures, increased winds, and decreased dew
points to reflect the drier and moving down into the region.
Across interior southern New Hampshire 90f is possible. With westerly flow
resulting in downsloping and helping to keep the sea breeze at
Bay have increased temperatures a bit above guidance for the
entire region as we make our first run at 90f.
Saturday afternoon a warm front will sag southward across the
region. This will be a relatively weak boundary with little moisture
however some afternoon showers or thunderstorms are possible. Have
limited pop to high chance as areal coverage is still
On Sunday we see north to northeasterly flow set up through the
region as front becomes a backdoor front slipping southward. The
result will be much cooler temperatures than the prior days
with much of the area staying in the 60s or even upper 50s. The
CT River Valley will be the exception where the mountains will
prevent the northeasterly flow from arriving and the valley will
assist in funneling warm air northwards allowing temperature to
climb back to the mid 70s.
Rain chances become increasingly likely on Sunday and into Monday.
Here a low pressure system will move out of the Canadian
prairies and help to induce widespread showers across the
region. The exact timing and amount of precipitation are low
confidence at this point due to the upper level flow. After the
end of the week the high pressure aloft has moved east and split
flow tries to develop with a cut off over the southeastern US.
This continue to introduce a lot of uncertainty for the end of
the weekend; uncertainty which is unlikely to be resolved for
another 36 to 48 hours when the northern stream wave will begin
to form over the Yukon. For now have left high chance pops in
for the entire Sunday - Monday period.
Aviation /07z Wednesday through Sunday/...
short term...areas of MVFR conditions will give way to VFR this
morning. VFR conditions are then expected today and tonight with
the exception of localized MVFR conditions across the mountains
and mid coast in scattered showers and thunderstorms this
high pressure and warm conditions will keep VFR conditions from
Thursday night into Saturday morning. Saturday afternoon some
scattered convection may result in MVFR showers in the
mountains. Further showers and lowering ceilings are expected on
Sunday and remaining into Monday as low pressure begins to move
into the region.
short term /through Thursday/...winds and seas expected to
remain below Small Craft Advisory level through Thursday.
gusty westerly flow on Friday will bring the outer waters to
Small Craft Advisory criteria as the pressure gradient between the departing low
pressure and building high to our south increase winds. A
backdoor front will cross the region on Saturday switching flow
to the northeast. Periods of showers with fog possible on Sunday
and into Monday.
today and tomorrow will be mostly dry. By Thursday relative humidity values
will fall to 25% across most of the area however the winds will
be quite light.
Friday will see gusty west to northwesterly flow around 25kt.
These winds will help to mix down dry air from aloft with relative humidity
dropping to around 30% across southern New Hampshire. This will
put southern New Hampshire near red flag criteria and will need to be
watched for possible fire wx headlines.