000
FXUS61 KGYX 020752
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
352 AM EDT Sun Apr 2 2023

.SYNOPSIS...
Gusty northwest winds today will diminish tonight as high
pressure crests the East Coast. A clipper crosses with some
showers on Monday, followed by another slow moving system with
more rain showers Wednesday and Thursday. High pressure will
build in late in the week on a gusty west wind.

&&

.NEAR TERM /THROUGH TONIGHT/...
Northwest winds have started to ramp up in the wake of the cold
front with gusts to around 25 mph or so, mainly across New Hampshire
and the western ME mountains. However, winds will start to pick up
farther south into ME here shortly with gusts as high as 40 mph
possible the rest of tonight and toward day break across most
of the area. While there`s still quite a bit of cloud cover
currently, a very dry airmass is in the process of working into
the area brought in by the NW flow. As this occurs, the cloud
cover is expected to erode as we get closer to and just after
daybreak this morning, especially downwind of the mountains.
However, until then, there may even be a couple of light
showers across southwestern ME into the Midcoast as the upper
trough moves through.

With the very dry air settling in we`ll have plenty of sunshine
today, and it will remain breezy with a tight pressure gradient and
good mixing, bringing those higher gusts down from aloft. Based on
forecast soundings, gusts to 30-35 mph, occasionally 40 mph,
are expected this morning to mid afternoon, but after that,
gusts should start to lessen as the pressure gradient relaxes.
Mixing to around 850mb supports high temperatures ranging from
the mid 30s to lower 40s south of the mountains.

Winds will further diminish this evening and tonight as high
pressure briefly settles overhead. With mostly clear skies
continuing, think we`ll have a good period of radiational cooling,
so I have leaned toward MOS for low temperatures. This will put lows
in the teens to lower 20s, but northern valleys could dip into the
single digits. However, we`re probably going to get some mid and
high clouds late, which could level off the cooling, especially
across the north.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...

The high pressure will get nudged off to the east on Monday as a
weakening area of low pressure moves east from the Great Lakes and
into southern Quebec, returning us to a southerly flow. So even with
the chilly start, the southerly flow will allow high temperatures
to reach the upper 40s to lower 50s, and mid to upper 50s
across southern NH. Winds are expected to become breezy during
the afternoon with gusts to around 30 mph possible.

As the low pressure and its associated frontal boundary continue to
approach, we`ll see an increase in cloudiness, especially across the
north, where some showers are possible beginning in the afternoon to
early evening hours (and snow showers in the higher elevations).
This boundary will sag south during the evening and overnight
with chances of showers expanding south to the rest of the area,
and there could be patchy fog as well. Temperatures remain mild
overnight, generally in the mid 30s to lower 40s. However,
partial clearing across northern areas could allow temps to get
a bit cooler.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Showery and at times quite mild weather dominates the long
term forecast, with potential for classic spring conditions
along the coast (read: marine fog and low ceilings) as well.
Overall right around what we would expect during the month of
April with steady snowpack melt over the interior and low (but
not zero) probability for flooding.

Starting Tuesday... an east-west oriented surface boundary will
be draped across southern New England. There`s some uncertainty
WRT where this boundary stalls and shifts as an upper level jet
rolls over it... which will be the biggest determining factor
in the forecast for our local area. Current consensus lays the
front across the southern third or so of the forecast area on
Tuesday resulting in some additional light rain showers (~20-30%
on DESI LREF analysis) and more cloud cover. Further north,
confidence in a partly sunny day is higher with a drier and
cooler airmass. High temperatures reach mostly into the 50s,
give or take depending on clouds and showers.

High pressure over Canada builds toward the Maritimes Tuesday
night into Wednesday, in response to a trough digging well
upstream through the northern Plains. This flow regime heavily
favors a CAD developing over Maine and much of New Hampshire...
except for in the Connecticut River Valley, where mountains are
more likely to block cool and humid air seeping down from the
northeast. At the same time, warm frontal forcing will be
increasing aloft with rain likely developing over or moving into
the area on Wednesday. Pockets of light freezing rain or other
mixed precip are possible in northern zones on Wednesday with
other places experiencing plain-rain. Given limited QPF and
uncertainty with how the CAD will behave as high pressure sinks
south of Nova Scotia and turns low-level flow southeasterly...
am not overly concerned about slick travel just yet, but it
certainly bears watching.

At this point in time Wednesday looks to be a classic coastal
New England spring day with a steep low level inversion forming
between the CAD and cool onshore flow along the coastal plain...
and a building plume of warm, humid air aloft. The result would
be a cool, damp, overcast day with potential for fog over the
bulk of the area, although the Connecticut River Valley and
perhaps down along the Mass border may escape this fate. Areas
with some sunshine or mixing can easily warm into the 50s...but
areas under the inversion are more likely to stay near or below
40 degrees.

Meanwhile on Wednesday an axis of moisture will be crossing
overhead, but without significant forcing to make much of it...
supported by low DESI LREF probabilities of wetting rains over
0.25" or so, concentrated along the international border, closer
to the trough aloft pushing across the Ottawa Valley. A cold
front eventually pushes across New England sometime Thursday...
which may reinvigorate precipitation chances, but without the
moisture depth seen on Wednesday. The cold front will almost
certainly provide mixing, which should clear out fog and allow
for much warmer temperatures in the 50s and 60s... perhaps
hitting 70 in the southern interior. All in all the Wed- Thu
event will likely lead to significant snow ripening and snow
melt over the interior and into the foothills, but barring any
shift in forcing... limited rainfall would limit flooding
threat.

Consensus timing has most areas dry on Friday, except for some
upslope shower potential with weakly cyclonic flow remaining
aloft. More noticeable will be the breezy northwesterly flow and
clearing skies, with temperatures closer to seasonal averages
in the 40s to low-50s. High pressure builds out of the Great
Lakes and into the New England states by the start of the
weekend with diminishing winds and fair weather.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
Short Term...MVFR ceilings are expected at HIE for another few
hours, but otherwise VFR at all sites through today with brisk
northwest winds gusting to 30-35 kt. Winds will diminish late this
afternoon and through tonight as high pressure builds into the
region with VFR continuing through most of Monday. A weakening
frontal boundary could then bring some low ceilings Monday afternoon
into Monday night as well as some showers. Higher potential for
restrictions appears to be toward HIE initially, but the rest of the
terminals could see restrictions as the weakening front advances
southward.

Long Term...Low CIGs and -SHRA may linger into early Tuesday
for southern terminals... otherwise VFR prevails Tuesday with
light southwesterly to northwesterly flow. Significant
restrictions are possible in low CIGs, SHRA, and perhaps some
fog Wednesday through early Thursday, particularly along the
coast. Conditions improve to VFR Thursday into Friday as a cold
front passes with gusty winds out of the west or northwest.

&&

.MARINE...
Short Term...Gale conditions are expected across the waters
into late this afternoon or early evening under brisk northwest
flow. After that, the current Gale Warning will likely need to
be replaced with a Small Craft Advisory through portions of
tonight as winds and seas gradually diminish as high pressure
builds in. High pressure shifts to the south and east on Monday,
and southerly winds will increase through the day as a low
pressure passes north of the St. Lawrence River Valley. Gusts
could possibly reach Gale Force over portions of the waters. As
the low pressure continues moving east into Monday night, winds
will veer to the southwest and subside as a weakening frontal
boundary sags south into the area.

Long Term...A front stalls near or south of the waters on
Tuesday with light shower activity possible along with light
flow out of the south or southwest. High pressure pushes this
boundary away Tuesday night into Wednesday and sets up a
northeasterly and then southeasterly flow, increasing to around
25 kts as low pressure passes well inland. Flow turns
southwesterly for Thursday before a cold front crosses and turns
winds around to the west and northwest by Friday... again
gusting to around 25-30 kts.

&&

.HYDROLOGY...
Rain has ended over the region this morning with temperatures
expected to stay in the 30s to near 40 today, which will slow or
end runoff into local water ways including that from snow melt.
Steady, modest rises are forecast to continue through today and
into tonight in some places... although only one river forecast
location, the Suncook at North Chichester, is forecast to reach
bankfull.

Mild and showery weather though the upcoming work week will
lead to additional ripening and melting of snowpack, especially
as dew points creep up Wednesday and Thursday. QPF doesn`t look
to be a major concern with any one system, and will come in
multiple rounds which will help to moderate runoff and
associated rises on area stream systems. Flooding risk is not
zero, however it is low.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Gale Warning until 6 PM EDT this evening for ANZ150-152-154.
     Gale Warning until 6 PM EDT this evening for ANZ151-153.

&&

$$

NEAR TERM...Combs
SHORT TERM...Combs
LONG TERM...Casey
HYDROLOGY...Casey

NWS GYX Office Area Forecast Discussion