377
FXUS61 KGYX 021337
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
937 AM EDT Thu May 2 2024

.SYNOPSIS...
Warm conditions in southwest New Hampshire will sharply
contrast cool, low overcast conditions elsewhere today. Rain
showers are possible anywhere, but will generally be most likely
and most frequent over central...northern...and eastern areas.
Drier weather returns Friday into Saturday, however the pattern
remains unsettled and humid with increasing clouds and more
showers late in the weekend. The upcoming work week starts on a
drying, clearing, and warming trend.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
938 AM Update...
Have introduced the chance for thunder over eastern areas this
morning as the precipitation exits the region. Another batch of
thunder will cross the region this afternoon. There will be a
wide range in afternoon high temperatures today with chilly
conditions over the eastern portions of the forecast area and
warm temps across southern New Hampshire.

640 AM UPDATE...Latest RAP13 analysis shows the center of high
pressure over upstate New York at this hour. It is slightly
deepening keeping convection going, so included thunder for
another hour across northern New Hampshire. Otherwise, just did
the normal refreshers to temperature, dewpoint, and winds with
little change to the going forecast.

Previous Discussion...
Impacts:
*No significant weather impacts expected

Some convection is rolling over the ridge early this morning
and is just about at the Vermont-New Hampshire border at the
time of this writing. RAP13 analysis shows it is out running the
shortwave that providing the forcing, however even though its
weakening, cloud tops are still cool so some isolated thunder is
still possible predawn in New Hampshire. At the very least this
will serve as the first round of showers today.

Otherwise a band of clouds associated with the warm front aloft
persists across the area with more forming upstream. These will
hamper warming today for Maine and Eastern New Hampshire with
highs expected to cap out in the low to mid 50s. The exception
will be in western and southern New Hampshire where, when the
surface warm front arrives, skies likely clear enough to allow
temperatures into the upper 60s and low 70s. How far into the
state this penetrates will be a question, but it looks like it
could make it to at least Concord before temperatures sharply
drop off. Positive theta-E along the warm front will also
provide some instability for thunderstorms to develop. SPC
mesoanalysis suggests 700-500mb lapse rates across central New
Hampshire this afternoon will be in the 6-7C/km range. Rain
showers will cross central Maine as well, but with the much
cooler temperatures these will not have a threat of lightning.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Impacts:
* No significant weather impacts expected

All showers will taper off quickly heading into the night as a
500 mb ridge begins to build into the area. This subsidence
following the rain will likely result in patchy fog in the usual
valley locations. Skies will start to clear from north to
south, but only partly, so would expect most of the area to see
lows in the 40s with some upper 30s north of the mountains where
the most clearing will be realized the most.

Skies will remain partly cloudy through the day Friday, but
with surface high pressure and a 500mb ridge continuing to build
in we will remain dry with highs in the upper 50s to mid 60s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Anomalously high heights will persist over the Northeast
through the duration of the extended forecast period... which
will allow an anomalously warm airmass to build into the mid-
levels. In spite of this, it is still very much Spring in New
England, and surface flow relative to the Gulf of Maine will
ultimately call the shots regarding the sensible weather
conditions. High pressure initially sits offshore this weekend,
which keeps conditions humid and cooler than average. A cold
front crosses late in the weekend with rain showers, with
offshore flow in its wake bringing fresh flow out of the west or
northwest into New England with warmer, drier air and sunnier
skies. The weather pattern remains active however with another
chance for rain around the the middle or latter part of next
week.

Starting Friday night... surface high pressure centered over
Labrador builds south along the Eastern Seaboard, re-centering
to near Nova Scotia by Sunday. At the same time, low pressure
near Hudson Bay slowly drifts east... bringing a slow-moving
cold front into the Northeast. Resultant northeasterly-turning-
southeasterly flow over our forecast area brings a steadily
moistening column over the weekend, leading to increasing clouds
and eventually rain showers late Saturday through Sunday.
Temperatures on Saturday will vary depending on proximity to the
coastline, with 60s over the interior of New Hampshire but 50s
more likely in Maine and toward the Seacoast... and the
immediate coastline sticking closer to SSTs in the 40s.
Thickening cloud decks and continued onshore flow produces a
fairly dreary Sunday with temperatures in the 40s and 50s and
rain showers. Forcing doesn`t look great, with the parent
circulation well north of the region; ensembles bring on average
0.25-0.4" of rain however would expect higher and lower
amounts, with an inch or so on the high end given decent
moisture depth and some areas possibly staying dry. Instability
doesn`t appear to be a major factor at this time.

The cold front crosses late Sunday into Monday, with showers
ending by the end of the day Monday... though cyclonic flow and
slowed frontal movement may delay improvement. Drier flow out
of the west will allow for stronger mixing with minimal
maritime influence, in turn allowing temperatures to warm
strongly into the 70s... except the 60s along the coast where a
weak onshore component persists, and across the north where
clouds and some showers likely hang around. Tuesday sees a
similar fate with highs again in the 60s and 70s and a sunnier
mix of clouds and sun.

The next wave moving through the upper level pattern approaches
New England by the middle of the week with flow again turning
southerly to onshore. Thus, can expect cloudier... more humid...
and likely cooler and showery weather to make a return sometime
in the middle or end of next week.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
Short Term...A mix of IFR and MVFR ceilings are whats out there
this morning with some light rain and fog. The fog will
dissipate later this morning but low ceilings in light rain
showers will persist through today. Thunderstorms may form and
move through central New Hampshire this afternoon briefly
impacting KCON and KMHT. Patchy fog may continue localized IFR
at the valley terminals Thursday night into early Friday
morning, otherwise Friday will see mostly VFR conditions.

Long Term...VFR prevails Sat with flow generally out of the E
AOB 15 kts. Lowered CIGs become more likely especially along the
coast Sat night thru Sunday, with IFR/ LIFR CIG/VSBY potential
as flow turns out of the S/SE. Restrictions would likely be more
periodic the more inland you are. Restrictions lift Mon into
Tue with W flow and daily sea breezes through early week.

&&

.MARINE...
Short Term...Conditions hazardous to small craft are not
expected. Winds will primarily be southeasterly today before
shifting northeasterly tonight as low pressure crosses the
waters. Winds will stay northeasterly through Friday morning,
before shifting back to southerly Friday afternoon.

Long Term...Northeast flow early Saturday turns southeasterly
through the day and into Sunday... then southerly with the
approach of a cold front Sunday night, remaining AOB 20 kts and
waves AOB 3 ft for the duration. Westerly flow returns for the
start of next week with daily seabreezes pulling flow
southwesterly over the coastal waters... to easterly along the
immediate shoreline.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$