Amherst, New Hampshire Weather Forecast Discussion

978
FXUS61 KBOX 121120
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
720 AM EDT Fri Sep 12 2025
.SYNOPSIS...
Dry weather with near seasonable temps today and Saturday. Rain
chances return Sunday with highs in the low to mid 70s. We then
return to dry weather and temperatures near or just warmer than
average through mid week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Key Messages...
* Dry, sunny, and a few degrees cooler than Thursday. Onshore flow
  keeps the coasts coolest.
A large surface high pressure will bring a cooler and drier airmass
to SNE to end the week with light onshore flow keeping the coasts
the coolest thanks to a weak pressure gradient. Expect highs along
the coast in the upper 60s to 70, while the warmest location will be
the CT valley, in the mid/upper 70s. Skies will be clear overnight
with light winds so have leaned toward MOS guidance for lows to
account for radiational cooling, down into the upper 40s/low 50s.
&&
.SHORT TERM /SATURDAY/...
Key Messages...
* Mostly dry Saturday but rain chances are increasing as we
  approach.
* Temperatures largely similar to Friday, but warmer
  along the immediate east coast and cooler along the south
  coast.
Mid level troughing continues over the northeast keeping the cooler
than average airmass in place. However, we`ll see some variations
from Friday because of the increasing pressure gradient ahead of an
approaching trough; steering flow increases from the south so while
some inland areas and the immediate east coast will be warmer, the
immediate south will be cooler (near 70) thanks to flow off the
water. We`ll also see increasing clouds through the day from NW to
SE as moisture increases ahead of a weak trough for Sunday;
while most will likely remain dry, guidance has been shifting
to a slight chance of showers as early as the latter half of
Saturday so we`ll have to watch those trends/timing of the
trough.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Key Messages...
* Chance for showers and thunderstorms Sunday then drying out for
  next week.
* Seasonable temperatures continue early, warming a bit by mid week.
Sunday we`ll see a mix of clouds and sun much of the day with rain
and even some thunderstorms possible thanks largely to a
shortwave trough providing enough lift to act on PWATs of 1-
1.25" while dewpoints in the low 60s contribute to several
hundred J/kg of CAPE. Overall lift is lacking and QPF amounts
look unimpressive though there is some disagreement amongst the
global ensembles. The EPS indicates only a 10% chance of
exceeding a tenth of an inch while the GEFS is more robust with
40-50%. Forecast now is for several hundredth of an inch
possible on Sunday though some locations may not see any rain.
Again, there remains a good amount of uncertainty as to the
timing and placement of rain showers which will come into better
focus in the next 12-24 hours.
Looking into next week while Monday may be a bit of a transitional
period, guidance has backed off on the potential for this
disturbance lingering well into next week, looking more like high
pressure and mid level ridging once again bring dry weather to the
region. Temperatures likely moderate a bit under the ridge as well,
with highs back toward the upper 70s even near 80 in spots.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
12Z TAF Update:
Today and tonight: High confidence.
VFR through the period. NE winds 5-10 kt inland, NE to E 10-15
kts for the eastern coastal airports. May see some FEW-SCT cloud
decks 4-6kft for the interior in the afternoon. Winds tonight become
light and variable. Patchy fog possible for the interior
terminals after 09z, mainly in the valleys.
Saturday: High confidence.
VFR. S winds 5-10 kts.
KBOS Terminal...High confidence in TAF.
KBDL Terminal...High confidence in TAF.
Outlook /Saturday Night through Tuesday/...
Saturday through Saturday Night: VFR.
Sunday: VFR. Slight chance SHRA, slight chance TSRA.
Sunday Night: VFR. Slight chance SHRA.
Monday through Tuesday: VFR.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Winds tonight should range between 15-20 kt (with occasional gusts
to 25 kt northeast waters), which then slowly ease into today
tonight. Seas 4ft or less all waters.
Outlook /Saturday Night through Tuesday/...
Saturday through Saturday Night: Winds less than 25 kt.
Sunday: Winds less than 25 kt. Slight chance of rain showers,
slight chance of thunderstorms.
Sunday Night: Winds less than 25 kt. Slight chance of rain
showers.
Monday through Tuesday: Winds less than 25 kt.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.
&&
$$
SYNOPSIS...BW
NEAR TERM...BW
SHORT TERM...BW
LONG TERM...BW
AVIATION...BW/Mensch
MARINE...BW

NWS BOX Office Area Forecast Discussion