675
FXUS61 KBOX 132013
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
413 PM EDT Sun Jul 13 2025

.SYNOPSIS...
Mainly dry with seasonably warm and humid conditions continue
through most of Monday. A frontal system could bring showers
and thunderstorms Monday afternoon and evening. Increasing heat and
humidity around the middle of next week with increasing
confidence in the need for Heat Advisories for at least
Wednesday and Thursday. Trending cooler and drier for the
weekend.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Key Points:

* Continued humid with near to slightly above normal temperatures

Yet another night of stratus and areas of fog developing. Muggy
conditions continue with lows in the 60s.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Key Points

* Seasonably weather again on Monday

* Frontal system may bring heavy rain and localized flash flooding
  late Monday

* Muggy Monday Night as well with above normal temperatures

Not much in terms of wind fields expected for Monday. Thus, am more
concerned about the flash flooding risk than severe weather with any
thunderstorms tomorrow. The main factors will be slow storm motion,
deep warm rain processes and modest instability. Cannot completely
rule out the risk of strong gusty winds with any thunderstorms.
Still too much uncertainty for a Flood Watch just yet as its tough
to pin down locations just yet.

Not much change to the overall pattern Monday night. Expecting yet
another night of low clouds with areas of fog. One subtle change is
having more of a southwest wind. That could confine the stratus and
fog more over the coastal plains of MA and RI, with more valley fog
and low clouds elsewhere in southern New England.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Key Messages:

* Hot and humid during the middle of next week, with elevated
  heat indices around 95-100F. Heat Advisories likely for at
  least Wed & Thur

* Becoming more unsettled late Thursday-Friday with increasing
  chances for showers/storms.

Tuesday-Thursday:

Heat and Humidity...

Weak mid-level ridging persists over the region Tuesday and
Wednesday with more zonal flow arriving Thursday. Temperatures aloft
increase with 850mb temperatures peaking at around 20C in the Weds-
Thurs timeframe. Ensemble guidance shows a plume of above normal
moisture in the flow which will add increased humidity to the mix.
Temperatures Tuesday through at least Thursday will range in the
upper 80s to mid 90s with the exception of the immediate coast. With
the the added element of higher humidity, it will feel more like mid
90s to near 100 Wednesday and Thursday. This combo provides a good
signal for potential heat impacts. NWS Heat Risk reflects this
potential well with Heat Risk in the Major Category Wednesday and
Thursday. It will be borderline Tuesday, with heat indices in the
low to mid 90s. There is a high probability that we will need Heat
Advisories for Wednesday and Thursday. We`ll need to keep an eye on
cloud cover for Thursday as this may limit highs a bit. Friday may
also end up being a hot day as well with ensembles showing little
change in the temperatures aloft with again a similar risk of clouds
limiting high temperatures.

Precipitation...

Tuesday and Wednesday stay mainly quiet when it comes to the passage
of any substantial system. Despite a weakly forced atmosphere, above
normal moisture, hot temps, and marginal daytime instability will
support isolated shower activity. Ensemble members are still spread
across the board with timing and given the low coverage nature of
the showers and lack of definitive forcing. This has made it it bit
more difficult to message in the forecast. Overall, expect a
tropical-like atmosphere with periods of higher cloud cover and
perhaps a spot shower.

There will be a better signal for more organized forcing later
Thursday and a weak trough shifts in from the west. This will bring
higher chances for more widespread showers/storms. Weak winds aloft
will support slower storm motions and given the high amounts of
moisture signal a threat for flash flooding. We`ll have to keep eyes
on that as we go through the week.

Friday-Weekend:

Ensemble guidance shows the main axis of the trough pushing across
the region by early Saturday. Similar story to Thursday with
increased chances for showers/storms later Friday ahead of an
approaching cold front. Winds aloft are slightly higher than
Thursday, but slower moving storms still look to bring a potential
threat for flash flooding. Friday may be another potentially hot
day. Ensemble members show more of a wider envelope of solutions for
temperatures Friday. However, there are still plenty of very warm
members that would support another Heat Advisory criteria given the
humidity. We`ll have to watch cloud cover as this could keep it cool
enough to not meet Advisory criteria.

Behind the trough, conditions dry out through the day on Saturday.
Ensembles hint at potential for another system later Sunday,
although confidence is low this far out.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
Forecaster Confidence Levels...

Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

Today: Moderate confidence.

IFR/LIFR stratus and fog dissipating by 16z, then VFR
conditions for the rest of the day. South winds at 5-10 knots.

Tonight: High Confidence

IFR/LIFR CIGS build north again tonight with continued ESE flow.
stratus should have similar timing to last night.

Monday: Moderate Confidence

VFR after IFR CIGS burn off again. Chance for showers and
thunderstorms mainly across the interior

KBOS Terminal...Moderate confidence in TAF.

IFR CIGS lifting to M/VFR 14-15z similar to the last couple
days. VFR this afternoon. IFR stratus likely around the same
time tonight

KBDL Terminal...High confidence in TAF.

IFR CIGS lifting to M/VFR 12-13z similar to the last couple
days. VFR this afternoon. Less certain about low status again
for tonight.

Outlook /Tuesday through Friday/...

Tuesday: VFR. Slight chance SHRA, slight chance TSRA.

Tuesday Night through Wednesday: VFR.

Wednesday Night: VFR. Slight chance SHRA, slight chance TSRA.

Thursday through Thursday Night: VFR. Breezy. Slight chance
SHRA, slight chance TSRA.

Friday: Breezy. Chance SHRA, chance TSRA.

&&

.MARINE...
Forecaster Confidence Levels...

Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.

Today through Monday...High confidence.

Weak pressure gradient will keep winds/seas below Small Craft
Advisory thresholds through Sunday: seas 2-3 ft with E winds
over the southern waters and SE winds over the eastern waters up
to 15 kts during the afternoon hours, remaining light in the
overnight hours. Main concern for mariners will be areas of fog
tonight that may redevelop again tonight.

Outlook /Tuesday through Friday/...

Tuesday: Winds less than 25 kt. Slight chance of rain showers.

Tuesday Night through Wednesday Night: Winds less than 25 kt.

Thursday: Winds less than 25 kt. Seas locally approaching 5 ft.
Slight chance of rain showers.

Thursday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Slight chance of rain showers, slight chance
of thunderstorms.

Friday: Winds less than 25 kt. Seas locally approaching 5 ft.
Slight chance of rain showers, slight chance of thunderstorms.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$

SYNOPSIS...Belk/Mensch
NEAR TERM...Belk
SHORT TERM...Belk
LONG TERM...Mensch
AVIATION...Belk/Mensch
MARINE...Belk/Mensch