Dense Fog Advisory 8, NWS Boston/Norton, MA

692 
WWUS71 KBOX 120742
NPWBOX

URGENT - WEATHER MESSAGE
National Weather Service Boston/Norton MA
342 AM EDT Thu Aug 12 2021

RIZ005-122100-
/O.CON.KBOX.EH.W.0001.210812T1600Z-210813T0000Z/
/O.CON.KBOX.FG.Y.0008.000000T0000Z-210812T1200Z/
/O.CON.KBOX.EH.A.0001.210813T0000Z-210814T0000Z/
Bristol RI-
Including the city of Bristol
342 AM EDT Thu Aug 12 2021

...DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 8 AM EDT THIS
MORNING...
...EXCESSIVE HEAT WARNING REMAINS IN EFFECT FROM NOON TODAY TO
8 PM EDT THIS EVENING...
...EXCESSIVE HEAT WATCH REMAINS IN EFFECT FROM THIS EVENING
THROUGH FRIDAY EVENING...

* WHAT...For the Excessive Heat Warning, dangerously hot
  conditions with heat index values up to 105 expected. For the
  Dense Fog Advisory, visibility less than one mile in dense fog.
  For the Excessive Heat Watch, dangerously hot conditions with
  heat index values up to 105 possible.

* WHERE...Bristol RI County.

* WHEN...For the Excessive Heat Warning, from noon today to 8 PM 
  EDT this evening. For the Dense Fog Advisory, until 8 AM EDT 
  this morning. For the Excessive Heat Watch, from this evening 
  through Friday evening.

* IMPACTS...Extreme heat and humidity will significantly 
  increase the potential for heat related illnesses, 
  particularly for those working or participating in outdoor 
  activities. Hazardous driving conditions due to low visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

If driving, slow down, use your headlights, and leave plenty of
distance ahead of you.

&&

$$

CTZ002>004-MAZ003>007-010>019-026-RIZ001>004-122100-
/O.CON.KBOX.EH.W.0001.210812T1600Z-210813T0000Z/
/O.CON.KBOX.EH.A.0001.210813T0000Z-210814T0000Z/
Hartford CT-Tolland CT-Windham CT-Eastern Franklin MA-
Northern Worcester MA-Central Middlesex MA-Western Essex MA-
Eastern Essex MA-Eastern Hampshire MA-Eastern Hampden MA-
Southern Worcester MA-Western Norfolk MA-Southeast Middlesex MA-
Suffolk MA-Eastern Norfolk MA-Northern Bristol MA-
Western Plymouth MA-Eastern Plymouth MA-Northern Middlesex MA-
Northwest Providence RI-Southeast Providence RI-Western Kent RI-
Eastern Kent RI-
Including the cities of Hartford, Windsor Locks, Union, Vernon, 
Putnam, Willimantic, Greenfield, Orange, Barre, Fitchburg, 
Framingham, Lowell, Lawrence, Gloucester, Amherst, Northampton, 
Springfield, Milford, Worcester, Foxborough, Norwood, Cambridge, 
Boston, Quincy, Taunton, Brockton, Plymouth, Ayer, Foster, 
Smithfield, Providence, Coventry, West Greenwich, East Greenwich,
Warwick, and West Warwick
342 AM EDT Thu Aug 12 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT FROM NOON TODAY TO
8 PM EDT THIS EVENING...
...EXCESSIVE HEAT WATCH REMAINS IN EFFECT FROM THIS EVENING
THROUGH FRIDAY EVENING...

* WHAT...For the Excessive Heat Warning, dangerously hot
  conditions with heat index values between 105 and 109 expected.
  For the Excessive Heat Watch, dangerously hot conditions with
  heat index values up to 105 possible.

* WHERE...Much of Southern New England, except for the Berkshires
  and southeast coastal New England.

* WHEN...For the Excessive Heat Warning, from noon today to 8 PM 
  EDT this evening. For the Excessive Heat Watch, from this 
  evening through Friday evening.

* IMPACTS...Extreme heat and humidity will significantly 
  increase the potential for heat related illnesses, 
  particularly for those working or participating in outdoor 
  activities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

MAZ002-008-009-122100-
/O.CON.KBOX.HT.Y.0008.210812T1600Z-210813T0000Z/
/O.CON.KBOX.EH.A.0001.210813T0000Z-210814T0000Z/
Western Franklin MA-Western Hampshire MA-Western Hampden MA-
Including the cities of Charlemont, Chesterfield, and Blandford
342 AM EDT Thu Aug 12 2021

...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TODAY TO 8 PM EDT
THIS EVENING...
...EXCESSIVE HEAT WATCH REMAINS IN EFFECT FROM THIS EVENING
THROUGH FRIDAY EVENING...

* WHAT...For the Heat Advisory, heat index values up to 99
  expected. For the Excessive Heat Watch, dangerously hot
  conditions with heat index values between 97 and 105.

* WHERE...The eastern slopes of the Berkshires.

* WHEN...For the Heat Advisory, from noon today to 8 PM EDT this 
  evening. For the Excessive Heat Watch, from this evening 
  through Friday evening.

* IMPACTS...Extreme heat and humidity will significantly 
  increase the potential for heat related illnesses, 
  particularly for those working or participating in outdoor 
  activities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecasts and warnings for updates on this
situation. Be prepared to drink plenty of fluids, stay in an air-
conditioned room, stay out of the sun, and check up on relatives
and neighbors.

Young children and pets should never be left unattended in
vehicles under any circumstances. This is especially true during
warm or hot weather when car interiors can reach lethal
temperatures in a matter of minutes.

&&

$$

MAZ020-021-RIZ006-007-122100-
/O.CON.KBOX.FG.Y.0008.000000T0000Z-210812T1200Z/
/O.CON.KBOX.HT.Y.0008.210812T1600Z-210813T0000Z/
Southern Bristol MA-Southern Plymouth MA-Washington RI-Newport RI-
Including the cities of Fall River, New Bedford, Mattapoisett, 
Narragansett, Westerly, and Newport
342 AM EDT Thu Aug 12 2021

...DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 8 AM EDT THIS
MORNING...
...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TODAY TO 8 PM EDT
THIS EVENING...

* WHAT...For the Dense Fog Advisory, visibility one quarter mile 
  or less in dense fog. For the Heat Advisory, heat index values 
  up to 99 expected.

* WHERE...In Massachusetts, Southern Bristol MA and Southern 
  Plymouth MA Counties. In Rhode Island, Washington RI and 
  Newport RI Counties.

* WHEN...For the Dense Fog Advisory, until 8 AM EDT this 
  morning. For the Heat Advisory, from noon today to 8 PM EDT 
  this evening.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur. Hazardous driving conditions due to low 
  visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

If driving, slow down, use your headlights, and leave plenty of
distance ahead of you.

&&

$$

MAZ022>024-RIZ008-121200-
/O.CON.KBOX.FG.Y.0008.000000T0000Z-210812T1200Z/
Barnstable MA-Dukes MA-Nantucket MA-Block Island RI-
Including the cities of Chatham, Falmouth, Provincetown, 
Vineyard Haven, Nantucket, and New Shoreham
342 AM EDT Thu Aug 12 2021

...DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 8 AM EDT THIS
MORNING...

* WHAT...Visibility one quarter mile or less in dense fog.

* WHERE...In Massachusetts, Barnstable MA, Dukes MA and 
  Nantucket MA Counties. In Rhode Island, Block Island RI County.

* WHEN...Until 8 AM EDT this morning.

* IMPACTS...Hazardous driving conditions due to low visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If driving, slow down, use your headlights, and leave plenty of
distance ahead of you.

&&

$$

For more information from the National Weather Service visit
https://weather.gov/box

962 
WWUS71 KBOX 120942
NPWBOX

URGENT - WEATHER MESSAGE
National Weather Service Boston/Norton MA
542 AM EDT Thu Aug 12 2021

RIZ005-122245-
/O.CAN.KBOX.FG.Y.0008.000000T0000Z-210812T1200Z/
/O.CON.KBOX.EH.W.0001.210812T1600Z-210813T0000Z/
/O.CON.KBOX.EH.A.0001.210813T0000Z-210814T0000Z/
Bristol RI-
Including the city of Bristol
542 AM EDT Thu Aug 12 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT FROM NOON TODAY TO
8 PM EDT THIS EVENING...
...EXCESSIVE HEAT WATCH REMAINS IN EFFECT FROM THIS EVENING
THROUGH FRIDAY EVENING...
...DENSE FOG ADVISORY IS CANCELLED...

* WHAT...For the Excessive Heat Warning, dangerously hot 
  conditions with heat index values up to 102 expected. For the 
  Excessive Heat Watch, dangerously hot conditions with heat 
  index values up to 99 possible.

* WHERE...Bristol RI County.

* WHEN...For the Excessive Heat Warning, from noon today to 8 PM 
  EDT this evening. For the Excessive Heat Watch, from this 
  evening through Friday evening.

* IMPACTS...Extreme heat and humidity will significantly 
  increase the potential for heat related illnesses, 
  particularly for those working or participating in outdoor 
  activities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

MAZ020-021-RIZ006-007-122245-
/O.CAN.KBOX.FG.Y.0008.000000T0000Z-210812T1200Z/
/O.CON.KBOX.HT.Y.0008.210812T1600Z-210813T0000Z/
Southern Bristol MA-Southern Plymouth MA-Washington RI-Newport RI-
Including the cities of Fall River, New Bedford, Mattapoisett, 
Narragansett, Westerly, and Newport
542 AM EDT Thu Aug 12 2021

...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TODAY TO 8 PM EDT
THIS EVENING...
...DENSE FOG ADVISORY IS CANCELLED...

* WHAT...Heat index values up to 99 expected.

* WHERE...In Massachusetts, Southern Bristol MA and Southern 
  Plymouth MA Counties. In Rhode Island, Newport RI and 
  Washington RI Counties.

* WHEN...From noon today to 8 PM EDT this evening.

* IMPACTS...Hot temperatures and high humidity may cause heat 
  illnesses to occur.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

MAZ022>024-RIZ008-121045-
/O.CAN.KBOX.FG.Y.0008.000000T0000Z-210812T1200Z/
Barnstable MA-Dukes MA-Nantucket MA-Block Island RI-
Including the cities of Chatham, Falmouth, Provincetown, 
Vineyard Haven, Nantucket, and New Shoreham
542 AM EDT Thu Aug 12 2021

...DENSE FOG ADVISORY IS CANCELLED...

Fog will gradually lift this morning and should dissipate by mid 
morning. However, the more widespread dense fog has dissipated,
therefore the Dense Fog Advisory has been cancelled. 

$$

CTZ002>004-MAZ003>007-010>019-026-RIZ001>004-122245-
/O.CON.KBOX.EH.W.0001.210812T1600Z-210813T0000Z/
/O.CON.KBOX.EH.A.0001.210813T0000Z-210814T0000Z/
Hartford CT-Tolland CT-Windham CT-Eastern Franklin MA-
Northern Worcester MA-Central Middlesex MA-Western Essex MA-
Eastern Essex MA-Eastern Hampshire MA-Eastern Hampden MA-
Southern Worcester MA-Western Norfolk MA-Southeast Middlesex MA-
Suffolk MA-Eastern Norfolk MA-Northern Bristol MA-
Western Plymouth MA-Eastern Plymouth MA-Northern Middlesex MA-
Northwest Providence RI-Southeast Providence RI-Western Kent RI-
Eastern Kent RI-
Including the cities of Hartford, Windsor Locks, Union, Vernon, 
Putnam, Willimantic, Greenfield, Orange, Barre, Fitchburg, 
Framingham, Lowell, Lawrence, Gloucester, Amherst, Northampton, 
Springfield, Milford, Worcester, Foxborough, Norwood, Cambridge, 
Boston, Quincy, Taunton, Brockton, Plymouth, Ayer, Foster, 
Smithfield, Providence, Coventry, West Greenwich, East Greenwich,
Warwick, and West Warwick
542 AM EDT Thu Aug 12 2021

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT FROM NOON TODAY TO
8 PM EDT THIS EVENING...
...EXCESSIVE HEAT WATCH REMAINS IN EFFECT FROM THIS EVENING
THROUGH FRIDAY EVENING...

* WHAT...For the Excessive Heat Warning, dangerously hot 
  conditions with heat index values up to 105 expected. For the 
  Excessive Heat Watch, dangerously hot conditions with heat 
  index values up to 102 possible.

* WHERE...Portions of northern Connecticut, central, eastern, 
  northeastern, southeastern and western Massachusetts and 
  northern Rhode Island.

* WHEN...For the Excessive Heat Warning, from noon today to 8 PM 
  EDT this evening. For the Excessive Heat Watch, from this 
  evening through Friday evening.

* IMPACTS...Extreme heat and humidity will significantly 
  increase the potential for heat related illnesses, 
  particularly for those working or participating in outdoor 
  activities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Drink plenty of fluids, stay in an air-conditioned room, stay out
of the sun, and check up on relatives and neighbors. Young
children and pets should never be left unattended in vehicles
under any circumstances.

Take extra precautions if you work or spend time outside. When
possible reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose fitting clothing when
possible. To reduce risk during outdoor work, the Occupational
Safety and Health Administration recommends scheduling frequent
rest breaks in shaded or air conditioned environments. Anyone
overcome by heat should be moved to a cool and shaded location.
Heat stroke is an emergency! Call 9 1 1.

&&

$$

MAZ002-008-009-122245-
/O.CON.KBOX.HT.Y.0008.210812T1600Z-210813T0000Z/
/O.CON.KBOX.EH.A.0001.210813T0000Z-210814T0000Z/
Western Franklin MA-Western Hampshire MA-Western Hampden MA-
Including the cities of Charlemont, Chesterfield, and Blandford
542 AM EDT Thu Aug 12 2021

...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TODAY TO 8 PM EDT
THIS EVENING...
...EXCESSIVE HEAT WATCH REMAINS IN EFFECT FROM THIS EVENING
THROUGH FRIDAY EVENING...

* WHAT...For the Heat Advisory, heat index values up to 99 
  expected. For the Excessive Heat Watch, dangerously hot 
  conditions with heat index values up to 97 possible.

* WHERE...Western Hampshire MA, Western Hampden MA and Western 
  Franklin MA Counties.

* WHEN...For the Heat Advisory, from noon today to 8 PM EDT this 
  evening. For the Excessive Heat Watch, from this evening 
  through Friday evening.

* IMPACTS...Extreme heat and humidity will significantly 
  increase the potential for heat related illnesses, 
  particularly for those working or participating in outdoor 
  activities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecasts and warnings for updates on this
situation. Be prepared to drink plenty of fluids, stay in an air-
conditioned room, stay out of the sun, and check up on relatives
and neighbors.

Young children and pets should never be left unattended in
vehicles under any circumstances. This is especially true during
warm or hot weather when car interiors can reach lethal
temperatures in a matter of minutes.

&&

$$

For more information from the National Weather Service visit
https://weather.gov/box

Area Forecast Discussion
National Weather Service Boston/Norton MA
421 PM EDT Wed Aug 11 2021

.SYNOPSIS...
A multiple-day stretch of oppressive to dangerous heat and
humidity continues. Heat indices today in the mid to upper 100s
tomorrow, and the lower to middle 100s on Friday. Scattered
afternoon to early evening thunderstorms are possible through
Friday, a few of which may become strong to severe. Better shot
for more widespread rainfall late on Friday into Saturday as a
cold front moves through. This will break the heat/humidity.
Drier and more seasonable air in place for Sunday into early
next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
4 PM Update...

.Tonight.

We'll have a decent shot at convection this afternoon/evening
over the western zones as a weak-surface trough associated with
a short-wave aloft advances through southern New England. The
anomalous heat and moisture has supplied the region with a very
unstable atmosphere consisting of 2500+ J/kg of MLCAPE.
Convergence along the surface trough axis should provide enough
lift to initiate convection. The limiting factor for severe
thunderstorms this evening will be the lack of deep-layer shear.
0-6 KM shear values are set to top out around 20 knots.
Nonetheless, high mixed layer LCLs and DCAPE > 1000 J/kg will
produce a favorable environment for damaging wind gusts. With
fairly steep mid-level lapse rates, we can't rule out small hail
either, but winds appears to be the primary threat this evening
as well torrential down pours. Any convection that develops
should begin to die down around or before midnight.

After the remaining showers/storms taper off tonight we'll be
left with nothing but heat and humidity as deep-southwest flow
continues. We'll have a shot at record high minimum temperatures
at couple of our climate sites. See the climate section of the
AFD for details. Generally we can expect lows to bottom out in
the low-mid 70s with the urban heat islands possibly holding in
the upper 70s!

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
.Tomorrow.

Excessive heat warning in effect for all of southern New
England minus the south coast, Cape, Islands, and east slopes of
The Berkshires. Temperatures in the mid 90s and dewpoints in
the mid 70s will result in heat index values of 105F or higher.
The hottest areas are expected to be in the CT and Merrimack
river valleys. Will also be on the look out for another round of
scattered convection tomorrow afternoon/evening over the
western areas. SPC has placed the western half of the forecast
area in a marginal risk zone for severe weather. Damaging winds
and large hail will be the primary threat. There is some
uncertainty in whether or not convection will be able to
initiate as the current forcing looks weak. However, with robust
instability (2000+ J/kg CAPE) and weak CIN, it won't take much
to initiate convection. Timing is up in the air as well as this
will be dependent on the arrival of a second surface trough
axis. Currently expecting this feature too arrive in western
MA/CT by early evening.

.Tomorrow Night.

A very similar forecast to tonight. Early evening convection
should die down by midnight leaving the region with another
night of oppressive humidity. Overnight lows expected to bottom
out in the mid-upper 70s which will once again put us in a
position to break record high minimum temperatures.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Highlights...

* Oppressive heat & humidity continues on Fri, with highs in the mid
  to upper 90s with heat indices 100-109 degrees Fri away from the
  immediate south coast.

* Risk for a few strong to severe storms with isolated damaging wind
  being the main threat late Friday and again sometime on Saturday
  with the passage of a strong cold front.

* Turning cooler and much less humid Sunday into the new work week.

Details...

Models continue to be in excellent agreement on the oppressive heat
and humidity continuing on Friday. Southwest flow along with 850 mb
temperatures in the +19C to +21C range and 925mb temperatures as
high as +26 to +28C should again yield high temperatures in the mid
90s away from the immediate south coast as well as Cape Cod and the
Islands each day. It does look like we could get higher actual air
temperatures but slightly lower dew points on Friday than on
Thursday, with better chance for upper 90s especially across Eastern
MA and RI with winds aloft out of the northwest/west bringing in
slightly drier air. Either way, the heat indices will work out to be
yet again in the 100 to 109F range so we have continued the
Excessive Heat Watch through Friday for much of Southern New
England.

Besides, there will be little nighttime relief, especially in the
urban population centers like Boston. In fact, overnight lows in
metro Boston may struggle to drop below 80 degrees overnight Friday
into Saturday due to urban heat island effect. With elevated air
temperatures, oppressive humidity and little nighttime relief ,
vulnerable population should take extra care to limit outdoor
exposure and be sure to hydrate regularly.

The other concern will be the potential for diurnally driven
scattered showers & thunderstorms. The SPC currently has a Day 3
marginal severe risk for interior MA/CT, although the timing and
areal coverage of potentially strong to severe convection hinge on
how storms evolve on Thursday. We do have higher confidence in more
widespread showers and thunderstorms associated with a strong cold
front passage sometime on Saturday. Given that Southern New England
looks to be roughly in the favorable right entrance region of a
70+kt jet streak, a few strong to severe storms with damaging winds
are possible.

Depending on the timing of the front, this could allow for
potentially one more warm and humid day with heat indices reaching
the 90s again. A faster frontal passage would allow much of Sat to
be dry along with cooler and/or less humid weather. Either way,
cooler and much less humid air will arrive by Sunday with dew points
falling into the 50s to low 60s. We look to start the new work week
with dry and seasonably mild weather (average highs upper 70s to low
80s) thanks to surface high pressure in place. Increasingly
unsettled weather looks to return by mid next week.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
Forecaster Confidence Levels.

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

Through 00Z...
High confidence

VFR with south/southwest winds across the interior.VCSH/VCTS
possible this afternoon for the western terminals. Embedded
MVFR ceilings possible over The Cape where there are some
scattered low clouds. ACK remains LIFR through the TAF period
with dense fog developing after near sunset.

Tonight

Shower and thunderstorm activity dies down by midnight. Interior
remains in VFR conditions. Fog develops around The Cape and
Islands tonight resulting in IFR/LIFR ceilings and visibilities.

Tomorrow

Fog and low ceilings lift to MVFR at The Cape Terminals by mid
to late morning. ACK remains in IFR/LIFR. VFR across the
interior.

Tonight...Moderate confidence.

Possible ongoing scattered TSRA (some still on the strong side)
in the interior thru 02z, but weakening trends to dry
conditions by midnight. Though generally VFR for most, MVFR-IFR
stratus maintains itself especially favored near southeast New
England. SW winds 7-12 kt.

Thursday...Moderate to high confidence.

Overall similar to today. Any sub-VFR ceilings in the interior
burn off by mid to late morning to VFR, but MVFR stratus may
linger near southeast New England. Reduced confidence in the
timing and development of TSRA in the interior; looks again to
be more favored late in the day moving in from central and
eastern NY, but possible isolated storms as soon as 18z.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...Moderate confidence in TAF.

Outlook /Friday through Monday/...

Friday: Mainly VFR, with local MVFR possible. Slight chance
SHRA, isolated TSRA.

Friday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.

Saturday: Mainly VFR, with areas MVFR possible. Chance SHRA,
slight chance TSRA.

Saturday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.

Sunday through Monday: VFR.

&&

.MARINE...
Forecaster Confidence Levels.

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

Marine...High Confidence

Southwest winds with gusts from 15-20 knots will persist through
tomorrow night. Patchy areas of dense fog will be possible
overnight and tomorrow morning over the south coastal waters.
Otherwise expecting fairly quiet conditions across the coastal
waters to end the week. There will be a slight chance for
isolated showers/thunderstorms over the coastal waters tomorrow
night.

/Outlook /Friday through Monday/...

Friday: Winds less than 25 kt. Seas locally approaching 5 ft.

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

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

Saturday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Chance of rain showers.

Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft.

Sunday Night through Monday: Winds less than 25 kt.

&&

.CLIMATE...
Record Daily High Temperatures for August 12-13

August 12

BOS 101 in 1944
BDL 98  in 1944
PVD 100 in 1944
ORH 99  in 1944

August 13

BOS 100 in 1944
BDL 99  in 2016
PVD 100 in 2005
ORH 98  in 1944

Record Daily Warmest Low Temperatures for August 12-13

August 12

BOS 78 in 2016
BDL 74 in 1905
PVD 76 in 1944
ORH 74 in 1896

August 13

BOS 75 in 1944
BDL 74 in 2005
PVD 77 in 2005
ORH 75 in 1896

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert from 11 AM to 11 PM EDT Thursday for
     CTZ002>004.
     Excessive Heat Warning from noon to 8 PM EDT Thursday for
     CTZ002>004.
     Heat Advisory until 8 PM EDT this evening for CTZ002>004.
     Excessive Heat Watch from Thursday evening through Friday
     evening for CTZ002>004.
     Air Quality Alert until 11 PM EDT this evening for CTZ002.
MA...Excessive Heat Warning from noon to 8 PM EDT Thursday for
     MAZ003>007-010>019-026.
     Heat Advisory until 8 PM EDT this evening for MAZ002>021-026.
     Excessive Heat Watch from Thursday evening through Friday
     evening for MAZ002>019-026.
     Air Quality Alert until 11 PM EDT this evening for MAZ010>012.
     Heat Advisory from noon to 8 PM EDT Thursday for MAZ002-008-
     009-020-021.
RI...Air Quality Alert from 11 AM to 11 PM EDT Thursday for
     RIZ001>008.
     Excessive Heat Warning from noon to 8 PM EDT Thursday for
     RIZ001>005.
     Heat Advisory until 8 PM EDT this evening for RIZ001>007.
     Excessive Heat Watch from Thursday evening through Friday
     evening for RIZ001>005.
     Heat Advisory from noon to 8 PM EDT Thursday for RIZ006-007.
MARINE...None.

&&

SYNOPSIS...Chai/RM
NEAR TERM...RM
SHORT TERM...RM
LONG TERM...Chai
AVIATION...Chai/RM
MARINE...Chai/RM
CLIMATE...

Hazardous Weather Outlook
National Weather Service Boston/Norton MA
434 PM EDT Wed Aug 11 2021

MAZ003>007-013>019-026-122045-
Eastern Franklin MA-Northern Worcester MA-Central Middlesex MA-
Western Essex MA-Eastern Essex MA-Western Norfolk MA-
Southeast Middlesex MA-Suffolk MA-Eastern Norfolk MA-
Northern Bristol MA-Western Plymouth MA-Eastern Plymouth MA-
Northern Middlesex MA-
434 PM EDT Wed Aug 11 2021

...HEAT ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING...
...EXCESSIVE HEAT WARNING IN EFFECT FROM NOON TO 8 PM EDT THURSDAY...
...EXCESSIVE HEAT WATCH IN EFFECT FROM THURSDAY EVENING THROUGH
FRIDAY EVENING...

This Hazardous Weather Outlook is for central Massachusetts,
eastern Massachusetts, northeastern Massachusetts, southeastern
Massachusetts and western Massachusetts.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Heat Advisory.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Excessive Heat Warning.
   Excessive Heat Watch.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

MAZ002-008-009-122045-
Western Franklin MA-Western Hampshire MA-Western Hampden MA-
434 PM EDT Wed Aug 11 2021

...HEAT ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING...
...HEAT ADVISORY IN EFFECT FROM NOON TO 8 PM EDT THURSDAY...
...EXCESSIVE HEAT WATCH IN EFFECT FROM THURSDAY EVENING THROUGH
FRIDAY EVENING...

This Hazardous Weather Outlook is for western Massachusetts.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Heat Advisory.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Heat Advisory.
   Excessive Heat Watch.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

CTZ003-004-RIZ001>005-122045-
Tolland CT-Windham CT-Northwest Providence RI-
Southeast Providence RI-Western Kent RI-Eastern Kent RI-Bristol RI-
434 PM EDT Wed Aug 11 2021

...HEAT ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING...
...AIR QUALITY ALERT IN EFFECT FROM 11 AM TO 11 PM EDT THURSDAY...
...EXCESSIVE HEAT WARNING IN EFFECT FROM NOON TO 8 PM EDT THURSDAY...
...EXCESSIVE HEAT WATCH IN EFFECT FROM THURSDAY EVENING THROUGH
FRIDAY EVENING...

This Hazardous Weather Outlook is for northern Connecticut and
northern Rhode Island.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Heat Advisory.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Air Quality Alert.
   Excessive Heat Warning.
   Excessive Heat Watch.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

CTZ002-122045-
Hartford CT-
434 PM EDT Wed Aug 11 2021

...AIR QUALITY ALERT IN EFFECT UNTIL 11 PM EDT THIS EVENING...
...HEAT ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING...
...AIR QUALITY ALERT IN EFFECT FROM 11 AM TO 11 PM EDT THURSDAY...
...EXCESSIVE HEAT WARNING IN EFFECT FROM NOON TO 8 PM EDT THURSDAY...
...EXCESSIVE HEAT WATCH IN EFFECT FROM THURSDAY EVENING THROUGH
FRIDAY EVENING...

This Hazardous Weather Outlook is for northern Connecticut.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Air Quality Alert.
   Heat Advisory.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Air Quality Alert.
   Excessive Heat Warning.
   Excessive Heat Watch.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

MAZ010>012-122045-
Eastern Hampshire MA-Eastern Hampden MA-Southern Worcester MA-
434 PM EDT Wed Aug 11 2021

...AIR QUALITY ALERT IN EFFECT UNTIL 11 PM EDT THIS EVENING...
...HEAT ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING...
...EXCESSIVE HEAT WARNING IN EFFECT FROM NOON TO 8 PM EDT THURSDAY...
...EXCESSIVE HEAT WATCH IN EFFECT FROM THURSDAY EVENING THROUGH
FRIDAY EVENING...

This Hazardous Weather Outlook is for central Massachusetts and
western Massachusetts.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Air Quality Alert.
   Heat Advisory.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Excessive Heat Warning.
   Excessive Heat Watch.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

ANZ230>237-250-251-254>256-122045-
Boston Harbor-Cape Cod Bay-Nantucket Sound-Vineyard Sound-
Buzzards Bay-Rhode Island Sound-Narragansett Bay-Block Island Sound-
Coastal waters east of Ipswich Bay and the Stellwagen Bank National
Marine Sanctuary-Massachusetts Bay and Ipswich Bay-
Coastal waters from Provincetown MA to Chatham MA to Nantucket MA
out 20 nm-
Coastal Waters extending out to 25 nm South of Marthas Vineyard and
Nantucket-
Coastal Waters from Montauk NY to Marthas Vineyard extending out to
20 nm South of Block Island-
434 PM EDT Wed Aug 11 2021

This Hazardous Weather Outlook is for Massachusetts and Rhode
Island coastal waters.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

RIZ006-007-122045-
Washington RI-Newport RI-
434 PM EDT Wed Aug 11 2021

...HEAT ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING...
...AIR QUALITY ALERT IN EFFECT FROM 11 AM TO 11 PM EDT THURSDAY...
...HEAT ADVISORY IN EFFECT FROM NOON TO 8 PM EDT THURSDAY...

This Hazardous Weather Outlook is for southern Rhode Island.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Heat Advisory.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Air Quality Alert.
   Heat Advisory.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

MAZ022>024-122045-
Barnstable MA-Dukes MA-Nantucket MA-
434 PM EDT Wed Aug 11 2021

This Hazardous Weather Outlook is for southeastern Massachusetts.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

MAZ020-021-122045-
Southern Bristol MA-Southern Plymouth MA-
434 PM EDT Wed Aug 11 2021

...HEAT ADVISORY IN EFFECT UNTIL 8 PM EDT THIS EVENING...
...HEAT ADVISORY IN EFFECT FROM NOON TO 8 PM EDT THURSDAY...

This Hazardous Weather Outlook is for southeastern Massachusetts.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Heat Advisory.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Heat Advisory.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

RIZ008-122045-
Block Island RI-
434 PM EDT Wed Aug 11 2021

...AIR QUALITY ALERT IN EFFECT FROM 11 AM TO 11 PM EDT THURSDAY...

This Hazardous Weather Outlook is for southern Rhode Island.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Air Quality Alert.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

For more information on upcoming hazardous weather, please see the
Area Forecast Discussion on our webpage for the latest forecast
thinking. There is also our Enhanced Hazardous Weather Outlook at
www.weather.gov/box/ehwo

For the latest updates...please visit our webpage at
www.weather.gov/boston

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www.facebook.com/nwsboston

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@NWSBoston