Boston, MA Weather Forecast Office Presentation Created
3/1/2018 8:22 AM Follow us on Twitter Follow us on Facebook
Flood Related Hazards
Wind Related Hazards
Severe Weather Related Hazards
National Weather Service
Thursday, March 01, 2018 8:21 AM
What Has Changed?
Hurricane Force Wind Gusts likely
across Cape/Islands. Property
damage and numerous power
outages possible.
Hurricane Force Wind Watches
across the southeast New England
waters.
Winter Storm Watch Issued for the
east slopes of the Berkshires and
Worcester Hills.
High Impact/Long Duration Coastal
Storm Friday Into Saturday
Hazards
Boston, MA Weather Forecast Office Presentation Created
3/1/2018 8:22 AM Follow us on Twitter Follow us on Facebook
Main Points Hazard Impacts Location Timing
Coastal
Flooding
Significant flooding of shore
roads/severe beach erosion. Major
coastal flooding possible, which may
result in some property damage &
flood areas that are not usually
impacted.
Eastern MA coast including
Nantucket.
Late Friday morning,
Friday night and
Saturday high tide
cycles.
Marine 25 to 35 foot seas across the eastern
waters possible with NEwind gusts of
55 to 65 knots.
All Coastal Waters with
strongest wind gusts. Friday into Saturday.
Strong Winds
Tree damage/scattered power
outages possible. Strongest
Cape/Islands with possible property
damage + numerous power outages.
Eastern MA and RI and
especially Cape/Islands. Friday into Saturday
Heavy Rain/
Fresh Water
Flooding
Heavy Rain with urban/poor drainage
street flooding threat. A few
rivers/small streams may approach or
exceed flood stage.
Eastern MA/RI.
Heavy rain threat Friday
but some river flooding
possible into the
weekend.
Rain changing
To Wet Snow
Rain changes to wet snow in some
locations. Very low confidence on
snow accumulations, but power
outages possible if higher amts occur.
Greatest Risk Interior high
terrain, but can not be ruled
out across other locations.
Mainly Friday afternoon
into Friday night.
Boston, MA Weather Forecast Office Presentation Created
3/1/2018 8:22 AM Follow us on Twitter Follow us on Facebook
None Limited Elevated Significant Extreme
None Limited Elevated Significant Extreme
None Limited Elevated Significant Extreme
None Limited Elevated Significant Extreme
None Limited Elevated Significant Extreme
Summary of Greatest Impacts Coastal Flooding/Beach Erosion: Eastern MA
Wind Damage: Highest Risk Eastern MA/RI
Fresh Water Flooding: Highest Risk Eastern MA/RI
Wet Snow - Low Confidence: Greatest Risk High Terrain
Marine: All southern New England Waters
Boston, MA Weather Forecast Office Presentation Created
3/1/2018 8:22 AM Follow us on Twitter Follow us on Facebook
Timing
• Several tide cycles will be impacted. Especially
Friday mid day into Saturday mid-day.
Minor Coastal Flooding
• Partial inundation within the flood zone, especially for low-lying
areas.
• Vulnerable shore roads with up to a foot of water inundation
possible. May be flooding of a few vulnerable basements.
• Some beach erosion with heavy surf.
Timing
• Some impacts possible late tonight, but most likely Wednesday
peaking Wednesday morning
Moderate to Major Coastal Flooding
• Inundation within the flood zone. Vulnerable shore roads inundated at least a foot
of water up to 3 feet. Road closures. Vulnerable basements flooded as well.
• Beach erosion with heavy surf. A few sections of near-shore escape roads
weakened or washed out, especially in historically vulnerable low spots.
• Storm surge breaching dunes and possibly seawalls in scattered locations to result
in damage to shoreline buildings, mainly in historically vulnerable spots.
• Moderate damage to marinas, docks, and piers. Several small craft broken away
from moorings (especially unprotected areas).
• Shoreline road washouts are possible due to the combination of storm surge and
large breaking waves.
High Impact (5-7 ft Depth)
• Large areas of deep inundation in the flood zone.
• Severe beach erosion. Several sections of near-shore roads washed out.
• Low-lying escape routes severely flooded.
• Breaching of dunes and possibly seawalls in scattered locations.
• Structural damage to shoreline buildings, with a few washing into the sea.
• Moderate to major damage to marinas, docks, and piers. Many small craft broken away from moorings and lifted onshore and stranded.
Extreme/Catastrophic Impact (7ft+ Depth)
• Widespread deep inundation within flood zone.
• Water possibly reaching several miles inland.
• Extreme beach erosion. Several new cuts. Many large sections of near-shore roads washed out.
• Low-lying escape routes severely flooded.
• Surge breaching dunes and possibly seawalls in widespread locations.
• Structural damage to shoreline buildings, several washing into the sea.
• Extensive damage to marinas, docks, and piers.
• Numerous small craft broken away from moorings, lifted onshore and stranded.
Low Impact (1-3 ft Depth)
• Partial inundation within the flood zone, especially for low-lying areas.
• Moderate to locally major beach erosion.
• Very heavy surf breaching dunes in isolated locations, mainly in historically vulnerable spots.
Moderate Impact (3-5 ft Depth)
• Partial inundation within the flood zone.
• Major beach erosion. A few sections of near-shore escape roads weakened or washed out, especially in historically vulnerable low spots.
• Storm surge breaching dunes and possibly seawalls in scattered locations to result in damage to shoreline buildings, mainly in historically vulnerable spots.
• Moderate damage to marinas, docks, and piers. Several small craft broken away from moorings (especially unprotected areas).
Minor Coastal Flooding
• Vulnerable shore roads flooded with up to a foot of
water.
• Most roads remain passable but some may be
closed briefly around high tide.
• Some basements may flood.
• Beach erosion possible due to rough surf.
Moderate to Major Coastal Flooding
• Shore roads flooded with up to 3 feet of water.
• Many shore roads impassable and closed around
high tide. Some may be washed out due to storm
surge and large breaking waves.
• Large debris washed ashore, including on shore
roads.
• Many basements flooded.
• Severe beach erosion. Dunes breached.
• Sea walls may be damaged.
• Damage possible to shoreline buildings, mainly in
historically vulnerable spots.
• Damage to marinas, docks, and piers. Smaller
craft may break away from moorings, especially in
unprotected areas.
Providence
495
95
95
195
3 to 4 Foot Surge Expected
Nantucket
Plymouth
Boston
Moderate to Major
Moderate to Major
Coastal Flooding – Surge / Inundation
Minor
Moderate
Major
Extreme
Boston, MA Weather Forecast Office Presentation Created
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Forecast Maximum Wave Heights
Definitions Storm Surge Marine
None No coastal flood risk No marine hazard risk
Limited
< 1 foot of inundation
Localized vulnerable
shoreline roads &
property will briefly flood
Winds 15 to 24 knots
and/or
Waves ≥ 2 feet
Elevated
1-2 feet of inundation
Few shoreline roads &
property will flood
Low threat of
property damage
Winds 25 to 33 knots
and/or
Waves ≥ 5 feet
Significant
2-3 feet of inundation
Several shoreline roads
& property will flood
Risk to life; elevated
threat of property
damage
Winds 34 to 47 knots
and/or
Waves ≥ 10 feet
Extreme
3-5 feet of inundation
Many shoreline roads &
property will be damaged
Coastal community
flooding
Evacuations necessary
Winds ≥ 48 knots
and/or
Waves ≥ 20 feet
Impacts Storm Surge Marine
None None None
Limited
Inundated shore roads
Basement flooding,
Minor beach erosion
Difficult boating
conditions for small
boats
Elevated
Isolated road closures,
Scattered homes and
businesses flooded,
Moderate beach erosion
Low risk of rough seas,
Rough boating
conditions
Significant
Scattered road closures,
Numerous homes and
businesses flooded,
Major beach erosion
Medium risk of rough
seas, Hazardous boating
conditions
Extreme
Numerous road closures,
Widespread homes and
businesses flooded,
Extensive beach erosion
High risk of rough seas,
Dangerous, life-
threatening boating
conditions
Mariners
• Northeast wind gusts 65 to 75
mph (55 to 65 kts).
• Long duration of duration of
very strong winds Friday into
Saturday. Strongest winds
Friday afternoon and night.
• Hurricane force wind gusts
coupled with 25 to 35 foot seas
will result in a life threatening
situation for Mariners. Mariners
are urged tor return to port by
this evening.
Boston, MA Weather Forecast Office Presentation Created
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Forecast Maximum Wind Gusts
Hurricane Force Wind Gusts may result in property damage and numerous power outages.
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Forecast Storm Total Precipitation
Greatest Risk For Some Urban Flooding Along With A Few Rivers And Streams.
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Forecast Storm Total Snowfall
These Specific Snow Accumulations Are Quite Uncertain. Please see best/worst case scenarios for a better idea of possible outcomes and impacts.
Boston, MA Weather Forecast Office Presentation Created
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Forecast Storm Total Snowfall (Worst Case)
WORST CASE: Low probability but very high impact. Rain changes to heavy Wet snow. 6-12+ Inches falls resulting in power outages.
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Forecast Storm Total Snowfall (Best Case)
BEST CASE: Precipitation remains all rain with just a very small snow accumulation in the high terrain with little impact.
Boston, MA Weather Forecast Office Presentation Created
3/1/2018 8:23 AM Follow us on Twitter Follow us on Facebook
Threat Event Summary
Confidence: High confidence in moderate to major coastal flooding along the
eastern MA coast. High confidence in damaging wind gusts across eastern
MA/RI and especially Cape/Islands. Very low confidence in wet snow
accumulations with a wide variety of possible outcomes and impacts.
What:
Where: All of Southern New England. Greatest concern Eastern MA.
When: Friday into Friday night but strong winds continue into Saturday.
Significant coastal flooding,
beach erosion across eastern
MA coast.
Heavy Rain may result in
urban/street flooding and a
few rivers may go into flood
across eastern MA/RI.
Damaging wind gusts eastern
MA/RI. Hurricane force wind
gusts Cape/Islands w/numerous
power outages possible.
Rain may eventually change to
wet snow in some locations.
Greatest risk high terrain+SE MA.
Snow accums highly uncertain.