[Tropical] Hurricane Local Statement

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WTUS81 KLWX 040939
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DCZ001-MDZ003>006-011-013-014-016>018-503>508-VAZ031-036>040-050>057-501-502-505>508-WVZ053-041745-

Tropical Storm Isaias Local Statement Advisory Number 29
National Weather Service Baltimore MD/Washington DC  AL092020
539 AM EDT Tue Aug 4 2020

This product covers Eastern West Virginia, Central and Western Maryland,
Northern and Northwestern Virginia, and District of Columbia

**LIFE THREATENING FLASH FLOODING...STRONG WINDS AND RISK OF TORNADOES TODAY**


NEW INFORMATION
---------------

* CHANGES TO WATCHES AND WARNINGS:
    - None

* CURRENT WATCHES AND WARNINGS:
    - A Tropical Storm Warning is in effect for Anne Arundel,
      Arlington/Falls Church/Alexandria, Calvert, Carroll, Central
      and Southeast Howard, Central and Southeast Montgomery,
      Charles, District of Columbia, Fairfax, King George, Northern
      Baltimore, Northwest Harford, Northwest Howard, Northwest
      Montgomery, Prince Georges, Prince William/Manassas/Manassas
      Park, Southeast Harford, Southern Baltimore, Spotsylvania, St.
      Marys, and Stafford

* STORM INFORMATION:
    - About 180 miles south of Washington DC or about 210 miles
      south-southwest of Baltimore MD
    - 36.3N 77.5W
    - Storm Intensity 70 mph
    - Movement North-northeast or 20 degrees at 28 mph

SITUATION OVERVIEW
------------------

Tropical Storm Isaias will move rapidly to the north northeast
passing near or over St. Mary's County this morning and exit the
Chesapeake Bay by midday.

Life-threatening flash flooding of small streams and creeks is
likely today as rainfall associated with Isaias continues to spread
northward. Widespread rainfall totals of 3 to 6 inches are expected
with locally higher amounts possible. The highest amounts are
expected over the I-95 corridor through early afternoon.

Tropical storm force winds are likely along and east of the I-95
corridor this morning. Tree damage and power outages are possible in
this area. There is also a risk of isolated tornadoes across
southern Maryland through this morning. Moderate coastal flooding is
also likely along the western shores of the Chesapeake Bay and at
Washington DC Southwest Waterfront today. Minor coastal flooding is
likely along other tidal waters.


POTENTIAL IMPACTS
-----------------

* FLOODING RAIN:
Potential impacts from the flooding rain are still unfolding across
along and east of Interstate 95. Remain well guarded against
life-threatening flood waters having extensive impacts.

If realized, these impacts include:
    - Major rainfall flooding may prompt many evacuations and rescues.
    - Rivers and tributaries may rapidly overflow their banks in
      multiple places. Small streams, creeks, canals, arroyos, and
      ditches may become dangerous rivers. In mountain areas,
      destructive runoff may run quickly down valleys while
      increasing susceptibility to rockslides and mudslides. Flood
      control systems and barriers may become stressed.
    - Flood waters can enter many structures within multiple
      communities, some structures becoming uninhabitable or washed
      away. Many places where flood waters may cover escape routes.
      Streets and parking lots become rivers of moving water with
      underpasses submerged. Driving conditions become dangerous.
      Many road and bridge closures with some weakened or washed out.

* WIND:
Potential impacts from the main wind event are now unfolding across
southern Maryland. Remain well sheltered from dangerous
wind having possible significant impacts. If
realized, these impacts include:
    - Some damage to roofing and siding materials, along with damage
      to porches, awnings, carports, and sheds. A few buildings
      experiencing window, door, and garage door failures. Mobile
      homes damaged, especially if unanchored. Unsecured lightweight
      objects become dangerous projectiles.
    - Several large trees snapped or uprooted, but with greater
      numbers in places where trees are shallow rooted. Several
      fences and roadway signs blown over.
    - Some roads impassable from large debris, and more within urban
      or heavily wooded places. A few bridges, causeways, and access
      routes impassable.
    - Scattered power and communications outages, but more prevalent
      in areas with above ground lines.

Elsewhere across Eastern West Virginia, Central and Western Maryland,
Northern and Northwestern Virginia, and District of Columbia, little
to no impact is anticipated.

* TORNADOES:
Potential impacts from tornadoes are still unfolding across southern
Maryland. Remain well braced against a tornado event
having possible limited impacts. If realized,
these impacts include:
    - The occurrence of isolated tornadoes can hinder the execution
      of emergency plans during tropical events.
    - A few places may experience tornado damage, along with power
      and communications disruptions.
    - Locations could realize roofs peeled off buildings, chimneys
      toppled, mobile homes pushed off foundations or overturned,
      large tree tops and branches snapped off, shallow-rooted trees
      knocked over, moving vehicles blown off roads, and small boats
      pulled from moorings.

Elsewhere across Eastern West Virginia, Central and Western Maryland,
Northern and Northwestern Virginia, and District of Columbia, little
to no impact is anticipated.

* SURGE:
Potential impacts from the main surge event are now unfolding along
the Tidal Potomac River and western shore of the Chesapeake Bay.
Remain well away from locally hazardous surge having moderate impacts. If
realized, these impacts include:
    - Localized inundation with storm surge flooding mainly along
      immediate shorelines and in low-lying spots, or in areas
      farther inland near where higher surge waters move ashore.
    - Sections of near-shore roads and parking lots become overspread
      with surge water. Driving conditions dangerous in places where
      surge water covers the road.
    - Moderate beach erosion. Heavy surf also breaching dunes, mainly
      in usually vulnerable locations. Strong rip currents.
    - Minor to locally moderate damage to marinas, docks, boardwalks,
      and piers. A few small craft broken away from moorings.

PRECAUTIONARY/PREPAREDNESS ACTIONS
----------------------------------

If you are prone to flooding or in an area under a coastal flood warning
be prepared for the possibility of a quick and dramatic
rise in water levels.

If a tornado warning is issued for your area, quickly move to the
safest place within your shelter. Protect your head and body.

* ADDITIONAL SOURCES OF INFORMATION:
- For information on appropriate preparations see ready.gov
- For information on creating an emergency plan see getagameplan.org
- For additional disaster preparedness information see redcross.org

NEXT UPDATE
-----------

The next local statement will be issued by the National Weather
Service in Baltimore MD/Washington DC around 830 AM EDT, or sooner if
conditions warrant.

$$
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