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Short Term Forecast

Short Term Forecast
National Weather Service Baltimore MD/Washington DC
837 PM EDT Sat Jul 20 2019

MDZ503-VAZ031-052-053-501-502-505-506-WVZ053-210100-
Northwest Montgomery-Fairfax-Eastern Loudoun-Clarke-Prince
William/Manassas/Manassas Park-Northern Fauquier-Western
Loudoun-Southern Fauquier-Jefferson-
837 PM EDT Sat Jul 20 2019

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT WEST CENTRAL
MONTGOMERY...LOUDOUN...NORTHWESTERN FAIRFAX...EASTERN CLARKE...
NORTHEASTERN FAUQUIER...NORTHWESTERN PRINCE WILLIAM AND SOUTHERN
JEFFERSON COUNTIES...

At 837 PM EDT, radar indicated strong thunderstorms were located
along a line extending from near Leesburg to near The Plains to near
Hume. Movement was east at 25 mph.

Gusts of 40 to 50 mph and half inch hail are possible with these
storms.

Locations impacted include...
Centreville, Reston, Leesburg, South Riding, Herndon, Broadlands,
Lansdowne, Lowes Island, Brambleton, Warrenton, Dulles International
Airport, Ashburn, Linton Hall, Sterling, Chantilly, Great Falls, Bull
Run, Countryside, Purcellville and Haymarket.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 3909 7732 3882 7744 3870 7773 3879 7798
      3892 7784 3917 7783
TIME...MOT...LOC 0037Z 287DEG 24KT 3914 7756 3890 7770 3880 7793

$$

MM



Hazardous Weather Outlook

Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
739 PM EDT Sat Jul 20 2019

ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-212345-
Chesapeake Bay north of Pooles Island MD-
Chesapeake Bay from Pooles Island to Sandy Point MD-
Chesapeake Bay from Sandy Point to North Beach MD-
Chesapeake Bay from North Beach to Drum Point MD-
Chesapeake Bay from Drum Point MD to Smith Point VA-
Tidal Potomac from Key Bridge to Indian Head MD-
Tidal Potomac from Indian Head to Cobb Island MD-
Tidal Potomac from Cobb Island MD to Smith Point VA-
Patapsco River including Baltimore Harbor-
Chester River to Queenstown MD-Eastern Bay-
Choptank River to Cambridge MD and the Little Choptank River-
Patuxent River to Broomes Island MD-
Tangier Sound and the inland waters surrounding Bloodsworth
Island-District of Columbia-Southern Baltimore-Prince Georges-
Anne Arundel-Charles-St. Marys-Calvert-Southeast Harford-
Prince William/Manassas/Manassas Park-Fairfax-
Arlington/Falls Church/Alexandria-Stafford-Spotsylvania-
King George-
739 PM EDT Sat Jul 20 2019

This Hazardous Weather Outlook is for the Maryland portion of the
Chesapeake Bay, Tidal Potomac River, and adjacent counties in
central Maryland and northern Virginia as well as the District of
Columbia.

.DAY ONE...Tonight

An Excessive Heat Warning is in effect from until 9 PM EDT this
evening.

An isolated severe thunderstorm with damaging wind gusts is
possible this evening.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

An Excessive Heat Watch remains in effect from late Sunday morning
through Sunday evening.

Thunderstorms are likely late Sunday through Monday, and may be
capable of producing damaging wind gusts or flooding.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

$$



Excessive Heat Warning

URGENT - WEATHER MESSAGE
National Weather Service Baltimore MD/Washington DC
440 PM EDT Sat Jul 20 2019

DCZ001-MDZ004>006-011-013-014-016>018-503>508-VAZ036>040-050>057-
501-502-505-506-210445-
/O.CON.KLWX.EH.W.0002.000000T0000Z-190721T0100Z/
/O.CON.KLWX.EH.A.0004.190721T1500Z-190722T0100Z/
District of Columbia-Frederick MD-Carroll-Northern Baltimore-
Southern Baltimore-Prince Georges-Anne Arundel-Charles-St. Marys-
Calvert-Northwest Montgomery-Central and Southeast Montgomery-
Northwest Howard-Central and Southeast Howard-Northwest Harford-
Southeast Harford-Nelson-Albemarle-Greene-Madison-Rappahannock-
Orange-Culpeper-Prince William/Manassas/Manassas Park-Fairfax-
Arlington/Falls Church/Alexandria-Stafford-Spotsylvania-
King George-Northern Fauquier-Southern Fauquier-Western Loudoun-
Eastern Loudoun-
Including the cities of Washington, Frederick, Ballenger Creek,
Eldersburg, Westminster, Reisterstown, Cockeysville, Baltimore,
Bowie, Suitland-Silver Hill, Clinton, College Park, Greenbelt,
Laurel, Camp Springs, Glen Burnie, Annapolis, Severn, South Gate,
Severna Park, Arnold, Odenton, St. Charles, Waldorf,
Lexington Park, California, Chesapeake Beach, Huntingtown,
Dunkirk, North Beach, Lusby, Prince Frederick, Germantown,
Damascus, Bethesda, Rockville, Gaithersburg, Silver Spring,
Lisbon, Columbia, Ellicott City, Jarrettsville, Aberdeen,
Lovingston, Charlottesville, Stanardsville, Madison, Orange,
Gordonsville, Culpeper, Dale City, Manassas, Woodbridge,
Lake Ridge, Montclair, Reston, Herndon, Annandale, Centreville,
Chantilly, McLean, Franconia, Arlington, Alexandria,
Falls Church, Falmouth, Fredericksburg, Dahlgren, Warrenton,
Turnbull, Purcellville, Leesburg, Ashburn, and Sterling
440 PM EDT Sat Jul 20 2019

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM EDT THIS
EVENING...
...EXCESSIVE HEAT WATCH REMAINS IN EFFECT FROM SUNDAY MORNING
THROUGH SUNDAY EVENING...

* HEAT INDEX VALUES...Around 110 to 115 degrees due to
  temperatures in the upper 90s to around 100 degrees and
  dewpoints in the lower to middle 70s. The highest heat indices
  will be near and east of Interstate 95.

* IMPACTS...Dangerously high temperatures and humidity could
  quickly cause heat stress or heat stroke if precautions are
  not taken.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a prolonged period of
dangerously high temperatures will occur. The combination of
extreme temperatures and high humidity will create a dangerous
situation in which heat illnesses are expected. Check in on
relatives and neighbors.

An Excessive Heat Watch means that a prolonged period of
dangerously high temperatures is possible. Prepare for extreme
temperatures and high humidity which would create a situation in
which heat illnesses are expected.

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 light weight and loose fitting clothing when
possible and drink plenty of water.

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 911.

&&

$$



Excessive Heat Watch

URGENT - WEATHER MESSAGE
National Weather Service Baltimore MD/Washington DC
440 PM EDT Sat Jul 20 2019

DCZ001-MDZ004>006-011-013-014-016>018-503>508-VAZ036>040-050>057-
501-502-505-506-210445-
/O.CON.KLWX.EH.W.0002.000000T0000Z-190721T0100Z/
/O.CON.KLWX.EH.A.0004.190721T1500Z-190722T0100Z/
District of Columbia-Frederick MD-Carroll-Northern Baltimore-
Southern Baltimore-Prince Georges-Anne Arundel-Charles-St. Marys-
Calvert-Northwest Montgomery-Central and Southeast Montgomery-
Northwest Howard-Central and Southeast Howard-Northwest Harford-
Southeast Harford-Nelson-Albemarle-Greene-Madison-Rappahannock-
Orange-Culpeper-Prince William/Manassas/Manassas Park-Fairfax-
Arlington/Falls Church/Alexandria-Stafford-Spotsylvania-
King George-Northern Fauquier-Southern Fauquier-Western Loudoun-
Eastern Loudoun-
Including the cities of Washington, Frederick, Ballenger Creek,
Eldersburg, Westminster, Reisterstown, Cockeysville, Baltimore,
Bowie, Suitland-Silver Hill, Clinton, College Park, Greenbelt,
Laurel, Camp Springs, Glen Burnie, Annapolis, Severn, South Gate,
Severna Park, Arnold, Odenton, St. Charles, Waldorf,
Lexington Park, California, Chesapeake Beach, Huntingtown,
Dunkirk, North Beach, Lusby, Prince Frederick, Germantown,
Damascus, Bethesda, Rockville, Gaithersburg, Silver Spring,
Lisbon, Columbia, Ellicott City, Jarrettsville, Aberdeen,
Lovingston, Charlottesville, Stanardsville, Madison, Orange,
Gordonsville, Culpeper, Dale City, Manassas, Woodbridge,
Lake Ridge, Montclair, Reston, Herndon, Annandale, Centreville,
Chantilly, McLean, Franconia, Arlington, Alexandria,
Falls Church, Falmouth, Fredericksburg, Dahlgren, Warrenton,
Turnbull, Purcellville, Leesburg, Ashburn, and Sterling
440 PM EDT Sat Jul 20 2019

...EXCESSIVE HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM EDT THIS
EVENING...
...EXCESSIVE HEAT WATCH REMAINS IN EFFECT FROM SUNDAY MORNING
THROUGH SUNDAY EVENING...

* HEAT INDEX VALUES...Around 110 to 115 degrees due to
  temperatures in the upper 90s to around 100 degrees and
  dewpoints in the lower to middle 70s. The highest heat indices
  will be near and east of Interstate 95.

* IMPACTS...Dangerously high temperatures and humidity could
  quickly cause heat stress or heat stroke if precautions are
  not taken.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

An Excessive Heat Warning means that a prolonged period of
dangerously high temperatures will occur. The combination of
extreme temperatures and high humidity will create a dangerous
situation in which heat illnesses are expected. Check in on
relatives and neighbors.

An Excessive Heat Watch means that a prolonged period of
dangerously high temperatures is possible. Prepare for extreme
temperatures and high humidity which would create a situation in
which heat illnesses are expected.

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 light weight and loose fitting clothing when
possible and drink plenty of water.

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 911.

&&

$$



U.S. Dept. of Commerce
NOAA National Weather Service
1325 East West Highway
Silver Spring, MD 20910
E-mail: w-nws.webmaster@noaa.gov
Page last modified: May 16, 2007
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