Small Craft Advisory
Small Craft Advisories are
issued for the Tidal Potomac River and the Chesapeake
Bay when one or both
of the following conditions is expected to begin within 36 hours:
1) sustained winds of 18
knots to 33 knots
OR
2) frequent gusts (duration of two or more hours)
between 18 knots and 33 knots.
OR
3) waves of 4 feet or higher
Gale Warning
Gale Warnings are issued for
the Tidal Potomac River and the Chesapeake Bay when one or both of
the following conditions is expected to begin within 36 hours and not
directly associated with a tropical cyclone:
1) sustained winds of 34
knots to 47 knots
OR
2) frequent gusts
(duration of two or more hours) between 34 knots and 47 knots.
Storm Warning
Storm Warnings are issued for
the Tidal Potomac River and the Chesapeake Bay
when one or both of the
following conditions is expected to begin within 36 hours and not directly
associated with a tropical cyclone:
1) sustained winds of 48
knots to 63 knots
OR
2) frequent gusts (duration of two or more hours) of 48
knots to 63 knots
Hurricane Force Wind Warning
Hurricane Force Wind Warnings are issued for
the Tidal Potomac River and the Chesapeake Bay when one or both of the following conditions is expected to begin within 36 hours and not directly associated with a tropical cyclone:
1) sustained winds of 64 knots
or greater
OR
2) frequent gusts (duration of two or more hours) of 64
knots or greater
Special Marine Warning
A warning of potentially hazardous weather conditions of short duration
(up to 2 hours) affecting areas included in a CWF that are not adequately
covered by existing marine warnings and producing one or more of
the following:
1) Sustained marine convective winds (showers/thunderstorms)
or associated gusts of 34 knots or greater
AND/OR
2) Hail three quarters of an inch or more in diameter
AND/OR
3) Waterspouts
Severe Thunderstorm Watch
A Severe Thunderstorm Watch is
issued when severe thunderstorms are possible in and near
the watch area. It does not mean that they will occur. It only means
they are
possible.
Severe thunderstorms are
defined as follows:
1) Winds of 58 mph or higher
AND/OR
2) Hail 1 inch in
diameter or larger.
Severe Thunderstorm Warning
A Severe Thunderstorm Warning
is issued when severe thunderstorms are occurring
or imminent in the
warning area.
Severe thunderstorms are
defined as follows:
1) Winds of 58 mph or higher
AND/OR
2) Hail 1 inch in
diameter or larger.
Tornado Watch
A Tornado Watch is issued when
severe thunderstorms and tornadoes are possible in
and near the watch area. It does not mean that they will occur. It only means
they are
possible.
Severe thunderstorms are
defined as follows:
1) Winds of 58 mph or higher
AND/OR
2) Hail 1 inch in
diameter or larger.
Tornado Warning
A Tornado Warning is issued
when a tornado is imminent. When a tornado warning
is issued, seek safe shelter immediately.
Tropical Storm Watch
A Tropical Storm Watch is issued when a tropical cyclone containing winds of 34 to 63 kt (39 to 73 mph) or higher poses a possible threat, generally within 48 hours. These winds may be accompanied by storm surge, coastal flooding, and/or river flooding.
The watch does not mean that tropical storm conditions will occur. It only means
that these conditions are possible.
Tropical Storm Warning
A Tropical Storm Warning is issued when sustained winds of 34 to 63
kt (39 to 73 mph) or higher associated with a tropical cyclone are
expected in 36 hours or less. These winds may be accompanied by storm
surge, coastal flooding, and/or river flooding.
Coastal Flood Watch
A Coastal Flood Watch is issued when moderate to major coastal flooding
is possible. Such flooding would potentially pose a serious risk to
life and property.
Coastal Flood Watches are issued for coastal areas along the Tidal
Potomac River and coastal areas along the Chesapeake Bay.
Coastal Flood Warning
A Coastal Flood Warning is issued when moderate to major coastal flooding
is occurring or imminent. This flooding will pose a serious risk
to life and property.
Coastal Flood Warnings are issued for coastal areas along the Tidal
Potomac River and areas along the Chesapeake Bay.
Coastal Flood Advisory
A Coastal Flood Advisory is issued when minor or nuisance coastal flooding is occurring or imminent.
Coastal Flood Advisories are issued for coastal areas along the Tidal
Potomac River and areas along the Chesapeake Bay.
Flash Flood Watch
A Flash Flood Watch is issued
when conditions are favorable for flash flooding. It does not mean
that flash flooding will occur, but it is possible.
Flash Flood Warning
A Flash Flood Warning is
issued when flash flooding is imminent or occurring.
Flood Watch
A Flood Watch is issued
when conditions are favorable for flooding. It does not mean
flooding will occur, but it is possible.
Flood Warning
A Flood Warning is issued when
flooding is imminent or occurring.
River Flood Watch
A River Flood Watch is
issued when river flooding is possible at one
or more forecast points along a river.
River Flood Warning
A River Flood Warning is
issued when river flooding is occurring or imminent at one or more
forecast points along a river.
Excessive Heat Watch
An Excessive Heat Watch is issued when there is a potential
for the heat index value to reach or exceed 110 degrees
within the next 24 to 48 hours.
Excessive Heat Warning
An Excessive Heat Warning
is issued when the heat index value is expected to reach or
exceed 110 degrees within the next 12 to 24 hours. An Excessive Heat
Warning may be issued for lower criteria if it is early in
the season or during a multi-day heat wave.
Heat Advisory
A Heat Advisory is issued when the
heat index value is expected to reach 105 to 109 degrees within the
next 12 to 24 hours.
A Heat Advisory may be issued for lower criteria if it is early in the season
or during a multi-day heat wave.