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| Watch / Warning / Advisory |
Criteria for Issuance |
WMO / AWIPS Headers |
| Tornado
Watch |
Issued when observed and/or expected atmospheric
conditions support the formation of tornadic storms within the next 6
hours. Coordinated issuance between the Storm Prediction Center and NWS
Mobile. |
WWUS20 KWNS / SEL(1-5) |
| Tornado
Warning |
Issued when observational data (NEXRAD doppler
weather radar or credible field storm spotters) indicate a tornado is
forming or has developed over a county (or portion of a county). Issued
for short, near term periods (0.5 to 1.5 hours). |
WFUS54 KMOB / BHMTORMOB |
| Severe
Thunderstorm Watch |
Issued when observed and/or expected atmospheric
conditions support the formation of severe thunderstorms within the next
6 hours. Coordinated issuance between the Storm Prediction Center
and NWS Mobile. The National Weather Service considers a thunderstorm
to be severe if it produces hail at least 3/4-inch in diameter, winds
of 58 mph or greater, or a tornado. |
WWUS20 KWNS / SEL(1-5) |
| Severe
Thunderstorm Warning |
Issued when observational data (NEXRAD doppler
weather radar or credible field storm reports) indicate the formation
of severe storms over a county (or portion of a county). Issued
for short, near term periods (0.5 to 1.5 hours). The National Weather
Service considers a thunderstorm to be severe if it produces hail at least
3/4-inch in diameter, winds of 58 mph or greater, or a tornado. |
WUUS54 KMOB / BHMSVRMOB |
| Flood
Watch |
Issued when a potential of significant flooding
(or life threatening flash flooding) exists within the next 12 to 24 hours.
|
WGUS64 KMOB / BHMFFAMOB |
| Flash
Flood Warning |
Issued when observational data (NEXRAD doppler
weather radar or credible field storm reports) indicate very heavy rain
sufficient to produce rapid flash flooding, or flash flooding is already
occurring or is apparently imminent (as with a dam break). Issued
for short, near term periods (1 to 4 hours generally). |
WGUS54 KMOB / BHMFFWMOB |
| Urban
/ Small Stream Flood Advisory |
Issued when observational data (NEXRAD doppler
weather radar or credible field storm reports) indicate rainfall sufficient
to cause nuisance flooding of poorly drained urban or small streams. Issued
for short, near term periods (1 to 4 hours generally). |
WGUS84 KMOB / BHMFLSMOB (issued under the Flood Statement header) |
| Coastal Flood Watch |
Issued when strong winds blowing onshore results
in above normal tides and an increased risk of coastal flooding within
the next 12 to 24 hours. Coastal flooding occurs when tidal waters
along the coast inundate the shoreline...damaging piers, homes, berms,
and coastal roadways. |
WHUS44 KMOB / BHMCFWMOB |
| Coastal Flood Warning |
Issued when coastal flooding becomes imminent
or is expected within the next 12 hours. Coastal flooding occurs
when tidal waters along the coast inundate the shoreline...damaging boats,
piers, homes, berms, and coastal roadways. |
WHUS44 KMOB / BHMCFWMOB |
| Tropical
Storm Watch |
Issued by the NWS/National Hurricane Center
when tropical storm force winds (39 to 73 mph) are possible over the coastal
areas within the next 36 hours. Coordinated issuance between NHC
and NWS Mobile. |
WTNT(1-5) KNHC / TCPAT(1-5) |
| Tropical
Storm Warning |
Issued by the NWS/National Hurricane Center
when tropical storm force winds (39 to 73 mph) are possible over the coastal
areas within the next 24 hours. Coordinated issuance between NHC
and NWS Mobile. |
WTNT(1-5) KNHC / TCPAT(1-5) |
| Hurricane
Watch |
Issued by the NWS/National Hurricane Center
when hurricane force winds (74 mph and above) are possible over the coastal
areas within the next 36 hours. Coordinated issuance between NHC
and NWS Mobile. |
WTNT(1-5) KNHC / TCPAT(1-5) |
| Hurricane
Warning |
Issued by the NWS/National Hurricane Center
when hurricane force winds (74 mph and above) are expected over the coastal
areas within the next 24 hours. Coordinated issuance between NHC
and NWS Mobile. |
WTNT(1-5) KNHC / TCPAT(1-5) |
| Inland Tropical Storm Watch |
Issued when sustained winds of 40 to 73 mph (associated with landfalling tropical systems) are possible over inland areas within the next 24 to 36 hours. | WWUS74 KMOB / BHMNPWMOB |
| Inland Tropical Storm Warning | Issued when sustained winds of 40 to 73 mph (associated with landfalling tropical systems) are possible over inland areas within the next 12 to 24 hours. | WWUS74 KMOB / BHMNPWMOB |
| Inland Hurricane Watch | Issued when sustained winds of 74 mph or greater (associated with landfalling tropical systems) are possible over inland areas within the next 24 to 36 hours. | WWUS74 KMOB / BHMNPWMOB |
| Inland Hurricane Warning | Issued when sustained winds of 74 mph or greater (associated with landfalling tropical systems) are possible over inland areas within the next 12 to 24 hours. | WWUS74 KMOB / BHMNPWMOB |
| Special
Marine Warning |
Convective (thunderstorm based) winds over
the coastal waters of 34 knots or greater within the next 1 to 3 hours. |
WHUS54 KMOB / BHMSMWMOB |
| Small
Craft Advisory (marine) |
Synoptic (large scale) prevailing winds over
the coastal waters of 20 to 33 knots, expected or occurring within the
next 12 to 24 hours. |
FZUS54 KMOB / BHMCWFMOB (issued as a headline in the Coastal Waters Forecast product) |
| Gale Warning
(marine) |
Synoptic (large scale) prevailing one minute
winds over the coastal waters of 34 to 47 knots, or frequent gusts in
excess of 34 knots, expected or occurring within the next 12 to 24 hours. |
FZUS54 KMOB / BHMCWFMOB (issued as a headline in the Coastal Waters Forecast product) |
| Storm
Warning (marine) |
Synoptic (large scale) prevailing winds over
the coastal waters of 48 knots or greater expected or occurring within
the next 12 to 24 hours. |
FZUS54 KMOB / BHMCWFMOB (issued as a headline in the Coastal Waters Forecast product) |
| High Surf Advisory |
Issued anytime heavy wave action in the surf breaker zone provides for significantly rough conditions at the beaches. These high surf conditions pose a greater risk for the loss of life to recreational swimmers (due to significantly increased deadly rip current potential), as well as an increased potential for significant damaging beach erosion. Issued when the conditions are expected (or observed to be occurring) within the next 12 to 24 hours . | WHUS44 KMOB / BHMCFWMOB |
| Wind Advisory |
Issued when sustained wind over land areas
(lasting one hour or frequent gusts) of 25 to 39 mph are expected within
the next 12 to 24 hours. These winds are not associated with thunderstorms. |
WWUS74 KMOB / BHMNPWMOB |
| High Wind Watch/Warning | Issued when sustained wind over land
areas (lasting one hour or frequent gusts) are expected to be 40 mph or
greater within the next 12 to 24 hours. These winds are not associated
with thunderstorm or tropical systems. |
WWUS74 KMOB / BHMNPWMOB |
| Winter
Storm Watch |
Issued for a potential of significant wintry
precipitation (with amounts of a 1/4 inch or more of ice, or 2 inches
or more of snow, or a 1/4 inch or more of sleet over the forecast area)...generally
within 24 to 36 hours of the expected event. |
WWUS44 KMOB / BHMWSWMOB |
| Winter
Storm Warning |
Issued for a greater potential of a significant
mixed wintry precipitation event (1/4 inch or more of ice, 2 inches of
snow, or a 1/4 inch or more of sleet over the forecast area)...generally
within 24 hours. |
WWUS44 KMOB / BHMWSWMOB |
| Heavy
Snow Warning |
Issued when 2 inches or more of snow are expected
to fall within the next 12 to 24 hours. |
WWUS44 KMOB / BHMWSWMOB |
| Ice Storm
Warning |
Issued when 1/4 inch or more of ice accrual
on exposed surfaces is expected within the next 12 to 24 hours. |
WWUS44 KMOB / BHMWSWMOB |
| Winter
Weather Advisory |
Issued when a mixture of light freezing drizzle(<1/4
inch accrual), freezing rain (<1/4 inch accrual), sleet(<1/2 inch
accumulation), or snow (1/2 to less than a 2 inch accumulation) is expected
within the next 12 to 24 hours. |
WWUS44 KMOB / BHMWSWMOB |
| Snow Advisory |
Issued when a light accumulation (1/2 inch
to less than 2 inches) of snow is expected within the next 12 to 24 hours. |
WWUS44 KMOB / BHMWSWMOB |
| Freeze Watch/Warning |
Issued when light freezing temperatures are
expected to pose a threat to new growth at the start and end of the growing seasons (spring and fall)...or after an extended
period of unusually warm weather. Issued mainly for agricultural
and gardening interests. Watch for 24-48 hours in advance of event...Warning
12-24 hours in advance. |
WWUS74 KMOB / BHMNPWMOB |
| Hard Freeze Watch/Warning |
Issued when deep freezing temperatures (less than 26
degrees for at least 5 hours) are expected within the next 12
to 24 hours. This type of freeze is characterized as a "hard freeze"...posing
a threat to exposed water pipes, farm equipment, automobile radiators,
livestock, etc. Watch for 24-48 hours in advance of the event...Warning 12-24 hours in advance. |
WWUS74 KMOB / BHMNPWMOB |
| Frost Advisory |
Issued when a frost is expected at the start
and end of the growing seasons within the next 12 to 24 hours. Frost
can occur at temperatures of 33 to 36 degrees in light wind and clear
sky conditions. Mostly issued to alert the potential of frost burn
on sensative outdoor plants. |
WWUS74 KMOB / BHMNPWMOB |
| Wind Chill Advisory |
Issued when the wind chill is expected to fall
to zero degrees Fahrenheit (or below) for 3 hours or more (within the
next 12 to 24 hours). Alerts the public to an increased risk of
frost bite and rapid damage to exposed skin surfaces. |
WWUS44 KMOB / BHMWSWMOB |
| Excessive Heat Watch | Issued for potenial of an excessive heat
event occurring within the next 24 to 48 hours. Excessive heat events
are those when the heat index rises to at least 110 F...and the minimum
air temperature has not gone (or is forecast to not go) below 80 degrees
for at least a 48 hour period. If the heat event appears to be more
likely to verify at the Advisory criteria (see below)...then a Watch is
not generally issued. |
WWUS74 KMOB / BHMNPWMOB |
| Excessive Heat Warning | Issued for excessive heat events occurring within the next 12-24 hours where the heat index rises to at least 110 F...and the minimum air temperature has not gone (or is forecast to not go) below 80 degrees for at least a 48 hour period. | WWUS74 KMOB / BHMNPWMOB |
| Heat Advisory |
Issued for excessive heat events occurring
within the next 12-24 hours when the heat index rises to at least 108
F...and the minimum air temperature has not gone (or is forecast to not
go) below 78 degrees for at least a 48 hour period. |
WWUS74 KMOB / BHMNPWMOB |
| Dense Fog Advisory |
Issued when dense fog (with visibility less
than a quarter mile) covers a significant area. Issued for a period
within the next 6 to 18 hours generally. Widespread dense fog can
pose a significant travel problem (delays, hazards) to motorists as well
as those navigating on inland waterways (rivers, bayous, etc). |
WWUS74 KMOB / BHMNPWMOB |
10/24/05 - Jeff Garmon, NWS Mobile
National Weather Service
Mobile/Pensacola Weather Forecast Office
(251) 633-6443
sr-mob.webmaster@noaa.gov
Page last modified: June 3, 2005Disclaimer Privacy Policy