NWS Upton Watch, Warning and Advisory Criteria
Important Note: These criteria are for the National Weather Service Forecast Office in Upton, NY. These values do not necessarily apply to other offices around the country.
| Winter Season Watches, Warnings and Advisories |
Winter Storm Warning
Issued for a winter weather event in which there is more than one predominant hazard, (i.e., snow and ice, snow and sleet, sleet and ice or snow, ice and sleet), and one of the warning criteria listed above is expected to be met. For example, it would be issued if 6 inches of snow were expected in 12 hours, with sleet mixing in at times. A winter storm warning may be issued for heavy snow combined with strong winds of 25-34 mph that will cause blowing and drifting of the snow. A warning may still be warranted if the events exceed advisory criteria, but fall just short of warning criteria and will significantly impact mass transit and/or utilities. A Winter Storm Watch is issued when these conditions may be met 12 to 48 hours in the future.
Heavy Snow Warning
Issued when snow is expected to accumulate 6 inches or more in 12 hours, or 8 inches or more in 24 hours.
Blizzard Warning
Issued for sustained wind or frequent gusts greater than or equal to 35 mph accompanied by falling and/or blowing snow, frequently reducing visibility to less than 1/4 mile for three hours or more. A Blizzard Watch is issued when these conditions may be met 12 to 48 hours in the future.
Ice Storm Warning
Issued when freezing rain is expected to produce ice accumulations of 1/2" or greater, or cause significant disruptions to travel or utilities.
Wind Chill Warning
Issued when wind chill values will reach -25°F or colder. A Wind Chill Watch is issued when these conditions may be met 12 to 48 hours in the future.
Winter Weather Advisory
Issued for a winter weather event in which there is more than one hazard present, (i.e., snow and ice, snow and sleet, or snow, ice and sleet) meeting or exceeding above defined advisory criteria for at least snow or freezing rain, but remaining below warning criteria. For example, it would be issued if 4 inches of snow were expected with sleet or freezing rain mixing in at times.
Snow Advisory
Issued when snow accumulation meets or exceeds 3 inches in 12 hours, but not exceed 6 inches. An advisory may still be warranted if lesser accumulations will significantly impacts mass transit and/or utilities.
Blowing Snow Advisory
Issued when blowing snow is expected to occasionaly reduce visibilities to 1/4 mile or less with winds less than 35 mph. The event should last at least 3 hours.
Snow and Blowing Snow Advisory
Issued when sustained winds or frequent gusts of 25 to 34 mph are expected to be accompanied by falling snow and blowing snow, occasionally reducing the visibility to 1/4 mile or less. The event should last at least 3 hours.
Freezing Rain Advisory
Issued when a trace of ice accumulations are expected from freezing rain and/or drizzle, but not to exceed 1/2".
Wind Chill Advisory
Issued when wind chill values will reach -15°F to -24°F.
| Severe Weather Watches, Warnings and Statements |
Severe Thunderstorm Warning
Issued when there is evidence based on radar or a reliable spotter report that a thunderstorm is producing, or about to produce, wind gusts of 58 mph or greater, structural wind damage, and/or hail 3/4 inch in diameter or greater.
Severe Thunderstorm Watch
Is issued by the Storm Prediction Center when conditions are favorable for the development of severe thunderstorms over a larger-scale region. Tornadoes are not expected in such situations, but isolated tornado development cannot be ruled out.
Tornado Warning
Issued when there is evidence based on radar or a reliable spotter report that a tornado is imminent or occurring.
Tornado Watch
Is issued by the Storm Prediction Center when conditions are favorable for the development of severe thunderstorms and tornadoes over a larger-scale region.
Special Weather Statement for Near Severe Thunderstorms
Issued for strong thunderstorms that are below severe levels, but still may have some adverse impacts. Usually issued for the threat of wind gusts of 40-58 mph or hail up to 3/4 inch in diameter.
| Flooding Watches, Warnings and Advisories |
Flash Flood Warning
Issued when flash flooding is imminent, generally within the next 6 hours. Usually issued based on observed heavy rainfall (measured or radar estimated) for dangerous small stream or urban flooding, but may also be issued for significant dam or levee failures that have occurred or are imminent.
Flash Flood Watch
Issued generally when there is the possibility of flash flooding or urban flooding over an area within the next 6 to 48 hours.
Flood Warning for River Forecast Point
Issued when a river gauge has exceeded, or is forecast to exceed, a predetermined flood stage.
Flood Watch
Issued when there is the possibility of widespread general flooding over an area within the next 36 hours.
Flood Advisory
Issued when flooding is imminent or occurring, generally within the next 6 hours, but is not expected to substantially threaten life and property.
Coastal Flood Warning
Issued when moderate or worse tidal flooding or storm induced flooding is occurring, imminent or highly likely along coastal areas within approximately the next 12 hours.
Coastal Flood Watch
Issued when conditions are favorable for moderate or worse tidal flooding or storm induced flooding along coastal areas within approximately 12 to 36 hours.
Coastal Flood Advisory
Issued when minor to locally moderate tidal flooding or storm induced flooding is expected along coastal areas.
| Non-Precipitation Watches, Warnings and Statements |
High Wind Warning
Issued when sustained winds of 40 mph or more are expected for 1 hour or longer, or for wind gusts of 58 mph or more for any duration. A High Wind Watch is issued when these conditions may be met 12 to 48 hours in the future.
Wind Advisory
Issued when sustained winds of 30 to 39 mph are expected for 1 hour or longer, or wind gusts of 46-57 mph for any duration.
Excessive Heat Warning
Issued when heat index values are expected to reach or exceed 105°F for 2 consecutive hours. An Excessive Heat Watch is issued when these conditions may be met 12 to 48 hours in the future.
Heat Advisory
Issued when maximum daytime heat index values are expected to reach 100 to 104°F for two consecutive hours. NOTE: There is one exception to this policy. For New York City only, a Heat Advisory is issued when the heat index is forecast to reach 95 degrees for two consecutive days or 100 degrees for any length of time..
Freeze Warning
Issued when nighttime minimum temperatures are expected to reach 32°F or lower in the growing season. They are usually issued to highlight the first few freezes of the fall, or unusually late freezes in the spring. A Freeze Watch is issued when these conditions may be met 12 to 48 hours in the future.
Frost Advisory
Issued when nighttime minimum temperatures are expected to range from 33°F to 36°F in the growing season.
Air Stagnation Advisory
Issued only at the request of the Environmental Protection Agency (EPA), whenever atmospheric conditions are stable enough to cause air pollutants to accumulate in a given area.
Dense Fog Advisory
Issued when fog is expected to reduce visibilities to 1/4 mile or less.
| Fire Weather Watches and Warnings |
Red Flag Warning
Issued to indicate the imminent danger of severe fire weather with a relatively high probability of occurrence. Usually the fire danger is in the very high to extreme category. A Red Flag Warning will normally be issued for potential severe fire weather events in less than 24 hours. A Red Flag Warning may or may not be preceded by a Fire Weather Watch.
Fire Weather Watch
Issued to advise of the possible development of a red flag event in the near future. Usually fire danger is in the very high to extreme category. A Fire Weather Watch will normally be issued 12 to 72 hours in advance of the expected onset of severe fire weather conditions.
| Tropical Weather Watches, Warnings and Advisories |
Hurricane Warning
Issued by the National Hurricane Center when hurricane conditions (winds of greater than or equal to 62 kts or greater than or equal to 74 mph) are expected in coastal areas within 24 hours or less.
Hurricane Watch
Issued by the National Hurricane Center when hurricane conditions are possible in coastal areas within 36 hours.
Tropical Storm Warning
Issued by the National Hurricane Center when tropical storm conditions (winds of 34 to 63 kts or 39 to 73 mph) are expected in coastal areas within 24 hours or less.
Tropical Storm Watch
Issued by the National Hurricane Center when tropical storm conditions are possible in coastal areas within 36 hours.
Inland Hurricane Wind Warning
Issued when a tropical cyclone is expected to spread hurricane force winds inland within 24 hours or less. An Inland Hurricane Wind Watch is issued when these conditions may be met 12 to 24 hours in the future.
Inland Tropical Storm Wind Warning
Issued when a tropical cyclone is expected to spread tropical storm force winds inland within 24 hours or less. An Inland Tropical Storm Wind Watch is issued when these conditions may be met 12 to 24 hours in the future.
| Marine Weather Warnings and Advisories |
Hurricane Force Wind Warning
Issued for sustained winds or
frequent gusts of 64 knots or greater within 36 hours, not associated with a tropical system.
Storm Warning
Issued for sustained winds or
frequent gusts of 48 to 63 knots within 36 hours, not associated with a tropical system.
Gale Warning
Issued for sustained winds or
frequent gusts of 34 to 47 knots within 36 hours, not associated with a tropical system.
Small Craft Advisory
Issued for sustained winds or
frequent gusts of 25 to 33 knots and/or seas 5 feet or higher within 48 hours.
Special Marine Warning
Issued to convey information regarding hazardous convective activity or other short-term weather events occurring over the water or which may impact those on the water that are not covered by the current forecast.
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