Storm Impacting the Northwest U.S.; Fire Weather Conditions in Southern California; Severe Weather in the South

A Pacific storm is bringing areas of low elevation rain, moderate to heavy mountain snow, and high winds to the Northwest. Strong Santa Ana winds and very dry conditions are producing elevated to critical fire weather conditions in southern California. Isolated strong to severe thunderstorms are possible through early Wednesday morning across parts of northeast Texas into western Tennessee. Read More >

Cold Weather Decision Support

Instructions: Select desired Time and Region, then choose a Forecast or Duration button to view image

The images below are the official NWS minimum temperatures, wind chill forecasts, and durations of these values at or below different thresholds in degrees Fahrenheit for the next 7 days. This data is determined by NWS forecasters to be the most likely outcome based on evaluation of data from computer models, satellite, radar, and other observations.

Time

Region

Forecast

Duration: Temperature

Duration: Wind Chill

These graphics are updated at least twice per day, around 4:15 AM/4:15 PM.
Temperature and Wind Chill Graphic

Cold Weather Related Warning/Watch/Advisory Criteria

The NWS Hazard Simplification (Haz Simp) project has led to changes to our cold weather related product suite beginning this season. These changes are designed to simplify the communication of information, improve understanding, and enhance the utility of forecasts and warnings. Detailed information about these changes can be found in the Service Change Notice and the Haz Simp Cold One-Pager.

Cold Temperature related Warning and Watch statements will be issued by the National Weather Service in Tampa Bay when the following criteria is forecast:

Freeze Warning - issued within 12 hours, or up to 24 hours out if confidence is high, when temperatures are expected to drop to 32° Fahrenheit or lower for 2 or more hours.
Freeze Watch - issued during the first 48 hours when temperatures could drop to 32° Fahrenheit or lower for 2 or more hours.

NOTE: Although specific Hard Freeze Warning/Watch products are no longer issued, a mention of Hard Freeze will be indicated in the WHAT bullet of the Freeze Warning/Watch statement for the likelihood/potential of temperatures 27° Fahrenheit or lower for 2 or more hours.

Wind Chill related Warning, Watch, and Advisory statements will be issued when wind speeds are forecast to be 10 mph or greater and the following criteria is forecast:

Extreme Cold Warning - issued within 12 hours, or up to 24 hours out if confidence is high, when Wind Chill values are expected to drop to 10° Fahrenheit or lower across the Nature Coast (Levy, Citrus, Sumter, and Hernando Counties) or 20° Fahrenheit or lower across the rest of West Central and Southwest Florida, for 3 or more hours.
Extreme Cold Watch - issued during the first 48 hours when Wind Chill values could drop to 10° Fahrenheit or lower across the Nature Coast (Levy, Citrus, Sumter, and Hernando Counties) or 20° Fahrenheit or lower across the rest of West Central and Southwest Florida, for 3 or more hours.
Cold Weather Advisory - issued within 12 hours, or up to 24 hours out if confidence is high, when Wind Chill values are expected to drop to 25° Fahrenheit or lower across the Nature Coast (Levy, Citrus, Sumter, and Hernando Counties) or 35° Fahrenheit or lower across the rest of West Central and Southwest Florida.

Frost related Advisory statements will be issued when the following criteria is forecast:

Frost Advisory - issued within 12 hours, or up to 24 hours out if confidence is high, when temperatures are expected to drop to between 33° and 36° Fahrenheit with good radiational cooling conditions (e.g., light winds and clear skies) which will allow frost to form on the ground.

However, frost can occur on cars and rooftops when observed 2 meter (or about 6 feet) above ground temperatures are as high as 38° Fahrenheit. This is because materials like metal and glass radiate heat very efficently and therefore readily cool to the frost point. In addition, cars and rooftops are often better exposed (from multiple planes) and thus radiate heat more quickly than other objects. It should be noted that other meteorological factors such as wind speed and moisture also come into play when assessing the potential for frost. Subtle changes in these values can also be factors why one area sees frost and another nearby location does not. For instance, even a light wind speed of 3-5 mph can keep the atmosphere "mixed", thus preventing widespread frost formation.

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Storm Impacting the Northwest U.S.; Fire Weather Conditions in Southern California; Severe Weather in the South

Cold Weather DSS