Warm temperatures from today through the weekend will bring severe thunderstorms, heavy rain and critical fire conditions, according to the National Weather Service (NWS).
According to its short-range forecast, temperatures across a large section of the South will be 15 to 25 F above average, with fire weather threats at critical levels in the southern and central High Plains and the southern Rockies over the weekend. For the southern to central Plains up through to the Ohio Valley, heavy rainfall and strong to severe thunderstorms are forecast.
From today, a “rapidly intensifying” low-pressure system is forecast, bringing unsettled weather from across the central portion of the country to the Great Lakes and the Northeast, says NWS. The weather service forecasts that a deep upper-level trough will spread mountain snow showers and lower-elevation rain across the southwestern U.S. this morning, and will move eastward.
According to NWS, the low-pressure system will intensify over the central High Plains, leading to a higher chance of snow in the central Rockies later today, with rain and thunderstorms expanding eastward through the central Plains and the Ohio Valley. This is expected to lead to flooding tonight in the Ohio Valley.
Even though there is a chance of snow, the fire weather threat remains at critical levels through tomorrow across the southern to central High Plains and the southern Rockies. According to NWS, locally strong winds, very warm temperatures and low relative humidity are expected across these areas in the wake of the storm. Many of these areas can expect high temperatures in the range of 80 to 90 F ahead of the approaching cold front.
As the storm intensifies and heads toward the upper Midwest, wind-driven cold rain is forecast to spread across the central Plains tomorrow. NWS says that some of this rain could change over to wet snow by the night across the region. The southern Plains will also see showers and thunderstorms, which will move into the Mississippi Valley by Sunday.
The Pacific Northwest will also experience heavy rain, according to NWS. A new upper-level trough will move into the region by the weekend, with locally heavy rain for the coastal ranges and snowfall for the Cascades. Portions of the Washington and Oregon Cascades might see as much as 1 to 2 feet of new snowfall going through tomorrow.
The different types of fire warnings
There are three types of fire alerts issued by the NWS:
- Red Flag Warning—Be ready to take action and be extremely careful with open flames
- Fire Weather Watch—Be prepared as a “Watch” alerts land managers and the public that upcoming weather conditions could result in extensive wildland fire occurrence or extreme fire behavior
- Extreme Fire Behavior—This alert means that wildfire is likely to rage out of control, behaving erractic and dangerously. One or more of the following criteria must be met:
- Moving fast or a high rate of spread
- Prolific crowning or spotting
- Presence of fire whirls
- Strong convection column
For more information on how to stay safe during severe weather, visit the NWS website.