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FNUS28 KWNS 251939

Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0238 PM CDT Wed Apr 25 2018

Valid 271200Z - 031200Z

An upper ridge over the western U.S. at the beginning of the period
will shift east into the Plains by Day 5/Sun. In the wake of the
upper ridge, an upper trough will move onshore the Pacific coast and
deepen as it slowly tracks across the western states. The western
trough will persist through the weekend, eventually ejecting east
across the Rockies into the Plains near the end of the period. Some
increasing fire weather potential is possible across portions of the
southwestern states into the southern High Plains through at least
Day 6/Mon.

...Day 3-4/Fri-Sat -- Southwestern States...

Warm, dry and windy conditions will overspread portions of southern
NV, UT and northern AZ Day 3-4/Fri-Sat ahead of the deepening upper
low/trough. Critical meteorological conditions will be possible
across parts of NV, UT and AZ, however, fuel conditions remain
questionable and preclude any probabilities at this time.

Some modest midlevel moisture will stream north across parts of the
southwestern U.S. PW values around 0.50 inches with steep lapse
rates and forecast MUCAPE around 100-200 J/kg should be adequate for
isolated dry thunderstorms near the Mogollon Rim and into parts of
southeast AZ. A deeply mixed boundary layer with inverted-v type
thermodynamic profiles also support some gusty and erratic winds
near any storms that develop. By Saturday, some thunderstorm
potential will shift east into eastern AZ and parts of NM, through
confidence is lower in both coverage and in whether storms would
remain dry.

...Days 5-7/Sun-Tue -- Southern Rockies and Southern High Plains

By Day 5/Sun, the western trough will be strengthening with height
falls across AZ/NM late in the period. Gusty winds and low RH
conditions are possible across parts of southern AZ, however, the
surface pressure gradient will remain weak and temperatures will be
cooler further north. Additionally, rainfall is expected across
parts of AZ into NM on Saturday and will limit fire weather concerns
across the region.

On Day 6/Mon, critical fire weather potential will increase across
parts of the southern Rockies and adjacent southern/central High
Plains. Where fuels are dry, large fires could spread rapidly. A lee
low will deepen across eastern CO with a tightening surface pressure
gradient oriented across the southern High Plains. A dryline will
extend southward from the low in the TX Panhandle /South Plains
vicinity. Behind the dryline, expect very low RH and strong winds.

Some elevated fire weather potential could persist into Day 7/Tue
across parts of western TX and eastern NM but confidence is too low
at this time to include probs due to potential rainfall Monday night
as the dryline retreats westward.

..Leitman/Nauslar.. 04/25/2018

...Please see for graphic product...

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