647
FNUS21 KWNS 131635
FWDDY1

Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1134 AM CDT Thu Jun 13 2024

Valid 131700Z - 141200Z

The main change to the updated Day 1 Fire Weather Outlook was to add
isolated dry thunderstorm highlights to portions of central and
northern AZ. Fuels across this region are becoming critically
receptive to wildfire spread, with ERCs exceeding the 90th
percentile over several locations. Thunderstorms are expected to be
brief and sparse through much of the afternoon, with a slight
increase in coverage possible tonight. While thunderstorm coverage
may not reach 10 percent over any short interval of time, the
longer-term summation of strikes (wet or dry) over fuels primed for
ignitions suggests that isolated dry thunderstorm highlights are
warranted. Otherwise, the previous forecast remains on track, with
occasionally Elevated dry and breezy conditions still expected over
portions of the Lower Colorado River Basin.

..Squitieri.. 06/13/2024

.PREV DISCUSSION... /ISSUED 0159 AM CDT Thu Jun 13 2024/

...Synopsis...
A midlevel trough will advance eastward across southern CA, while a
related belt of moderate/strong southerly flow aloft overspreads
western AZ into southern NV and UT. This will promote a tightening
surface pressure gradient and 15-20 mph sustained southerly surface
winds across these areas. These winds, coupled with a deep/dry
boundary layer (single-digit RH) and receptive fuels, will favor
elevated to locally critical fire-weather conditions.

Additionally, isolated thunderstorms are possible during the late
afternoon into the overnight hours across portions of AZ into UT --
aided by ascent preceding the aforementioned midlevel trough. If
afternoon thunderstorms can develop, these storms would be
high-based in an environment characterized by a deep inverted-V
thermodynamic profile -- and isolated lightning-induced ignitions
would be possible. However, confidence in afternoon storm
development is low owing to very marginal instability, precluding
Dry Thunderstorm highlights at this time. Confidence in thunderstorm
development is higher during the overnight period, when a mix of
wet/dry storms are expected. However, increasing boundary-layer RH
and midlevel moisture may temper the overall threat of ignitions.

...Please see www.spc.noaa.gov/fire for graphic product...

$$