Fire Weather Outlook Discussion
Issued by NWS
Issued by NWS
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... $$