502
FNUS21 KWNS 181700
FWDDY1

Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1159 AM CDT Thu Jul 18 2024

Valid 181700Z - 191200Z

Isolated dry thunderstorm chances were adjusted in line with recent
observations and trends. The most notable change was to remove
isolated dry thunder from Utah. Morning sounding observations from
SLC indicated 0.91" of precipitable water. Surface objective
analysis and satellite observations further supports this, with
around 0.80-0.90" of precipitable water extending across
southwestern Utah into northern Utah. Some of the region across
central Nevada was also trimmed to account for increasing moisture
across southern Nevada, as well as recent trends in ERCs dropping to
around the 60th percentile with recent rainfall/increased humidity.
Though high-based storms with gusty outflow are likely, afternoon
coverage in these areas will also be increasing today, with
relatively slow storm motions which should aid in reducing the dry
lightning risk.

..Thornton.. 07/18/2024

.PREV DISCUSSION... /ISSUED 1256 AM CDT Thu Jul 18 2024/

...Synopsis...
Isolated dry thunderstorms are expected over most of the Great Basin
and portions of the Upper Colorado River Basin Thursday afternoon
and evening. A shallow plume of mid to upper-level moisture will
remain in place Thursday within a broad ridge extending over most of
the western CONUS. Orographic ascent juxtaposed with this moisture,
combined with relatively low PWAT values and a very well-mixed
boundary layer up to or exceeding 3 km, will support isolated dry
lightning. Some locations within the Isolated Dry Thunderstorm area
across UT may receive wetting rains, but these areas were too
confined to exclude them given fairly widespread ERC percentiles
above 85. In addition to dry thunderstorms, westerly downslope gusty
winds and low relative humidity may support very localized elevated
fire weather conditions in the southern lee of the Cascades.

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

$$