Henderson, NV...St. George, UT...Flagstaff, AZ...Bullhead City, AZ...Kingman, AZ...
ZCZC SPCFWDDY1 ALL
FNUS21 KWNS 231524
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1024 AM CDT Sat Jun 23 2018
Valid 231700Z - 241200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN GREAT
BASIN INTO NORTHERN ARIZONA...
Critical fire weather conditions are expected to develop across
portions of the southern Great Basin and into northern Arizona this
afternoon/evening. Locally critical fire weather conditions
(sustained surface winds of 10-20 mph; RH values of 5-20%) should
develop across portions of eastern Utah and into western/southern
Colorado this afternoon into the evening along/ahead of an
approaching mid-level jet. The elevated area was expanded farther
into Colorado to reflect this.
Very hot/dry/unstable conditions (surface temperatures 100+ F and
single digit RH) are expected to develop in the Sacramento Valley,
which should locally enhance the thermal trough and surface winds.
Farther south in the Central Transverse Ranges and vicinity, winds
will increase as the pressure gradient enhances between onshore flow
and hot/dry interior valleys. This will lead to locally critical
fire weather conditions (sustained surface winds 10-20 mph; RH
values of 5-20%) including wind gusts around 40 mph.
.PREV DISCUSSION... /ISSUED 0147 AM CDT Sat Jun 23 2018/
An upper-level trough will dig into the southern/eastern Great Basin
today. Enhanced mid-level flow will exist across parts of western
Nevada, Utah, and northern Arizona. At the surface, a trough will be
draped from western Colorado into southern California.
...Great Basin and southwest CONUS...
Critical fire weather conditions are expected for parts of the
southern Great Basin and northern Arizona. Strong surface heating
will help to mix down enhanced mid-level flow from a passing
upper-level trough. A weak surface trough in the region will also
aid in increasing surface winds. Across this area surface winds of
25 mph will be common amidst 5-15% RH. Minor changes have been made
to the critical area from the previous forecast to account for small
shifts in where strong surface flow will exist. Some areas of
eastern Utah may experience locally critical fire weather
conditions, but winds will only intermittently reach 25 mph.
Surrounding the critical area, a broad area of elevated fire weather
conditions will exist. RH values of 5-15% will be common across
these areas, but surface winds will not likely reach critical levels
as these areas will be displaced from the strongest mid-level flow.
...Portion of the Sacramento Valley...Central Traverse Ranges and
Strong mid-level flow along the backside of the upper-level trough
will lead to elevated to locally critical fire weather conditions in
the parts of the Sacramento Valley. RH will drop to 5-15% with
downsloping flow, but surface winds will generally be to light at
15-20 mph to warrant critical designation.
Farther south, the approaching upper-level trough will lead to a
deepening surface trough over southern California and southwest
Nevada. This enhanced pressure gradient will lead to elevated to
locally critical fire weather conditions in the Central Traverse
Ranges and adjacent northern/eastern valleys. RH of 5-10% will be
present with surface winds reaching 20-25 mph. Recent guidance
suggests that locally critical areas within this region are likely;
however, winds of 20+ mph will not generally persist for long enough
periods to warrant an added critical region.
...Please see www.spc.noaa.gov/fire for graphic product...
CLICK FOR DAY 1 FIREWX AREAL OUTLINE PRODUCT (KWNSPFWFD1)