ZCZC SPCFWDDY1 ALL
FNUS21 KWNS 261653
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1153 AM CDT Mon Jun 26 2017
Valid 261700Z - 271200Z
...CRITICAL FIRE WEATHER AREA FOR SCATTERED DRY THUNDERSTORMS ACROSS
PORTIONS OF EASTERN OR AND SOUTHWEST ID...
...CRITICAL FIRE WEATHER AREA FOR STRONG WINDS/LOW RH ACROSS
PORTIONS OF THE SOUTHERN CA MOUNTAINS AND ADJACENT FOOTHILLS...
...CRITICAL FIRE WEATHER AREA FOR STRONG WINDS/LOW RH ACROSS
PORTIONS OF NORTHWEST NV...
...CRITICAL FIRE WEATHER AREA FOR STRONG WINDS/LOW RH ACROSS
PORTIONS OF SOUTHERN/EASTERN NV...WESTERN UT...NORTHWEST AZ...
The primary changes to the forecast involve categorical upgrades
across parts of southern/eastern CA.
A Critical area for strong winds/low RH has been added across
portions of the southern CA mountains and adjacent foothills --
especially those foothills toward the general direction of the
desert (eastward). The VAD wind profiles at Sulphur Mountain (VTX)
and Santa Ana Mountains (SOX) are indicating relatively enhanced
(20-40 mph) westerly winds around 3.5-6.5 kft above ground. This is
highlighting the strong flow aloft that will be manifested at the
surface by vertical mixing across the added Critical area. Across
this area, westerly surface winds of 20-30 mph with higher gusts are
expected to combine with RH of 3-10 percent as hot surface
temperatures materialize and fuels remain dry. Poor RH recovery and
continued strong winds are expected to support critical conditions
into tonight.
Elevated areas over portions of the Great Basin / AZ and southern CA
have been connected -- adding areas along and east of the crest of
the southern Sierra mountains to Elevated designation. This is where
enhanced downslope winds are expected to combine with reduced RH.
Also, the southern CA Elevated area has been expanded westward
toward the coast, especially in Santa Barbara, Ventura, and Los
Angeles Counties. Diurnally enhanced vertical mixing into the dry
air aloft (e.g., PW around one-half inch per Vandenberg Air Force
Base 12Z sounding) will support minimum RH around 8-15 percent
inland and removed from the marine layer, amid modestly enhanced
winds.
The remainder of the forecast is unchanged.
..Cohen.. 06/26/2017
.PREV DISCUSSION... /ISSUED 0245 AM CDT Mon Jun 26 2017/
...Synopsis...
Shortwave trough currently off the northern CA coast will continue
progressing east-northeastward, reaching central OR by the early
afternoon and southern ID by the evening. Continued eastward
progress of this shortwave trough will take it through much of the
northern Rockies by 12Z Tuesday. Overall progression of this system
will result in the breakdown of the upper ridge which has remained
in place across much of the Intermountain West for the past week.
Additionally, the passage of the this shortwave trough will result
in both wind-driven and lightning-caused fire weather threats today
from the Pacific Northwest south into AZ today. Farther east, upper
troughing covering much of the central/eastern CONUS at the
beginning of the period will shift eastward as several shortwave
troughs track quickly through its base.
...Great Basin...AZ...
Strengthening mid-level flow coupled with deep boundary-layer mixing
and a tightening surface pressure gradient will support gusty winds
from southern OR across much of the Great Basin and into central AZ.
The strongest winds (i.e. sustained 20-25 mph) are anticipated
across northeast NV, where the mid-level flow is the strongest, and
across southern/eastern NV and adjacent southwest UT and northwest
AZ where the surface pressure gradient is the tightest.
Above-average temperatures are anticipated areawide with minimum RH
values ranging from the mid-teen to upper single-digits. As a
result, critical fire weather conditions are expected in those areas
where the winds are strongest.
...Pacific Northwest...Northern Rockies...
Mid-level moisture associated with the approaching shortwave trough
will advect into the Pacific Northwest/northern Rockies atop a very
dry antecedent airmass. Forecast soundings across much of the region
reveal deeply mixed inverted-v profiles by the early afternoon.
During the afternoon, PW values will likely range from around 1"
across central OR to closer to 0.60" across south-central ID. This
gradient in moisture combined with a deeply mixed boundary layer and
at least moderately fast storm motions (around 30 kt) will result in
an environment supportive of dry thunderstorm. The highest coverage
of dry storms is expected across east-central OR and southwest ID. A
more hybrid storm mode is anticipated across the remainder of Oregon
and into WA. Less storm coverage is anticipated across the remainder
of ID, with most of this storms expected to be on the drier side.
...Mountains and Western/desert Foothills of Southern CA...
Strong onshore flow is expected across much of the interior portions
of southern CA today. Best overlap of the windy and dry conditions
with receptive fuels will be across the higher elevations and
western/desert foothills during the afternoon and evening. Elevated
to locally critical fire weather conditions are anticipated across
these areas.
..Central/Eastern MT...
A strong surface pressure gradient will exist over the region
between the lower pressures to west (associated with the
aforementioned shortwave trough) and remnant high pressure across
the northern Plains/upper MS valley. This gradient will support
breezy southeast surface winds (i.e. 15-20 mph) from the early
afternoon through the evening. Above-average temperatures (i.e.
highs in the 90s) amidst a dry airmass will support afternoon RH
values from 15 to 20 percent. Guidance still suggests some
dissociation between the strongest winds (over north-central MT) and
the lowest RH (over southeast MT). Resulting conditions support an
elevated fire weather threat but the dissociation between the
strongest winds and lowest RH values currently precludes a critical
delineation.
...Please see www.spc.noaa.gov/fire for graphic product...
Risk
Area (sq. mi.)
Area Pop.
Some Larger Population Centers in Risk Area
Critical
60,699
725,955
Flagstaff, AZ...Farmington, NM...Prescott, AZ...Prescott Valley, AZ...Gallup, NM...
ZCZC SPCFWDDY2 ALL
FNUS22 KWNS 261742
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1242 PM CDT Mon Jun 26 2017
Valid 271200Z - 281200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NORTHERN AZ AND
NORTHWEST NM...
Primary changes to the Day-2 Fire Weather Outlook are as follows:
1. The northern AZ Critical area has been expanded eastward into
northwest NM and has been expanded slightly westward, based on the
latest model guidance's depiction of enhanced low/midlevel flow
overlapping with a deep boundary layer characterized by hot surface
temperatures and 3-11 percent RH. West-southwesterly surface winds
of 20-25 mph are expected across the Critical area.
2. The northern part of the Elevated area surrounding the Critical
area has been expanded eastward into extreme southwest SD and far
western parts of the NE Panhandle. The latest model guidance
suggests that a deep boundary layer with adequately low surface RH,
coinciding with enhanced winds, will materialize west of a
sharpening lee trough amid sufficiently dry fuels. Confidence in
critical winds/RH occurring on any more than a brief/spotty/marginal
basis is too limited for Critical designation at this time.
3. The Isolated Dry Thunderstorm area has been expanded eastward
into extreme southwest SD and far western parts of the NE Panhandle,
with the anticipation that thunderstorm activity will spread farther
east amid the deep boundary layer and produce minimal precipitation
before reaching richer moisture.
4. An Elevated area has been added across portions of the southern
CA mountains and adjacent foothills, where lingering enhanced winds
are expected to combine with low RH. Poor RH recovery is expected in
many areas for Tuesday night, resulting in a long-duration period of
enhanced fire-weather potential.
No other changes have been made to the ongoing forecast.
..Cohen.. 06/26/2017
.PREV DISCUSSION... /ISSUED 0258 AM CDT Mon Jun 26 2017/
...Synopsis...
Shortwave trough over the northern Rockies at the beginning of the
period -- 12Z Tuesday -- will progress eastward through the northern
Plains, reaching the upper MS Valley early Wednesday morning.
Farther east, a pair of phased shortwave troughs will move through
the upper trough initially over the eastern CONUS. Progression of
these shortwave troughs will act to deamplify the parent upper
trough. As a result, a largely zonal pattern is anticipated across
the CONUS by 12Z Wednesday. At the surface, high pressure will shift
eastward into OH and TN valleys while a low moves eastward across
the Dakotas. Cold front attendant to this low will move across the
northern and central High Plains.
...Southwest...Great Basin...Central Rockies...
Another day of above-average temperatures and afternoon RH values in
the single digits is anticipated across much of the western CONUS,
including portions of the Southwest, Great Basin, and central
Rockies. Some breezy winds are also anticipated, primarily a result
of the enhanced mid-level flow coupled with deep boundary-layer
mixing. Best combination of windy and dry conditions with dry fuels
is expected across portions of the central/north-central AZ.
Critical fire weather conditions are expected here with elevated to
locally critical conditions anticipated across the remainder of the
region.
...Southwest WY...
Thunderstorms are expected across much of the northern Rockies
during the afternoon. However, high storm coverage, modest storm
motions, and high PWs suggest mainly wetting rains with much of this
activity. The only exception appears to be across southwest WY where
a deep mixed boundary layer will support high cloud bases and ample
sub-cloud precipitation evaporation. Mean storm motion is this area
is also expected to be around 35-40 kt. These meteorological
conditions support increased fire danger due to isolated dry
thunderstorms.
...Please see www.spc.noaa.gov/fire for graphic product...
