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U.S. Day 1 Fire Weather Outlook
ZCZC SPCFWDDY1 ALL
FNUS21 KWNS 181606
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1106 AM CDT Thu Jun 18 2026
Valid 181700Z - 191200Z
The Isolated Dry Thunderstorm area was expanded slightly over
portions of northern CA, far southwest OR, and far west NV. The
latest forecast guidance shows convection spreading slightly farther
eastward over the lower elevations of western NV this afternoon.
Forecast guidance also shows convection forming this afternoon over
the terrain-favored areas, especially near the Shasta-Trinity
National Forest and neighboring high and mid elevations where fuels
are receptive to fire activity. As was previously mentioned, the
pre-storm environment over this region supports mostly dry
thunderstorms with limited precipitable water below 3/4 inch and
storms motions above 15 mph. Though coverage is expected to
decrease, nocturnal convection is also not out of the question over
this region tonight.
..Stearns.. 06/18/2026
.PREV DISCUSSION... /ISSUED 0157 AM CDT Thu Jun 18 2026/
...Synopsis...
A large-scale ridge will continue building over the Southwest into
the Great Basin today. Meanwhile, a midlevel trough will begin to
impinge on the northwestern periphery of the ridge.
...Dry Thunderstorms...
Forcing for ascent preceding the midlevel trough will aid in the
development of isolated high-based thunderstorms over the Sierra
during the afternoon into the evening hours. Inverted-V profiles and
0.4-0.7 inch PW will favor mostly dry thunderstorms, and given
increasingly dry/receptive fuels, isolated lightning-induced
ignitions are a concern.
Farther east, a mix of wet-dry thunderstorms are also expected over
parts of southeastern AZ into southwestern NM -- along the
northwestern periphery of a deeper midlevel moisture plume. Here, a
deep sub-cloud layer may tend to limit accumulating rainfall with
this activity, resulting in some concern for lightning-induced
ignitions where fuels are dry. However, the overlap of dry
thunderstorms over receptive fuels appears too limited for Dry
Thunderstorm highlights at this time.
...Central NC and vicinity...
Enhanced deep-layer south-southwesterly flow will overspread the
area ahead of an approaching cold front, resulting in 15-20 mph
sustained southwesterly surface winds. Diurnal heating ahead of
increasing cloud coverage and eventually rainfall may yield a brief
overlap of 35-40 percent RH with these breezy winds -- supporting a
brief period of locally elevated fire-weather conditions where fuels
are dry over parts of central NC.
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U.S. Day 2 Fire Weather Outlook
ZCZC SPCFWDDY2 ALL
FNUS22 KWNS 181913
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0213 PM CDT Thu Jun 18 2026
Valid 191200Z - 201200Z
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF NORTHWEST
NEVADA...NORTHEAST CALIFORNIA...AND EXTREME SOUTHERN OREGON...
An area of Scattered Dry Thunderstorm risk was introduced for Day
2/Friday across portions of northeastern CA, northwestern NV, and
far southern OR. The latest forecast guidance indicates a higher
coverage of thunderstorms that begin in the mid-morning hours on Day
2/Friday and drift toward the northeast as storm coverage and
intensity increases through the late morning and afternoon hours
across the drawn area. Even so, limited low level moisture and storm
motions of 15-30 mph will maintain the threat of this area of
concentrated convection remaining mostly dry. Adjustments in the
form of slight expansions were made to the existing Isolated Dry
Thunderstorm area as well. These small changes were commensurate
with the areal expansion of thunderstorms indicated by the latest
forecast guidance, especially along the northern CA coast and in
central portions of OR. The Elevated wind/RH area was also expanded
to include the remainder of the Mojave and much of the Colorado
Deserts in southern CA where dry and receptive fuels will coexist
with afternoon RHs near 5-10% and south/southwest winds sustained at
15-20 mph.
..Stearns.. 06/18/2026
.PREV DISCUSSION... /ISSUED 0158 AM CDT Thu Jun 18 2026/
...Synopsis...
A midlevel trough will continue eastward across parts of northern CA
into the Great Basin -- resulting in the breakdown of an upper ridge
over the region.
...Dry Thunderstorms...
Large-scale forcing for ascent accompanying the midlevel trough and
ample midlevel moisture across northern CA into the northern Great
Basin and Intermountain West will support the development of widely
scattered high-based thunderstorms beginning as early as Friday
morning and persisting into the evening hours. While around 0.75
inch PW will promote a mix of wet-dry thunderstorms, quick storm
motions and a well-mixed boundary layer should still tend to limit
rainfall accumulations with much of this activity. Given preceding
days of warm/dry conditions and increasingly receptive fuels,
lightning-induced ignitions and locally strong/erratic outflow winds
are a concern.
...Great Basin into the Southwest and central Rockies...
Enhanced deep-layer southwesterly flow preceding the midlevel trough
will overspread a deeply mixed boundary layer across the region
during the afternoon. The combination of 10-15 percent RH and 15-20
mph sustained south-southwesterly surface winds atop dry fuels will
favor elevated to locally critical fire-weather conditions.
U.S. Day 3-8 Fire Weather Outlook
ZCZC SPCFWDD38 ALL
FNUS28 KWNS 182158
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0458 PM CDT Thu Jun 18 2026
Valid 201200Z - 261200Z
...Synopsis...
An active weather pattern will maintain high fire risks across the
western United States through Day 3/Saturday before a temporary
shift in the upper-level flow takes place. The upper-level trough
contributing to ongoing fire weather risk will move onshore and
weaken as it traverses the Great Plains. This transitions the
western states into a brief period of zonal flow aloft, though
embedded shortwave troughs will continue to provide impactful fire
weather conditions, before ridging returns to the Intermountain
West. This pattern will reinforce unseasonably warm, dry conditions
and accelerate fuel drying across the region. Conversely, expansive
troughing will dominate the Northeast, sending periodic cold fronts
and widespread precipitation across the eastern United States to
suppress regional fire threats.
...Day 3/Saturday...
...central Pacific Northwest...
An area of 40% probability of Critical conditions was introduced
along and east of the Cascades in central WA and OR as the
aforementioned mid-level shortwave trough transits the region,
dragging a frontal boundary with it. West to northwest winds of
15-20 mph amid afternoon RHs of 10-15% and critically dry fuels will
support at least an Elevated fire weather risk.
...southern Pacific Northwest, Sierra Nevada, and northern Great
Basin...
As the main upper-level trough axis tracks eastward on Day
3/Saturday, mid-level moisture moving ahead of the system will
interact with strong synoptic forcing. Quick storm motions, limited
low-level moisture, and resultant high cloud bases will support a 10
percent probability of dry thunderstorms across portions of the
Pacific Northwest, the Sierra Nevada, and the upper Great Basin.
Strong, erratic outflow winds and locally breezy ambient conditions
will accompany these dry cells. The latest forecast guidance
indicates the exact footprint of this dry lightning risk may
fluctuate slightly as the system tracks eastward.
...Southwest, southern Great Basin, and central Rocky Mountains...
To the south, deep vertical mixing and a tightening surface pressure
gradient will accelerate southerly to westerly winds. This flow will
transport a dry air mass across areas with critical fuel
receptiveness. Current forecast parameters support maintaining a 40
percent critical fire weather probability for Saturday across a wide
expanse. The combination of sustained breezy conditions,
single-digit relative humidity, and highly receptive fuels will
foster an environment where rapid fire spread is possible through
the conclusion of the weekend. Thus, a 70 percent probability of
Critical fire weather was introduced over the Four Corners region
and adjoining areas. A small chance for a mostly dry thunderstorm or
two also exists over portions of the central Rockies and this
potential will be watched with future forecast issuances.
...Day 4/Sunday...
...Southwest and southern Great Basin...
As the aforementioned mid-level shortwave trough moves through the
Intermountain West and over the Great Plains, it will support lee
surface troughing which will enhance surface winds across portions
of the Southwest. Specifically, over western NM, where warm and dry
air will overlap best with these winds, an area of 40% probability
of Critical wind/RH has been added.
..Stearns.. 06/18/2026
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