Red Flag Warning 6, NWS Spokane, WA

995 
WWUS86 KOTX 300315
RFWOTX

URGENT - FIRE WEATHER MESSAGE
National Weather Service Spokane WA
815 PM PDT Sat Jul 29 2023


WAZ703-704-300415-
/O.EXP.KOTX.FW.W.0006.000000T0000Z-230730T0300Z/
Okanogan Valley (Zone 703)-Methow Valley (Zone 704)-
815 PM PDT Sat Jul 29 2023

...RED FLAG WARNING HAS EXPIRED FOR WIND AND LOW RELATIVE
HUMIDITY...

Relative humidity has risen to above critical thresholds.

$$

Area Forecast Discussion
National Weather Service Spokane WA
252 PM PDT Sat Jul 29 2023

.SYNOPSIS...

The region is expected to experience ongoing warm and dry weather
for the majority of the time. There is a slight possibility of
thunderstorms occurring from Saturday night through Sunday,
although any thunderstorms that do form are likely to be dry and
produce minimal rainfall. Additionally, the weekend will bring
breezy winds that could contribute to the spread of fires. Looking
ahead, the warm and dry conditions are expected to continue
throughout the upcoming week.

&&

Tonight through Sunday: Satellite imagery this afternoon reveals a
tightly wound low pressure system spinning just off the coast of
Vancouver Island. The center of the low will remain in place for the
next 48 hours or so with a weak cold front slowly push across
Washington. The front is currently draped across northwest
Washington at 1:00 PM this afternoon and is progged to shift into
the Cascades overnight. Then the front looks to shift more into
eastern Washington on Sunday as a shortwave disturbance rotates
around the low and gives it a further eastward nudge.

We'll be monitoring the potential for nocturnal convection
tonight with models showing modest amounts of mid level
instability increasing over the Inland Northwest overnight into
Sunday morning. Earlier this morning we saw a little bit of
altocumulus castellanus (ACCAS) drift across the region with an
area of weak instability at mid levels. Most unstable CAPEs will
increase a bit more for tonight, but there is still the question
of if it will be enough. The NAM analyzed around 100-200 J/kg of
MUCAPE with the ACCAS earlier this morning. For tonight, the 12Z
NAM is indicating around 100-200 J/kg additional CAPE for
tonight. We should also see a bit more lift synoptically with the
front bit further east. The 12Z GFS, NAM, and ECMWF all indicate
an enhancement of high level Total Totals of 30- 38 Celsius. The
values vary depending on the model. Unsurprisingly, the NAM is on
the higher end of this range and indicates the better instability
a bit further west more so over eastern Washington from the basin
to the Okanogan Highlands and points eastward. Whereas the GFS and
ECMWF, has the axis of better higher level total totals more so
over southeast Washington into the central to northern Idaho
Panhandle. Signals are there for the potential of nocturnal
thunderstorms tonight, but placement is uncertain anywhere east of
a line from Omak to Moses Lake and coverage is likely to be
isolated at best. Any thunderstorms that do develop will likely
have little in the way of rainfall, and will be capable of
starting new fires.

The incoming front will tighten the pressure gradient across the
region as well, and in particular across the Cascade Mountains.
Breezy west to southwest winds of 10-20 mph is expected for the
afternoon hours on Sunday. Wind gusts of up to 25-30 mph is expected
on the higher benches around Chelan and Wenatchee and on the
Waterville Plateau. Dry and breezy conditions will increase the risk
for fire spread for any new or ongoing fires.

Sunday night through Monday night: The flow aloft turns more
westerly behind tomorrow's frontal passage. Less moisture will
decrease any chance for seeing showers, or thunderstorms for that
matter. Skies will be clear and temperatures a bit cooler both
Sunday into Monday. Highs both Sunday and Monday will be in the
upper 80s to low 90s, which is right around normal for late July
considering we are in the climatologically hottest part of the year.
/SVH

Tuesday through Saturday: A ridge pattern will be in place over the
region through Thursday as a Low positions itself off the coast. It
will bring a dry, warming trend. Probabilities of relative
humidities less than 10% are near 50%. Chance for 100 degree day
probabilities have pulled back to less than 10% for most locations
across the Inland Northwest. The region is still expected to see
widespread 90 degrees plus. Ensembles continues to have the Low
pull in the southern monsoonal moisture by the end of the week.
Timing differences make the Thursday through Saturday confidence,
on arrival of moisture, low. They continue to keep the bulk of
precip to the East over Montana. Thunder chances have increased
over the Idaho Panhandle during the afternoon periods. It will be
something to continue to monitor. Highs will dip a few degrees
lower from Wednesday highs but still be warm. Lows will be in the
60s. /JDC

&&

.AVIATION...
00Z TAFs: VFR conditions will prevail. Gusty winds near 30 mph
will continue from KOMK to KEAT through the afternoon. Increasing
chance of thunderstorms in the Idaho Panhandle will late this
evening that could contain gusty and erratic winds. Winds will
calm overnight before another round expected late morning and
afternoon on Sunday. /JDC

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        60  87  55  87  53  90 /  20  20   0   0   0   0
Coeur d'Alene  58  87  55  87  53  89 /  20  20   0   0   0   0
Pullman        53  84  50  83  48  87 /  20  10   0   0   0   0
Lewiston       66  93  62  93  61  96 /  20  10   0   0   0   0
Colville       52  88  46  87  45  89 /  20  20   0   0   0   0
Sandpoint      56  87  51  86  48  88 /  20  20   0   0   0   0
Kellogg        62  85  60  84  58  87 /  20  20   0   0   0   0
Moses Lake     57  89  52  88  53  91 /  10   0   0   0   0   0
Wenatchee      63  87  58  88  60  91 /   0   0   0   0   0   0
Omak           60  91  56  90  56  92 /  10  10   0   0   0   0

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&