711
FXUS66 KOTX 301150
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
450 AM PDT Wed Jul 30 2025

.KEY MESSAGES...

- High Temperatures 90s to 100s through Thursday with Moderate
  and Major HeatRisk.

- Isolated dry thunderstorms today. Scattered, wet and dry
  thunderstorms on Thursday and scattered, wet thunderstorms on
  Friday.

- Gusty winds and lightning primary hazards for Wednesday into
  Thursday with a transition to heavy rainfall, hail, and gusty
  winds Thursday afternoon into Friday.

&&

.SYNOPSIS...
Temperatures be very warm through Thursday with highs in 90s
and low 100s. Isolated dry thunderstorms on Wednesday over the
mountains will bring a risk for new fire starts. There are
increasing chances for wet thunderstorms with gusty winds and
isolated hail Thursday and Friday.

&&

.DISCUSSION...
Today: a ridge strengthening and moving eastward across Canada will
warm temperatures up to around 10 degrees above normal for this time
of year. High temperatures today and tomorrow will be in the high
90s through the low 100s. Overnight temperatures will be 5-8 degrees
above normal for this time of year. These warmer overnight
temperatures could create some problems for people prone to heat-
related illnesses if they don`t have access to adequate cooling.
Widespread Moderate to localized Major HeatRisk is anticipated
through much of the forecast area today and tomorrow. A shortwave
embedded within the southerly flow will move across Oregon. This
lift combined with the warm flow brings chances for thunderstorms
this afternoon and evening. Mid and low level relative humidity is
very low, so these thunderstorms are anticipated to be mostly dry
with very little precipitation. Main impacts include lightning
induced fire starts and gusty outflow winds. Much of these
thunderstorms are anticipated to be along the Cascade crest,
Okanogan Highlands, Northeast Mountains, and the northern Idaho
Panhandle, where the NBM currently shows a 5-10 percent chance of
thunder. Surface-based CAPE tomorrow in these areas is 200-500 J/kg.
While probabilities are lower, some CAMs are showing cell
development in the Spokane area, Upper Columbia Basin, and Lewiston
areas.

Thursday through Friday: Lower heights and moisture forming over
California will result in a more robust surge of warmth and moisture
Thursday through Friday. A stronger shortwave will move through the
area around this time, bringing continuing chances of thunderstorms.
These thunderstorms will be wetter, as PWATs surge to 120-150
percent of normal. NBM percentages increase to a 10-30 percent
chance of thunder these days, and coverage becomes more widespread.
Highest chances for thunderstorms on Thursday are along the Cascade
crest, whereas highest chances on Friday are in the Northeast
Mountains and northern Idaho Panhandle. Surface based CAPE values
increase on Thursday and Friday to 1000-1500 J/kg. With these wet
thunderstorms, alongside chances of lightning and gusty outflow
winds comes chances for high rain totals, which could bring flash
flooding to burn scars. On Friday in particular, there is a 50-70
percent chance of 0.10 inches of rain or more in the Northeast
Mountains and northern Idaho Panhandle. While CAMs are picking up
well on the thunderstorm potential, some uncertainty exists in the
location of the shortwave, which could change where the highest
thunderstorm potential is.

Saturday and Sunday: Models show a low pressure system in the Gulf
of Alaska weakening, but those lower heights will still move into
the Pacific northwest as flow becomes more westerly. This will lower
temperatures to a little cooler than normal beginning Friday.
Cluster guidance is somewhat agreeable on lower heights moving in
over the weekend. As we move into next week, long range models are
favoring another low pressure system moving through, though clusters
are undecided. /AS

&&

.AVIATION...
12Z TAFS: Generally VFR conditions prevail. The atmosphere is
warm and unstable and there is a subtle increase in midlevel
moisture today. This is resulting in weak midlevel buildups
around Spokane-Cd`A this morning with a 5-10% chance to produce
sprinkle or a rogue lightning strike. This afternoon cumulus
buildups are expected over over the northern mountains with a
10-20% chance for showers or thunderstorms. Omak, Republic,
Colville, and Deer Park carry the highest chances. A few cells
may come in vcnty of COE-GEG but given the low probabilities,
were left out of the 12z TAF issuance.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: High confidence
in VFR conditions through the TAF period. Low confidence in
morning thunderstorms around Spokane-Cd`A though a few elevated
cells with bases above 10K ft have been observed on radar.
Moderate confidence in isolated afternoon thunderstorms over the
northern mountains. /sb

&&

.FIRE WEATHER...
A Red Flag Warning is in effect for Fire Weather Zone 696 from
Wednesday 1 PM to 9 PM due primarily for hot and unstable
conditions. Southerly flow will allow for elevated moisture to
advect into the Cascades with PWATs increasing to 0.60-0.70
inches (~120%) of normal on Wednesday. Very warm temperatures
with highs in the 80s and very steep low level lapse rates
(8-10C/km) will support deep mixing with mixing heights 12k-13k
feet AGL over the Cascades. Additionally, there will be a small
risk (15%) chance for isolated thunderstorms. The boundary
layer will be very dry on Wednesday with deep inverted-V
soundings that support mostly dry thunderstorms if development
occurs. These sounding profiles also indicate the potential for
gusty and erratic outflow winds.

A fire weather watch has been issued for the North Cascades to
the Okanogan Highlands for Thursday where there is increasing
confidence for scattered thunderstorms. Very warm and dry
conditions at the surface suggest decreased probabilities for
wet storms though a few cores will be capable of wetting rains.
Gusty outflow winds will be a major concern near heavier cells.
This activity will be capable of abundant lightning and new fire
starts, especially in dry fuels where last week`s thunderstorm
activity skipped over.


&&

.Preliminary Point Temps/PoPs...
Spokane        97  67  97  64  82  60 /   0  10  10  50  50  40
Coeur d`Alene  95  67  95  63  83  60 /   0  10  10  50  60  50
Pullman        95  61  92  57  79  55 /  10  10  10  60  50  30
Lewiston      101  71  98  69  89  66 /  10  20  20  50  50  30
Colville       95  57  96  55  83  53 /  10  20  10  40  70  60
Sandpoint      92  62  92  59  80  56 /   0  10  10  50  70  60
Kellogg        93  67  94  64  79  62 /  10  20  20  60  60  50
Moses Lake    101  68 100  66  85  59 /   0  10  10  40  30  20
Wenatchee     100  75  99  72  84  66 /  10  10  30  40  40  20
Omak          100  69  99  67  87  63 /   0  20  20  40  50  40

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
WA...Red Flag Warning from 1 PM this afternoon to 9 PM PDT this
     evening for East Washington Central Cascades (Zone 696).
ID...None.

&&

$$