Flash Flood Warning 7, NWS Spokane, WA

233 
WGUS76 KOTX 272116
FFSOTX

Flash Flood Statement
National Weather Service Spokane WA
216 PM PDT Sat May 27 2023

WAC047-272126-
/O.CAN.KOTX.FF.W.0007.000000T0000Z-230527T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Okanogan WA-
216 PM PDT Sat May 27 2023

...FLASH FLOOD WARNING FOR THE BURN SCAR IS CANCELLED FOR WEST 
CENTRAL OKANOGAN COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 4861 12060 4860 12044 4859 12042 4845 12018
      4837 12022 4835 12035

$$

Butler

Area Forecast Discussion
National Weather Service Spokane WA
1046 AM PDT Sat May 27 2023

.SYNOPSIS...
Warm temperatures through the weekend and early next week for the
Inland Northwest. Isolated to scattered showers and thunderstorms
are expected at times through Sunday. Monday looks drier, then
shower chances start to expand again Tuesday into Thursday.

&&

.DISCUSSION...

Saturday and Sunday: The upper level low is slowly drifting south as
seen from water vapor satellite this morning. I can't help but sing
the Journey Song "The Wheel In The Sky Keeps On Turning" when I see
these very well defined circulations. The mid and upper level flow
(500mb and 700mb) out of the east to northeast is advecting in some
relatively warmer air aloft today and Sunday. The flow aloft is also
quite weak with 5-10 knots today and 10-15 knots Sunday.
Moisture/humidity is on the rise, as PWAT increases to 160% of
normal. We continue to see some healthy dynamics and lift in place
that should drive convection initiation. Forecast soundings showcase
the tall skinny CAPE which is an indicator more of heavy rain
producing storms rather than severe, given we are seeing the weak
shear environment and high moisture through a deep layer. Can't rule
out that we'll see thunder today though, as the national blend of
models gives most of the Idaho Panhandle a 30-55% chance for
thunderstorms (greater chance the farther north) and the northeast
WA mountains and Okanogan Highlands a 30-40% chance of
thunderstorms. Anything that does develop today will be capable of
producing heavy rain and likely ponding of water, localized flooding
due to the slow movement. Sunday the thunder threat is much less as
the Low exits the region and we begin to see weak, flat ridging
building in from the west. The Weather Prediction Center again has
eastern WA and the Idaho Panhandle in a marginal risk for excessive
rainfall outlook through Sunday morning; alluding to localized
flooding and slow moving, heavy rain producing storms.

The tricky part of this forecast has been the exact location of
showers and storms. While the high resolution guidance is well aware
of and advertising isolated to scattered showers and storms, the
exact timing and progression differs depending on which model you
look at. Most of these showers and storms are not high impact and
are more of the persistent showery and localized heavy rain variety.
It is very much what I'd describe as typical Spring showers. /Dewey

Monday through Friday: In general, models are in solid agreement
that the region will remain in an overall progressive pattern
through the week. Monday and Tuesday will feature a zonal flow
aloft as the persistent upper level low from the past several
days slowly meanders southward and another one begins to slowly
slip down from the Gulf of Alaska. This will keep most of the
region dry as temperatures creep into 80 degree territory. The
best chances for showers and weak thunderstorms will be across far
southeast Washington and the Camas Prairie on Monday and Tuesday.

An upper level trough and cold front begins to move into the region
Tuesday into Wednesday, which looks to bring a period of breezy to
gusty southwest winds and precipitation to the Idaho Panhandle. High
temperatures will cool back into the 70s for the rest of the work
week. Increasing south to southwest flow from this trough and a
low churning in the Gulf of Alaska combined with an upper level
ridge building east of the Continental divide will bring another
period of afternoon showers and thunderstorms Thursday into the
weekend.

Beyond the extended forecast (aka next weekend), ensembles are
beginning to hint at a more impactful period as they are in solid
agreement of PWATS increasing to near an inch. This type of signal
definitely raises some flags for the potential for heavy
precipitation and relatively stronger thunderstorms during this
period, but it is too far out in the forecast to make any specific
conclusions. This will be something we keep an eye over the next
week. /vmt

&&

.AVIATION...
18Z TAFS: VFR conditions are expected through the period for
prevailing conditions at area air fields. The TAF sites with the
highest probabilities of seeing thunderstorms include GEG, SFF,
and COE. There is a 20-30% chance of thunderstorms occurring at
those locations. Confidence is low on exact timing of VCTS at the
TAF sites, but have included this at GEG, SFF, COE, EAT to show
increasing probabilities and the uptick in convection. As with any
storms that develop, periods of gusty and erratic winds and heavy
rain are expected.

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        76  55  77  54  81  53 /  50  40  10   0   0   0
Coeur d'Alene  73  54  75  54  80  52 /  70  40  20  10   0   0
Pullman        71  53  74  52  79  51 /  40  40  20   0   0   0
Lewiston       79  59  82  58  87  59 /  40  30  20  10   0   0
Colville       78  51  79  51  81  49 /  50  30  20  10   0   0
Sandpoint      71  52  73  53  79  51 /  70  40  30  10   0   0
Kellogg        68  55  70  54  77  53 /  80  50  40  10   0   0
Moses Lake     83  54  85  52  86  52 /  20  20   0   0   0   0
Wenatchee      82  55  84  54  84  54 /  30  10   0   0   0   0
Omak           83  56  85  55  85  53 /  30  20   0   0   0   0

&&

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