Area Forecast Discussion
Issued by NWS Spokane, WA

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FXUS66 KOTX 281014
AFDOTX

Area Forecast Discussion
National Weather Service Spokane WA
314 AM PDT Thu Mar 28 2024

.SYNOPSIS...
Precipitation becomes showery today with the potential for
afternoon thunderstorms. Showers will continue into Friday with a
small chance for thunderstorms northeast Washington into North
Idaho. Then a warming and drying trend is expected through the
weekend into early next week.

&&

.DISCUSSION...
Today through Friday night: AN upper level low pressure system
will sit off the Washington coast today and send energy across
the Inland Northwest keeping the weather active. A shortwave
disturbance can be seen on Infrared Satellite imagery early this
morning rotating through eastern Oregon and will clip portions of
southeast Washington into the southern portions of the Idaho
Panhandle. Precipitation will increase from the Northeast Blue
Mountains, into the Lewiston-Clarkston Valley, Pullman/Moscow, and
northeastward across Potlatch, Deary, and Clarkia this morning.
These areas will be on the northern fringe of this passing
shortwave with precipitation amounts light generally up to
between 0.05-0.15 inches.

The atmosphere looks to destabilize into this afternoon. The cold
pool will remain offshore with the upper level low, but we should
have enough in the way of colling aloft paired with insolation to
result in scattered showers and isolated thunderstorms. The RUC
model shows a vorticity maximum that pushes eastward across the
region between 2:00 PM (around Wenatchee) to 10:00 PM (into the
Northern Panhandle). This shortwave disturbance should aid in the
development of convective showers and resulting thunderstorms. The
higher terrain will see more in the way of coverage of convection
due to the differential surface heating alone; because of this,
the higher terrain will see a 20-25%. The lower percentage (10%)
is assigned to the eastern Basin into the Spokane/Coeur d`Alene
Area and Palouse into the Lewiston-Clarkston Valley. Thunderstorms
today will be capable of small hail (up to the size of a pea),
gusty winds up to 30 mph, isolated cloud to ground lightning
strikes and brief heavy rain. Winds today will be a bit breezy
from the south to southwest. Winds will be most breezy over the
western portion of the basin and up the Okanogan Valley sustained
10-20 mph with gusts up to 25-30 mph.

Showers will continue mainly over the mountains Thursday night
into Friday. There will be a smaller chance for thunderstorms
(15%) for Friday afternoon, and these isolated thunderstorms are
expected mainly over the Okanogan Highlands, to the Northeast
Mountains, and over the Northern Panhandle. Showers in general
should be less in coverage compared to this afternoon (Thursday).
Showers on Friday will also dissipate more quickly once the sun
sets in the evening. Temperatures through Friday will be right
around normal for late March with highs in the 50s for most
locations. /SVH

The Weekend: The upper level ridge moves from the Gulf of Alaska
eastward toward the Pacific Northwest. Saturday northerly winds
will push down the Okanogan Valley with gusts up to 20 mph.
Saturday Night/Sunday a north south oriented wave will move down
the front side of the ridge. Main impact will be an increase in
clouds through the overnight and early Sunday morning hours.
Northerly winds will be more widespread on Sunday, but still
fairly light with gusts 10 to 20 mph. Only sensible weather
through the weekend will be some very isolated showers across the
mountains of the ID Panhandle.

Monday and Tuesday: The ridge moves over the region and begins to
fold over as the low moves into the desert southwest. Mostly clear
to partly cloudy skies and temperatures above average is
forecast. Tuesday will be the warmest day with highs in the 60s to
low 70s as 850 mb temps warm under the southerly flow. Temps 10
to 15 degrees above average for the beginning of April will be
welcomed and short lived. The GFS ensemble wants to bring
precipitation past the crest into the northern mountains and ID
Panhandle by Tuesday afternoon. EC keeps it dry. Will keep the
NBMs 20% chance of afternoon showers, but suspect subsequent
forecasts will become drier and the better precip chances move to
Wednesday and beyond. Tuesday afternoon and early evening there is
a 30-50% chance of gusts to 25 mph for much of the region.

Wednesday and Thursday: Confidence is moderate to high that there
will be a pattern change from the ridge to a more unsettled
trough-like pattern. There are still some discrepancies in the
details, but expect temperatures to return to near average by
Wednesday and below average by Thursday. Showers will return to
the region with even some wet non accumulating snow to the valleys
by Thursday morning. Breezy winds continue Wednesday with a 40-60%
chance of gusts to 25 mph across the Columbia Basin into Spokane
and the Palouse region. /Nisbet


&&

.AVIATION...
06Z TAFS: VFR to MVFR stratus will continue overnight in Eastern
Washington and North Idaho. KCOE has a 60% chance of MVFR cigs
through 18z. KMWH has a 30% of IFR cigs through 09z but should
clear out to VFR. There is a slight chance (10%) of fog for
extreme eastern WA/North ID. Scattered thunderstorms are expected
over much of the region on Thursday, particularly in the Idaho
Panhandle from 18-03z.

FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: Low confidence for
MVFR/brief IFR condition timing across the region through tonight
for KCOE-KGEG-KSFF-KLWS-KMWH.

------------------------

Confidence descriptors:
Low - Less than a 30 percent chance
Moderate - 30 to 70 percent chance
High - Greater than a 70 percent chance

For additional probabilistic information for NWS Spokane airports,
please refer to the Aviation Dashboard on our webpage:
https://www.weather.gov/otx/avndashboard

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        50  33  52  31  55  31 /  40  30  20   0   0   0
Coeur d`Alene  48  33  49  30  53  30 /  60  50  30   0  10  10
Pullman        48  33  49  31  54  32 /  60  40  40   0  10  10
Lewiston       54  38  54  35  59  37 /  70  30  30   0   0   0
Colville       50  31  51  26  54  27 /  60  30  40  10   0   0
Sandpoint      45  33  47  29  51  29 /  70  60  60  10  10  10
Kellogg        45  34  47  31  51  32 /  70  50  50   0  20  10
Moses Lake     56  33  57  32  61  35 /  10  10  10   0   0   0
Wenatchee      53  35  54  34  58  37 /  20  10  10   0   0   0
Omak           53  35  57  31  59  32 /  20  20  30  10   0   0

&&

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

$$


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