003
ACUS11 KWNS 172204
SWOMCD
SPC MCD 172204
ORZ000-WAZ000-180000-

Mesoscale Discussion 1673
NWS Storm Prediction Center Norman OK
0504 PM CDT Wed Jul 17 2024

Areas affected...northeast OR and eastern WA

Concerning...Severe potential...Watch unlikely

Valid 172204Z - 180000Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated to widely scattered dry thunderstorms will be
capable of localized strong to severe gusts across parts of
northeast Oregon into eastern Washington through mid-evening. The
disorganized and localized nature of the threat will preclude a
severe thunderstorm watch.

DISCUSSION...Isolated high-based, low-topped thunderstorms are
ongoing across parts of the Blue Mountains in northeast OR to the
east side of the Cascades in southern WA. This activity is being
aided by a minor mid-level impulse that will drift northeast across
the region through this evening. Surface temperature-dew point
spreads across the Columbia and Snake River Valleys are quite large
from 60-65 F, with 50s spreads farther north in eastern WA across
the Columbia Plateau. This is yielding a very deeply mixed
thermodynamic profile which will be conducive to dry microbursts as
thunderstorms gradually expand northeastward into early evening. The
meager buoyancy and modest large-scale forcing for ascent should
yield isolated to widely scattered convective coverage. The belt of
enhanced mid/upper flow attendant to the minor impulse is
consistently progged to remain on the backside of the convection to
its south in eastern OR. This should inhibit appreciable
organization, suggesting a spotty strong to severe gust threat.

..Grams/Gleason.. 07/17/2024

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...OTX...PDT...

LAT...LON   44981891 45282025 45872075 47082076 47781970 47881897
            47901846 47771745 46531718 44921827 44981891