371
FXUS66 KPDT 121026 AAA
AFDPDT

Area Forecast Discussion...Updated
National Weather Service Pendleton OR
326 AM PDT Wed Jun 12 2024

Updated aviation discussion

.SHORT TERM...Today through Friday night...Near-seasonal
temperatures and mostly clear skies will prevail today under dry
zonal flow. Surface winds will be significantly lighter than
Tuesday, with typical diurnally driven onshore winds through the
Cascade gaps.

Thursday, the 500-mb pattern will become more amplified as an
anomalously deep upper-level closed low approaches in the
Northeast Pacific and an upper-level ridge builds over the
Rockies. Flow aloft will turn southwesterly in response, and
although the upper-level ridge axis will be east of our CWA,
above-normal afternoon high temperatures are forecast area-wide.
While chances are very low (<5% chance), an afternoon shower
cannot be completely ruled out across the Blue Mountains.

By late Thursday afternoon and evening, onshore-directed pressure
gradients will increase as a mid-level shortwave and attendant dry
cold front propagate onshore. Additionally, a robust LLJ of 30-45
kts is advertised through the Columbia River Gorge (CRG) and
Kittitas Valley (KV) as well as across the Lower Columbia Basin
and foothills of the Blue Mountains. Forecast soundings suggest
favorable profiles for gusty winds reaching the surface, so while
confidence is not high (<60% chance), brief advisory-level wind
gusts appear possible through the CRG/KV.

Friday, breezy to windy onshore winds will continue as the parent
upper low tracks towards the PacNW. Aside from "chance" (25-54%)
to locally "likely" (55-74%) PoPs along the WA Cascade crest, dry
conditions are expected. Temperatures will be near seasonal
normals on Friday. Plunkett/86

&&

.LONG TERM...Saturday through Wednesday...Models begin the period
in pretty good agreement with an upper level trough near the
coast, but they begin to diverge on its impact and persistence
over the area through the remainder of the period. WPC cluster
analysis shows the majority (80-85%) sticking with a troughy
pattern while one member (which varies) shows a few periods of
zonal flow. Ensembles favor a more troughy pattern as well. Given
consistency, confidence is high (80-85%) we`ll see an upper level
trough move over the Pacific Northwest over the weekend, but
confidence decreases to moderate (50- 60%) on its longevity. At
this time, we`re only expecting convection over the mountains with
the lower elevations remaining relatively dry. Cooler
temperatures are expected beneath the trough averaging 5-10
degrees below normal.

The chance (40-60%) of a wetting rain (0.1 of an inch or more)
remains confined to the Cascades over the weekend, but does
increase to a moderate chance (30-40%) over the mountains of
Northeast Oregon Monday. Earle/81

&&

.AVIATION...12Z TAFs...VFR conditions will prevail through the
period. Clear skies with winds 10 kts or less, except KDLS 10-15 kts
with higher afternoon gusts decreasing overnight. Earle/81

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  76  46  82  53 /   0   0   0   0
ALW  79  48  86  56 /   0   0   0   0
PSC  81  51  87  57 /   0   0   0   0
YKM  81  45  84  49 /   0   0   0   0
HRI  81  48  87  56 /   0   0   0   0
ELN  76  46  82  50 /   0   0   0   0
RDM  77  43  81  43 /   0   0   0   0
LGD  75  45  84  50 /   0   0   0   0
GCD  80  47  89  49 /   0   0   0   0
DLS  79  50  84  53 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&

$$

SHORT TERM...86
LONG TERM....81
AVIATION...81