844
FXUS66 KPDT 020341
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
841 PM PDT Mon Jul 1 2024

.EVENING UPDATE...Slight change to the forecast. Ground
observations are showing winds to continue to be gusty through the
Yakima and Kittitas Valleys with sustained winds around 17 mph
this last hour and gusting 20 to 25 mph. Guidance shows winds
will likely continue to be breezy between 15 to 20 with gusts to
30 mph (80% probabilities) to continue through those areas
through 11 PM before settling down and averaging between 5 to 10
mph. Otherwise, no changes to the forecast.


&&

.PREV DISCUSSION... /issued 430 PM PDT Mon Jul 1 2024/

SHORT TERM...Tonight through Thursday...A persistent northwest flow
aloft through the short term as a ridge oh high pressure builds over
the eastern Pacific and slowly moves towards the coast. A weak
shortwave in the northwest flow has been clipping the region today
producing some convective showers from far eastern Wallowa county
eastward. The showers over eastern Wallowa county will come to an
end this evening. Otherwise, skies will be mostly clear overnight.
Some locally breezy conditions (10-20 mph gusts 20s) along the east
slopes of the Cascades will also linger into the evening before
decreasing.

A second shortwave in the northwest flow will clip the region on
Tuesday but with the main convection staying further to the north
over the northern Idaho Panhandle. The main impact will be some more
locally breezy conditions developing along the east slopes of the
Cascades that linger into the evening before decreasing.

One last shortwave will again clip the region on Wednesday as it
dives into western Montana. Again the main convection remains north
and east of the forecast area with the main impact being the locally
breezy conditions along the east slopes of the Cascades.

High temperatures over the next couple of days will remain near
normal with highs in the 80s in the lower elevations and 70s in the
mountains.

LONG TERM...Thursday through Monday...Models in pretty good
agreement with the overall pattern, but differ in strength and
position of upper level high. These discrepancies are reflected in
the WPC cluster analysis. 85-90% of WPC cluster members show an
upper level ridge over the Pacific Northwest through the period.
They do vary in the position and amplitude of the ridge, especially
Monday. These variations will have an impact on just how hot it gets
and whether or not mid level moisture makes it over our southern CWA
early next week. The ensemble models paint a similar picture with
the ECMWF showing a more amplified pattern (hotter and drier) while
the GFS is a little more moderated but still hot and dry. ECMWF`s
highs for Sunday are about 5-10 degrees higher than GFS`s. By the
end of the period, 40-45% of the members show an upper level trough
over the Gulf of Alaska trying to nudge the upper high eastward and
weaken it while 55-60% keep the ridge over the area. At this time,
will lean towards the upper level high persisting through the
period. In summary, confidence is very high (90-100%) an upper level
ridge will impact the area with above normal temperatures but
confidence decreases on just how hot.

We`ll have to keep an eye on mid-level moisture rotating around the
upper level high as it settles in over the four corners area late in
the period. This scenario is prone to allowing moisture to creep
into southern parts of our CWA for afternoon/evening convection. At
this time, most of the moisture heads out to sea keeping the mid-
levels too dry (precipitable water anomalies are near/slightly below
normal), but we`ll continue monitoring it closely for possible fire
weather concerns early next week. Earle/81

AVIATION...00Z TAFS...Skies will remain mostly clear with only a
FEW-SCT cumulus clouds over the next 24 hours. WNW winds 10-15G25kt
this afternoon will diminish to light terrain driven winds tonight
but will increase again Tuesday afternoon. However, wind speeds will
be slightly less than today.  Wister/85

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  54  82  51  82 /   0   0   0   0
ALW  57  86  54  85 /   0   0   0   0
PSC  60  88  57  89 /   0   0   0   0
YKM  57  86  53  87 /   0   0   0   0
HRI  58  87  55  88 /   0   0   0   0
ELN  58  80  53  83 /   0   0   0   0
RDM  47  82  45  84 /   0   0   0   0
LGD  51  80  48  78 /   0   0   0   0
GCD  48  83  47  82 /   0   0   0   0
DLS  62  82  57  87 /   0   0   0   0

&&

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

$$

SHORT TERM...91
LONG TERM....81
AVIATION...85