828
FXUS66 KPDT 051117
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
417 AM PDT Wed Jun 5 2024

Updated aviation discussion

.SHORT TERM...Today through Friday...Quiet weather will prevail over
the forecast area for the next couple of days as high pressure
centered to our south begins to take hold over the region. The ridge
axis associated with this high keeps amplified flow aloft overhead
and just to our north, but mid-level flow is zonal and the airmass
is pretty dry, so expecting mostly clear skies for the rest of the
work week, with temperatures building heading into the weekend.
Highs look to climb into the 90s by the end of the period across our
lower elevation and valley zones. Expecting mostly light winds,
however the strength of the high to our south could drive some NE
breezes through the Basin and down into central Oregon Thursday and
Friday afternoon.

The ridge begins to develop a bit of a negative tilt by Friday,
allowing for some SW flow aloft to advect moisture into the area,
namely for southern Oregon. The ridge axis remains overhead, so
first instinct is to go with a dry forecast, however the NAM depicts
quite a bit of mid-level moisture for the area combined with
instability. Models are in disagreement, so did include a small area
of slight chance storms around Grant, Crook, and Deschutes Counties,
all right along our southern border, but am leaning towards it being
dry Friday, with better storm chances occurring during the weekend.
Evans/74

.LONG TERM...Saturday through Wednesday...The upper level ridge will
be over the region Saturday as a weak upper level trough approaches
the coast. This will maintain the warmer then normal high
temperatures of 85 to 95 across the lower elevations which is 10-15
degrees above normal. It will also turn the flow a little more
southerly and enhance instability over central and northeast Oregon
leading to convective showers and a slight chance of thunderstorms.
Deterministic models begin to differ on how this weak upper level
trough impacts the region Saturday night into Sunday with the GFS
continuing to progress the trough eastward across the Pacific
Northwest while the ECMWF forms a closed low that drops into
northern California. The ensembles show a similar divergences but
maintains a more progressive eastward progression of the trough
across the forecast area. So, based on that the forecast maintains
the eastward movement of the convective showers and thunderstorm
potential for Sunday with the focus being over the eastern mountains
and coming to an end in the evening. This will also lower high
temperatures around 5-10 degrees compared to Saturday.

Monday through Wednesday the weather pattern will be dominated by a
flat upper level ridge over the region for dry breezy conditions and
high temperatures at or slightly above normal for this time of
year.

&&

.AVIATION...12Z TAFs...VFR conditions will prevail over the
next 24 hours under generally clear skies. All sites expect light
winds of 10 knots or less.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  75  49  83  54 /   0   0   0   0
ALW  77  51  86  56 /   0   0   0   0
PSC  79  52  88  57 /   0   0   0   0
YKM  78  47  87  53 /   0   0   0   0
HRI  79  50  88  55 /   0   0   0   0
ELN  75  47  84  54 /   0   0   0   0
RDM  79  46  84  51 /   0   0   0   0
LGD  75  50  83  53 /   0   0   0   0
GCD  81  51  89  55 /   0   0   0  10
DLS  79  52  88  58 /   0   0   0   0

&&

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

$$

SHORT TERM...74
LONG TERM....91
AVIATION...87