Area Forecast Discussion


from: NWS Pendleton, OR

000
FXUS66 KPDT 040402
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
902 PM PDT Sun Jul 3 2022

.UPDATE...
Latest radar imagery showed a few showers and thunderstorms
lingering, but quickly decreasing, mainly over far eastern Oregon.
Areal coverage and intensity is much less than 24 hours ago.
Guidance does suggest that there will be renewed development
toward morning in central Oregon, that will move northeastward.

With this update, adjusted pops mainly to make the necessary
changes based on the latest guidance and expected coverage
overnight. Otherwise, just made minor adjustments to temps.

&&

.AVIATION...
06Z TAFS...VFR conditions are expected through the TAF period.
SHRA and TSRA activity is rapidly decreasing and is well east of
the TAF sites at this time.

DLS continues to gust to around 30 kts but will decrease to 10 kts
or less later tonight. DLS will gust 15 to 20 kts on Monday.

PSC is gusting around 20 kts. They will also decrease below 10
kts later tonight and remain that way through the period.

All other locations should remain 10 kts or less through the TAF
period, except BDN and RDM which could gust 10 to 15 kts Monday
afternoon.

&&

.PREV DISCUSSION... /issued 416 PM PDT Sun Jul 3 2022/

Updated for Aviation...

SHORT TERM...Tonight through Tuesday night. The latest radar was
showing showers and thunderstorms mainly over the eastern half of
the region and this pattern is expected to continue overnight.
Some of the storms may become strong and produce gusty winds and
hail...frequent lightning...brief heavy rain. The sref and href
had the convection focusing in the blue and wallowa mountains.

The low pressure slowly moves inland later tonight...and the
models were showing moisture advecting into the southern sections
of the area and extending northeast into the blue/wallowa mountains
toward Monday morning. Although some of the models have this area
back further west effecting the entire area and the forecast was
more aggressive with the areal coverage. Therefore showers and
thunderstorms are expected across the area into Monday afternoon
and Monday evening.

The low pressure system drifts north and some drier conditions
may move into the region Monday night. However our area remains in
a moist southwest flow and showers may develop mostly over
Central Oregon overnight Monday and expand further east across the
Ochocos and eastern mountains Tuesday along with isolated
thunderstorms by Tuesday afternoon. As the low pressure drifts
further north the showers are expected decrease and mostly be
confined along the WA/OR cascades Tuesday night.

Temperatures are expected to remain below normal tomorrow climbing
into the 70s with 60s in the mountains before a warming trend in
forecast into midweek.

LONG TERM...Wednesday through Sunday...Ensemble and deterministic
guidance are both in excellent agreement that another upper-level
cut-off low will form off the coast of the Pacific Northwest by
Wednesday, with an upper ridge axis over the High Plains. This will
place us under southwesterly flow aloft which will pump moisture
into the area and facilitate shower and thunderstorm development
each afternoon through at least Thursday. By Friday, uncertainty
grows as models struggle to resolve the cut-off low; concensus seems
to be that the low will transform into an open wave, but significant
timing differences are apparent when examining deterministic runs,
and even ensemble means show substantial run-to-run variance.
Delving into ensemble clusters hints at the potential for yet
another cut-off low forming off the SW Oregon and NW California
coast, a feature also seen in ensemble means, but some deterministic
runs and ensemble clusters do not show this feature and instead
build a ridge over the Pacific Northwest. Hence, confidence in
details of the pattern are low for Friday through Sunday and beyond.
Plunkett/86

AVIATION...
00Z TAFS....VFR conditions are expected through the TAF period.
Looking at current radar, there are a few SHRA/TSRA but less
areal coverage than on Saturday. Additionally, it appears that
for the most part these SHRA/TSRA should remain east of the TAF
sites, not not including any TSRA at this time. If any cell were
to impact an individual TAF, will handle with amendments over the
next few hours.

Winds have been gusting 25 to 30 kts at DLS and this will continue
through the evening, before decreasing to 10 kts or less. Most
other sites have been gusting to around 15 kts or 15 to 20 kts,
and there will continue to be occasional gusts before everyone
drops to 10 kts or less this evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  56  76  54  80 /  10  30  10  20
ALW  57  77  56  84 /  10  20  10  20
PSC  59  81  58  86 /   0  50  10  10
YKM  51  77  51  82 /   0  20  10  20
HRI  57  80  56  84 /  10  40  10  20
ELN  53  74  51  80 /  10  30  10  20
RDM  47  73  52  75 /  20  40  20  40
LGD  52  70  51  76 /  20  50  20  40
GCD  50  74  51  79 /  30  30  20  30
DLS  55  80  58  82 /  10  20  20  30

&&

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

$$

SHORT TERM...77
LONG TERM....86
AVIATION...77

NWS PDT Office Area Forecast Discussion