Area Forecast Discussion
Issued by NWS Pendleton, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KPDT 270939
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
239 AM PDT Tue Jul 27 2021

.SHORT TERM...Today through Thursday. Moisture continues to move
north across the forecast area with satellite showing partly to
mostly cloudy skies. Some enhancement to the clouds over the
Oregon Cascades south to the California border with showers and
thunderstorms early this morning. This activity will move across
the region during the morning hours. Another impulse over northern
Nevada will continue to move northward today with additional
showers and storms for the afternoon and evening. Dewpoints are in
the upper 40s to mid 50s so will be more humid than normal. Highs
in the 80s to mid 90s. This pattern will continue Wednesday and
Thursday with an upper ridge inland providing a southerly flow
into the Pacific northwest. Monsoon moisture and weak impulses
with bring partly cloudy skies with a chance of showers or
thunderstorms each day. The HRRR model indicates a significant
decrease in smoke and haze the next few days. Heights will be
rising a little and high temperatures will be increasing with
upper 80s and 90s. Some locations near 100 by Thu.

.LONG TERM...Friday through Tuesday...Ensembles remain in excellent
agreement through the period.  General southerly upper level flow
continues over the area as we remain between a trough off the BC
coast and a ridge over the Rockies.  As we slip into next week, the
ridge begins to weaken and shifts south resulting in southwesterly
flow and a 5-10 degree decrease in daytime high temperatures.  The
peak heat is expected Friday as increased cloud cover will limit
insolation Saturday and Sunday despite 500MB heights not peaking
until Saturday.  PWATs are well above normal with Eastern Oregon
approaching 200 percent over the weekend as another blob of
monsoonal moisture invades the area. This moisture moves east of the
area by Tuesday.

The best chance of showers and thunderstorms will be Saturday and
Sunday during the late afternoon and evening.  The deterministic
models show several weak disturbances moving through the southerly
flow during this time period. Storms will develop over the mountains
but will likely have a hard time moving too far into the Columbia
Basin as a strong cap will impede their progress northward.  Given
the expected moisture laden atmosphere, storms have the potential of
producing very heavy rainfall in a short period of time.  Earle

&&

.AVIATION...Previous discussion...06Z TAFS. Mainly vfr conditions
can be expected at all taf sites. However an isolated shower may
approach any taf site until 12z except for taf sites kykm and kpsc.
Meanwhile isolated tsra may develop near taf sites krdm and kbdn
between 22z-04z and lvl mvfr conditions may be approached.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  90  66  95  64 /  20  20  10  10
ALW  93  70  97  69 /  20  20  10   0
PSC  95  69  99  66 /  20  10  10   0
YKM  95  64  97  64 /  10  10  10   0
HRI  94  69  99  66 /  20  20  10   0
ELN  92  62  94  61 /  10  10  10   0
RDM  85  59  92  56 /  40  40  10  10
LGD  90  64  91  60 /  20  20  10  10
GCD  90  62  92  61 /  30  40  10  10
DLS  91  66  97  66 /  20  10  10   0

&&

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

$$

SHORT TERM...94
LONG TERM....81
AVIATION...81


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.