778
FXUS66 KPDT 041051
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
351 AM PDT Thu Jul 4 2024

.UPDATED AVIATION DISCUSSION

.AVIATION...12Z TAFS...VFR conditions will remain through this
TAF period with clear skies. Winds will be generally light.
Feaster/97

&&

.PREV DISCUSSION... /issued 259 AM PDT Thu Jul 4 2024/

SHORT TERM...Today through Friday...A ridge of high pressure
continues building offshore of the region shown from the water
vapor imagery. This supports a warming trend of high temps in the
90s to lower 100s across the forecast area with temps 5-20 degrees
above normal into next week. Observed from the NBM, probability
of exceeding 100 degrees for Friday is broadly 20- 50% around the
Columbia Basin and the eastern Columbia River Gorge, but locally
60-80% for central OR. Given the incoming heat wave and low
relative humidity, this will facilitate Moderate to Major HeatRisk
across the lower elevations and elevated concerns for fire
weather potential due to critically dry environment. And due to
these conditions, heat advisories and warnings have been issued
starting Friday into next week. Winds will be light across the
forecast area with occasional wind gusts between 15-25mph around
Kittitas valley (80-100% confidence). Feaster/97

LONG TERM...Saturday through Thursday...Sensible weather concerns
through the extended forecast will revolve around a prolonged
heatwave that will bring Moderate to Major HeatRisk across many
lower elevation and mountain valley locations.

An upper level ridge of high pressure will be the main synoptic
feature impacting the region through the latter half of next week.
The ridge axis will start offshore western CONUS on Saturday, then
gradually push east over the region where it will be centered
along the 114W Meridian by Thursday. With the ridge overhead, very
dry conditions will develop area-wide, while very hot
temperatures develop and linger through Thursday. Winds will also
generally be light with locally breezy conditions developing in
the afternoons through late next week.

High temperatures across most lower elevations will generally be
between 100 to 105 degrees (confidence 90-100%), while
temperatures between 105 to 110 will develop across the Columbia
Basin (confidence 75-90%). Ensembles also indicate that
temperatures between 95 to 100 degrees will develop in some
mountain valley locations across the Cascade east slopes, Blues,
and Wallowas by early next week(confidence 75-85%). Lawhorn/82

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  90  58  95  61 /   0   0   0   0
ALW  93  60  98  63 /   0   0   0   0
PSC  94  62 100  64 /   0   0   0   0
YKM  93  59 100  62 /   0   0   0   0
HRI  95  60 101  62 /   0   0   0   0
ELN  92  59  98  63 /   0   0   0   0
RDM  93  53  98  57 /   0   0   0   0
LGD  87  55  92  57 /   0   0   0   0
GCD  91  55  96  57 /   0   0   0   0
DLS  97  65 104  67 /   0   0   0   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Excessive Heat Warning from noon Friday to 10 PM PDT Thursday
     for ORZ041-044-507-508-510.

     Heat Advisory from noon Friday to 10 PM PDT Thursday for ORZ505-
     511.

WA...Excessive Heat Warning from noon Friday to 10 PM PDT Thursday
     for WAZ024-026>029-521.

     Heat Advisory from noon Friday to 10 PM PDT Thursday for WAZ523.

     Fire Weather Watch from Friday afternoon through Friday evening
     for WAZ690.

&&

$$

SHORT TERM...97
LONG TERM....82
AVIATION...97