899
FXUS66 KPDT 180923
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
223 AM PDT Tue Jun 18 2024

.SHORT TERM...Today through Thursday...

Bottom Line Up Front

1.  Dry and warm conditions favor the period with slight chances of
mountain showers/thunderstorms

2. A thermal trough will bring warm temperatures to the region by
midweek

Models show the upper level low that has been over the area is
moving off to the east taking the cooler air along with it.
Precipitation will diminish leaving only a slight chance (less than
30%)  of showers and thunderstorm over the eastern mountains of
Wallowa County and showers along the WA Cascades before clearing out
completely this afternoon. Model derived soundings show the eastern
portion of Wallowa County will see MUCAPE up to 400 J/kg, lapse
rates of 8.4 C/km, lifted index of -2, however, bulk shear is low at
15 kts. With that said, can not rule out an occasional roll of
thunder of flash of lighting along the far eastern mountains this
afternoon.  Once the trough exists later in the afternoon, early
evening, models show the upper level flow to turn more zonal. Drier
conditions will accompany the zonal flow.

Looking at the surface, models do show a weak thermal trough
wiggling its way northward and in place over the area by Wednesday
bringing with it much warmer temperatures. EFI shows temperatures
are still near normal to just below normal remaining a bit on the
cooler side today with 79% of the raw ensembles showing Pendleton
and Central Or to be in the mid 60s to low 70s, the Gorge and Basins
in the mid to upper 70s with the higher terrains in the mid to upper
50s. As the thermal through moves overhead by Wednesday,
temperatures will increase nearly 10 degrees with over 70% of the
raw ensembles showing Pendleton and central OR in the upper 70s to
low 80s, the Gorge and Basins in the low to mid 80s and the higher
terrains in the mid 60s. Thursday temperatures will be 2 to 5
degrees warmer. 65% of the raw ensembles show Pendleton and central
OR in the mid to upper 80s, the Gorge and Basins in the low 90s and
the higher terrains in the upper 60s to low 70s. Bennese/90

.LONG TERM...Friday through Monday..A trough over the area early
Friday will give way to a ridge which will remain over the area
Saturday before moving eastward on Sunday as a cold front and
upper trough move into the Pacific Northwest. Hot temperatures are
expected Friday and Saturday with highs 10 to 15 degrees above
normal. Highs will mainly be in the upper 80s to lower 90s on
Friday and in the 90s on Saturday.

The trough will bring some precipitation potential to the
Washington Cascades, but the rest of the area will remain dry. The
low rain chances will remain over the Washington Cascades through
Monday, but little if, any rain is expected across the majority of
the area through the extended period.

High temperatures will be closer to normal (though still above) on
Sunday, then a few degrees below normal on Monday before returning
to close to or slightly above normal on Tuesday.  Sunday`s highs
will generally be in the low to mid 80s.  On Monday high
temperatures will be in the upper 70s to lower 80s and then back in
the 80s on Tuesday.

Winds are expected to be mainly light through the period, though
they will be a bit breezy later Saturday and especially Sunday with
the passage of the front and with the trough moving across.

Overall, model guidance is in generally good agreement through
Tuesday, when disagreement becomes more substantial.  THe ECMWF
deterministic has a more zonal pattern while the GFS has another
trough approaching.  The ensemble clusters show a bit more support
for the ECMWF with 33% supporting its solution, though the clusters
are fairly even split for the other model solutions.  Of course
there is natural variability in the guidance at this time range.


&&

.AVIATION...12Z TAFS...VFR conditions and decreasing clouds at
PDT and ALW are expected. Winds are generally be 10 kts or less.


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  73  45  83  51 /   0   0   0   0
ALW  76  48  85  54 /   0   0   0   0
PSC  78  49  87  55 /   0   0   0   0
YKM  76  47  84  53 /   0   0   0   0
HRI  78  48  88  53 /   0   0   0   0
ELN  76  46  82  51 /  10   0   0   0
RDM  72  39  81  46 /   0   0   0   0
LGD  68  41  78  47 /  10   0   0   0
GCD  70  41  80  48 /   0   0   0   0
DLS  78  52  88  58 /   0   0   0   0

&&

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

$$

SHORT TERM...90
LONG TERM....77
AVIATION...77