Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 262142
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
242 PM PDT TUE JUL 26 2016

.SHORT TERM...Tonight through Friday evening...A weak disturbance
has caused some convective clouds to develop over mountain ridges in
northeast Oregon and along the Washington Cascade east slopes. Best
instability is over northeast Oregon, primarily Wallowa county. A
slight chance of showers and/or thunderstorms remains possible over
Wallowa county until around 5 or 6 pm. After that time the air mass
in this area will dry further while reduced heating will limit
instability. Thus expect dry conditions over all of southeast
Washington, and northeast and central Oregon during the tonight
period.

For the bulk of the Wednesday through Friday evening period, a dry
west flow will persist across the Pacific Northwest. There may be
just enough lingering moisture and instability for a few afternoon
cumulus clouds over the mountain ridges Wednesday, but no precip or
storms are expected. The air mass will be drier yet and much more
stable Thursday into Friday. Thus expect dry conditions with very
little in the way cloud cover on these two days. Afternoon high
temps will be above seasonal through this period. Highs Wednesday
should be similar to today. High temps will then rise a few degrees
each day afterward, with Friday being the hottest day. Lower Basin
highs Friday will run in the 100 to 105 degree range. 90

.LONG TERM...Saturday through Tuesday...An amplifying mid/upper
level trough in British columbia on Saturday will cause flow aloft
over the Pacific Northwest to back from the west to the WSW during
the day on Saturday, which is not enough of a change in direction of
mid level streamlines to transport mid level moisture and marginal
instability NE Oregon on Saturday. As such I have kept a dry
forecast for Saturday. The aforementioned trough will drag a dry
cold front through the region this coming weekend and this will
usher in a marine push on Saturday and Sunday, which will result in
breezy to locally windy conditions and the start of a cooling trend
that commences on Saturday and continues Sunday with cooler daytime
high temepratures 3-5 degrees below normal on Monday and Tuesday
with highs both days in the 80s at lower elevations. Since vastly
different solutions from the GFS and ECMWF 12Z model runs. The GFS
takes a strong mid/upper level trough across the region Tuesday and
the ECMWF takes the mid/upper level trough through a day earlier, on
Monday. The 12Z Canadian model run  preforms in a similar manner to
the ECMWF 12Z run in terms of the timing the trough passage to occur
on Monday. Given the degree inconsistency among the models for
Monday and Tuesday, I decided to keep a dry forecast for Monday and
Tuesday to stay in agreement with neighboring NWS Weather Forecast
Offices in the Pacific Northwest. Polan

&&

.AVIATION...Previous Discussion...18z TAFS...VFR conditions will
persist across all TAF sites for the next 24 hours. Sustained winds
through this afternoon will be 7-13 kts, except at KDLS where winds
will be around 20 kts with gusts to 28-30 kts. Winds will decrease
tonight to 4-10 kts. Polan

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  59  94  60  97 /   0   0   0   0
ALW  67  95  68  98 /   0   0   0   0
PSC  64  98  62 100 /   0   0   0   0
YKM  63  98  62 101 /   0   0   0   0
HRI  62  97  62 100 /   0   0   0   0
ELN  62  95  62  98 /   0   0   0   0
RDM  47  93  48  95 /   0   0   0   0
LGD  53  91  52  93 /   0   0   0   0
GCD  55  95  55  97 /   0   0   0   0
DLS  63  95  63 101 /   0   0   0   0

&&

.PDT Watches/Warnings/Advisories...
OR...None.
WA...None.
&&

$$

90/99/99



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