063 
FXUS66 KPDT 042311 AAA
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
411 PM PDT Sun Apr 4 2021

.Updated aviation discussion

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...The cold front, 
associated with the digging trough, is currently transversing our 
area as winds continue to increase and shift from southwest to 
northwest this afternoon. A Wind Advisory has been issued for the
Kittitas Valley until 9 PM tonight, as current observations 
across the valley have incurred advisory criteria wind speeds and 
gusts. The thermal gradient has allowed for gusts of up to 55 mph 
to occur, peaking over the next 6 hours before slowly subsiding 
tonight into Monday morning. Winds are also expected to be quite 
breezy across the region as the front passes, but should stay 
below advisory criteria as these areas are less influenced by the 
thermal gradient due to its orientation. Precipitation has mainly 
stayed to our north with this system, but will drop into our area 
later this evening. The Basin should stay dry, with the majority 
of precipitation occurring in the mountains. The Northern Blues 
should receive some snowfall on the back-end of this system 
tonight into early Monday. Expecting a minimal amount of snow, as 
the WA Cascades and Blues could pick up 0.5 to 1 inch, and the OR 
Cascades staying less than 0.5 inch. The big takeaway from this 
system will be the cooling temperatures behind the front. High 
temperatures will drop 5 to 10 degrees from tonight into Monday, 
hovering in the mid-to-upper-50s range as the lows stay 
relatively unchanged in the low-to-mid-30s. Snow levels will also
be dropping overnight tonight between 1000-2500 feet before 
rebounding back between 4000-5000 feet by Tuesday. 

A weak ridge builds just behind the departing system on Monday, 
bringing a return to drier conditions. This ridge stays through 
and into the extended period, keeping conditions dry and winds 
calm through Tuesday. 75

.LONG TERM...Wednesday through Sunday...Wednesday through Friday 
will be met with a westerly flow aloft and a few embedded waves 
bringing snow/rain showers to the Cascades with a chance of 
snow/rain showers over the eastern mountains. In general, snow 
levels will be around 3500-4500 feet during the day and 2500-3500 
feet at night.  Occasional breezy winds can also be expected during 
this time.  Models are in general agreement for the PacNW through 
the end of the work week but fall out of alignment during the 
weekend.  Despite the differences, models show some form of a trough 
around Saturday but the strength and timing are in question. Most 
ensemble members are clustering around a trough over BC and 
Washington with a strong westerly flow beneath the trough over 
Oregon.  At this time, it does not appear to be a late season heavy 
snow pattern for the mountains and valleys but this could change if 
the trough becomes more amplified and organized.  The trough may 
also bring gusty winds to the area.  NBM currently keeps PoPs less 
than 15 pct for Sunday but confidence is low based on model 
inconsistency and a continued westerly flow.  Wister/85


&&

.AVIATION...00Z TAFs...VFR conditions will prevail for the next 24 
hours. A weak disturbance may bring some -SHRA to KPDT and KALW this 
evening, but elsewhere will remain dry. It will be breezy with winds 
locally as high as 15-25 kts, especially in the Lower Columbia Basin 
and adjacent valleys. Winds will diminish late this evening, and 
clouds will also decrease as the weather disturbance departs the 
area.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  33  57  32  66 /  20  10   0   0 
ALW  36  58  37  67 /  40  10   0   0 
PSC  35  63  35  69 /  20   0   0   0 
YKM  30  64  32  69 /   0   0   0   0 
HRI  33  63  33  70 /  20   0   0   0 
ELN  30  60  32  64 /   0   0   0   0 
RDM  23  57  22  68 /  10  10   0   0 
LGD  32  50  29  62 /  30  20   0   0 
GCD  32  51  31  65 /  20  20   0   0 
DLS  35  62  35  67 /   0   0   0   0 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...Wind Advisory until 9 PM PDT this evening for WAZ026.

&&

$$

SHORT TERM...75
LONG TERM....85
AVIATION...88