482 
FXUS66 KPDT 121730
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1030 AM PDT Fri Apr 12 2019

Updated aviation discussion

.SHORT TERM...Today and tonight...A moist northwest flow continues 
today with the main moisture plume now oriented northwest to 
southeast across eastern Washington and into northeast Oregon. Most 
of the precipitation is now confined to these areas as upslope 
showers continue to feed into the northern Blue Mountains. Some snow 
is still expected through the day with snow levels rising up to 
around 5000 feet in the afternoon. Expect current winter storm 
warnings and advisory to be allowed to expire at 11 AM as the trend 
will be for showers to decrease this afternoon. The upper level 
ridge of high pressure off the coast will begin to shift inland 
today and will eventually bring the precipitation to an end by this 
evening.  


&&

.HYDROLOGY...Rain amounts of 0.50 to close to an inch have occurred 
along and over the Blue Mountains over the past 12 hours. This has 
kept the streams and river high with some increase in flows 
overnight.  As shower activity slowly shifts east today, should 
start to see flow decrease, but will be quite slow with some 
flooding along them expected through tonight.  Will continue current 
areal warnings over the next 24 hours.  River flood warnings will 
continue to Umatilla at Gibbon, Walla Walla at Touchet and John Day 
at Service Creek. 93  

.AVIATION...18Z TAFs...Scattered upslope showers will continue near 
ALW/PDT into this afternoon with ceilings around 050-070 AGL while 
the remaining terminals stay dry and partly cloudy. Skies will 
continue clearing overnight but then increasing high clouds return 
early Saturday. Winds remain generally less than 10KTs, except 10-
15KTs at DLS today. 

&&

.PREV DISCUSSION... /issued 251 AM PDT Fri Apr 12 2019/ 

SHORT TERM...Today through Sunday night. Strong northwest flow
aloft remains over the region this morning. Skies are mostly
cloudy. Radar continues to show precipitation over northeastern
Oregon and southeastern Washington with good upslope flow into the
Blues. Expecting a tenth to a quarter inch additional rain here.
Snow level about 4-5k with several more inches snow accumulation
this morning. Elsewhere amounts will be much less. Offshore upper
ridge building into the region later today. Clouds and 
precipitation will be decreasing. Fair weather tonight with the 
ridge overhead. An upper level trough will then push a cold front 
through the forecast area Saturday. This will bring additional 
rain with some higher elevation snow. Breezy westerly winds late 
in the day after frontal passage. Another brief break Sunday with 
a drier westerly flow aloft. Partly to mostly cloudy skies. The 
next system then moves into the Pacific northwest Sunday night and
Monday with rain and higher elevation snow again. 94

LONG TERM...Monday through Friday...Precipitation will continue 
Monday into Tuesday as moist westerly, then southwesterly flow ahead 
of an upper level low coming ashore near the mouth of the Columbia 
River streams through the region. QPF amounts will be on the lighter 
side, .2 to .4 inches in the mountains falling largely as snow (snow 
levels 3000-4000 ft) with less than a tenth of an inch for the lower 
elevations falling as rain. Majority of model/ensemble solutions 
shift the ridge in the Pacific onshore by late Wednesday and keep it 
over the Inland Northwest through the remainder of the forecast 
which should result in warming and drying conditions with highs in 
the lower elevations reaching the upper 60s to lower 70s by Friday. 
While the drier conditions will be good news for those living near 
streams, creeks and rivers, high temperatures in the northern Blues 
will be in the mid 50s to lower 60s continuing a rapid melt-off 
where there is still a substantial amount of snow water equivalent 
waiting to come down above 4500 feet. Peck



&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  57  38  56  38 /  40  10  60  60 
ALW  59  40  57  41 /  50  10  70  70 
PSC  65  41  59  41 /  30   0  50  20 
YKM  63  37  58  36 /  10   0  50  10 
HRI  63  40  59  40 /  30   0  50  30 
ELN  58  36  53  35 /  10   0  50  10 
RDM  56  30  56  34 /  10   0  30  30 
LGD  51  33  54  36 /  60  20  50  90 
GCD  50  33  55  36 /  40  10  30  70 
DLS  63  40  57  40 /  10   0  60  40 

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning until 11 AM PDT this morning for ORZ502-
503.

     Winter Weather Advisory until 11 AM PDT this morning for ORZ050.

WA...Winter Storm Warning until 11 AM PDT this morning for WAZ030.

&&

$$

91/93/93