Area Forecast Discussion

from: NWS Pendleton, OR

FXUS66 KPDT 141009 CCA

Area Forecast Discussion
National Weather Service Pendleton OR
300 AM PDT Mon Jun 14 2021


.SHORT TERM...Today through Wednesday night...Latest radar was
continuing to show a plume of moisture along the wa/or cascades.
Some convection fired over this area yday but with the cooler temps
and cloud cover lacked the energy to produce strong storms and a
similar case may be today. Meanwhile further east isold tsra did
fire up over Grant county that extended north along the blue/wallowa
mtns yday in the better energy area despite a dry rap/hrr model and
may continue with this aggressive approach.

A low pressure system over the epac that was responsible for the
moisture will remain stationary while keeping the region in a
southerly moist flow aloft. The leading edge of the showers and
embedded tsra over the cascades will drift slowly east today. A
challenge will be with the timing and advancement of the pcpn.
Additional moisture ahead of the plume may advect into the eastern
zones later today that may develop additional showers and
thunderstorms over this area.

Some of the storms over the eastern sections may become strong
depending on where there is abundant sunshine to generate enough
energy/instability. The forecast was more aggressive in adding and
expanding the convective coverage to include the blues/wallowas and
surrounding area this afternoon/eve.

As the plume advances slowly east all of the region should be
impacted in some way with showers and isold tsra this evening. A
focus will be tonight when the rap/hrr were producing a developing
area of showers and thunderstorms over north central oregon and
south central Washington. The confidence is increasing that this
area should develop between 03z to 07z tonight and expand in
coverage and intensity before drifting north by Tuesday morning.
Elsewhere showers with isolated tsra will persist across most of the
region with the best chance of convection over the eastern forecast
area later tonight and Tuesday morning.

The models were persistent in keeping a swath of rain showers and
isold tsra from central oregon northeast into the blues/wallowa
Tuesday before this area decreases in coverage and moves east and
away from our area Tuesday night. By Wednesday drier conditions can
be expected with a warmer afternoon temps.

.LONG TERM...Thursday through Monday...Dry and hot conditions will
prevail in the long term as zonal flow gives way to broad ridging
heading into the weekend. Ensembles in pretty good agreement on
this, with highs reaching the low to mid 90s in the Basin, with
upper 80s into low 90s in central OR, and 70s and 80s in the
mountains by Friday. NBM and ensembles keep highs pretty stagnant
through the period, as the ridge lacks a strong magnitude needed for
more robust warming. Ensembles then try to bring in a weak shortwave
late Saturday into Sunday, which may increase the winds a bit to
create elevated fire weather concerns. At this time, winds look to
be only slightly breezy, but NBM does have RHs plummeting into the
low to mid teens across much of the forecast area in light of high
pressure over our area. Recent wetting of fuels may help a bit, but
even a slight breeze can be problematic given critical RHs.

Beyond the weekend, ensembles are pretty consistent on introducing
another ridge into the area. Much of the long term period and
beyond, as a result, looks to be hot and dry as we head into the
summer solstice. 74

.AVIATION...06Z TAFS...VFR conditions will prevail at all terminals
this evening. There have been some weak convection at or near KRDM,
KBDN, KDLS and KYKM this evening, but the strongest storm was hear
KYKM. Brief MVFR conditions are possible with some of the stronger
storms due to reduced visibility. Breezy to windy conditions will be
associated with showers and thunderstorms tonight through Monday
evening with the strongest winds being 20 to 30 kts, but most winds
will be from 10 to 20 kts with some higher gusts. 88


PDT  83  53  72  46 /  10  60  30  10
ALW  88  57  75  51 /  10  70  40  10
PSC  87  61  79  52 /  10  70  40   0
YKM  77  53  78  44 /  40  20  30   0
HRI  86  58  77  50 /  10  60  30  10
ELN  75  52  72  45 /  40  20  30  10
RDM  70  46  69  37 /  50  30  30  10
LGD  84  55  71  44 /  20  50  30  20
GCD  87  50  77  43 /  20  30  30   0
DLS  73  56  74  50 /  50  20  30   0





NWS PDT Office Area Forecast Discussion