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000
FXUS66 KPDT 271722
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
1022 AM PDT FRI MAY 27 2016

updated aviation discussion

.SHORT TERM...Morning Update...An upper level low will remain over
British Columbia through at least tonight. The upper flow will
gradually turn from northwesterly to westerly through tonight.
Meanwhile the low level flow will remain westerly and onshore. Thus
temps today and tonight will run slightly below seasonal, and winds
will be breezy to locally windy into the evening. The best chances
of showers will be near the Cascade crest due to slop over from the
west side. There may also be a few stray showers over the northern
Blues and Wallowa county at times today. Otherwise conditions will
be dry through tonight. Overall the forecast package is on track
with updates being made to wind speeds, shower locations, sky cover
and high temps. 90

.LONG TERM...Previous Discussion...An upper low will move just north
of the area Sunday evening. There will likely be sufficient
instability over the far eastern mountains for a few showers and
thunderstorms ending by late in the evening. For the remainder of
the period a building upper ridge will result in a significant warm-
up next week. By Thursday high temperatures could reach the middle
90s in the lower elevations with 80s in the mountains. The warm
weather could continue on Friday. The GFS model hints at some minor
potential for isolated storms on Thursday and Friday but it may be
breaking down the ridge too quickly. For this forecast package
followed the ECMWF solution which holds onto the ridge until the
first part of next weekend. The only period of significant winds
will be Sunday evening with breezy to windy conditions in the lower
elevations.

&&

.AVIATION...18Z Tafs...VFR conditions will prevail through the
forecast period. Expect a few CU over and near the mountains
today then SCT-BKN mid and high clouds overnight and
Saturday. Winds will be sw-nw at 10-20KT except 20-30KT at KDLS and
15-25KT at KPDT this afternoon. Winds decrease overnight.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  65  43  69  49 /   0   0  10  10
ALW  65  46  69  50 /  10   0  10  10
PSC  72  46  72  47 /   0   0  10  10
YKM  70  42  72  47 /  10  10  10  10
HRI  70  44  72  46 /   0   0  10  10
ELN  63  44  69  47 /  10  10  10  10
RDM  63  32  68  39 /   0  10  10  10
LGD  61  36  64  42 /  10  10  10  10
GCD  64  37  68  41 /  10  10  10  10
DLS  66  47  73  52 /  10  10  10  10

&&

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

$$

90/78/91





000
FXUS66 KPDT 270844
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
144 AM PDT FRI MAY 27 2016

.SHORT TERM...Today through Sunday...A broad upper trough
is currently settling over the Pacific Northwest. There is limited
moisture with this system and the main effects are breezy to windy
conditions and some clouds. There are a few showers over eastern and
northeast Washington but expect those to remain to the north of the
CWA. Pressure gradients are tight and this is resulting in breezy to
windy conditions now...which will continue into tonight. The trough
axis is then forecast to move eastward with a westerly flow taking
over behind the trough on Saturday. There may be a few upslope
showers over the northeast mountains and some spill over moisture
onto the Cascade east slopes. Elsewhere it will remain dry. On
Sunday the flow is expected to become southwest with some increase
in moisture and instability over the northeast mountains. Though
this is not an ideal thunderstorm pattern there is enough confidence
to have a chance of afternoon showers and a slight chance of
afternoon thunderstorms in the forecast over the northeast mountains
on Sunday into Sunday evening. At this time am only weak
thunderstorms are expected. There will be a slow warming trend today
through Sunday with cooler than normal highs today...warming to the
mid to upper 70s in the lower elevations by Sunday...which will be
near normal. 88

.LONG TERM...Sunday night through Friday...an upper low will move
just north of the area Sunday evening. There will likely be
sufficient instability over the far eastern mountains for a few
showers and thunderstorms ending by late in the evening. For the
remainder of the period a building upper ridge will result in a
significant warm-up next week. By Thursday high temperatures could
reach the middle 90s in the lower elevations with 80s in the
mountains. The warm weather could continue on Friday. The GFS model
hints at some minor potential for isolated storms on Thursday and
Friday but it may be breaking down the ridge too quickly. For this
forecast package followed the ECMWF solution which holds onto the
ridge until the first part of next weekend. The only period of
significant winds will be Sunday evening with breezy to windy
conditions in the lower elevations. 78

&&

.AVIATION...12Z Tafs...VFR conditions will prevail through the
forecast period. Expect SCT-BKN mid and high clouds and perhaps a
few CU mainly over the mountains during the afternoon. Winds will be
sw-nw at 10-15KT except 20-30KT at KDLS and 15-25KT at KPDT this
afternoon. 78

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  63  43  69  49 /  10  10  10  10
ALW  63  46  69  50 /  10  10  10  10
PSC  73  46  72  47 /  10   0  10  10
YKM  70  42  72  47 /  10  10  10  10
HRI  70  44  72  46 /   0  10  10  10
ELN  64  44  69  47 /  10  10  10  10
RDM  64  32  68  39 /  10  10  10  10
LGD  61  36  64  42 /  10  10  10  10
GCD  63  37  68  41 /  10  10  10  10
DLS  66  47  73  52 /  10  20  10  10

&&

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

&&

$$

88/78/78





000
FXUS66 KPDT 270447 AAA
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
940 PM PDT THU MAY 26 2016

.UPDATE...A low pressure system to our north had tightened pressure
gradients across the area creating breezy to windy conditions today.
Since then these tight gradients had lessened resulting in
allowing the wind advisory to expire over the gorge. However brief
wind gust between 30 to 40 mph are still possible this evening across
most portions of our area.

Meanwhile a west wind was creating some upslope flow and a few
showers are possible tonight over the cascade crest. Elsewhere a
weak disturbance could brush our far nw cwa and a few showers are
possible over the northern blue mountains and along and near the
wallowa mountains overnight. Otherwise our overnight low temps
remain in the ball park and the present short term forecast appears
on track for now.

&&

.AVIATION...Brief wind gusts to 30 to 35 kts are possible across
most taf sites until 08z. Otherwise mainly vfr conditions should
persist across all taf sites for the next 24 hours.

&&

.PREV DISCUSSION... /issued 249 PM PDT THU MAY 26 2016/

Short Term...Tonight through Sunday...A mostly dry cold front
associated with an upper level low over British Columbia continues
to move across the region this afternoon. Precip with this front
will be limited to a few showers over Wallowa county and along the
Cascade east slopes. Winds are breezy to windy in the Gorge, and
across the Columbia Basin and it`s adjacent valleys. Local very
windy conditions will continue to be possible into early evening,
especially in the Gorge. Thus will continue the current advisory in
the Gorge. The upper low will linger over British Columbia Friday
through Sunday. As such will see a persistent westerly onshore flow
through this period. Winds will be breezy to windy again Friday and
Friday evening. Winds will be lighter over the weekend. Generally
can expect dry conditions across the area due to the west flow.
There will be some showers at times near the Cascade crest and into
the Cascade east slopes, as well as over our northeastern mountain
zones. A wave in the flow on Sunday may cause isolated to scattered
showers over our eastern zones as well as near the Cascade crest.
Also a slight chance of thunderstorms may be possible over Union and
Wallowa counties Sunday afternoon due to this wave. 90

Long Term...Sunday night through Thursday...Models in fair
agreement on upper ridge building across the region beginning Monday
which a chance for an intrusion of moisture from the south by
Thursday. GFS has an upper level low pressure area scooting by
across northern WA and ID panhandle Sunday night and Monday. Will
keep a small chance for thunder in Wallowa County Sunday night and
small chance for showers along the Central WA Cascades. This will
also keep breezes going in the Kittitas valley. With the upper level
ridge, we will see above normal temperatures return for Tuesday
through Thursday. The warm temperatures aloft combined with short
nights will lead to poor humidity recovery overnight on the ridges
which may be a concern for land managers. Both GFS/EC models agree
on increasing moisture by Thursday so have put in a chance for
thunderstorms over mainly the mountains.

Aviation...Previous Discussion...18z TAFs...Westerly winds
increasing becoming 15-30kt. Strongest winds likely at KDLS and
KPDT. Weak instability with cumulus developing at 040-070. Otherwise
upper low moving into the Pac NW with sct-bkn 200.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  45  66  43  71 /  10  10  10  10
ALW  49  66  46  71 /  10  10  10  10
PSC  49  73  46  74 /  10  10   0  10
YKM  40  70  42  74 /  10  10  10  10
HRI  48  70  44  74 /  10   0  10  10
ELN  45  64  44  71 /  10  10  10  10
RDM  34  64  32  70 /  10  10  10  10
LGD  41  61  36  66 /  10  10  10  10
GCD  39  63  37  70 /  10  10  10  10
DLS  49  66  47  75 /  10  10  10  10

&&

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

$$

97/97





000
FXUS66 KPDT 261248
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
547 AM PDT THU MAY 26 2016

.SHORT TERM...Today through Saturday afternoon...Westerly flow aloft
will occur today across forecast area ahead of a large upper low
pressure system digging southeast over British Columbia. This flow
pattern will sinking air and thus subsidence east of the Cascades,
which will produce dry conditions across the region through this
afternoon.

Increasing pressure gradients will produce windy conditions in the
Eastern Columbia River Gorge and a Wind Advisory is in effect for
this area from 11 AM this morning through 8 PM this evening.

Tonight and Friday the aforementioned low opens up to a broad
mid/upper level trough, which will cover British Columbia as well as
WA/OR. Forecast area will remain on the southern flank of the trough
thus giving us westerly flow aloft and therefore dry conditions
through Friday afternoon, except for slop over showers along the
east slopes of the WA/OR Cascades. Friday night and Saturday the
same synoptic scale flow pattern continues in place for a
continuation of dry conditions, but with a chance of showers near
the crests of the Cascades.  Polan

.LONG TERM...Saturday night through Wednesday. Upper level trough
moving across the Pacific Northwest Sunday into Monday. This will
result in partly to mostly cloudy skies with scattered showers.
Some instability Sun afternoon could bring a few thunderstorms over
central and northeast Oregon. This system will keep temperatures
near normal levels with highs in the 60s and 70s. A ridge will then
build across the area Tuesday into early Wednesday with clear to
partly cloudy skies and warmer temperatures. Highs will be in the
70s to lower 80s. An approaching trough may bring some showers and
thunderstorms Wed night into Thursday. 94

&&

.AVIATION...12z tafs. Westerly winds increasing today becoming 15-
30kt. Weak instability with cumulus developing at 040-070. Otherwise
upper low moving into the Pac NW with sct-bkn 100-200.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  70  45  66  44 /   0  10  10  10
ALW  72  49  66  48 /   0  10  10  10
PSC  77  49  71  49 /   0   0  10   0
YKM  76  43  70  44 /   0  10  10  10
HRI  75  48  69  46 /   0  10  10  10
ELN  68  46  64  45 /   0  10  10  10
RDM  67  34  63  35 /   0  10  10  10
LGD  66  41  61  39 /   0  10  10  10
GCD  68  40  63  37 /   0  10  10  10
DLS  70  50  66  49 /   0  10  10  10

&&

.PDT Watches/Warnings/Advisories...
OR...Wind Advisory from 11 AM this morning to 8 PM PDT this evening
     for ORZ041.

WA...Wind Advisory from 11 AM this morning to 8 PM PDT this evening
     for WAZ024.

&&

$$

99/94/94





000
FXUS66 KPDT 251621
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
921 AM PDT WED MAY 25 2016

.SHORT TERM...Morning Update...An upper level trough will continue
to weaken and shift east today. Thus upper level flow will become
increasingly northwesterly and drier. Surface flow will become
increasingly onshore with breezy winds through the Cascade gaps,
particularly into the Gorge and the Kittitas Valley. These winds
will keep high temps slightly below seasonal in the Gorge, the
Kittitas Valley, and over north-central and central Oregon. There
will be enough instability and lingering moisture for isolated to
scattered showers from the Blue mountains east to Wallowa county and
south through Grant county. Instability over Wallowa county may be
sufficient for stray, brief thunderstorms from mid afternoon to
early evening. Elsewhere, a few showers may occur over mountain
ridges. Updates this morning included adding the mention of
thunderstorms in Wallowa county, adjusting shower coverages, winds
and high temps. 90

.LONG TERM...Previous Discussion...Weak upper level trough over
the region Saturday and Sunday with northwest flow aloft. Scattered
showers over the Cascades and Blues otherwise partly to mostly
cloudy skies. Temperatures near normal with highs in the 60s to mid
70s. Upper level ridge building into the area Monday and Tuesday
with partly cloudy skies and warmer temps. Highs in the 70s with
near 80 in the Columbia basin. No significant winds expected through
the extended period.

&&

.AVIATION...Previous Discussion...12Z TAFS...Sct-bkn 040-070 today
and tonight. Winds increasing late morning into the afternoon
becoming westerly 10-25kt.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  74  48  69  46 /   0   0  10  10
ALW  74  52  70  50 /  10   0  10  10
PSC  80  52  76  50 /   0   0   0  10
YKM  79  48  72  44 /  10   0   0  10
HRI  78  51  73  49 /   0   0   0  10
ELN  73  48  65  46 /   0   0  10  10
RDM  66  38  65  36 /  10   0  10  10
LGD  69  44  65  42 /  20  10  10  10
GCD  69  42  66  41 /  20  10  10  10
DLS  72  52  68  51 /  10   0  10  10

&&

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

$$

90/94/91





000
FXUS66 KPDT 251037
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
324 AM PDT WED MAY 25 2016

.SHORT TERM...Today through Friday night...Weak flow aloft
today is associated with a broad long wave mid/upper level trough.
Very marginal shallow layer of instability will yield scattered rain
showers in the Blue Mountains eastward to Idaho this afternoon.
Elsewhere, dry conditions expected through this afternoon. Tonight
and Thursday westerly flow aloft will occur across forecast area
ahead of a large upper low digging southeast over British Columbia.
This flow pattern will produce dry conditions across the region
through Thursday afternoon. Thursday night and Friday the
aforementioned low opens up to a broad upper level trough, which
covers British Columbia as well as WA/OR. Forecast area will remain
on the southern flank of the trough thus giving us westerly flow
aloft and therefore dry conditions through Friday afternoon, except
for slop over showers along the east slopes of the WA/OR Cascades.
Friday night the same synoptic scale flow pattern continues in place
for a continuation of dry conditions, but with a chance of showers
near the crests of the Cascades.  polan

.LONG TERM...Saturday through Tuesday. Weak upper level trough over
the region Saturday and Sunday with northwest flow aloft. Scattered
showers over the Cascades and Blues otherwise partly to mostly
cloudy skies. Temperatures near normal with highs in the 60s to mid
70s. Upper level ridge building into the area Monday and Tuesday
with partly cloudy skies and warmer temps. Highs in the 70s with
near 80 in the Columbia basin. No significant winds expected through
the extended period. 94

&&

.AVIATION...06Z TAFS...VFR conditions expected to prevail over the
next 24 hours at all terminals. SCT-BKN clouds around 5k ft AGL will
continue to affect KBDN and KRDM for the next several hours before
gradually lifting/scattering out. Otherwise just a FEW to SCT mid
level clouds expected...mainly between 5k to 10k ft AGL through the
period...with the greatest cloud cover percentage expected during
the afternoon hours Wednesday as diurnally induced clouds develop(CU)
...especially over and INVOF the mountains. There will be a chance
for showers or even a thunderstorm Wednesday afternoon over the Blue
Mountains and into Wallowa County. It will remain dry elsewhere.
Winds stay generally light overnight...mainly less than 12 KTS at
all TAF sites. Then winds increase after 25/18z to between 10-20
KTS...except KDLS which will have WNW winds of 15 to 30 KTS
Wednesday afternoon. 77

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  73  48  69  46 /   0  10  10  10
ALW  75  52  70  50 /  10  10  10  10
PSC  81  52  76  50 /   0  10   0  10
YKM  78  48  72  44 /   0  10   0  10
HRI  79  51  73  49 /   0  10   0  10
ELN  72  48  65  46 /   0  10  10  10
RDM  67  38  65  36 /  10  10  10  10
LGD  67  44  65  42 /  20  10  10  10
GCD  68  42  66  41 /  10  10  10  10
DLS  73  52  68  51 /   0  10  10  10

&&

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

$$

99/94/94





000
FXUS66 KPDT 250421
AFDPDT

Area Forecast Discussion
National Weather Service Pendleton OR
920 PM PDT TUE MAY 24 2016

.UPDATE...Only minor adjustments made to PoPs, sky cover, temps and
winds as the short term forecast appears to be generally on track.
Sky cover was lowered some over the Columbia Basin tonight as the
diurnal clouds dissipate quickly. Sky cover was also lowered
tomorrow in the Columbia Basin as the brisk westerly flow and mid
level dry air should inhibit cloud development here. Temperatures
were raised 1-3 degrees over the Lower Yakima Valley and Columbia
Basin as the latest guidance indicated highs reaching into the lower
80s here Wednesday afternoon. Still expecting CU build up with a
chance of showers and a slight chance of thunderstorms over the
Eastern Mountains and Wallowa County again Wednesday afternoon
...PoPs were massaged to between 20-40 percent here in the
afternoon...except near 60 percent over the Eagle Caps. Instability
is looking marginal...with MUCAPE between 200-500 J/Kg and LIs
between 0 and minus 2.5 so continued with only a slight chance of
thunder. The other story for Wednesday will be the increasing winds
over the Columbia Gorge, Kittitas Valley and into the Lower Columbia
Basin. At this time winds look to stay under advisory criteria on
Wednesday afternoon...with west to northwest winds of 20-30 MPH and
gusts to near 40 MPH in the above mentioned locations. Winds are
still looking a bit stronger heading into Thursday for much of the
same areas and extending into the foothills zones...winds could push
advisory criteria at times on Thursday for parts of the area. Will
also need to watch for patchy blowing dust in the Lower Columbia
Basin with the stronger winds developing. On another note...
although fuels are still generally moist and min RHs are only
forecast to be in the 25-35 percent range any grass fires that may
start (human caused) have the potential to spread quickly both
Wednesday and Thursday afternoon in the breezy/windy conditions. 77

&&

.PREV DISCUSSION... /issued 345 PM PDT TUE MAY 24 2016/

SHORT TERM...tonight through Friday...weak cyclonic flow will be
over the region through Friday transitioning to a strong upper low
passing just north of the forecast area Thursday night and Friday.
For this evening there will be a few showers over the eastern
mountains with a very slight chance of a thunderstorm over Wallowa
County. On Wednesday the short term models depict a bit more
instability over the eastern mountains so have maintained a slight
Chance of thunderstorms for the afternoon and evening. Winds will
pick up in the Kittitas Valley and Columbia Gorge during the
afternoon and evening and could push advisory levels. High
temperatures Wednesday will be mostly in the 70s lower elevations
with 60s in the mountains. On Thursday expect mostly dry and
slightly cooler conditions but there will be some wind impacts.
Winds in the Columbia Gorge and Kittitas Valley could reach advisory
levels. For Friday the upper low will be passing to the north. The
trajectory of the low does not lend itself to much airmass
destabilization or moistening of the airmass. Thus just expect a few
mountain showers and continued breezy/windy conditions in the
Cascade gaps. 78

LONG TERM...Friday night through Tuesday. Previous forecast
discussions focused on the cool and unsettled weather for the first
half of the Memorial holiday weekend, but latest runs are showing
less amplitude of the upper level trough and more of a westerly flow
aloft than a cyclonic flow over WA/OR. Therefore, showers and
thunderstorms do not appear to be strong with heavy downpours like
what was observed last weekend. The threat of thunderstorms on
Friday evening and Saturday will be slight chance at best and mainly
from the Blue Mtns eastward. The first shortwave trough will exit
the region Friday night, and high pressure building behind the
system will result in gusty winds, especially through the Kittitas
Valley and the Eastern Columbia River Gorge. Another shortwave
trough will follow on Memorial Day with similar weather conditions.
The biggest concern for the holiday weekend will be the unseasonably
cool temperatures, mainly at night. There could also be light snow
accumulations above 5000 feet Friday evening. Wister

AVIATION...00Z TAFS. VFR conditions will prevail with sct-bkn
layers of stratocumulus and cumulus through Wednesday afternoon.
Winds will be less than 15 knots but NW winds 15-25 knots can be
expected at KDLS this afternoon and again after 20Z/25th.  Wister

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  50  73  48  70 /  10  10  10  10
ALW  52  76  51  71 /  10  10  10  10
PSC  51  81  52  76 /  10   0  10   0
YKM  48  80  48  72 /  20   0  10   0
HRI  51  80  50  74 /  10  10  10   0
ELN  49  74  47  67 /  10  10  10  10
RDM  40  68  37  65 /  10  10  10  10
LGD  45  68  44  65 /  20  20  20  10
GCD  43  70  42  67 /  10  10  10  10
DLS  54  73  52  69 /  10  10  10  10

&&

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

$$

77/85/77





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