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000
FXUS66 KPQR 120401 AAA
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
900 PM PDT Thu Apr 11 2024

Updated Aviation discussion

.SYNOPSIS...
A front offshore will bring light rain to the region overnight into
early Friday, with lingering showers on Friday. Then, high pressure
will build, lasting into Sunday. Best day will be Saturday, with
temperatures well into the 60s. But, such pleasant weather will be
fleeting, as pattern change for next week. High pressure will sit
offshore as upper trough digs over the Rockies. This will bring
cooler temperatures, with some showers from time to time.
&&

.SHORT TERM...Increasing clouds across the region this afternoon into
this evening. A front offshore will push light rain to the coast
between 5 and 7 pm, with that rain lasting into the overnight hours.
Not heavy, but enough to make things wet. This front will be
weakening as it moves slowly eastward, with rain becoming more spotty
in nature to east of the Cascades and Willapa Hills.

A 1005 mb low, sitting well offshore of the Pac NW this afternoon,
will drop southeastward through Friday, ending up off well west of
the San Francisco Bay area by Fri evening. As such, will not see all
that much cooler air aloft push inland on Friday behind our front, as
that cooler air will be shunted southward and mostly offshore. So,
will see tonights front weaken further and fall apart over western
Oregon on Friday. As such, will go with decreasing shower potential,
from south Washington to Lane County through the day. Will trend
forecast to reflect that pattern.

As the low remains farther south over Calif into Nevada on Saturday,
will see high pressure over Washington and north Oregon. This will
bring warmer temperatures to the region, with highs well into the 60s
for most inland areas, with upper 50s to lower 60s on the coast.
Overall, will remain dry. But, with easterly flow (thanks to the low
to the south), will see some potential for scattered showers over the
Cascades, mainly to south of Mount Jefferson. Could even see a shower
or two drift farther to the west, such over the Willamette Valley. If
so, any rainfall would be very light. Not expecting any thunder, but
can not rule such over the Cascades for SAT afternoon into the early
evening.                            /Rockey


.LONG TERM...SUNDAY THROUGH WEDNESDAY...Showers potential decreasing
through the day on Sunday as the low over the Calif shifts farther
east into the southern Great Basin. Ensemble guidance is in good
agreement regarding a new low pressure area moving from British
Columbia southeastward over the Pac NW into the Rockies early next
week. With this, will have a few waves of moisture may clip us with
showers at their edge at times. Snow levels will be around 1500 ft
Monday and Tuesday night, but QPF values look to be light and
non-impactful. From Wednesday onwards, WPC cluster analysis shows a
60% chance of high pressure building back in, increasing to 80% on
Thursday. There`s currently potential for an omega block situation
with this ridge, bringing a dry and warm conditions.       /JLiu
&&

.AVIATION...Southwest flow aloft while a weak frontal boundary
sits along the coast this evening. Some light rain will push
inland overnight but main front will likely dissipate as the upper
low offshore moves south toward California through Friday.
Predominately MVFR exists along the coast, dropping to IFR at
times. Conditions are likely to improve at the coast to VFR by
20Z Friday. Conditions likely remain VFR inland overnight and
through Friday, as guidance suggests there is generally less than
a 25% chance of MVFR CIGS. Surface winds become light and variable
overnight, then turn northerly on Friday. Could see some wrap
around showers and possibly a thunderstorm Friday evening across
southern parts of the forecast area.

PDX AND APPROACHES...Expect predominately VFR with lowering CIGS
overnight into Friday morning. Light rain possible through 18Z
Friday, during which time there is around a 10-20% chance of MVFR
conditions. West winds expected to be come light and variable
overnight, then winds turn back northwest to around 10 kt for
Friday afternoon. /DH

&&

.MARINE...Weak high pressure will slip eastward as a cold front
approaches from the west late this evening. S/SW winds will turn
W/NW as the front approaches and passes the region. Winds will
start out on the light side around 10 knots before picking up to
between 20-25 knots with gusts around 20 knots for the outer
waters by late Friday morning. This has prompted a Small Craft
Advisory for the outer waters beginning at 18Z and continuing
through 00Z Sunday. Have kept the inner waters out of the Small
Craft due to lower confidence. Rain will accompany the cold front
as it passes approaches the northern Oregon/southern Washington
coasts this evening and overnight. Winds will relax Saturday
afternoon, possibly below Small Craft, but look to increase again
late Saturday evening which may warrant a continuation or
expansion of the advisory. A W/NW swell at 5-7 feet will persist
through Friday night, building to around 10 feet Saturday. -Batz

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory from 5 AM to 11 AM PDT Friday for PZZ210.

     Small Craft Advisory from 2 PM Friday to 5 PM PDT Saturday for
     PZZ271>273.
&&


$$

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