906
FXUS66 KPQR 121709 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
1008 AM PDT Wed Jun 12 2024

Aviation Discussion Updated...

.SYNOPSIS...High pressure maintains our mild and dry weather through
Thursday. Then, changes, as a cooler upper low shifts across the
region. This will bring showers for Fri through Sun, and maybe an
afternoon/evening thunderstorms on Sat and Sun. Then, dry and mild
for most of next week, as high pressure rebuilds offshore.

Key Messages...

-  Morning clouds, otherwise sunny and mild today and Thursday.

-  Breezy north winds on the coastal waters today thru Thursday.

-  Cooler with increasing clouds for Friday. Mostly dry, with
   chance of showers for coast/Coast range north of Tillamook.

-  Cool with showers this weekend. Generally, have a small
   chance (15-25%) of afternoon/evening thunderstorms.

&&

.SHORT TERM...(Today through Friday)...Apparently, Mother Nature has
smiled upon the Pacific NW, giving us more pleasant weather. High
pressure will remain anchored offshore. This will maintain low level
northerly flow. As such, will see areas of low clouds, mainly over
the coastal waters and close to shore this am, and over the Cascades
and foothills. But, air mass remains dry aloft, so any clouds will
break apart quickly this am, with sunny skies afterwards. Overall,
temperatures will be near seasonal levels for mid-June, with upper
50s to mid 60s along the coast, and lower to middle 70s for the
inland valleys, including the Cowlitz, Columbia and Willamette River
valleys.

Not much change in the overall pattern for tonight and Thu. But, will
have fewer clouds around in the morning. Should see a bit warmer
temperatures across the inland valleys, with afternoon highs up about
3 to 5 deg, with mid to upper 70s.

Changes arrive later Thu night into Fri, as the upper ridge offshore
weakens. This due to upper trough over the Gulf of Alaska digging
southeastward towards the Pac NW. Models still depicting weakening
front pushing to the coast early Fri morning, then working its way
across the region through rest of the day Fri. As such, should see
lot more in way of clouds, and with that, cooler temperatures for
Fri. Models still show some precipitation, albeit somewhat light in
rainfall. Does appear bulk of the moisture will be over western
Washington. So, will maintain increasing chance of showers, with
highest potential along the coast and Coast Range to north of
Tillamook. Areas to south and east of Portland likely stay dry.

.LONG TERM...Saturday through Tuesday...Saturday, most ensemble
members agree on troughing entering the region with below-normal 500
mb heights. In this scenario, we would see increasing chances for
widespread precipitation and below average temperatures. For now, the
NBM`s 25-60% chance of PoPs across northwest Oregon and southwest
Washington at the end of the week look reasonable. Sunday to Tuesday,
the majority of ensemble members (>85%) continue to show broad
troughing over the Pacific Northwest, maintaining a generally cool
and potentially wet start to next week.   /Alviz

&&

.AVIATION...High pressure keeps VFR conditions and clear skies
throughout the period for most terminals. Only exception is a
brief period of MVFR CIGs in the interior valley until 18Z
Wednesday, as these few clouds continue to deteriorate.

NW winds pick up this afternoon throughout the terminals, with
gusts up to 30 kt along the coast and up to 20 to 25 kt inland,
lasting until 00Z-06Z Thu. Winds will become fairly light
thereafter.

PDX AND APPROACHES...Predominantly VFR and clear skies throughout
the TAF period, with a few deteriorating clouds causing high-end
MVFR CIGs until 18Z Wednesday. NW winds have begun to pick up this
morning, with gusts up to 20 kt expected between 00Z-08Z
Thursday. Winds will become light again thereafter.
-JH

&&

.MARINE...Wind-driven Small Craft Advisory will be maintained
until Thursday night. Seas are currently around 7-9 feet at 10
seconds, with northerly winds gusting up to 25 kt, increasing to
near 30 kt this evening into tonight. Tomorrow, winds will gust up
to 25 kt and decrease below Small Craft Advisory criteria by
Thursday night. Seas will have settled to 5 to 7 ft around this
time, but may remain choppy. Next front will arrive late Friday,
with winds shifting back to W or SW winds of 10 to 15 kt for late
Fri into early Sun.
-JH

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT Thursday for PZZ251>253-
     271>273.
&&

$$

www.weather.gov/portland

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