149
FXUS66 KPQR 150509 CCA
AFDPQR

Area Forecast Discussion...Corrected
National Weather Service Portland OR
843 PM PDT Fri Jun 14 2024

Updated Aviation Discussion

.SYNOPSIS...
Cooler over the weekend as a weak cold front pushes
inland from the northeast Pacific. Will see rainfall and a
slight chance (20%) for thunderstorms along the northern
portions of the forecast area. Coolest temperatures will fall on
Sunday before a trend towards a warmer and drier pattern comes
mid next week.

&&

.SHORT TERM...Now through Sunday Night...
Now through Sunday Night...Minimal change in the
forecast as the overall pattern remains on track. The low
pressure system and associated front spin just offshore with
rain falling along the north Oregon and south Washington coasts.
This rain will intensify through the evening, but will be more
showery in nature so there will be periods without rain. High
resolution models are quite "bubbly" with the simulated
reflectivity which can be connected to very sporadic yet
moderate rainfall at times. Chances for thunder have remained
the same (around 20%), but the overall areal coverage is
greater. The HREF is showing around a 20-30% chance of thunder,
especially in southern Washington. However, given the overall
strength of this system, even if chances are higher, the number
of strikes remains limited. Have decided to lower chances to
around 20% to account for this. Areas with the higher
probabilities are along the northern coast and northern Coast
Range.

Rain will be more widespread, as will temperature drops tonight
through Sunday. Rain accumulation does not appear impressive,
but, considering it will be showery, there may be periods of
heavier rain. Precipitable water amounts are not robust enough
for any kind of concerns...moreso washing your car level rain.

Models have come into better agreement on Sunday with a more
fine detailed forecast. There may be some lingering instability
which can be observed in the vorticity advection and the
alignment of the jet to the area. However, the trough is
flattening, and the jet is pushing further south inching us out
of the left exit region (more convective portion of the jet),
and into more "neutral" territory. Sunday will be dominated by
cooler air and a few lingering showers. -Muessle


.LONG TERM...Monday through Friday...The overall synoptic
pattern is comprised of a broad trough transitioning into a
ridge. Ensemble clusters are in very good agreement, especially
given the length of time into the future. Overall will see a
warmer and drier pattern starting Tuesday. Seasonable
temperatures in store with light winds, and no precipitation.
-Muessle


&&

.AVIATION...A weak cold front continues to cross Oregon this
evening with another, stronger cold front inching closer to the
area. The second front will begin to cross the area around 06Z and
exiting the region by around 12Z. Cooler air moving in aloft
behind the front will increase instability late tonight and into
Saturday, supporting increasing shower activity and possibly a
few thunderstorms. This pattern will support variable conditions
with VFR conditions expected outside of any precip and MVFR/IFR
conditions within any showers or storms that may develop. This
second front will also result in a slight chance of thunderstorms
(25% probability) for areas north of KCVO starting around 12Z-15Z
Saturday.

Any thunderstorms will have the potential to produce small hail
along with gusty and erratic winds.

Southerly winds across the airspace will become more westerly
after the first frontal passage.

PDX AND APPROACHES...VFR under scattered and broken mid level
clouds (6-8 kft) will give way to low- end VFR/high- end MVFR
conditions, with cigs likely hovering around 2-4 kft as a series
of fronts move eastward through 18Z Saturday. The post frontal
airmass late tonight into Saturday afternoon will support showers
and a slight chance (25%) for thunderstorms. -Batz/42

&&

.MARINE...
Relatively benign conditions through the weekend and
into the start of the upcoming week. Seas around 5 to 7 ft at 9
to 11 seconds. A weak front will bring southerly winds through the
evening, before a stronger front will cause winds to become more
westerly tonight/early Saturday morning. Late Sunday/early Monday
strong northwesterly winds will return and will likely bring
marginal Small Craft Winds to all waters. There is still some
uncertainty in the timing and strength of the Monday system.
-42

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...None.
&&

$$

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