FXUS66 KMFR 091107
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
407 AM PDT Sun Jun 9 2024

.DISCUSSION...Yesterday was the most active day in terms of
thunderstorm activity. Just over 500 lightning strikes were
recorded yesterday ending at midnight, with over 400 of those
strikes concentrated in Klamath and Lake Counties. Shower and
thunderstorm activity is continuing overnight tonight into the
early morning hours, though thunderstorms have certainly
diminished in coverage. As of this writing (~3am PDT), there has
only been about 20-25 lightning strikes since midnight associated
with activity across northern Klamath and Lake Counties. The
forcing mechanism for all this activity is a weak, but not
insignificant, trough that is moving into the region this morning.
We do expect showers and isolated thunderstorms to continue
through the morning hours, mainly across northern portions of the
forecast area.

As this trough pushes farther inland, shower and thunderstorm
activity will increase again later today. The focus of activity
will be shifted somewhat eastward today, mainly over Lake and
Modoc Counties, with some isolated potential extending westward
into Klamath County. We do expect the greatest coverage of
showers/thunderstorms to be somewhat earlier today compared to
previous days, peaking in the early afternoon vs late
afternoon/evening as in previous days. We could see some strong
storms today, but the chance for severe is fairly low (5 to 10%).
While the atmosphere is fairly similar to previous days with
similar CAPE and LI values, bulk shear is weaker today, around 20
to 30 kts, and the forcing mechanism is moving through early
enough in the day to limit the peak heating contribution.
Regardless, with any thunderstorms that develop today, expect
strong gusty winds as well as the potential for hail.

Aside from convective activity, the general cooling trend will
continue today. The most notable cooling is expected east of the
Cascades where high temperatures are expected to be about 7 to 10
degrees cooler. West Side will cool further as well, but only by a
few degrees. The trough will push the moist unstable air and
associated shower/thunderstorm activity east of the area by early
this evening, and the atmosphere will stabilize for much of the
week.

We'll see a transition to zonal flow on Monday, but heights will
build with some semblance of a flat ridge over the region. This
west to east flow will maintain a stable air mass through at least
mid week, so we'll lose the thunderstorm potential after today.
Additionally, we don't expect any sharp warm ups through then, but
with building heights, temperatures will warm by a few degrees on
Monday, resulting in daily high temperatures that are around 10
degrees warmer than normal Monday and Tuesday. There will be a
few shortwaves that pass through in this westerly flow, bringing
some slight cooling and breezy afternoon winds on Wednesday and
Thursday, but conditions will remain dry through the week.

A larger pattern change is looking more likely Friday into next
weekend as low pressure moves into the region from the northwest.
While details vary at this time, confidence is increasing a
cooler pattern with temperatures trending below normal over the
weekend. It'll likely remain dry across the area, though there are
some slight chances of precipitation in the forecast next weekend,
favored along the coast and north of the Rogue- Umpqua Divide.
Stay tuned as details become more clear. /BR-y

&&

.AVIATION...09/06Z TAFs...Thunderstorms are largely calming down
over areas east of the Cascades, with only a few isolated cells
traveling to the northeast over Lake County. Instability remains
through the night, so further development is not impossible.
Thunderstorm chances of 15-20% will persist over northern Lake and
Klamath counties overnight before higher 20-40% chances return
across the east side Sunday afternoon. The highest chances will be
across southern Lake County.

Marine stratus will return to the Oregon coast this evening as well,
with ceilings currently fluctuating between VFR and MVFR levels. IFR
ceilings are possible early Sunday morning before sunlight clears
out the marine layer. VFR levels will generally continue through the
day on Sunday, with gusty winds expected across the area in the
afternoon. -TAD

&&

.MARINE...Updated 200 AM Sunday, June 9, 2024...Moderate west
swell will move through the waters today, gradually subsiding into
Monday. Meanwhile, a thermal trough will strengthen along the
northern California coast resulting in gusty north winds and steep
to very steep seas, mainly south of Port Orford today into Monday.
Conditions will at least remain hazardous to small craft through
Wednesday morning, especially south of Cape Blanco. Then, the
thermal trough will strengthen further bringing stronger north
winds and steep seas to all waters Wednesday afternoon and evening
with possible gales and very steep seas south of Cape Blanco.
-Spilde

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 AM PDT Monday
     for PZZ356-376.

     Hazardous Seas Warning until 11 AM PDT Monday for PZZ356-376.

&&

$$

MNF/MAS