905
FXUS66 KMFR 171015
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
315 AM PDT Fri May 17 2024

.DISCUSSION...Satellite imagery shows marine stratus along the coast
north of Cape Blanco, Coquille Basin and now filling into most of
the Umpqua Basin and along the Cascades. The marine stratus could
also get banked up along the north Facing slopes of the Siskiyous
and possibly the south end of the Rogue Valley, just south of
Ashland towards daybreak.

Dry weather will continue today with the aforementioned cloud cover
dissipating during the morning hours with mostly clear skies by the
afternoon. Onshore flow will result in cooler afternoon temperatures
for interior locations this afternoon. Along the coast, the marine
stratus could linger north of Cape Blanco for most of the day,
although it could peel back just off the coast for a few hours late
this afternoon and early evening, before returning.

This weekend we`ll be under the influence of weak upper troughing,
with the upper trough north of our area Saturday, then dropping
south Sunday. However the track of the upper trough does not favor
precipitation. So while it will remain dry, afternoon temperatures
will be in line with seasonal norms. We`ll still experience the
typical late afternoon and early evening gusty breezes for the
interior westside valleys and east of the Cascades this weekend.

The majority of next week will be dry. The one exception could be
Tuesday afternoon and Tuesday night as a weak upper trough drops in
from the northwest. Odds are it will remain dry, but a few showers
cannot be ruled out along the north coast, Umpqua Basin and northern
Cascades.

Wednesday and Thursday are likely to be dry, then as we get towards
the end of next week, the operational ECMWF shows a stronger upper
low moving into our area bringing a higher chance of precipitation.
In contrast the operational GFS is dry with the upper trough sliding
over the interior which typically results in dry weather. Looking
further, some members the GFS ensembles show precipitation in our
area and the majority of the individual ECMWF members show
precipitation, therefore we`ll keep at least a slight chance of
precip in the forecast for portions of the forecast area.
-Petrucelli


&&

.AVIATION...17/06Z TAFs...Along the coast and just offshore, MVFR
and IFR ceilings will persist north of Cape Blanco and beyond 5 nm
from shore this morning, then skies will clear with VFR ceilings the
rest of the TAF period with weak offshore flow. Gusty north winds
are likely late this morning into this evening, with breezy north
winds lasting into tonight.

Inland, the marine stratus has filled into the Coquille Basin and
most of the Umpqua Basin and is banked up along the Umpqua Divide
and Cascades, with MVFR ceilings. It`s possible the marine stratus
could slip just over the Umpqua Divide towards daybreak, but the
Medford terminal will remain VFR. The marine stratus will burn off
late this morning with VFR ceilings returning, then low clouds will
develop again late this evening in the Umpqua Basin resulting in
MVFR ceilings for Roseburg. Elsewhere, VFR conditions will continue
with breezy winds in the afternoon and early evening hours.
-Petrucelli


&&

.MARINE...Updated 200 AM Friday, May 17, 2024...A thermal
trough pattern will maintain gusty north winds and steep to very
steep seas through the weekend. Seas will be steepest and winds will
strongest south of Cape Blanco, and during the afternoons and
evenings. The thermal trough strengthens again today, especially
towards the late afternoon, and a brief period of northerly gales is
possible late this afternoon beyond 15 nm from shore and south of
Pistol River.

The thermal trough will linger through the weekend, maintaining
gusty north winds and steep to very steep seas. Conditions improve
early next week as the upper level pattern changes and the thermal
trough gets disrupted through the first half of the week. /BR-y/CSP


&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT
     Saturday for PZZ350-356-370-376.

Hazardous Seas Warning until 11 PM PDT Saturday for PZZ356-376.

&&

$$