447
FXUS66 KMFR 301811
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1111 AM PDT Thu May 30 2024

.UPDATE...Updated Aviation discussion for 18z TAFs.

&&

DISCUSSION...The forecast is on track for today. An upper ridge
will develop through the day, bringing a 5-10 degree increase in
afternoon highs across the area. Friday`s highs will also increase
before the ridge moves eastward, allowing for a cooler weekend
with little activity expected. There will be very slight (~5%)
thunderstorm chances over Modoc and eastern Siskiyou counties on
Friday night, then over southern Lake County on Saturday
afternoon. Those chances clearly aren`t impressive, but when
everything else is 0%, they`re worth noting.

Please see the previous discussion for additional details about
the short- and long-term forecast. -TAD

AVIATION...30/18Z TAFs...VFR conditions prevail over the region and
are expected to persist through the day. Northerly winds will pick
up again this morning and afternoon, and gusts could reach 20-25 kts.

Some low clouds could form in the valleys of Coos and western
Douglas County, but are not expected to impact the North Bend or
Roseburg terminals.
-Miles

MARINE...Updated 830 AM Thursday, May 30, 2024...A thermal trough
is bringing gusty north winds, with wind-built chaotic seas
expected in all waters today. The thermal trough will strengthen
further through the day, peaking this evening and persisting
through at least Friday evening; resulting in gale force winds for
most areas south of Cape Blanco and for isolated instances across
the waters between Bandon and Cape Blanco. Meanwhile small craft
conditions will expand north over the rest of the waters that will
last into at least Friday evening.

The thermal trough will weaken overnight Friday into Saturday and
north winds will diminish as an upper trough approaches. Calmer seas
are expected by the weekend and into early next week after the wind
waves have diminished. -Schaaf/Miles

PREV DISCUSSION... /Issued 318 AM PDT Thu May 30 2024/

DISCUSSION...Ridging will then remain in control through Friday,
with dry conditions and a warming trend that will peak with well
above normal highs Friday afternoon. The thermal trough will
return during this time, resulting in strong north to northeast
winds in the coast range and a Chetco Effect, which will lead to
warmer temperatures around Brookings than elsewhere on the coast.

A weak trough and front then arrive late Friday into early
Saturday, and although very little, if any, measurable rain is
expected outside of the immediate coast, afternoon temperatures
will be about 5 to 10 degrees cooler Saturday than on Friday.

A second, much deeper trough will arrive late Sunday into Monday,
and this will reinforce the cooling trend, bringing temperatures
down below normal for Monday. Temperatures will only be half the
story, however, as the system is forecast to produce measurable
rain for almost all areas along and west of the Cascades, with a
decent chance for some areas to the east as well. Model moisture
values for this event are high, and would be significant even
during the winter, but will pass through the area quickly. This
means that the band of moderate to heavy precipitation will not
last long, entering the coast late Sunday evening and
exiting/dissipating Monday morning. Some post-frontal showers
will continue into Monday afternoon, but all precipitation should
come to an end by Monday evening.

For the rest of the week, there is quite a spread amongst the
model solutions, mainly resulting from differences in how strong
the next ridge will be, and the timing of when it builds in
overhead. In other words, we know that the remainder of the week
will trend dry and much warmer, likely well above normal for
early June, but the magnitude and timing of that heat remains
could be delayed by a day or so from the current forecast. -BPN

&&

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

PACIFIC COASTAL WATERS...Gale Warning until 11 PM PDT Friday for
     PZZ356-376.

Small Craft Advisory until 11 PM PDT Friday for PZZ350-370-376.

&&

$$