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Area forecast discussion 
National Weather Service Medford or
214 PM PST Wednesday Feb 10 2016

Discussion...the ridge axis is now to our east and a southwest flow
has set up bringing high and middle level clouds through the area. This
will continue into tonight. Tonight, a warm front will move towards
the area then lift north on Thursday. Some of the models continue to
show show precipitation breaking out inland tonight and during the
day Thursday. In particular the 12z GFS is the most bullish with the
coverage of the qpf, but suspect this may be a bit overdone. In
short the upper ridge is still rather strong and should be enough to
weaken any system that moves inland tonight into Thursday. Currently
we have mostly slight chance of precipitation for inland locations and
can't see any reason to increase them at this point.

Additional shortwave activity ahead of the approaching trough will
move through Thursday evening, then the main upper trough pushes east
into the area Friday morning. This will bring the best chance for
measurable rain. Snow levels will lower on Friday, but will remain
Above All the passes through Friday evening. A moist westerly flow
aloft will continue Friday night with most showers along and west of
the Cascades, but they are expected to be light with snow levels
between 4500 and 5000 feet. Therefore were not expecting much, if
any impact on any of the roads in the Cascades.

500 mb heights increase some as weak ridging builds into the area
Saturday. Conditions should be dry during the day, then a warm front
will arrive Saturday night bringing steady light to moderate
precipitation. The best chance for heavier precipitation will be in
the northern part of the area west of the Cascades Saturday
evening, then the focus will shift south Saturday night. Snow
levels Saturday night will increase and likely be Above All the
passes. -Petrucelli

Long term...Sunday through Wednesday...a warm front with good
isentropic ascent will ride over the top of a Flat Ridge on
Sunday. This combined with deep onshore west-northwest flow will
result in rain, focused on north and west facing terrain along
and west of the Cascades with lighter rain in the valleys. Rain
chances diminish south and east of the mountains. Snow levels will
be well above the major passes and likely above 8000 feet in most
areas. The warm front will shift northward in the afternoon and
isentropic lift will ease...effectively shutting off rainfall
from south to north across the County Warning Area late Sunday afternoon and
night.

Models indicate the ridge will strengthen a bit over the area Monday
with most, if not all precipitation remaining to the north of the
County Warning Area. Models differ a bit with respect to another shortwave riding
over the ridge Monday night into Tuesday. The GFS keeps it way to
the north where it would have no impact on our weather. The ecwmf
though has it farther south. Due to the uncertainty, we have
indicated slight chance to chance probability of precipitation from the coast to the Cascades
and north of the Umpqua Divide. It should stay dry in the Rogue
Valley.

Confidence is fairly high that the next significant upper trough to
impact the area will arrive Tuesday night into Wednesday. The surface
cold front will be just offshore late Tuesday night, then move across
the area Wednesday into Wednesday night. Rain is likely from the
coast to the Cascades with high chances even over the east side.
Snow levels start out high ahead of the front, but could drop down to
3000 feet behind the front by Thursday morning. Spilde

&&

Aviation...for the 10/18z taf cycle...VFR is expected to prevail
at the terminals over the next 24 hours. However, temporary MVFR
ceilings/visible and partial terrain obcurations are possible west of the
Cascades with light rain at times, especially near the coast. Spilde



&&

Marine...updated 300 am PST Wednesday Feb 10 2016... a weakening cold
front will continue to move in today resulting in gusty south
winds...building seas...and some light rain or drizzle.
This cold front will then linger over the area with periods of
showers expected through Friday morning before it moves inland.
Seas will build further tonight through Thursday...likely peaking in
the 14 to 16 foot range at 18 seconds Thursday night into Friday
morning. Another frontal system is now expected Saturday night into
Sunday.



&&

Mfr watches/warnings/advisories...
or...
California...none.

Pacific coastal waters...Small Craft Advisory for hazardous seas until 4 PM PST this
afternoon for pzz350-356-370-376.
Small Craft Advisory for hazardous seas from 4 am Thursday to 10
PM PST Sunday for pzz350-356-370-376.
Small Craft Advisory until 4 PM PST this afternoon for pzz370.
Small Craft Advisory from 10 am Thursday to 4 am PST Friday for
pzz370-376.

$$

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