Area forecast discussion
National Weather Service Medford or
300 PM PDT Sat may 18 2013
Discussion... the region is in for a temperature roller coastal
ride as active pattern remains over the West Coast through the
next week. The cold front moving through the region today with
showers continuing behind as lapse rates remain moderate as flow
becomes onshore. As surface cooling slowly progresses under the SC
deck in northwest portions of the area showers linger the longest through
the evening and overnight. Upper level ridge builds over the
region by late tonight with offshore flow developing over the
southern coastal range by Sunday morning. With the clearing in the
expanding offshore flow skies clear and the region sees a warm up
of over ten degrees tomorrows highs will be generally around
ten degrees higher than today's. Offshore flow remains overnight
Sunday with higher temperatures on the ridges starting the region off to
another good warm up Monday with temperatures warming around another ten
degrees. An upper level low moves into the region from the
northwest Monday night with a cold front moving through Tuesday.
850 mb temperatures are in the lower teens Tuesday morning...dropping to
around 0 c right behind the front. High temperatures over much of
the west side might be in the morning with temperatures dropping quickly
though the later afternoon as the front moves in combining with
showers. By Wednesday morning the ec and GFS have come in much
better agreement with the cold air mass...both showing 850 temperatures
in the -3 to -4 c range...bringing a late season dusting of snow
to possibly as low as 300 feet. With the very warm temperatures
and sun for the preceding days this snow should melt very quickly
except for locations where there is still snow on the ground. Have
more broad-brushed the remainder of the extended as both the GFS
and the ec wobble a cutoff low over the Pacific northwest through the
remainder of the week. The GFS has remained the most consistent
with yesterdays much more southerly position of the ec now
trending closer to yesterday's GFS solution...and have leaned more
heavily towards the GFS with this in mind.
&&
Aviation...ceilings will lower across the area through this
evening as a cold front continues to move toward the coast. MVFR
conditions along the coast will spread into the Umpqua basin
through this evening. Expect obscurations to be near total across
the coastal mountains, spreading to the Cascades, Siskiyous, and
Marble Mountains through this evening. There is a slight chance of
afternoon and evening thunderstorms over lake and Modoc counties.
This evening expect some IFR along the coast and MVFR in the
Umpqua basin as well as in northwest flow upslope areas along and
near the Cascades and Siskiyous. Otherwise VFR should prevail.
Overnight partial clearing will occur with patchy MVFR dissipating
to mostly in the Umpqua basin. It will clear to VFR all areas
between sunrise and noon on Sunday as high pressure becomes well
established. Btl
&&
Mfr watches/warnings/advisories...
or...none.
California...none.
Pacific coastal waters...Small Craft Advisory for winds from 11 am Sunday to 5 am PDT
Tuesday for pzz356.
Small Craft Advisory for hazardous seas from 11 am Sunday to 5
am PDT Tuesday for pzz356.
Small Craft Advisory for winds from 2 PM Sunday to 11 PM PDT
Monday for pzz350-370.
Small Craft Advisory for hazardous seas from 2 PM Sunday to 11
PM PDT Monday for pzz350-370.
Small Craft Advisory for winds from 5 am to 2 PM PDT Sunday for
pzz376.
Hazardous seas warning from 2 PM Sunday to 11 PM PDT Monday for
pzz376.
Gale Warning from 2 PM Sunday to 11 PM PDT Monday for pzz376.
Small Craft Advisory for hazardous seas from 5 am to 2 PM PDT
Sunday for pzz376.
$$
Sven
