Area Forecast Discussion
Issued by NWS Medford, OR

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FXUS66 KMFR 242217

Area Forecast Discussion
National Weather Service Medford OR
317 PM PDT Mon Apr 24 2017

.DISCUSSION...Alright, it is wet enough, the reservoirs are full,
just let it stop for a little bit. The current system is slowly
tapering off with snow showers continuing the strongest in the
Cascades. with the strong nearly straight onshore 700 mb flow near
50 kt terrain has been the biggest factor on where the bulk of
the precipitation has and is occuring. There is no real "break" in
the action as light isolated showers continue overnight ahead of
the next system that moves Tuesday morning. A warm front brings a
rain sheild with the triple point looking to be off the coast of
southern Washington state. The real next soaking comes in
Wednesday, and again an atmospheric river event is indicated with
southerly low level winds feeding moisture from the south as the
system moves in on the nose of a 160 kt jet. The area is closer to
the nose of the jet but still in the less favorable right exit
region but there is strong upper level divergence and with the
southwest flow there is strong upper motion throughout the column
to provide heavy rain rates through the day until an upper level
ridge builds and pushes the jet north of the region. The ridge
continues to build with a thermal trough deepening on the coast
with offshore flow by friday morning. Sven

.EXTENDED DISCUSSION...Friday through Monday...The models are in
pretty good agreement showing the mean ridge near or over our area.
Which gives us moderate to high confidence we`ll actually have a
stretch of dry weather. The mean trough on Friday sets up over the
central part ofthe U.S. with the ridge axis near 135w with a dry
northwest flow. The ridge axis shifts east along the Oregon coast
Saturday, then flattens out some on Sunday as a weak front moves
north of our area. The GFS and Canadian flattens out the ridge more
with a slightly stronger upper trough zipping through Washington
state. In contrast the ECMWF shows more ridging on Sunday. All the
models show the ridge flattening out Monday with a northwest flow.
However the best chance for precipitation will remain northwest of
our area. In addition the CFSv2 weekly anomalies for the past 2 days
support the idea of a dry anomaly for next week. Therefore
confidence is moderate to high we`ll have an extended period of dry
weather with temperatures slightly above normal. -Petrucelli


.AVIATION...24/12Z TAF CYCLE...Over the coastal waters, along the
coast, near the coastal ranges, and in the Umpqua Basin MVFR
CIGs/VIS and local IFR CIGs in rain and rain showers with higher
terrain obscured will persist through this evening. Low level wind
shear will affect KOTH and KRBG through approx 17Z this morning.
Over the remainder of the area...mainly MVFR this morning improving
to VFR this afternoon, except for occasional MVFR in showers. Higher
terrain will remain obscured as rain/snow persists into the evening.
Freezing levels will be 4500-5500 feet. Gusty winds to 35 kt are
possible at KLMT for a few hours this afternoon. Mainly MVFR is
expected tonight. BTL/Spilde


.MARINE...Updated  130 PM PDT Monday 24 April 2017...High pressure
will build southwest of the waters this evening...then move east
tonight. A front will move through the area Tuesday...followed by
another one Wednesday. Small craft advisory conditions will
accompany these systems. Offshore high pressure will build Thursday
and persist into the weekend. This will bring northerly winds to the
area that may meet Small Craft Advisory criteria at times...mostly
from Cape Blanco south.


OR...Winter Weather Advisory until 11 PM PDT this evening for


Pacific Coastal Waters...Small Craft Advisory from 11 AM to 11 PM PDT Tuesday for
     Small Craft Advisory for hazardous seas until 5 AM PDT Tuesday
     for PZZ350-356-370-376.
     Small Craft Advisory for hazardous seas from 11 AM to 11 PM PDT
     Tuesday for PZZ350-356-370-376.


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