Area Forecast Discussion
Issued by NWS Medford, OR

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FXUS66 KMFR 251608

Area Forecast Discussion
National Weather Service Medford OR
908 AM PDT Tue Apr 25 2017

.UPDATE...Morning update... Light rainfall has been ovserved over the
coast for most of the morning. That rain is spreading inland and has
just reached the Rogue Valley. Precipitation will continue to spread
into the Cascades, but do not expect it to reach the East Side
today. A warm front will approach later this afternoon, bringing
more rainfall and high snow levels. Recent model runs show
precipitation amounts trending down for inland areas, with
downsloping in the Rogue and Umpqua valleys. So, lowered POP and QPF
grids in areas for this evening. Will spend this shift fine tuning
precipitation and wind details for today and tomorrow. For more
information see previous discussion. -MSC


.AVIATION...25/06Z TAF CYCLE...Overall, expect a mix of VFR/MVFR
ceilings overnight into Tuesday morning with higher terrain
obscured. A warm front will approach the coast Tuesday morning with
ceilings and visibility there lowering to IFR in the afternoon. A
mix of VFR/MVFR will prevail inland Tuesday afternoon with areas of
higher terrain obscured. -Spilde


.MARINE...Updated  230 AM PDT Tuesday 25 April 2017...Winds and seas
are at a minimum early this morning with west swell lingering at
advisory levels south of Gold Beach. Swell heights will diminish
into this afternoon but seas will be increasing with wind driven
seas. A warm front will bring rain with gusty south winds reaching a
peak at advisory strength in the late afternoon and early evening.
Improvement will be very slight and very brief late this evening
before the trailing cold front brings another episode of building
seas.  Winds are likely to be near advisory strength and seas at
advisory strength late tonight into Wednesday morning.  Offshore
high pressure will build Thursday and persist through the weekend.
This will bring northerly winds that will likely meet small craft
advisory criteria...strongest from Gold Beach south. We will go with
a model blend in the long term as there is uncertainty in how
quickly these strong northerly winds will develop. The 00Z NAM
indicates advisory strength as early as Thursday afternoon while the
GFS holds off until Friday morning. -DW



NZUS99 KMFR 251600

Scattered showers will continue this morning mainly
west of the Cascades. By early this afternoon a strong westerly
jet will bring the next front to the coast with warm frontal rain
this afternoon into the evening. Rainfall amounts for tonight
through the end of Wednesday range from around an inch at the
coast to about 0.75" for Douglas and Josephine Counties, and
around 0.50" in western Siskiyou County. Confidence is moderate
that the Medford area will see more around a third of an inch of
rain during this period. Overall, even the Modoc area and Lake
County are expected to see around a tenth to a quarter of an inch
of rain through Wednesday. Snow levels this afternoon will be
around 5500-6000 feet and Crater Lake could see another inch of
new snow; however, the snow levels tonight are expected to rise to
7500-8000 feet and could be as high as 9000 feet at Mount Shasta.

Precipitation is expected to taper off Wednesday night but onshore
flow will keep showers going at the coast and into the Umpqua
Basin Thursday with only isolated showers elsewhere.

Northwest flow aloft continues on Friday and we expect isolated
upslope showers into the Cascades and the Siskiyous. The GFS shows
a warming trend but also continuing onshore flow with showers into
the Roseburg area.

The weather for next weekend is expected to be warm and dry as
guidance continues to advertise a ridge building into our forecast
area. There could be a fire weather and marine concern due to the
thermal trough building along the coast, with stronger N to NE
winds and drier atmosphere for the coastal range. /FB




Pacific Coastal Waters...Small Craft Advisory until 11 PM PDT this
evening for      PZZ350-356-370-376.      Small Craft Advisory for
hazardous seas until 11 AM PDT      Wednesday for PZZ356-376. Small
Craft Advisory for hazardous seas from 11 PM this evening      to 11
AM PDT Wednesday for PZZ370.      Small Craft Advisory for hazardous
seas until 11 AM PDT      Wednesday for PZZ350.


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