Area Forecast Discussion
Issued by NWS Medford, OR

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FXUS66 KMFR 261626
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
926 AM PDT FRI AUG 26 2016

.DISCUSSION...The forecast was updated to increase coverage of low
clouds and fog over the coastal waters and south coast today, and
also to cancel the fire weather watch that covered portions of the
southern Oregon Cascades and Cascade foothills. Some thinning of
the coastal stratus is expected during the day before it thickens
and surges northward tonight into Saturday morning. Meantime, it
will remain hot and very dry inland through this weekend.
The strength of afternoon and evening winds will be mainly near
seasonable levels during the next few days, but west to southwest
winds east of the Cascades look to trend stronger Saturday into
Monday.

A change to cooler temperatures is expected during next week.
Conditions during the first half of the week look to remain dry
with high temperatures trending to around normal levels. Uncertainty
increases beyond Wednesday.

&&

.AVIATION...26/12Z TAF cycle...The latest fog product shows stratus
creeping up the coast bringing IFR/LIFR to areas south of Bandon.
The offshore flow has weaken which could allow local fog with
temporary MVFR to IFR VIS to form around KOTH near sunrise. Not
confident this will happen or it will be a prevailing condition, so
kept a TEMPO in the TAF. If the marine stratus does not make it into
North Bend, then VFR cigs will continue through this afternoon, then
a marine surge will result in IFR/LIFR CIGS early this evening
through tonight. Elsewhere, VFR conditions will continue through the
TAF period. -Petrucelli

&&

.MARINE...Updated 200 AM PDT, Friday 26 August 2016...The strongest
winds early this morning will be over the outer waters. Even then
they will remain below small craft and will diminish over time this
morning. The primary threat to small craft will be from residual
fresh swell over the outer waters, but the coverage area is not as
great and this has been updated in the detailed hazards. Winds will
be light this weekend, possibly into the early part of next week as
weak low pressure resides over the area. Seas are expected to be
quite light early next week, then they may increase later in the
week as fronts move through. -Petrucelli


&&

.FIRE WEATHER...Updated 850 AM PDT, Friday 25 August
2016...Current surface analysis shows the thermal trough centered
along the west side valleys from the Rogue Valley north to
northwest through the Umpqua Basin. The hottest temperatures and
lowest relative humidities are expected today. As what typically
occurs this time of the year, the thermal trough will shift east
of the Cascades late this afternoon. As a result, winds shift from
east to northeast to north to northwest late this afternoon into
this evening. Relative humidities in much of the area are
expected to end up low enough for that portion of red flag
conditions to be met, but winds will not be strong...only near to
slightly below typical strength this afternoon and evening.

The models are in pretty good agreement advertising a very slight
cooling this weekend then more noticeable cooling next week. We
could actually have max temperatures end up below normal with
higher humidities by mid-week. We could also get our first chance
of precipitation in the northwest part of the region by next
Wednesday.

Another item we`ll have to keep a close eye on this weekend will
be a strengthening trend of gusty southwest to west winds east of
the Cascades with low relative humidities. By Sunday or Monday,
the combination of the two may be enough to warrant red flag
conditions, so watch for updates on this. In the 6 to 14 day
period, the probability increases for cooler than normal
conditions with some precipitation...at least in the northwest
portion of our area. -Petrucelli/DW

&&

.PREV DISCUSSION... /Issued 451 AM PDT FRI AUG 26 2016/

An end to the very hot pattern continues to approach on the
horizon week from now. Above normal temperatures continue through
the weekend. Offshore flow this morning transitions to gusty up-
valley flow this afternoon as the thermal trough moves over the
east side, as the pressure gradient west to east tightens mid
afternoon. This will bring gusty up-valley winds mid afternoon,
especially in the upper valleys in eastern Jackson and Douglas
counties and the Cascades. These winds will fade towards sunset.

The upper level ridge weakens Saturday and migrates east Sunday.
Models are in good agreement with the deepening of an upper level
trough offshore Monday. Winds also begin to become southerly
Monday, and begin to feed moisture into the region, especially at
mid levels. From Tuesday onward the GFS and ECMWF both have a
shortwave moving through on Tuesday, with slightly different
timing, the GFS being about 6 hours faster. This first front will
be mostly dry, bringing just cooler temperatures. With the broad
spread of ensemble plots have broad brushed the chances from Thursday
onward as the timing will most certainly changing in this pattern
from run to run over the next several days at least in this
pattern. the GFS is currently indicating a closed low wobbling
off the coast from Thursday onward while the ECMWF slowly migrates
an upper through through the region next weekend. With this in
mind, am not inclined to highlight nay period with higher that low
chance pops as confidence is low. Sven


&&

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

CA...None.

Pacific Coastal Waters...Small Craft Advisory for hazardous seas until
     11 AM PDT this morning for PZZ370-376.

$$

DW/SBN/JRS



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