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895
FXUS66 KMFR 091046
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
346 AM PDT Thu May 9 2024

.SHORT TERM...

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Temperatures continue to trend warmer this afternoon as high
pressure builds over the region with a thermal trough along the
coast. East breezes become widespread as well today, which will
aid in the warmer and almost summer like weather across the
region. Given the widespread east breezes, the coast will warm up
with highs up to 85 around Brookings and 75 in North Bend. Cooler
temperatures are anticipated east of the Cascades with a Lakeview
only around 65 and temperatures around 71 in Klamath Falls.

The thermal trough will begin to track eastwards as the surface
high east of the Cascades weakens. This usually leads to some
pretty warm weather and high temperatures are currently expected
to hit 90 degrees in a few valleys west of the Cascades. The NBM
probabilities show roughly a 50% chance of 90 around Roseburg on
Friday with about a 20% chance around Medford. These warmer
temperatures will linger into Saturday as the upper level ridge
remains in place.

Given temperatures in excess of 90 degrees in May, the NWS heat
risk algorithm is showing elevated heat risk in the valleys west
of the Cascades Friday and Saturday. Low temperatures are
anticipated to fall into the mid 50`s, so we still think this risk
is slightly misplaced. However, there will be many people heading
to cooler lakes and rivers this weekend. It`s worth noting there
is a well documented history of cold water related injuries or
rescues during the very warm weekends in Spring.

-Smith

.LONG TERM.../Issued 256 PM PDT Wed May 8 2024/ (Sunday through
Wednesday)...Dry and warm weather is expected to continue through
the forecast period. The one day that may be in question will be
Sunday afternoon and early evening for portions of northern Cal.
Sunday, very weak upper troughing will set up over the area. The
forcing is pretty weak. The operational GFS shows a stronger
trigger which could be enough to warrant a slight chance of
thunderstorms in northern California mid to late Sunday afternoon
and early Sunday evening. However, the majority of the individual
GFS ensemble members don`t show anything. The troughing while weak
is a little more pronounced in the operational ECMWF, but there
is no trigger. The ECMWF individual ensembles show several members
hint at something. Therefore we`ll keep a light chance of storms
in for Sunday afternoon and early Sunday evening.


Monday, a drier stable northwest flow sets up with the mean ridge
west of the forecast area. There could be some building cumulus
around and east of Mount Shasta Monday afternoon and evening, but
mid level moisture is lacking and the pattern is not one which is
favorable for thunderstorms. The pressure gradient will be tighter
resulting in gusty afternoon and early evening breezes east of the
Cascades and Modoc County. The thermal trough will be along the
coast in the morning with breezy east winds at the mid slopes and
ridges for the coastal mountains in southwest Oregon.

Tuesday through Wednesday will be dry, with the ridge centered
offshore. Temperatures will still be above normal, but not as warm
as what we are expecting later this week into this weekend.
-Petrucelli
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&&

.AVIATION...09/06Z TAFs...VFR prevails through Thursday evening.
Expect N-NE breezes along the coast and in the Umpqua Basin again
Thursday afternoon, while broad mainly E-NE flow can be expected
elsewhere. Overall, wind gusts won`t be quite as high as they were
on Wednesday, generally peaking in the 15-25 kt range. -Spilde

&&

.MARINE...
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Updated 215 AM Thursday, May 9, 2024...Northerly gales
south of Cape Blanco along with steep to very steep seas will
persist through 5 AM. The thermal trough will weaken today into
night, with conditions subsiding somewhat. Even so, steep to very
steep seas and gusty north winds will continue to bring hazardous
conditions. Lighter winds and calmer seas are expected Friday into
the weekend. -Spilde/Hermansen
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&&

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

PACIFIC COASTAL WATERS...Gale Warning until 5 AM PDT early this
     morning for PZZ356-376.

Small Craft Advisory until 5 AM PDT Friday for PZZ350-356-370.

     Hazardous Seas Warning until 5 AM PDT early this morning for
     PZZ350-370.

     Hazardous Seas Warning until 2 PM PDT this afternoon for PZZ376.

     Small Craft Advisory from 2 PM this afternoon to 5 AM PDT Friday
     for PZZ376.
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&&

$$