Roseburg, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

813
FXUS66 KMFR 192315
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
415 PM PDT Sat Jul 19 2025

.UPDATE...Updated Aviation Discussion.


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.AVIATION...20/00Z TAFs...VFR conditions persist along the coast but
expect IFR and local LIFR to fill in tonight through Sunday morning
for areas from Cape Blanco northward and Brooking southward. These
low ceilings are expected to develop between 05-08z, with improving
conditions around 18-20z. For inland areas, expect VFR areawide.
Gusty winds are expected in the late afternoons and early evenings
for area TAF sites.  Areas of haze and smoke from wildfires will
reduce visibilities in western Siskiyou County.


&&

.PREV DISCUSSION... /Issued 255 PM PDT Sat Jul 19 2025/

DISCUSSION...(Today through Friday)...
Overview:

Items of interest include the cooler temperatures albeit near normal
through most of the forecast (Monday is below normal), continued
dry/breezy conditions, and thunderstorm chances next week. Perhaps
the most noteworthy item is the fact we could have an active week
starting Monday with several days of thunderstorms potentially. At
this time, if we had to choose one day, Thursday looks like the
highest potential for strong to severe thunderstorms. That said,
each day Mon-Thurs (and to some degree Friday) could have
thunderstorms.

Further Details:

The overall pattern--more or less--can be summed up as a trough over
the Pacific Northwest through the next several days. By Monday, we
will see this influence our weather by bringing thunderstorm chances
across the region. There is some evidence of thunderstorms
potentially Monday morning, but this may be just showers until
daytime heating kicks into gear. The trough holds on through Tuesday
and while the "official" forecast doesn`t convey thunderstorms on
Tuesday, there is at least some small potential there that the NBM
hasn`t quite grabbed onto yet. This is likely due to outliers and
weighting functions, but as high resolution data comes in, we may
have a clearer picture. By Tuesday night, the trough over the PacNW
will transitions east, and a cut-off low will form over the Pacific
roughly off the coast of San Fransisco. This will meander around
this location through roughly Friday afternoon before getting absorb
into the mean flow. As this cut-off low forms, it will spread PVA
across the area and this pattern would be conducive for
thunderstorms as we reach peak heating each afternoon Wed/Thurs;
however, at this time Wednesday has no mention of thunderstorms but
that could change. Thursday is shaping up to see more thunderstorm
activity than as of recently where we have seen mostly isolated
storms. Thursday could be more scattered to perhaps widespread. That
being said, split flow patterns and cut-off lows can be tricky,
especially this far out. Ensemble members are showing the potential
for CAPE to reach values near 1000 J/kg with ample bulk shear (0-
6km) around 25 to 40 knots. Moisture advection will be ample with
very high theta-e values advecting into the region as well. This
setup could bring strong to severe storms across the region with
abundant lightning. We will have to see what happens when new data
comes in, especially the HiRes data. This being several days out and
a cut-off low situation, we could see changes to the orientation of
the trough which would affect moisture pull and timing/coverage of
convection. Stay tuned as we continue to monitor next week for
potentially active weather over several days.

-Guerrero


MARINE...Updated 100 PM PDT Saturday, July 19, 2025...A weak
thermal trough along the coast will maintain gusty north winds south
of Cape Blanco through tomorrow morning. This will result in low end
advisory level winds and steep seas south of Port Orford. Winds
weaken tomorrow afternoon as an upper level trough settles over the
region and disrupts the thermal trough pattern. Thereafter,
relatively light winds and seas are expected through much of next
week.

FIRE WEATHER...Updated 230 PM PDT Saturday, July 19, 2025...
Humidities are trending higher compared to 24 hours ago and that has
lowered the fire weather threat west of the Cascades. The hot dry
windy index has also trended lower compared to 24 hours ago.
However, it will remain rather breezy with wind gusts still pushing
that 25mph to 30 mph mark, which is already occuring around Summer
Lake and the Summit RAWS east of the Cascades.

RHs will continue to trend higher across the area and that will
keep any fire weather threat to just Modoc County and their
typical windy and breezy summer time weather. MOS Guidance hints
at sustained 10 to 20 with gusts to 30 mph with RH in the lower
teens around Alturas and the Devils Graveyard RAWS. That is
pretty darn close to red flag criteria with the gusty winds. We`ll
continue to headline the fire weather conditions in that zone
into Sunday.

The big topic will be the thunderstorm forecast and that is covered
in more detail in the discussion above.

-Smith

&&

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

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 AM PDT Sunday
     for PZZ356-376.

&&

$$