Helm, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

162
FXUS66 KMFR 051935
AFDMFR

Area Forecast Discussion
National Weather Service Medford OR
1235 PM PDT Sun Apr 5 2026

.DISCUSSION...

High clouds continue to move through the region this afternoon.
However, plenty of sun is still filtering through those higher
clouds and we`re anticipated to warm up into the lower 70`s again
today. A thermal trough is along the Cascades and that trough
will retreat farther to the east during the afternoon hours.
Overall, not much going on except for the above normal
temperatures today.

The flow pattern will become more onshore by tomorrow, although
temperatures will remain warm in the valleys with more upper 70`s
west of the Cascades and lower 70`s east of the Cascades. The
very low(10-20%) chance of thunderstorms persist on Monday.
Looking at soundings the amount of convective available potential
energy(CAPE) is low and only 100-200 J/kg. The SPC HREF
calibrated thunder algorithm is going with a 10-20% chance, so
felt that was fair. Don`t be surprised if nothing happens and we
just get some showers along and east of the Cascades Monday
afternoon and evening.

By Tuesday morning, an upper level trough in Canada starts to dig
down into Washington and Idaho with a cut off low off the coast of
northern California. In addition, a cold front should be moving
south during the day as well. This front stalls out over Central
Oregon during the day with highs in the mid 70`s in southern
Oregon and mid 60`s farther north of Eugene and Bend. The forecast
has also trended drier compared to yesterday with a 5-10% chance
of rain during the day. It seems 500 mb heights are amplifying
ahead of the cut off low, so that cuts off moisture and enhances
the sinking motion.

As that deeper trough digs further into the CONUS, the cutoff low
remains off our coast by Wednesday. The chance of rain is about 20
to 30 percent over our forecast area, although that could very
well trend lower depending on how this upper level low behaves.
Most ensemble members also seem to be targeting northern
California, so the probability for precipitation is higher there
compared to parts of Oregon.

This cutoff low begins to travel south along the California
coastline with some strong 500 mb divergence over our forecast
area on Thursday. This should result in showers and perhaps more
thunderstorms depending on CAPE. However, the PoP forecast
suggests a wet day with a 50-60% chance of rain Thursday morning
and afternoon.

The extended forecast is looking wet around Friday into next week
with the vast majority of ensemble members with precipitation in
the forecast.

-Smith

&&

.AVIATION...05/18Z TAFs...VFR conditions will persist through the
TAF period for most the area. LIFR ceilings are possible along the
coast(KOTH) later tonight as some weak onshore flow develops.

-Smith

&&

.MARINE...Updated 1200 PM PDT Sunday, April 5, 2026...Relatively
calm conditions are expected through this week. Another thermal
trough develops around Tuesday afternoon, bringing a period of
strong north winds and steep seas starting around Tuesday
afternoon and potentially for most of the week.

&&

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

CA...None.

PACIFIC COASTAL WATERS...None.

&&

$$