Scientific Forecaster Discussion
fxus65 krev 192107
Area forecast discussion
National Weather Service Reno Nevada
207 PM PDT Fri Jul 19 2019
mid-Summer heat will persist across the Sierra and western Nevada
this weekend and for most of next week. A few thunderstorms are
possible near the Sierra crest Saturday afternoon, with conditions
more favorable for showers and thunderstorms next week.
No big changes needed today, model and ensembles continue to show
a transition to a more favorable thunderstorm pattern this
weekend. Ridge of high pressure over The Four Corners region will
build westward into Nevada this weekend and generally remain in
place through at least the end of next week.
Heat will continue to build over the next couple days with afternoon
highs approaching 100 degrees across much of western Nevada this
weekend. Would not be surprised to see readings as high as 105 in
Pershing and Churchill counties for Sunday. Overnight lows will
also remain rather warm, low to mid 60s in western Nevada population
centers. Hot afternoons with limited overnight cooling will lead
to some heat health impacts for sensitive groups. Some "cooling"
is possible for mid week, but we're splitting hairs here with
only a couple-3 degrees of cooling on tap. Ensembles show the return
of the ridge toward the end of week, which may lead to another
round of heat impacts.
Thunderstorms still looking more possible this weekend as well. A
few storms are possible along the Sierra crest for late Saturday
afternoon between Carson Pass and Mammoth mtn. Nothing to
impressive here, but those out in the back country will want to
keep and eye to the sky.
Sunday and Monday still look interesting with jet segment
developing between the deep trough off the Pacific northwest coast
and the building ridge. While not a perfect set up, conditions do
look favorable for high based thunderstorms Sunday and Monday. A
few overnight storms are possible with the jet overhead as well.
Hot surface temperatures will allow for strong outflow from
thunderstorms and even collapsing towering cumulus clouds.
For mid week, ensembles show the Pacific trough will flatten the
ridge, this should suppress the thunderstorm threat to areas
south of I-80. Simulations beyond Tuesday showing quite a bit of
moisture with thunderstorms transiting to heavy rain, hail and
gusty outflows. Brong
VFR conditions, light afternoon and evening breezes today.
Thunderstorms may return to the Sierra crest between ktvl and kmmh
Saturday afternoon. Hot surface temperatures 95-105 are likely
across the Nevada valleys this weekend.
High based thunderstorms are possible Sunday and Monday from
north and west of kmmh to klol, strong outflows are the main
threat here. Threat for thunderstorms will continue through most
of next week. Brong
Busy fire weather conditions on tap this weekend and next week.
Pattern for dry thunderstorms continues to look interesting for
Sunday-Monday. Weak wave develops off the California coast on Saturday,
roughly between the deep trough off the Pacific northwest coast
and the building ridge. Ensembles continue to drive this wave and
jet streak into northern California on Sunday then hold it in
place over northeast California and northwest Nevada into Monday.
There isn't a ton of moisture available, but there is enough
instability for isolated dry thunderstorms starting late Sunday
afternoon and persisting into Monday. Overnight storms are also
possible Sunday and Monday nights. High based storms with hot
afternoon highs opens the door to efficient lightning ignitions
and strong outflow winds. Moisture increases over the region
south of I-80 beyond Tuesday with storms transitioning to wet,
heavy rain and gusty outflow producers.
Secondary concern is some breezy afternoon winds may return
Monday-Tuesday along the northern Sierra front and into
Lassen/northern Washoe counties. Peak gusts here could reach 30