Scientific Forecaster Discussion
fxus65 krev 142124
Area forecast discussion
National Weather Service Reno Nevada
124 PM PST Thu Nov 14 2019
Tranquil weather pattern continues into the weekend with cool
morning temperatures and above average highs. High pressure
weakens next week with temperatures likely returning to near
average. There is a very small chance we could see a low pressure
area moving into the region by the middle of next week that could
bring some showers.
Not much in the way of changes were made to the short term part of
the forecast. An upper level trough is still expected to swing
through the forecast area later tonight and early Friday. This is
a dry trough for our area so no pops are mentioned. We should see
an increase in ridge winds tonight.
Behind the trough there will be a shift to easterly winds at the
ridges for Friday night and slight cooling of high temperatures.
Still...these highs will remain above normal for mid-November.
Highs will remain in the 60s for the lower valleys and 50s for the
Sierra valleys through the weekend with some slight warming by
early next week.
The biggest change in the forecast today is the way the deterministic
models are trying to handle an upper level low next week. Both the
European model (ecmwf) and GFS have trended toward a wetter solution for late Tuesday
into late Wednesday as the low drops south along the coast of
California. Ahead of the low we would expect an increase in ridge
winds for Tuesday from the west-southwest with a shift to the
east-northeast by Thursday.
Many ensemble members differ on the handling of this low pressure
area with a few keeping the area under flat ridging while others
show some degree of troughiness next week. Because there is a wide
spread in the solutions...our confidence in any single solution
is quite low. We will show a increase in pops for late Tuesday
night into Thursday morning...but keep most areas at slight
chance or less.
The potential for multiple changes to the model solutions for
next week is quite high and we may see drastic changes in the
deterministic models every 6-12 hours. That is a reason enough to
not make significant adjustments to the forecast just yet.
VFR conditions are expected through the weekend into early next
week. Gusty west to Southwest Ridge winds are likely to develop
tonight causing some turbulence over and east of the Sierra. These
winds decrease late Friday morning then shift to the east
overnight and increase again. That will shift the turbulence
potential to areas west of the Sierra.
There is some potential for poorer flying conditions by the middle
of next week. Some model solutions show a low pressure area just
to our west by early Wednesday. That would support showers in the
mountains and another round of gusty ridge winds. But some models
are not as robust with this solution. There is a high degree of
uncertainty in expected conditions for next week at this time.