Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tucson Arizona
915 am MST Thursday Mar 15 2014
Synopsis...an upper level low over Arizona will move off to the
east by Sunday morning. This system will produce a few showers
across northern parts of the area into tonight with gusty westerly
winds late today. A second upper low will drop south across New
Mexico Saturday resulting in gusty northwest winds Saturday
afternoon. Beyond that an upper level ridge will maintain its
influence over the region into next week with dry weather and warmer
than normal temperatures.
Discussion...a low pressure system continued bring light showers to
areas mainly north and northeast of Tucson this morning. This upper
low had moved into west-central Arizona and will track through the
rest of the state this afternoon. Current forecast appeared to have
a pretty good handle on where the best chances of precipitation will
be this afternoon...mainly north and northeast of Tucson. Thus...no
updates necessary this morning.
Aviation...VFR conditions to persist today...with clouds above 10k
expect light winds this morning with winds becoming westerly at
12-18 kts with gusts of around 18-30 kts after 18z. The strongest
winds this afternoon will occur mainly from Tucson eastward to the
New Mexico border.
Fire weather...there is a chance of showers mainly across the White
Mountains today as a low pressure system moves just north of the
area. Dry conditions will then prevail area wide this weekend and
continue into the middle of next week. The 20-foot wind speeds and
relative humidities may approach critical fire weather thresholds at
some locales this afternoon...mainly over the extreme southeast
portion of Cochise County. On Saturday...red flag conditions may be
achieved in the Gila River valley...but durations may not be long
enough to meet criteria. In addition...fuel moisture is expected to
be sufficiently high to preclude fire growth from occurring.
Previous discussion...an upper level low will drift east across the
state today and across New Mexico tonight. This system will kick
off a few showers mainly north of Tucson and then primarily over
higher terrain as the air mass below 10000 feet remains very dry. The
system will keep a lid on temperatures and hold highs near seasonal
norms thanks to some clouds and the slightly cooler air mass
associated with the low. The low will also generate a decent
westerly breeze this afternoon as it moves on by...especially across
eastern portions of the area.
After this passes by a second system will drop southeast across the
Great Basin and through New Mexico Saturday into Saturday night.
This feature will pass by far enough to the east that the main
concern will be wind which will kick up Saturday afternoon. Again
this will primarily hit the eastern half of the forecast area with
gusty northwest winds...especially the Gila River valley where areas
of 20-30 miles per hour winds are likely.
Then a short wave ridge will build over the area Sunday into early
Monday with warming temperatures and an easterly breeze on Sunday.
A system passing by well to the north will bring a westerly breeze
to the region again both Monday and Tuesday afternoons.
Temperatures will remain warmer than normal continuing the long term
trend of above normal high temperatures.
Toward the end of the week the flow aloft is expected to become more
southwesterly with a trough of some sort developing off the West
Coast. This pattern will maintain the warmer than normal
temperatures...however there will be an increase in middle and upper
level moisture toward the end of the week. Will have to wait and
see if this change in the pattern will be able to wring out any
precipitation over the area or not next weekend. Cerniglia
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