Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tucson Arizona
237 am MST Sat Nov 28 2015
Synopsis...dry conditions are expected for Southeast Arizona for
this weekend and through the upcoming work week. Daytime
temperatures will be slightly below normal through Monday with
gradual warming thereafter.
Discussion...latest infrared/WV satellite imagery shows the quasi
stationary upper low over the Great Basin this morning with west to
southwest flow across Southeast Arizona on the southern periphery of
the low. There are still a few middle and high level clouds across far
southeast Cochise County which will continue to move away from the
area. Daytime temperatures this afternoon will remain just a few
degrees below normal for this time of year.
The upper low will gradually shift a bit farther northeast on Sunday
as a weak shortwave trough now near 38n/130w moves southeast and
shears out as it ejects eastward through base of the trough. This
will have little sensible weather impact as it moves through other
than perhaps a few high level clouds.
Fairly benign fast zonal flow for much of next week with brief flat
shortwave ridging Monday. Another weak shortwave trough is prognosticated
for Tuesday into Wednesday with some minor timing differences seen
in the models with the GFS being the slowest with this feature.
Regardless...little impact with this system other than some high
level clouds again. Then shortwave ridging again Thursday before the
next deeper trough approaches from the west by next weekend.
Daytime temperatures and morning lows will be a few degrees below
seasonal normals through Monday. Near normal temperatures are then
expected by Tuesday and Wednesday with the warmest temperatures by
Thursday and Friday with highs a few degrees above normal for early
Aviation...valid through 29/12z.
Clear skies will occur except for scattered clouds above 20k feet mean sea level
near the New Mexico border today and northwest of ktus Sunday
morning. Surface wind will be mainly less than 12 kts. Aviation
discussion not updated for taf amendments.
Fire weather...dry conditions will prevail into next Friday. Expect
terrain driven winds generally less than 15 miles per hour through Monday.
Occasional west to northwest gusts to around 20 miles per hour may occur Sunday
afternoon. A general east wind component at less than 15 miles per hour will
then occur Tuesday into Wednesday followed by somewhat stronger east
winds next Thursday.
Discussion...gl aviation/fire weather...Francis
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