Scientific Forecaster Discussion
fxus65 ktwc 221026
Area forecast discussion
National Weather Service Tucson Arizona
325 am MST Sat Jul 22 2017
Synopsis...scattered to numerous afternoon and evening
thunderstorms will prevail into early next week. The greatest
daily thunderstorm coverage should occur east to south of Tucson
with reduced thunderstorm activity across the western deserts.
Discussion...a few showers were still occuring as of 315 am this
morning along/near the international border in Cochise County.
Active weekend on tap across Southeast Arizona with scattered to
numerous showers and thunderstorms mainly in the afternoon and
evening with some activity continuing into the overnight hours. Main
threat today from slow moving storms will be heavy rain under a
continuing wet atmosphere with precipitable water values in the 1.5" to 1.75" range
with high amounts south across Sonora mx.
Flow aloft becomes more east-southeast tonight late tonight and potentially
southerly on Sunday as models suggesting inverted trof pushing
through. Sunday could end being gunked over with lots of showers
with isolated embedded thunderstorms.
Below normal high temperatures to continue this weekend. Based on
MOS data went ahead and lowered highs this weekend from previous
forecast. The forecast high in Tucson for Sunday is 89 degrees which
would be the first sub-90 high in July since 2010.
Monsoon train remains on the track next week while high temperatures
warm back to late July normal values.
Aviation...valid thru 23/12z.
VFR conditions with cloud decks generally 5k-10k ft above ground level with broken
layers above, and surface wind variable in direction mainly less
than 12 kts. Scattered thunderstorms and rain/rain showers developing after 22/18z and continuing
through the remainder of the period. Winds vicinity thunderstorms and rain could gust
40+ kts. Aviation discussion not updated for taf amendments.
Fire weather...scattered to numerous mainly afternoon and evening
thunderstorms will continue into early next week with locally heavy
rain and strong winds. Temperatures will remain below normal with a
continuation of elevated humidity levels through Tuesday. Wednesday
through Friday conditions will become a bit drier and warmer with
somewhat less convection. From 20-foot winds will mainly remain
below 15 mph with the exception of strong outflow winds in the
vicinity of thunderstorms.