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fxus65 ktwc 261532 

Area forecast discussion
National Weather Service Tucson Arizona
832 am MST Mon Jun 26 2017

Synopsis...the record heat will break this week, but still be
several degrees above average today and Tuesday. We still have
enough moisture around for another afternoon and early evening
with isolated to scattered showers and thunderstorms. Thereafter,
drying will significantly limit thunderstorms the remainder of
the week.


Discussion...another very warm morning with the Tucson morning low
of 83 degrees. This breaks the previous record high minimum of 82
from 2002 assuming it doesn't drop lower by midnight. 12z ktwc
sounding still showing decent moisture with a precipitable water value of 1.17
inches. However, drier and modestly warmer air just above 500 mb
with a much more discernible inversion on the sounding. The drier
air can be seen on WV imagery as well being advected in on northerly
to northwesterly flow aloft around the 500 mb high centered across
northern baja. Model guidance, both synoptic and convective allowing
are in good agreement regarding convection this afternoon initiating
over the mountains primarily from Tucson eastward and southward. The
flow pattern will drive the thunderstorms and associated outflows
towards the south today with some isolated coverage moving into the
valleys primarily of Graham, Greenlee, Cochise and Santa Cruz
counties. However, with that said, we aren't expected widespread
storms in the valleys. Otherwise, while temperatures will remain
just below excessive heat levels, it will still be quite hot.

As the subtropical high remains to our south and weakens slightly
for the next few days with increased westerly flow aloft, this will
allow drier air to move into the forecast area. For Tuesday, just a
slight chance of thunderstorms mainly across portions of Cochise
County, then just a few build-ups along the international border the
remainder of the work week. Temperatures will cool down a couple of
degrees this week but still slightly above normal which is still
quite hot. Signs are there that some increased moisture will sneak
back in by early next week, but we'll have to wait and see how that
plays out.


Aviation...valid thru 27/18z.
Sky clear-scattered clouds 10-15k ft above ground level from ktus west, and mainly scattered-broken
clouds at 8-12k ft above ground level east of ktus thru the forecast period.
Isolated to scattered rain showers/thunderstorms and rain mainly east and S of ktus this
afternoon. Ely surface wind this morning 10-14 kts becoming north to northwest this
afternoon 10-15 kts with a few higher gusts. A few of the stronger
thunderstorms and rain may produce wind gusts to 40 kts and brief MVFR conditions,
especially near kdug/kols. Aviation discussion not updated for taf


Fire weather...isolated to scattered thunderstorms generally east
and south of Tucson through Tuesday. Expect decreasing coverage of
thunderstorms Wednesday, with activity limited to near the
international border Thursday into the weekend. 20-ft winds will
exhibit diurnal trends with speeds mainly less than 15 mph through
Tuesday. Breezy west winds of 15 to 20 mph are likely on Wednesday
and Thursday afternoons, with weaker winds returning this weekend.
Periods of erratic gustiness may occur due to strong daytime heating
and/or thunderstorm outflows.


Twc watches/warnings/advisories...none.



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