Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 241642

Area Forecast Discussion
National Weather Service Tucson AZ
940 AM MST Sat Jun 24 2017

.SYNOPSIS...Very hot temperatures will continue this weekend.
We`ll also see increasing thunderstorm chances with the most
action on Sunday and Monday. Some drying will limit thunderstorms
the second half of the new week, with temperatures closer to
normal for late June as we back away from the record heat.


.DISCUSSION...Another very hot day on tap today along with an
easterly push of moisture into the area. Surface winds from the east
have already picked up at Safford and across southwestern New
Mexico. Gusty easterly winds near Lordsburg caused some blowing dust
issues along Interstate 10 this morning. This increase in moisture
will translate to more thunderstorms activity later this afternoon
and evening, mainly east and south of Tucson. Deeper moisture was
progged by the models to move into the area tonight and Sunday for
an upswing in thunderstorm activity tomorrow. Current forecast
looked on track, so no additional updates necessary this morning.
Please refer to the other sections in this product for more details.


.AVIATION...Valid thru 25/18Z.
FEW-SCT clouds at 8k-15k ft AGL thru the forecast period, with
ISOL`D-SCT SHRA/TSRA E/SE of KTUS this afternoon and evening. SFC
wind variable in direction and less than 10 kts through this
morning. This afternoon, expect WLY/NWLY wind at 10-14 kts with
gusts to 20 kts. SHRA/TSRA may produce wind gusts to 40 kts.
Aviation discussion not updated for TAF amendments.


.FIRE WEATHER...Scattered thunderstorms generally from Tucson
eastward and southward through Tuesday. Expect decreasing coverage
of thunderstorms Wednesday, with isolated to scattered thunderstorms
mainly east to south of Tucson. Dry conditions are forecast to
prevail across much of the area next Thursday and Friday.

Morning southeasterly winds and afternoon northwesterly winds will
be periodically gusty through the Gila River Valley this weekend.
Additionally, any convection which develops will be capable of
producing gusty erratic wind gusts in excess of 40 mph. Otherwise,
20-foot winds will then exhibit diurnal trends with speeds mainly
less than 15 mph, although some elevated afternoon gusts may occur
due to strong daytime heating.


.PREV DISCUSSION... Mid level moisture from the south and east is
wrapping back into the area around the high, and pushing
precipitable water values back near and then above 1 inch over the
next 24 hours.

That high is reconsolidating immediately overhead, so another day of
near record high temperatures with an Excessive Heat Warning still
in place. Convection chances will be highest around the eastern and
southern periphery of the high, so that would be our far eastern and
southern areas this afternoon. By tomorrow moisture will have pushed
far enough back into the area for better thunderstorm coverage
Sunday and Monday.

The ridge will weaken fairly quickly starting Monday as a dry zonal
flow sets up under a more active higher latitude pattern, and the
record height and thickness values we`ve been seeing over the past
week recede closer to normal levels. As this happens, temperatures
will do the same, and our chance of thunderstorms will diminish
considerably by Wednesday or Thursday.

Another tropical cyclone forming near the southern Mexican coast.
This one will likely take a more northwesterly track with both the
GFS and ECMWF taking the remains just southwest of the tip of Baja
around Tuesday or Wednesday next week. No direct impacts for us, but
it will probably help prime western Mexico with deeper moisture. It
could even contribute to moderate surge activity the second half of
next week.


Excessive Heat Warning until 7 PM MST Sunday for AZZ501>507-509-

Heat Advisory until 7 PM MST this evening for AZZ511-513.

Heat Advisory until 7 PM MST Sunday for AZZ514.

Excessive Heat Warning until 7 PM MST this evening for AZZ508.




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