Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 310418

Area Forecast Discussion
National Weather Service Tucson AZ
918 PM MST TUE AUG 30 2016

.SYNOPSIS...Moisture will be on the increase over the next few days.
Scattered afternoon and evening thunderstorms Wednesday and Thursday.
Drier conditions will return again by late in the week and into
the weekend.


.DISCUSSION...A few thunderstorms rolled back into the area this
afternoon, however our available moisture was still on the lighter
side with about 1 to 1.1 inches across most of Southeast Arizona.
Even with decent outflows we were unable to sustain significant
thunderstorm coverage.

Nice complex through central Sonora, watch for a low level shallow
push from the south overnight. Otherwise, the easterly flow
continues below 500mb and that should push us back into average
late monsoon thunderstorm coverage Wednesday and Thursday as
advertised by current forecasts. Latest analysis and 00z model
data continues this idea, so steady as she goes. Please see the
previous discussion below for additional details.


.AVIATION...VALID THRU 01/06Z. Partial clearing overnight from
earlier convection. Increasing thunderstorm chances after 31/18z
with brief MVFR conditions possible at terminal sites associated
with stronger storms. Easterly surface winds 10-15 kts through the
period, outside of strong and erratic thunderstorm outflows.
Aviation discussion not updated for TAF amendments.


.FIRE WEATHER...Wednesday and Thursday will be more active with
scattered showers and thunderstorms across the area. A drying
trend will then occur from west-to-east Friday into next weekend.
20-foot winds thru Wednesday will be mainly from the east at 10-15
mph with gusts of 20- 25 mph. Otherwise, 20-foot winds will be
terrain driven and less than 15 mph.


.PREV DISCUSSION...Precipitable water values continue to slowly
rise this afternoon and will peak on Wednesday when values are
forecast to be in the 1.25" to 1.75" range. Water vapor imagery
this afternoon showed an upper level disturbance moving north
across northern Mexico. Bulk of the dynamics with this system will
move into New Mexico tonight into Wednesday.

Wednesday and Thursday will be fairly active with scattered showers
and thunderstorms, some with heavy rain. Can`t rule out some blowing
dust issues once again NW of Tucson. Highs will be right around
normal as climatological summer comes to a close.

The first day of climatological fall starts of active with scattered
showers and thunderstorms.

Increasing southwest flow aloft on Friday in advance of west coast
upper level trof will spread drier air across the region once again
thus limiting storms to the far eastern areas.

Very little activity is expected across the area this weekend with
trof axis to our west continuing to bring a drier southwest flow
aloft over the area.

Early next week looks highly uncertain as the area may see some
tropical influences. Stay tuned.






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