Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 301624

Area Forecast Discussion
National Weather Service Tucson AZ
925 AM MST TUE AUG 30 2016

.SYNOPSIS...Moisture will be on the increase over the next several
days which will lead to isolated thunderstorms today and then
scattered afternoon and evening thunderstorms Wednesday through
Thursday. Drier conditions will return again by late next week and
into the weekend.


.DISCUSSION...Satellite imagery this morning showed a clear sky from
Tucson east with partly cloudy conditions over western/cental Pima
county. Morning Tucson sounding had a PW values of 1.09" which is up
43% versus Monday morning. This added moisture was mostly in the 850-
600 mb layer while its still really dry above 580 mb. Easterly
gradient below 700 mb has also increased versus 24 hours ago. This
had resulted in localized wind gusts up to 20 mph. This low level
easterly flow has increased surface dewpoints with values mostly in
the 40s and 50s, which is up 4-10 degrees versus 24 hours. Across
northern Mexico, there is an inverted trof that will play a role in
increasing moisture and areal coverage of showers and thunderstorms
on Wednesday.

For today the UofA runs of the 12z WRFNAM and 06z WRFGFS runs show
thunderstorm outflow moving SW across Pinal county from Gila county
storms. Could produce localized blowing dust issues late this
afternoon into this evening. Otherwise storms will struggle to move
off the higher terrain. As mentioned above Wednesday will see
greater areal coverage of storms.


Mostly clear skies through the morning hours, then isolated to
scattered -TSRA/-SHRA developing mainly from KTUS eastward after
30/19Z and continuing into the early evening. Winds generally from
the east under 15kts through the period except for strong erratic
outflows near thunderstorms. Aviation discussion not updated for TAF


.FIRE WEATHER...The coverage of showers and thunderstorms will
spread farther west today, though with the bulk of the coverage from
Tucson eastward. Scattered to numerous thunderstorms Wednesday for
much of the area before decreasing again Thursday. A drying trend
will then occur from west-to-east Friday into next weekend.
20-foot winds today and 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.





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