FXUS65 KTWC 272213
Area Forecast Discussion
National Weather Service Tucson AZ
313 PM MST Thu Apr 27 2017
.SYNOPSIS...Increasing winds this afternoon, then a return of
stronger and gusty winds Friday into Saturday. Blowing dust may
be an issue, especially in the vicinity of Interstate 10. A few
showers or thunderstorms are possible northeast of Tucson on
Friday. Cooler on Saturday followed by dry conditions with a
warming trend next week.
.DISCUSSION...Winds are increasing over the next 36 hours as a
strong ridge amplifies off the west coast and a system digs
through the intermountain west and front range of the rockies.
Main concern continues to be wind, with Red Flag Warnings today
and tomorrow, and now a Fire Weather Watch Saturday. We also now
have a Wind Advisory Friday afternoon and a Blowing Dust Advisory
for I-10 east of Tucson.
This next system is digging a littler further south than previous
systems as the ridge amplifies offshore. This will bring a decent
chance of showers or thunderstorms to mainly higher terrain areas
northeast of Tucson late Friday into Saturday (especially
mountains in northern Graham and Greenlee counties). Plenty of
cooler air behind a late April frontal passage Saturday with
daytime temperatures dropping from upper 80s to lower 90s tomorrow
to 70s on Saturday. Saturday night will be the coolest we've seen
in about 3 weeks, with 30s in valleys east and south of Tucson,
and 40s from Tucson westward. A few spots will probably freeze
Sunday morning in colder Cochise county valley locations.
The eastern flank of the ridge will start to assert itself into
our area early next week with a slow pattern shift. We still may
see a batch of gusty winds Tuesday and/or Wednesday with systems
digging sharply immediately downstream to our east, but not as
strong as this week. Otherwise dry and warmer.
As the slow and amplified pattern continues to gradually phase
across the CONUS next week, high pressure will bring hotter
temperatures the second half of the week. MOS numbers are not
handling the potential of the airmass very well. We may be
flirting with our first 100 at TIA by next Friday.
.AVIATION...Valid through 29/00Z.
SCT-BKN clouds above 20k ft AGL. SFC wind increasing this
afternoon to 15-25 kts with gusts to 35 kts. The strongest speeds
will be east of KTUS. Looking into Friday afternoon, stronger
winds will be impacting all terminal sites. Aviation discussion
not updated for TAF amendments.
.FIRE WEATHER...Strong and gusty winds will continue to be a concern
the next several days. Today, gusty winds have developed as
expected this afternoon with Red Flag conditions across much of
zone 152 and parts of southeast zone 151. This includes the higher
elevations of Whetstone Mountains near the Sawmill wildfire.
Even stronger winds can be anticipated Friday, but models continued
to show a modest increase in relative humidity values. However,
given the very dry fuels we have continued the Red Flag Warning.
The wind will remain elevated in speed Saturday across eastern
sections on the back side of an exiting system to the north.
Humidity values will also lower on Saturday, so critical fire
weather conditions will once again be a concern. A Fire Weather
Watch is now in effect Saturday afternoon and early evening for
locations east of Tucson. The wind settles down next week, but
very dry conditions will remain in place with some afternoon
breeziness at times.
Wind Advisory from noon to 8 PM MST Friday for AZZ503>514.
Blowing Dust Advisory from noon to 8 PM MST Friday for AZZ508-
Red Flag Warning until 7 PM MST this evening for AZZ151-152.
Red Flag Warning from 10 AM to 8 PM MST Friday for AZZ150>152.
Fire Weather Watch from Saturday afternoon through Saturday
evening for AZZ151-152.
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