Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tucson Arizona
845 PM MST Tuesday Mar 31 2015
Synopsis...a weather system passing north of the area will bring
gusty winds the second half of the week...especially late Wednesday
into Thursday. Otherwise expect dry conditions with temperatures
continuing to be warmer than usual.
Discussion...scattered convection south of Tucson today...mainly
across Santa Cruz and southern Cochise counties. Not a lot of rain
with those but several reports of strong outflow winds between 30
and 45 miles per hour. A few very light showers hanging on this evening.
Moisture actually continues to creep up the Sierra madres south of
the border, with 1 inch values pushing into central Sonora. An
increasing westerly flow over the next 36 hours will push much drier
air back into the region. Gusty winds late Wednesday into Thursday
are the main weather concern as outlined in the fire weather section
and previous discussion below.
Aviation...valid through 02/06z.
Isolated -shra this evening. Clearing skies...with just some
high-level cirrus later tonight and Wednesday. Locally gusty
west/southwest winds will develop Wednesday afternoon. Aviation
discussion not updated for taf amendments.
Fire weather...gusty west/southwest winds will occur mainly during
the afternoon and early evening hours into this weekend. The
strongest winds should are expected later Wednesday and especially
Thursday. Anticipating high coverage of sustained winds in excess of
20 kts with gusts to 35 kts...daytime minimum relative humidity values approaching
10 percent on Thursday afternoon...and the presence of high fire
danger in the White Mountains. Therefore...we have issued a Fire
Weather Watch valid between 10am-8pm MST Thursday for all of fire
weather zone 153. Field crews are encouraged to monitor subsequent
forecasts for the potential issuance of a red flag warning.
Previous discussion...a weak upper low tracking through Mexico will
exit the region tonight. Enough moisture and instability had
resulted in a few showers and thunderstorms this afternoon...mainly
in the White Mountains and near the international border. Will keep
the mention of this activity through early this evening with most of
it dissipating after Sundown. The main weather story will be the
increase in wind tomorrow and more so Thursday. Latest models track
the tail end of a system through southern Arizona on Thursday.
Thus...expecting winds to pickup in advance of the system tomorrow
and increasing more on Thursday as it passes through the region. The
increase in wind and dry conditions will result in some fire weather
concerns...especially for the White Mountains on Thursday. Please
refer to the fire weather section in this product for more details.
Continued dry with above normal temperatures into the weekend.
Fire Weather Watch for zone 153 Thursday.
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