Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 240405
Area Forecast Discussion
National Weather Service Tucson AZ
905 PM MST MON MAY 23 2016
.SYNOPSIS...Dry conditions with below normal daytime temperatures and
gusty afternoon winds will prevail this week. Expect windy
conditions across much of the area Wednesday as a low pressure
system approaches from the west.
.DISCUSSION...Water vapor imagery shows ridging extending from
southern Texas into the Great Lakes region. Meanwhile both the east
and west coasts of the nation are dominated by low pressure systems.
WV imagery currently shows a shortwave trough making its way across
central California. IR satellite imagery shows mostly clear skies
As of 04Z (9 PM MST), temperatures were generally in the 70s for
desert/valley locations, with the Tucson Intl Airport reporting a
temp of 79 degs. The high temp at TIA this afternoon was 91 degs,
which was 3 degs below normal for this date. These current readings
are on track with the inherited overnight low temps, so no changes
are planned, but will continue to monitor.
See the previous discussion below for details beyond tonight.
.AVIATION...VALID THRU 24/23Z.
Clear skies will prevail across most of southeast Arizona through
Tuesday afternoon. A few cirrus clouds above 25K ft agl may move
into the area near the very end of the forecast period. Surface wind
generally less than 10 kts between through around 24/16z. Increasing
surface wind aft 24/16z, with sly/swly surface wind at 12-20 kts and
gusts to around 25 kts aft 24/20z. Aviation discussion not updated
for TAF ammendments.
.FIRE WEATHER...A Fire Weather Watch is in effect from early
Wednesday afternoon through early Wednesday evening for much of Fire
Weather Zones 151 and 152 due to the combination of strong and gusty
southwest winds, low relative humidities and a high to very high
fire danger. Field crews are encouraged to monitor subsequent
forecasts on expected critical fire weather conditions Wednesday, as
well as the likelihood of this Fire Weather Watch being upgraded to
a Red Flag Warning.
Otherwise, dry conditions will prevail through next weekend. Daytime
minimum relative humidity will generally range from the upper single
digits to mid teens with fair overnight recoveries. Expect gusty
mainly southwest winds during the afternoon and early evening hours.
.PREV DISCUSSION...The southern branch of the large upper low over
the Pac NW will slowly migrate southward this week and move through
Arizona by the middle of the week. A tightening pressure gradient
ahead of this low will result in breezy conditions later this week
(especially Wednesday) along with noticeably cooler temperatures.
Desert highs which will top out in the 90s today and again tomorrow
will only reach the lower 80s by the middle of the week. BL moisture
is unimpressive with this trough, thus the only impacts will be an
increase in winds. While temperatures will recover somewhat,
longwave troughing will persist across the area late this week into
the weekend resulting in a prolonged period of sub-100 degree
surface temperatures with near-zero precip chances through at least
Fire Weather Watch from Wednesday afternoon through Wednesday
evening for AZZ151-152.
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