Forecast Discussion

Forecast Discussion for TWC NWS Office
989
FXUS65 KTWC 211041 AAA
AFDTWC

Area Forecast Discussion...UPDATED
National Weather Service Tucson
AZ 301 AM MST Wed Apr 21 2021

.UPDATE...Removed Fire Weather Zone 150 from the Thursday Fire
Weather Watch, otherwise no other changes.

.SYNOPSIS...A storm system will produce widespread gusty winds today
and to a lesser extent Thursday along with gradually cooling
temperatures into Friday. There is also a slight chance of showers
over the White Mountains Friday. After a rapid warmup this weekend,
another storm system may impact the area early next week.

&&

.DISCUSSION...It gonna be breezy and given the situation it will
begin to ramp up fairly early with gusty winds developing over
central/western Pima county as early as 9 am. Winds will then
surface steadily eastward through the late morning hours. Primary
concern, other than roving garbage cans, is the critical fire weather
conditions that will develop and an area wide Red Flag Warning is in
effect as a result. Another concern with winds this strong will be
areas of blowing dust out across the open desert and downwind from
the Willcox Playa. With the wind direction predominately southwest,
I-10 northwest of Tucson and east of Willcox may be impacted at times
this afternoon with reduced visibility. Winds ease this evening
except for the exposed mountain ridges where gusty winds will
continue through the night.

On Thursday the core of the midlevel winds will have shifted eastward
with the strongest winds occurring southeast of Tucson. Some areas
from the Huachuca Mountains eastward may reach critical fire weather
levels once again Thursday afternoon. After coordinating with
neighboring offices, we decided to leave the Thursday Fire Weather
Watch as is for the moment. By Friday, the axis of the storm should
be moving overhead pushing the stronger winds east of the area but
also resulting in cooler temperatures and a slight chance of showers
over the White Mountains.

Temperatures will rebound quickly this weekend as an upper level
ridge builds over the area behind the departing storm. Sunday should
be the warmest day through next Tuesday with highs in the lower to
mid 90s in the valleys from Tucson north and west. Guidance continues
to strongly suggest some sort of trough affecting the area early
next week although there is a wide variation in the solutions
primarily related to timing. Could be another period of strong winds
along with a slight chance for showers which would be a welcome
change if it were to occur.

&&

.AVIATION...Valid through 22/12Z.
SCT-BKN cirrus clouds today then clearing this evening. SFC wind
SWLY/WLY at 8-12 kts increasing rapidly aft 21/14Z, with SWLY SFC
wind at 20-30 kts and gusts to 30-40 kts between 21/18Z and 22/02Z.
Aft 22/02Z SFC wind becoming S-SWly 8-13 kts through the remainder
of the night. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...A Red Flag Warning is in effect for all of southeast
Arizona today from 11 am to 8 pm MST. Expect strong and gusty
southwest winds of 20-30 mph and gusts to 45 mph with very low
humidity levels. Critical fire weather conditions are possible again
over portions of southeast Arizona Thursday afternoon and evening,
roughly southeast of a line from Nogales to Vail to Clifton. A Fire
Weather Watch remains in effect for the above areas on Thursday
afternoon and early evening, with southwest winds of 15-25 mph and
gusts to 35 mph in the Fire Weather Watch area Thursday.

Otherwise, near normal temperatures are expected through Friday,
with above normal daytime temperatures this weekend. There is a
chance for another storm system early next week, with the potential
for strong winds and a small possibility of a few showers across
northern areas with cooler temperatures.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 11 AM this morning to 8 PM MST this
evening for AZZ150>154.

Fire Weather Watch from Thursday afternoon through Thursday
evening for AZZ151>154.

&&

$$

Public...Cerniglia
Aviation...Cerniglia
Fire Weather....Cerniglia

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NWS TWC Office Area Forecast Discussion