Severe Thunderstorm Warning 73, NWS Tucson, AZ

557 
WWUS55 KTWC 010117
SVSTWC

Severe Weather Statement
National Weather Service Tucson AZ
617 PM MST Mon Aug 31 2020

AZC019-010126-
/O.EXP.KTWC.SV.W.0073.000000T0000Z-200901T0115Z/
Pima-
617 PM MST Mon Aug 31 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL PIMA COUNTY HAS
EXPIRED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been allowed to expire.

LAT...LON 3203 11248 3231 11258 3246 11203 3211 11193
TIME...MOT...LOC 0116Z 256DEG 13KT 3226 11230 

$$

Area Forecast Discussion
National Weather Service Tucson AZ
222 PM MST Mon Aug 31 2020

.SYNOPSIS...Shower and thunderstorm chances will continue area
wide through Tuesday. Thereafter, thunderstorm chances will be
confined mainly south and east of Tucson. High temperatures will be
much cooler today into Wednesday, however it will be heating back up
in the latter portion of the week with highs back in the triple
digits for the lower deserts.

&&

.DISCUSSION...Current radar shows scattered showers and
thunderstorms mainly south and east of Tucson. Skies are clear
north of Tucson into Pinal County. This is in line with what CAM
solutions were showing this morning. Expect this storm activity
to continue into the evening with favored areas still being from
Tucson south and eastward as well as along the international
border in central/western Pima County. Some storms have been
fairly efficient with one hour rain totals between 0.75 to 1.25
inches. Localized heavy rainfall along with training storms will
be the primary threat for the rest of the day.

Tonight there is a threat for some isolated showers but nothing
widespread is expected. A shortwave trough will be making its way
southward today and move through the four corners region into New
Mexico Tuesday. Moisture will decrease some Tuesday but PWAT
values will still be around normal to even a little above normal
along the international border. With the trough and moisture
expect another day of scattered showers and thunderstorms for most
of the CWA with areas from Tucson southward most favored.
Localized heavy rainfall will again be a threat. Tuesday night
the 31/12Z NAM brings very heavy rainfall to the Catalinas, but
no other deterministic/ensemble model is really showing this
scenario. Also, the 31/18Z NAM has backed off the big rain totals,
but will need to evaluate future model runs. For now have a
chance for overnight precip Tuesday.

Wednesday drier air begins to move into the region but there will
still be enough residual moisture left for isolated showers and
thunderstorms. As the low moves off to the east a ridge builds
over the west centered over Nevada. By Thursday the moisture will
be gone with dry conditions expected. Temperatures will also begin
to increase Thursday. Friday into the weekend the high stays over
the west with its center meandering around southern Nevada/Utah
and northern Arizona. This will lead to temperatures being much
above normal again. There may be a threat of excessive heat Friday
into the weekend mainly for central and western Pima County. Will
have to monitor this. Moisture also finds its way back into the
area Saturday and Sunday leading to slight chance for precip
mainly for eastern locales. Also, models show the aforementioned
shortwave trough stalling and retrograding back into southern
Arizona/northern New Mexico this weekend. This scenario will need
to be watched as we get closer to the weekend.

&&

.AVIATION...Valid through 02/00Z.
SCT-BKN clouds 8-14k ft MSL thru much of valid period. Slight chance
of MVFR ceilings again tonight into early Tuesday morning near the
international border. Scattered TSRA/SHRA into Tuesday mainly from
Tucson southward. MVFR ceilings possible in or near TSRA/SHRA. Aside
from thunderstorm outflow gusts to 35 kts, surface winds generally
remain less than 12 knots with afternoon and evening winds out of
the west/northwest and variable at other times. Aviation discussion
not updated for TAF amendments.

&&

.FIRE WEATHER...Moisture and instability will linger through
Tuesday night with scattered showers and thunderstorms expected,
mainly during the afternoon hours. That said showers and storms are
possible through the nighttime hours. Elevated humidities and cooler
temperatures will linger through Wednesday. Afternoon and evening
thunderstorms winds could gust in excess of 40 mph today and
Tuesday. Otherwise general winds will be less than 15 mph with the
exception of Tuesday and Wednesday where northwest winds down the
Gila and over the White mountains will likely be in the 15-25 mph
range. Drier and warmer weather returns the end of next week and
into next weekend.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
None.

&&

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