Severe Thunderstorm Warning 57, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
151 PM MST Thu Jul 21 2022

.SYNOPSIS...

Very hot temperatures in the forecast for Friday - approaching
some records - with an uptick of monsoonal activity this weekend
and into next week.

&&

.DISCUSSION...

The mesoscale convective system (MCS) that moved through northern
Sonora Mexico last night has weakened, but residual cloud cover
and a few isolated showers remain. The 12z sounding from Tucson
was very moist, with precipitable water values over 1.8 inches and
moisture throughout the column. Instability was over 1000
J/kg...quite unstable. The challenge for today is that there are
several capping inversions notable in the sounding which may make
it more challenging for convection to get going. SPC HREF members
continue to highlight convection starting over the White Mountains
/ Mogollon Rim early this afternoon, and the best chance of
thunderstorms remaining mainly south of east of Tucson.

Additionally, an Excessive Heat Warning is in effect for the
western portions of the CWA through tomorrow evening. Based on the
latest guidance, we went ahead and added Zone 509 to the EHW.
Regardless, daytime highs in some areas may approach record
values. The record for Tucson is 108, and that's what we have in
as our forecast high.

Looking ahead past Friday, a more favorable monsoon pattern will
take shape as a subtropical high settles in over the four corners
region. Saturday and Sunday will likely be more active days, with
widespread moisture becoming more prevalent. This will likely
shift the impacts to more of a flooding threat.

With more monsoon activity, daytime high temps will gradually
return to more normal values.

&&

.AVIATION...

ISOLD-SCT SHRA/TSRA progged to develop again aft 21/19z, first
over the White Mountains and the border region in Cochise County
and east of KOLS in Santa Cruz County. Activity then spread west
to southwest but generally remains south and east of KTUS,
gradually diminishing aft 22/04Z. Lower cigs between 6-10k ft MSL
can be expected around precipitation, including gusty winds up
around 40 kts. Otherwise, cloud bases range 10-15k ft MSL with
diurnal sfc winds generally less than 12 kts. Aviation discussion
not updated for TAF amendments.

&&

.FIRE WEATHER...

Temperatures will remain several degrees above average trough Friday
with daily thunderstorm chances. Storms become more widespread this
weekend into next week as moisture increases area-wide, providing a
greater potential for heavy rainfall. Strong and erratic outflow
winds accompany the stronger storms, with otherwise diurnal wind
trends.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning from 11 AM to 8 PM MST Friday for AZZ501-
502-504-505-509.

&&

Public...Dang
Aviation...Singer
Fire Weather....Dang

Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson

Special Weather Statement
National Weather Service Tucson AZ
148 PM MST Thu Jul 21 2022

AZZ509-510-212130-
Upper Gila River and Aravaipa Valleys including Clifton/Safford-White
Mountains of Graham and Greenlee Counties including Hannagan Meadow-
148 PM MST Thu Jul 21 2022

...A strong thunderstorm will impact portions of north central Graham
and west central Greenlee Counties through 230 PM MST...

At 148 PM MST, Doppler radar was tracking a strong thunderstorm 19
miles west of Hannagan Meadow, or 43 miles northwest of Clifton,
moving south at 40 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Point-Of-Pines.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3308 10949 3319 11001 3351 10982 3348 10981
      3348 10975 3352 10973 3354 10968 3358 10967
      3359 10962 3361 10960 3362 10953 3363 10952
      3363 10950
TIME...MOT...LOC 2048Z 015DEG 53KT 3358 10966

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

MJS

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