Heat in Arizona, August 5, 2024

Area Forecast Discussion
National Weather Service Tucson AZ
903 AM MST Mon Aug 5 2024

.UPDATE...

Mostly clear skies this morning with some residual mid to high
clouds from showers overnight still lingering in southeastern
Pinal and western Pima counties. These clouds will clear out this
morning allowing for decent surface heating that will bring high
temperatures to around 100-106 degrees. The 12Z sounding shows
PWAT at 1.53 inches with a fairly saturated mid levels and drier
low levels. PWAT will be highest in western Pima county today with
values around 1.6 to 1.7 inches continually getting more dry
moving east across the area, driest in north Graham and Greenlee
counties with values around 0.7 to 1 inch.

HREF/CAMs show another fairly typical August monsoon day with
scattered showers across the area beginning roughly around 1 to 2
PM MST initially in the White mountains and higher terrain in
Cochise county. Isolated to scattered storms will become more
widespread as the afternoon progresses. Generally, storms will be
moving at 5 to 15 MPH to the southwest today. Based on high PWATs
and DCAPE values around 1000 to 1600 J/kg, the greatest concerns
associated with storms will be localized heavy rainfall leading to
flash flooding and blowing dust associated with thunderstorm
outflow winds.

&&

.PREV DISCUSSION... /issued 303 AM MST Mon Aug 5 2024/

.SYNOPSIS...Chances for thunderstorms and scattered showers will
continue through this week, with potential for heavy rainfall and
strong wind gusts. Hot temperatures continue today, before cooling
to near normal by mid-week.

&&

.DISCUSSION...Considerable cloud cover over the area early this
morning per satellite imagery with some embedded light showers per
radar. South of the border across Sonora MX a large MCS was still
on-going with outflow from this system likely initiating a gulf
surge later today. To our east, water vapor imagery showed an
inverted trof near the Texas Big Bend. This feature will be the
driver in our weather over the next several days.

Today, lingering light showers this morning with cloud cover
gradually decreasing. Partly cloudy this afternoon with widely
scattered showers and thunderstorms developing mainly east and
south of Tucson. Potential for a line of storms, per some CAMs,
developing this evening across Graham/Cochise counties and
pushing W/SW across Pima county late tonight. The usual threat of
wind gusts to 50 mph and brief heavy rain with storms today. Looks
for an MCS to develop south of Nogales this evening with outflow
from this system enhancing gulf surge overnight into Tuesday
morning.

Tuesday: The above mentioned inverted trof will be moving into
Sonora MX bringing increased dynamics aloft. At this time, looks
like areas west of a San Carlos to Sierra Vista line will see a
good chance of showers and thunderstorms. 05/00z HREF painting the
western half of the forecast area with 10-30% chance of seeing
thunderstorm wind gusts greater than 50 kts and with PW values
near 2" west of Tucson, an increased heavy rain and flash flooding
threat. SPC has the western half of the forecast area under a
marginal risk for severe wind gusts while WPC has pretty much the
same area under a slight risk for heavy rain (ERO).

Wednesday: The area will still be under the influence of the
inverted trof as it continues to move west. Likely a later start
to the convection with activity favoring more the evening versus
afternoon.

Thursday into the weekend: Drying out a little bit with daily
chances of showers and thunderstorms with uncertainty on which day
being more active than another.

Another hot day today, then near normal by mid-week before heating
up again this upcoming weekend.

&&

.AVIATION...Valid through 06/12z.
ISOLD -SHRA this morning, then SCTD -SHRA/-TSRA btwn 05/18z and
06/06z diminishing toward end of valid pd. MVFR conds and local
gusts to 50 kts near thunderstorms. Outside of thunderstorms
expect wind speeds less than 12 kts and following typical diurnal
trends. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Scattered showers and thunderstorms continue each
day through the forecast period. Min RHs today in the upper teens
to lower twenties in the lower locations and thirties in the
higher elevations will trend upward thereafter Tuesday and
Wednesday due to thunderstorm influences. Outside of thunderstorm
winds, 20-foot winds will generally be 15 mph or less, with
afternoon/early evening gusts to 20-25 mph and light winds
overnight.

&&

&&

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

Update...Malarkey

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