Severe Thunderstorm Warning 10, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
123 PM MST Sun Jun 23 2024

.SYNOPSIS...

Ample moisture will bring daily chances for thunderstorms to the
area through next week. Locally heavy rain will be likely with any
thunderstorm that develops, along with an isolated chance for
strong wind gusts. This will also knock several degrees off of
the heat. Temperatures may climb up a bit middle of next week as
high pressure builds overhead.

&&

.DISCUSSION...

The anomalously rich moisture plume remains in place across
southern Arizona, currently centered across the southwest with a
gradient over southeastern Arizona. GOES precipitable water
indicates values from around 1-1.25 inches near the New Mexico
border to 1.5-1.7 inches from Tucson-Nogales westward. Combined
with widespread surface dew points in the 60s this afternoon, the
moisture in place should remain sufficient to produce heavy
rainfalls for any convection that develops, especially in areas
with greater instability. This instability window should be
centered along an axis from the Santa Cruz County area and
through central to eastern Pima, as well as part of Cochise
county and potentially southern Graham county. This corridor is
where the overlap of precipitable water values to the west and
easterly mid- level lapse rates (associated with drier air moving
in from New Mexico) lies. Instability should remain more limited
for now in Pinal County as ongoing cloud cover there has kept
temperatures relatively cooler. Thunderstorms are expected to
develop this afternoon, with the strongest potential lying in the
corridor of best instability where SBCAPE could exceed 2000 J/kg.
Heaviest rainfall rates are most likely in this corridor as well,
given the moisture in place (as well as isolated severe wind
gusts). As convection forms closer to the International Border
early this afternoon, outflows should push activity towards the
Tucson area as the day goes on. Uncertainty with coverage
precluded a watch for flooding today, but messaging the heavy
rainfall rate potential is needed as an isolated threat for flash
flooding remains.

GOES water vapor imagery paints the picture for the coming days as
a stream of deep moisture amid easterly flow remains oriented
across the southern Gulf of Mexico through northern to central
Mexico, with a tropical disturbance moving over into Mexico today.
Between the push of Gulf moisture and the aid of the tropical
disturbance, the anomalously rich southeastern Arizona moisture
should nudge up a notch tomorrow. 12Z HREF ensemble max QPF shows
the spatial expansion of potential heavy rain across southeastern
Arizona Monday afternoon through the overnight hours. If this
trend holds through the upcoming model runs, messaging for Monday
may need to be ramped up. Daily convection chances remain in the
forecast through the remainder of the week as a mostly persistent
pattern aloft keeps moisture in place. A subtle westward nudge of
the upper level high may bring mid-level moisture down a touch by
the middle of next week, but with ample surface heating expected
every afternoon and evening should have at least some sort of
convective potential.

&&

.AVIATION...Valid through 25/00Z.

Scattered TSRA near KOLS from 24/20Z to 25/01Z, developing near
KTUS after 24/22Z. Isolated -SHRA or -TSRA possible elsewhere
through 25/03Z. Locally heavy rainfalls with any thunderstorms may
significantly reduce visibilities. Overall winds generally remain
under 12 kts with occasional gusts to 18Z in the afternoon, while
strong gusty outflow winds are possible under any thunderstorms. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...

Unseasonably rich moisture will keep relative humidity values
generally on the higher side through this week, along with daily
chances for thunderstorms. Moisture is expected to be deep enough for
some storms to generate locally heavy rain.

Temperatures may heat back up by mid week as high pressure builds
nearly overhead, however we should keep some storm chances around.

&&

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

Public...Edwards
Aviation...Edwards
Fire Weather....Edwards

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