113
FXUS65 KTWC 060927
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
227 AM MST Thu Jun 6 2024

.SYNOPSIS...High pressure will bring hotter temperatures over the
next several days. An Excessive Heat Warning is in effect for
today and Friday. A weather system will bring a modest moisture
increase Friday into the weekend, with a chance of thunderstorms
each afternoon mainly near the eastern mountains. Rainfall should
be limited, with strong and erratic winds being the main threat
along with lightning.

&&

.DISCUSSION...Water Vapor imagery shows the anticyclonic rotation
of the upper level high that is moving eastward over the Great
basin and passing over Arizona later today. These heights will
allow ample surface heating to cause Major Heat Risk for most of
Southeast Arizona. Some locations will be within 2-4 degrees of
record highs for the first week of June. Not to mention, overnight
lows will be also a few degrees within record high mins. The
temperature swings between the highs and lows won`t provide much
relief, especially with the urban heat island effect in larger
population centers. With that, an Excessive Heat Warning is
effect for today through Friday evening.

A modest push of moisture will be creeping into the region due an
upper level low sitting off the Baja California and with the aid
of the high pressure moving across the region. Today, the
moisture will be confined to the upper levels to bring in high
clouds and with some instability along the higher terrain to form
mainly dry thunderstorms. Friday has better chances as the
moisture works a little more into region along with better
instability (i.e. CAPE). With the combination of modestly high
DCAPE values and the lower levels staying fairly dry, this leads
to a higher potential for dry microbursts and along with gust
outflows. However, if any storm that forms has the potential to
keep temperatures at bay in its immediate surroundings due to
thick cirrus blow off, especially in the eastern part of the
state.

By the end of the weekend, the low will track across the region
and get absorbed into the larger pattern. The ensembles show the
ridge axis reasserting itself over the western United States and
another upper low developing over over the California coast again.
This could be another repeat of the weekend with possibly more
moisture to work with for storm development.

&&

.AVIATION...Valid through 07/00Z.
SCT-BKN high cloudiness AOA 20K ft AGL through most of the
forecast period. FEW-SCT mid level clouds AOA 10K ft AGL
developing after 06/18Z to the end of the forecast period.
Isold -TSRA possible near mountains after 06/20Z, mainly to the
east of KTUS. Typical wind patterns generally under 10 kts, with
some gustiness from the west and northwest in the afternoon hours.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Hotter the next few days with temperatures near record highs
today through Friday, with an Excessive Heat Warning for those
days. Minimum RH values in the single digits in the valleys with
poor overnight recoveries. A modest increase in moisture will
bring isolated thunderstorms mainly east of Tucson and towards the
White Mountains later today. Better chances for storms and as well
as coverage on Friday into the weekend. These storms will
generally be dry and can produce gusty and erratic winds along
with lightning. Outside of thunderstorms, winds generally remain
light through the remainder of the week and into the weekend, with
some afternoon breeziness.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning from 10 AM this morning to 8 PM MST
Friday for AZZ501>509.

&&

$$


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