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896
FXUS65 KPSR 260015
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
515 PM MST Tue Jun 25 2024

.UPDATE...
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Updated 00Z Aviation Discussion.
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&&

.SYNOPSIS...
Enhanced monsoonal moisture across the region will continue to
allow thunderstorm chances to persist into the weekend, overall
coverage will decrease and be confined mostly to the higher
elevations. Temperatures will continue to run several degrees
above normal, so hot and humid conditions will persist as well
during this period.

&&

.DISCUSSION...
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The early afternoon radar and satellite imagery showing the usual
midday showers and thunderstorms forming over the high country
north and east of Phoenix with the exception of an isolated storm
across far southern Maricopa County. Visible satellite imagery
has been showing a remnant MCV from overnight convection drifting
northwest across the SC AZ through the morning. This has resulted
in overall increased cloud cover for most areas and keeping
conditions more stable. The latest SPC Meso analysis subsequently
showing convective inhibition persisting across the Phoenix valley,
unlike yesterday when we had full sunshine and eroded the cap.

For the rest of today, the latest HRRR convective trends seem
reasonable given the aforementioned instability trends. Most of
the convection should remain over the high country with a steering
flow to the north and away from the Phoenix area. An exception is
likely into western Maricopa County into La Paz County ahead of
MCV where more insolation has occurred and cap has eroded.
Forecasting some convection to develop in these areas into early
this evening.

Shower and storm potential does try to trend downward as upper
level ridge retrogrades into AZ/NM region this week, which should
tend to inhibit convection, especially for the lower deserts.
HRRR hints at this trend on Wednesday. Also, by Thursday and
Friday, watching a stronger trough dig across the northern
Rockies, which will break down the ridge over AZ and also shunt
deeper moisture to the south with the development of a drier
west/southwest flow. This should further inhibit storm potential
and confine it to mainly far SE and Eastern AZ into first half of
the weekend.

After this trough passes to the northeast, ridge builds again
across the SE U.S. which will bring back the southerly flow and
moisture that is poised to move back north into the region as
early as Sunday. This will increase storm chances again into next
week. CPC outlooks for 8-14 days (the first week of July) favors higher
percentages for above normal precipitation.

As for temperatures, readings will remain above normal by several
degrees, but nothing on the record/extreme level. This will
maintain a consistent moderate HeatRisk across the region through
the period.
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.AVIATION...
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Updated at 0000Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:

The main aviation concern this evening will be the timing and wind
shifts of any outflow boundaries that move through the Phoenix
Metro. There are currently multiple outflows moving out of the
north. These outflows are expected to reach KDVT and KSDL around
02-03Z. Confidence is low that these outflows will reach KPHX and
KIWA, however, if they are able to reach these terminals it would
be around 03-05Z. These outflows will cause a wind shift to more
northerly. There are outflows from the NW and NE, but it is
uncertain at this time which one will dominate. Behind these
outflows winds will likely stay out of the north before going
light and variable during the overnight hours. Westerly winds will
redevelop by the mid-to-late morning time tomorrow. Occasional
gusts near 20 kt is also expected tomorrow afternoon. SCT-BKN mid
and high level clouds will continue through the TAF period as
well.

Southeast California/Southwest Arizona including KIPL and KBLH:

Winds will follow their typical diurnal patterns. There may be
some occasional gusts around 20 kt this evening at KIPL from
02-05Z. Gust near 20 kt are expected at KBLH again tomorrow
afternoon. The one thing to watch for this evening will be any
outflow boundaries reaching KBLH from the activity to the
northeast of the terminal that is in west-central AZ. The
potential timing of an outflow boundary looks to be between 05-07Z
and it would switch the winds to be northeasterly.
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&&

.FIRE WEATHER...
Monsoonal moisture will continue to result in daily chances for
shower and thunderstorm activity. The higher terrain areas will
see the greatest potential with some locally heavy rainfall with
any storms that develop. Best chances for storms are today, with a
gradual decrease in chances/coverage through Friday, where chances
drop around 15% or lower. Chances for wetting rains will
generally remain around 10-20% for the higher terrain areas and
5-10% for the lower deserts of south-central Arizona today, before
dropping below 10% across the region starting Thursday. With the
elevated moisture in place, MinRH values through the middle of
this week will range between 30-40% across the far eastern
districts to between 15-25% across the western districts before
slowly drying during the latter half of this week. Winds will
follow their typical daily tendencies, with gusty outflows from
any thunderstorm activity anticipated over the next several days.
Temperatures average several degrees above normal through the
forecast period.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&

$$

DISCUSSION...Frieders
AVIATION...Berislavich
FIRE WEATHER...Young/Frieders