Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 02/08/22

Area Forecast Discussion

National Weather Service Phoenix AZ

 527 PM MST Mon Feb 7 2022

.UPDATE...
Updated Aviation discussion.

&&

.SYNOPSIS...
High pressure anchored across the West will give Southern Arizona
and Southeast California an extended stretch of sunny and mild
weather. By the second half of the week, lower deserts will be
spending afternoons well into the upper 70s and lower 80s. No rain
is forecast through the weekend.

&&

.DISCUSSION...
Fairly unremarkable weather will continue through at least next
Monday, with above-normal temperatures and dry conditions.

Last night, fresh breezes rolled through parts of the region,
courtesy of a dry cold front emanating from a digging shortwave off
to our east. Dry and cool surface high pressure followed close
behind and now extends from the Four Corners to the Texas Big
Bend. Area ACARS soundings resolved the subtle cold advection that
has clipped our region as 850mb temperatures have fallen from
around +9C to +6C in the past 24 hours. This is only causing a
temporary pause in our warming trend.

Meanwhile, a dome of mid-level high pressure extends along the
California coastline. Over the next several days, the axis of this
ridging will move little. Ensemble guidance is in very good
agreement with the overall positioning of this player in our
weather story. This means that our area will sit on the eastern
periphery of the ridge.

Although a couple weak waves will deflect off to our east this
week, little to no deepening or moisture will be associated with
them. The only sensible weather will be locally breezy conditions
in our favored locations. The NBM depicts some locally stronger
gusts on Thursday and Saturday.

Therefore, the West Coast ridge will be the main driver of our
weather through the forecast period. For Phoenix, ensemble
guidance indicates that evening 850mb temperatures will be from
+13C to +15C from Wednesday through at least next Monday. This
will correspond to high temperatures across our lower deserts in
the upper 70s to lower 80s each afternoon. Climatology, combined
with closer proximity to the maximum subsidence beneath the upper
high, supports the warmest temperatures over our southwestern
zones (Yuma, El Centro). This is well-represented in probability
of exceedance products from the NBM 4.1. For example, on Thursday,
the probability of reaching 80F at Sky Harbor is 65%. That climbs
to over 90% at Yuma and El Centro.

What about a pattern change? By the tail-end of the forecast period
(next Monday-Tuesday), clusters finally start to diverge and
confidence begins to fall as some members show a stronger weather
system approaching our area. The 12Z EPS mean by next Tuesday
evening (2/15) indicates that 500mb heights over Arizona could
fall to around the 10th percentile of climatology - which would be
a stark change from the ridging that will precede it! It`s also
at that time when around 20% of the entire ensemble suite
(GEFS/EPS/GEPS) finally show some measurable precipitation around
here. Of course that comes with the natural caveat: this is 7-8
days out. But in the drought-stricken West, we are always looking
for that next rainfall opportunity. At the very least, there is
some evidence supporting a cool down next week.

&&

.AVIATION...Updated at 0026Z.

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

A period of light and variable winds can be anticipated this
evening before favoring downvalley/drainage patterns. At KPHX,
there may be a period of light southwest/west winds between 10Z-
15Z. As the inversion breaks by 16Z or so, more distinct easterly
winds can be anticipated followed by a slow trend to
northwesterly during the afternoon. Clear skies continue.

Southeast California/Southwest Arizona including KIPL and KBLH:

A northerly wind regime will remain in place but with light speeds
overall. Downvalley/drainage patterns will develop this evening
followed by predominantly light northerly winds by midday
Tuesday (sustained AOB 10kts). Clear skies continue.

&&

.FIRE WEATHER...
Wednesday through Sunday:
Dry conditions will continue through the period. A weak disturbance
glancing the area on Thursday may deliver enhanced breezes, with
gusts up to 20 mph possible. Otherwise, fairly light winds expected
through the period. Min RHs will range between 10-20% while max RHs
will range between 25-45%.

&&

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

$$

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DISCUSSION...Heil
AVIATION...AJ
FIRE WEATHER...Lojero