Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 05/25/21

Area Forecast Discussion

National Weather Service Phoenix AZ

 503 PM MST Mon May 24 2021

.UPDATE...Updated 00Z Aviation Discussion.


&&

.SYNOPSIS...
Temperatures have rebounded back near normal today, and will
hover at or slightly above average throughout the rest of the
week. The weather pattern this week will ensure very dry
conditions with only a few passing high clouds.

&&

.DISCUSSION...
The upper level low that brought cooler air into the region over
the weekend continues to exit to the northeast and is now in
southern Canada, with any lingering cool air rapidly moderating.
ACARS soundings show about a 2-4 C warming throughout the lower
atmosphere compared to yesterday at this same time. Upper level
heights are steadily climbing and are now near normal for the
date. This should lead to surface temperatures climbing into the
mid 90s today and near 100 degrees on Tuesday.

As we head into Tuesday and Wednesday, a very weak open wave
embedded in the southern periphery of the ridge will move into
southern California and dissipate over Arizona. There will only be
a minor increase in low level moisture and no instability to speak
of. Accordingly, no rain is expected. However, the increase in
high clouds and plateauing of upper level heights should keep
temperatures from getting much above about 100 F or so. For the
second half of the week ridging will increase in amplitude and
intensity, but not significantly, with 500 hPa heights peaking
around 585 dm by Thursday or Friday. Surface temperatures will
increase into the low 100s for this period. Friday and Saturday
look to be the warmest days. NBM temperature probabilities show a
10-20% chance of reaching 105 F on each of these days.

There is some signal that by next weekend another dry open wave
may approach from the west. WPC cluster analysis shows relatively
high confidence in this outcome. The main uncertainties for this
period relate to the amplitude of the trough as well as the
magnitude of the ridging to its north. The ECMWF ensemble is
slightly deeper with the trough signal, but overall all of the
global ensembles paint a similar picture. The main impacts of this
trough would be another plateauing of highs in the low 100s, a
slight increase in high cloudiness, and somewhat gustier winds.
With generally diffuse pressure and temperature gradients, most
likely this system will be of little consequence in the end.

&&

.AVIATION...Updated at 0002Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Diurnal wind tendencies will prevail through Tuesday with
increasing high clouds from the west during the day. Wind speeds
should generally remain aob 8 kts with periods of variability in
the morning and during diurnal shifts.

Southeast California/Southwest Arizona including KIPL and KBLH:
Winds will favor the west through tonight at KIPL and west to
southwest at KBLH. Both terminals will see a shift to the south by
late Tuesday morning. Speeds will increase up to 10-14 kts through
the afternoon and be strongest in the evening with gusts up to 20
kts. High clouds will spread across the area tonight, becoming BKN
Tuesday morning.

&&

.FIRE WEATHER...
Thursday through Monday:
With temperatures oscillating near to slightly above the seasonal
normal, extremely dry conditions will persist over all districts.
Occasional breeziness will be possible each afternoon, yielding a
slightly elevated fire danger on most days, with Sunday likely
being the windiest day. Afternoon minimum humidity levels will
regularly fall into the single digits with the driest locations as
low as 5%. Overnight recovery will only be poor to fair in a
15-35% range.

&&

.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.

&&

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

$$

DISCUSSION...Hodges
AVIATION...Benedict
FIRE WEATHER...Hodges/Kuhlman