Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 03/18/21

Area Forecast Discussion

National Weather Service Phoenix AZ

 420 PM MST Wed Mar 17 2021

.UPDATE...00z Aviation Discussion.

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.SYNOPSIS...
A warming trend will occur over the next few days with a return to
above normal temperatures by Thursday as high pressure builds across
the region. A weak disturbance late in the weekend into early next
week will lead to breezy conditions and temperatures dropping back
to around normal starting Sunday, but precipitation chances are
likely to be very limited. A second weather system may also affect
the region by the middle of next, likely leading to more cooler
temperatures and another chance for precipitation.

&&

.DISCUSSION...
High pressure has moved into the Desert Southwest and will now
remain stationary for the next few days. Visible satellite imagery
shows little to no cloud cover over the CWA and for several
hundred miles in any direction. ACARS soundings reveal a very dry
atmospheric column, but with somewhat cooler and more moist air
near the surface. This cooler air is a remnant of the previous
storm system, and will quickly moderate and mix out over the next
1-2 days. In fact, at 600 hPa temperatures have warmed nearly 15 C
compared to yesterday at this time, while 850 hPa temperatures
have warmed about 5 C. In general, 850 hPa temperatures will warm
an additional 2-4 C each of the next 2 days. High temperatures
will top out in the mid 70s today, lows 80s Thursday, and mid 80s
Friday and Saturday. NBM temperature probabilities show a 75%
chance of reaching at least 85 F in Phoenix Friday and Saturday.
Cloud cover will likely increase Thursday and Friday, but with
most of the moisture confined to the upper levels the effect on
temperatures will be minimal.

The ridge of high pressure will begin to break down and shift east
over the weekend in response to troughing developing over the
Pacific Northwest. Models are currently depicting an initial wave
to move through the area Sunday or Monday, with a second feature
possible the middle of next week. Ensemble guidance is now in good
agreement that the first feature will be positively tilted with
frontolysis leading to a relatively weak system. It`s main
effects are expected to be breezy conditions and return to near
normal temperatures. The second feature offers more uncertainty.
WPC cluster analysis shows two main ideas for how this feature may
evolve. About 2/3 of the ensemble members show a more progressive
and less amplified system that would lead additional breezy
conditions and near normal temperatures, but ultimately dry
conditions. The other 1/3 of ensemble members have a more
amplified and slower system, which would increase the odds of
seeing below normal temperatures and measurable precipitation. In
any case, relatively seasonal weather will likely persist for much
of next week with periods of breezy conditions.

&&

.AVIATION...Updated at 2320Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT; and
Southeast California/Southwest Arizona including KIPL and KBLH:

No weather concerns will exist through the TAF period under
occasional high cirrus decks. Diurnal directional tendencies
should occur around the typical times with speeds under 8-10 kts.
In many cases, light and variable winds will be common at all
terminals for prolonged periods.

&&

.FIRE WEATHER...
Saturday through Wednesday:
Strong high pressure on Saturday will lead to afternoon
temperatures in the low to mid 80s across the lower deserts.
Cooler conditions are likely Sunday to Wednesday with temperatures
dropping to near or slightly below normal. RH maximums of 40-55%
are expected each morning, and 10-20% each afternoon. Breezy
conditions are expected each day, with daytime gusts likely
reaching 20-25 mph with locally higher gusts.

&&

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

&&

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

$$

DISCUSSION...Hodges
AVIATION...Feldkircher/MO
FIRE WEATHER...Hodges/Kuhlman