Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/04/21
Area Forecast Discussion
National Weather Service Phoenix AZ
456 PM MST Sat Apr 3 2021
.UPDATE...Updated Aviation Discussion,
&&
.SYNOPSIS...
Well above normal temperatures will continue through Monday. Many
lower desert locations will rise to near or even exceed 100
degrees. A weather system passing to the north on Tuesday will
lead to cooler slightly cooler temperatures, but the lower deserts
will likely remain above normal with temperature at or above 90
degrees through the next week. Breezy to possibly windy conditions
are also likely to develop Monday and Tuesday.
&&
.DISCUSSION...
An anomalously strong and broad ridge is already in place across
the Southwest, but heights are on the rise today as an embedded
shortwave trough vacates the region. It may have been a cooler
start this morning in south-central AZ, but ACARS aircraft
soundings show most of the lower troposphere has warmed since
yesterday. So, during peak mixing this afternoon temperatures will
likely climb a few more degrees than they did yesterday. NBM
suggests some spots in the western CWA may even reach 100 this
afternoon.
High pressure is expected to be strongest, with the greatest
warming, over the region Sunday and Monday. NBM shows greater
chances for more widespread 100 degree highs across the warning
area Sunday and Monday, with 30-50% chance in Phoenix and upwards
of 50-70% chance in southeast CA and southwest AZ. Morning lows
are also expected to be on the mild side the next few mornings, in
the 60s. Both the afternoon highs and morning lows will be near
record daily levels for this time of year, with highs 15 degrees
above normal in most places to even upwards of 20 degrees above
normal in some spots. High clouds moving in from the west during
the day Sunday could limit afternoon highs from reaching their
full potential both Sunday and Monday. Regardless, with this being
an early season heat event and with it being Easter weekend,
extra precaution should be used as there will still be a low to
moderate heat risk.
A trough will dig into the Pacific Northwest early next week
before passing through the Great Basin on Tuesday. Although this
system will not directly impact the CWA, it will result in a
breezy to potentially windy couple of days and somewhat cooler air
will filter into the region. Current ensemble trends suggest
Monday afternoon and evening will see the strongest winds,
especially across southeast CA where EPS and GEFS indicates gusts
could approach 35-40 mph. These kinds of winds along with the
very dry conditions and heat will likely result in elevated fire
weather conditions. WPC cluster analysis shows relatively good
agreement on the track and timing of the trough trough passing to
the north, but some uncertainty remains with respect to its
amplitude. Cases with a more amplified trough result in cooler and
breezier conditions. Nevertheless, temperatures are expected to
remain above normal in any case through the next week. By next
weekend, ensemble means suggest broader troughing across the
western CONUS and more relaxing of the heights over the Southwest,
resulting in additional cooling, but there is still considerable
individual model spread at this point to say whether there will be
a more significant cool down.
If you read through the AFD you may have noticed no mention of
precipitation. It is expected to remain quite dry through the
next 7 days plus with only single-digit afternoon humidities.
&&
.AVIATION...Updated at 2350Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
With no aviation concerns winds will remain mostly light and
follow normal diurnal patterns. Occasional periods of light and
variable conditions will also be seen. Skies will remain clear
into tonight with an increase in FEW-SCT high cirrus clouds from
Sunday morning to afternoon.
Southeast California/Southwest Arizona including KIPL and KBLH:
Light SE winds at KIPL will switch to the west early this evening
and become breezy with some gusts into the teens going into
tonight. Otherwise directions will favor the W to NW at KIPL and
SW to S components KBLH. Skies will remain clear into tonight
with an increase in FEW-SCT high cirrus clouds from Sunday morning
to afternoon.
&&
.FIRE WEATHER...
Tuesday through Saturday:
Above normal temperatures are expected each day with highs in the
low to mid 90s. Very breezy conditions Tuesday may create elevated
fire weather conditions across the region. Otherwise, typical
afternoon breezes are likely through the rest of the week. No
precipitation is in the forecast with persistent very dry
conditions. Min RH values will be below 10% in most places each
day with overnight recoveries only in the 20-30% range.
&&
.CLIMATE...
Record high temperatures:
Date Phoenix Yuma El Centro
---- ------- ---- ---------
April 3 97 in 1943 103 in 1961 101 in 1961
April 4 98 in 1961 104 in 1961 103 in 1961
April 5 98 in 1989 103 in 1989 100 in 1989
&&
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Benedict/Hodges
AVIATION...Sawtelle
FIRE WEATHER...Benedict
CLIMATE...MO/Hodges