994
FXUS65 KPSR 081137
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
437 AM MST Mon Jul 8 2024

.UPDATE...Updated Aviation Discussion...

&&

.SYNOPSIS...
Extreme heat will continue across the region throughout this week as
strong high pressure remains overhead. Lower deserts will continue
to see afternoon high temperatures in the 112-122 degree range with
little to no overnight relief with overnight low temperatures ranging
from the low 80s to low 90s. Some moisture will start to move back
into the region by the middle to end of this week, leading to an
increase in thunderstorm chances for southeastern Arizona and the
Arizona high terrain.

&&

.DISCUSSION...
Upon analysis of upper- and mid-level water vapor satellite imagery
this morning, the strong high pressure system has not moved much and
is currently centered over the south-central California and Nevada
boarder. This high pressure system will slowly make its way eastward
over the next week, with very minimal change in its strength. The
500 mb height fields will continue to be within the 594-597dm range.
This will lead to the extreme heat continuing through the week. An
Excessive Heat Warning remains in effect through Thursday with
widespread Major HeatRisk with locally Extreme HeatRisk across the
Arizona lower deserts and southeastern California. The lower deserts
will continue to see afternoon high temperatures in the 112-122
range with overnight/early morning low temperatures ranging from the
low 80s to low 90s through at least Thursday. It is crucial to stay
proactive in protecting yourself from these extreme temperatures as
they can become deadly! Remember to stay hydrated; wear light, loose
fitting clothes; and try to limit your time outdoors, especially
during the hottest part of the day.

The center of the high pressure system will move into western
Arizona by the middle of the week, which will promote some moisture
advection into southern and eastern portions of Arizona. The
increase in moisture will lead to daily isolated afternoon and early
evening shower and storm chances across southeastern Arizona and
higher terrain locations in eastern Arizona for the latter half of
the work week. PWAT values will remain below 1" through Thursday and
near 1" on Friday across the Arizona lower deserts. This continued
dry air will keep the thunderstorm chances, across the AZ lower
deserts, near zero through the work week.

The high pressure system will continue its eastward trek, arriving
in the Four Corners Region this weekend. Global ensembles continue
to show PWAT values going above 1" across the Arizona lower deserts
this weekend. The increase in moisture will cause a slight cool down
in temperatures over the Arizona lower deserts, however the apparent
temperature will remain largely unchanged. Due to this the Excessive
Heat Warning may need to be extended into the weekend. The increased
moisture will also promote increased shower and thunderstorm
chances. This will lead to isolated showers and thunderstorms
possible across portions of the south-central lower deserts and
scattered showers and thunderstorms across the AZ higher terrain,
mainly during the afternoon and early evening hours.

&&

.AVIATION...Updated at 1137Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No major aviation weather concerns will exist through the TAF
period under generally clear skies. Slantwise visibility
reductions could become a reality later this morning due to smoke
moving southward over much of eastern Arizona. However, confidence
in visibility reductions at the surface is quite low. Winds will
follow typical diurnal trends, but west winds are expected to
return by around noon. Afternoon gusts up to around 20 kts will be
common late afternoon and early evening.

Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation weather concerns are expected through the next 24
hours under clear skies. Winds will favor the southeast at KIPL
through this afternoon before turning west southwest, whereas
directions will favor south southwest at KBLH. Speeds will
generally remain aob 12 kt sustained through the TAF period at
both terminals.

&&

.FIRE WEATHER...
Well above normal temperatures and dry conditions will continue
through the majority of this week. Daily afternoon high temperatures
will generally be in the 112-122 degree range across the lower
deserts and in the 95-110 degree range across the higher terrain.
MinRH values will range from 5-15% across the lower deserts and 10-
20% in the higher terrain, with overnight recoveries generally in the
30-50% range, through Friday. Winds will be fairly light and tend to
follow their typical diurnal patterns, with some occasional
afternoon gusts up around 20 mph. Limited moisture will start to
creep back into the region for the latter half of the work week,
leading to a slight chance for isolated thunderstorms in the higher
terrain. The very hot and dry conditions will lead to an increased
fire danger threat.

&&

.CLIMATE...

Record Highs

           Phoenix      Yuma      El Centro
          ---------    -------   -----------
July 8    115 (1985)  118 (1958)  117 (1942)
July 9    116 (1958)  119 (1958)  117 (1958)
July 10   115 (1958)  118 (1959)  116 (2021)
July 11   118 (1958)  118 (1958)  117 (1975)

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Excessive Heat Warning until 8 PM MST Thursday for AZZ530>555-
     559.

CA...Excessive Heat Warning until 8 PM PDT Thursday for CAZ560>570.

&&

$$

DISCUSSION...Berislavich
AVIATION...Kuhlman
FIRE WEATHER...Berislavich
CLIMATE...Berislavich/Kuhlman