109
FXUS65 KPSR 101013
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
313 AM MST Fri May 10 2024

.SYNOPSIS...
A warming temperature trend going through the weekend will result
in above normal temperatures and increasing chances of triple
digit highs across the lower deserts going into next week.
Otherwise, dry conditions will persist, with afternoon breeziness
continuing to cause areas of elevated fire weather conditions over
the next several days.

&&

.DISCUSSION...
Early morning satellite depicts few to scattered high clouds
spread out across southern Arizona, while water vapor imagery
shows a persistent east to west oriented longwave trough
entrenched across western CONUS. This trough has been responsible
for keeping temperatures at or below normal over the last several
days. However, this trough is expected to weaken over the next few
days, as anomalously strong ridging that is currently over the
Pacific Northwest impinges on this trough. However, negative or
neutral height anomalies will continue to persist over the next
several days, so while a warming trend will occur, it will mute
the absolute maximums of this warming trend to the low 100s at
most through early next week.

Ensembles have hedged towards stronger negative height anomalies
to persist across the region through the middle of next week,
resulting in lower probabilities of 100 degree highs for the
Phoenix area to generally a 30-50% range through most of next
week. Generally speaking, the warmest day based on the
deterministic NBM forecast will be Sunday (Monday) for the
western (eastern) districts as the trough weakens during this
period before reestablishing its position as the aforementioned
ridging flattens out early next week. Winds will continue to be
breezy during the afternoon hours as westerly flow persists
through this period, resulting in areas of elevated fire weather
conditions when combined with the very dry conditions (minimum
RH`s in the 10-15% range), mainly in higher terrain areas where
the gustiness will generally be stronger.

Looking towards late next week, ensembles continue to show
potentially more robust ridging building into the Desert
Southwest going into next weekend. However, ensembles show
considerable spread in regards to a troughing feature that may dig
southward across Alberta and Saskatchewan, which could dampen the
strength of this ridge. Thus, temperature trends are a bit more
uncertain, as chances for highs exceeding 100 degrees seem higher,
but should the more robust troughing occur, high temperatures
staying below 100 degrees would be a near certainty.

&&

.AVIATION...Updated at 0520Z.

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

Typical Spring diurnal wind tendencies are expected at all
terminals through the next 24 hours, with speeds at or below 10
kts and afternoon gusts into the middle-teens. There will also be
periods of light variability during the overnight/early-morning
hours and during diurnal transitions. Skies will remain mostly
clear, aside from FEW to SCT high clouds in Phoenix tonight
through Friday morning.

&&

.FIRE WEATHER...
Temperatures are expected to warm over the next several days, with
chances for highs reaching 100 degrees increasing above 50%, at
least for the western districts, by late this weekend.
Temperatures are expected to remain above normal going through
early next week. MinRHs will be in the 5-10% across the lower
deserts and in the 10-15% range across the higher terrain through
this weekend. Overnight recovery will be poor in the 20-40%
through tonight, before improved recoveries in the 30-60% range
heading into early next week. Typical springtime breeziness
continues through the weekend with afternoon and early evening
wind gusts of 20-25 mph. These breezy conditions combined with dry
fine fuels, and low RHs will likely create some elevated fire
weather conditions. Dry conditions persist into next week.

&&

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

$$

DISCUSSION...Young
AVIATION...Benedict
FIRE WEATHER...Young/Berislavich