Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 04/02/22

Area Forecast Discussion

National Weather Service Phoenix AZ

 446 PM MST Fri Apr 1 2022

.UPDATE...
Updated Aviation section.

&&

.SYNOPSIS...
Temperatures will remain around 5 degrees above normal through the
weekend before a fast moving, weak weather system briefly tempers
the warming early next week. However, heat will build back into the
region during the latter half of the week with afternoon readings
10 to 15 degrees above the seasonal average. In fact, a 25 to 50
percent chance exists that triple digit readings could impact
lower elevation communities towards the end of next week.

&&

.DISCUSSION...
A parade of progressive weather systems will march across the
northern half of the country through the middle of next week, while
the local forecast area remains on the southern periphery of any
notable forcing within tranquil quasi-zonal flow. One such system
was ejecting through the four corners this afternoon though
resulting in little more than shallow mountain cumulus. Otherwise,
ACARS soundings depict modest tropospheric warming in the past 24
hours yielding readings around 5F above normal. Over the next
several days, ensemble percentiles shows high confidence that lower
desert high temperatures will remain in the mid to upper 80s for
most locations.

Sunday into Monday, another low amplitude, unimpressive wave will
quickly pass through the CWA. With minimal dynamics and weak
moisture profiles, only a small subset of guidance suggests that a
few showers could develop over the White mountains and far eastern
Gila County. The main impacts will likely be a few clouds and
localized increased breeziness.

A substantial ridge will steadily build into the western Conus
during the middle and end of next week with all ensemble members
clustering into a pattern featuring strong high pressure encroaching
on the forecast area. The amplitude of the ridge will be somewhat
dependent on the proximity of a trough digging into the central
plains at the time, but this latter feature should ultimately have
very little effect on the temperature trends for the forecast area.
NAEFS 500 hPa heights still look to exceed the 95th percentile
(above 582dm) for early April resulting in afternoon highs nearly
15F above normal. Widespread high temperatures exceeding 90F will
be almost assured for lower elevation communities beyond Tuesday
with Thursday and Friday likely the hottest days.

NBM probabilities remain quite consistent in advertising ~25% chance
of central Phoenix hitting 100 F, with odds even higher (30-50%)
through far western Arizona and southeast California late in the
week. While certainly earlier than normal in the season to be
tempting the 100F threshold, high temperatures of this magnitude are
not unprecedented for early April and several degrees below record
territory. There is fair ensemble support suggesting this anomalous
ridge will break down into the following weekend, though the
magnitude of cooling and resulting pattern configuration is far more
uncertain.

&&

.AVIATION...Updated at 2346Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:

A transient ridge of high pressure will track across the Interior
West tonight and Saturday for generally westerly flow aloft above
FL100. Meanwhile, a subtle disturbance in the low-mid troposphere
(centered just west of San Diego) is causing southeast flow below
FL100. That will trend toward southwesterly during the day
Saturday. At the surface, light winds (below 10kts) with highly
variable directions (favoring south/southeasterly) are in place.
it is anticipated there will be a period this evening where the
variable winds will favor westerly directions before
downvalley/drainage patterns develop. This will be most noticeable
at KPHX (roughly between 03Z- 07Z). Anticipate a late arrival of
the typical nocturnal easterly winds at KPHX (after 10Z). After
the inversion breaks Saturday, expect light winds with variable
directions (favoring south-southeasterly) before trending to
southwesterly. KIWA and KSDL will become southwesterly earlier
than KPHX and KDVT. As for sky cover, clear skies.


Southeast California/Southwest Arizona including KIPL and KBLH:

A transient ridge of high pressure will track across the Interior
West tonight and Saturday for generally westerly flow aloft above
FL100. Meanwhile, a subtle disturbance in the low-mid troposphere
(centered just west of San Diego) is causing southeast flow below
FL100. That will trend to westerly in the afternoon Saturday. At
the surface, light winds (below 10kts) favoring south and
southeast directions are in place. At KIPL, it is anticipated
there will be a lot of directional variability for much of the
night and morning as directions vacillate between southwest and
west followed by more consistent southeasterly in the afternoon.
At KBLH, anticipate similar trends with the development of highly
variable directions this evening except perhaps a period of
southwesterly late this evening. This will be followed by more
consistent southerly winds (gusting to 20kts) Saturday afternoon.
As for sky cover, clear skies.

&&

.FIRE WEATHER...
Monday through Friday:
Temperatures at least 5 to 10 degrees above average will prevail
through the week with little to no chance of wetting rainfall. Only
a brief light shower would be possible in far eastern districts
Monday afternoon. Minimum afternoon humidity values will steadily dry
through the week with levels in a 15-25% range early in the week
falling solidly into the single digits beyond the middle of the
week. Correspondingly, fair to good overnight recovery in a 40-60%
will decrease closer to 20-30%. Seasonal afternoon upslope breezy
conditions will be common across the region with modestly stronger
gusts possible Monday afternoon.

&&

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

$$

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DISCUSSION...18/Hodges
AVIATION...AJ
FIRE WEATHER...18