Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 192046
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
146 PM MST Fri Apr 19 2019

.SYNOPSIS...
A gradual cooling trend will take hold this weekend into early
next week, but temperatures will still be above seasonal normals.
An increase in winds will also occur this weekend as a series of
mostly dry weather systems move across the Southwest. A warming
trend will commence again next week with some lower elevation
communities possibly flirting with 100 degrees during the latter
half of the week.

&&

.DISCUSSION...
An upper-level ridge has shifted just east of the region this
afternoon, with the increase in southwest flow aloft occurring
coincident with scattered cirrus moving into southeast California.
Temperatures continue to respond favorably the increase in mid-
level heights, with many locations in the mid-upper 90s as of 1 PM
MST across the lower deserts. May see some spots hit 100 F before
all is said and done, but regardless, today will be the hottest
day of the year so far for many spots. While not that unusual for
this time of year, several degrees short of record territory, and
a far cry from temperatures the region will experience in the
coming months, caution still should be taken for those working or
recreating outdoors during peak heating.

Temperatures will likely peak today before a modest cooling trend
takes hold as a series of mostly dry shortwave troughs move across
the Southwest. The first will be very low amplitude in nature,
with the main impact being a tightening surface pressure gradient
and increasing low-level westerly flow. Confidence is high enough
in gusty winds to warrant issuance of a Wind Advisory beginning
Saturday afternoon across parts of southeast California. Sundowner
winds could be an issue in the lee of the coastal range across
western Imperial County Saturday evening into Sunday morning. Elsewhere,
winds will be breezy, but generally below advisory thresholds.

The early week trough will only slowly eject eastward through the
middle of next week as the system becomes largely disassociated from
the northern stream jet influence. Operational and ensemble spread
grows increasingly during the middle and latter half of the week
with a majority of GEFS members holding lower heights into the SW
Conus into Wednesday while CMC member are much more aggressive in
pushing the system east and re-building heights over the forecast
area. As a result, have delayed the onset of more substantial warming
into Thursday and Friday; and even then, there is rather notable
uncertainty with respect to how amplified and persistent the
trailing ridge can become.

&&

.AVIATION...Updated at 1745 UTC.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
There are few aviation concerns through the TAF period with mostly
clear skies. The easterly winds will prevail for the next few
hours but should become westerly between 23Z and 01Z, before
becoming easterly late tonight. Wind speeds will stay mostly below
10 kts with just an occasional afternoon gust.

Southeast California/Southwest Arizona including KIPL and KBLH:
The biggest aviation concern will be the stronger wind speeds
late this evening, beginning around 06Z. Gusts as strong as 25 kts
will impact KIPL and other terminals west of the Colorado River.
These strong gusts will persist through the overnight hours. Wind
speeds closer to the river, including KBLH, will miss most of the
gusts but will see elevated wind speeds at or slightly above 10
kts.

Aviation Discussion not updated for amended TAFs.

&&

.FIRE WEATHER...
Monday through Friday:
Following a period of elevated fire weather conditions, the
weather for next week will be very typical for late April with the
usual afternoon upslope gustiness, relatively light overnight
winds, afternoon humidity levels falling into the single digits
and teens, and fair to good overnight recovery. Weather conditions
for prescribed burning activity look very good during the Tuesday-
Friday time frame. Temperatures will begin to warm back close to
the 100 degree mark late in the week as high pressure re-builds
over the region.

&&

.SPOTTER INFORMATION STATEMENT...
Spotter activation is not expected for the next 7 days.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory from 1 PM to 10 PM PDT Saturday for CAZ560-564-566.

     Wind Advisory from 1 PM Saturday to 6 AM PDT Sunday for CAZ562.

&&

$$

DISCUSSION...Rogers/MO
AVIATION...Deems
FIRE WEATHER...Rogers/MO


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