000
FXUS65 KPSR 141103
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
403 AM MST Wed Nov 14 2018

.UPDATE...Updated Aviation Discussion...

&&

.SYNOPSIS...Temperatures will remain several degrees below normal
today, before a warming trend brings temperatures closer to
seasonal normals by later this week. Dry conditions and light
winds will continue through the end of the week, before a weak
storm system potentially affects the region early next week.

&&

.DISCUSSION...Another cold morning is on tap across the forecast
area, with lows in the 30s to low 40s over the lower deserts, and
sub-freezing temperatures across the higher terrain east of
Phoenix. A batch of high clouds is approaching from southern
California, but otherwise, satellite imagery shows a relatively
benign weather pattern in place as an amplified upper ridge
remains fixed along the Pacific coast. This feature will remain
dominant into the weekend, supporting modest midlevel height rises
over the Southwest and a subsequent warming trend. Temperatures
should return very close to seasonal normals (mid-70s at Phoenix)
by Thursday, amidst dry conditions and light winds. Overnight lows
will also warm to well above-freezing area-wide for all but the
very highest elevation spots north and east of Phoenix.

A gradually strengthening of southern stream westerlies will occur
this weekend, effectively undercutting the amplified upper ridge
over the western CONUS. This will portend a potentially more
active synoptic pattern for the Southwest, with the first notable
disturbance forecast to affect the region Tuesday. Model guidance
has become much more consistent with the timing and overall
depiction of this feature, tracking it across northern Sonora and
southern Arizona. Given its fast moving nature and relatively
limited spatial extent, moisture will generally be lacking and
keep the highest precipitation chances confined to the south and
east of Phoenix. More uncertainty enters the forecast in the wake
of this feature, with the broad signal continuing to favor mean
troughing near the Pacific coast, and the potential for another
disturbance to impact the region during the middle to later part
of next week.

&&

.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:

Generally light northeasterly winds will prevail through tonight.
Winds be may breezy for a period late this morning after mixing
commences with to around 15 kts. High cirrus affect the region into
this afternoon with gradually clearing this evening.

Southeast California/Southwest Arizona including KIPL and KBLH:

No other aviation concerns through the period under periods of high
clouds. Winds will remain light out of the west at KIPL and north at
KBLH.

Aviation Discussion not updated for amended TAFs.

&&

.FIRE WEATHER...
Friday through Tuesday: High pressure will prevail across the
region, resulting in dry conditions and temperatures within a
couple degrees of seasonal normals. Winds will remain light and
diurnally driven. Daytime humidity values will bottom out in the
mid- teens across the lower deserts, but will begin to increase
slightly by Tuesday ahead of a weak storm system moving into the
Southwest. At this time, the potential for any precipitation
appears low across the area.

&&

.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.

&&

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

$$

DISCUSSION...Rogers
AVIATION...Kuhlman
FIRE WEATHER...Rogers

NWS PSR Office Area Forecast Discussion