828
FXUS65 KTWC 190849
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
149 AM MST Sat Oct 19 2024

.SYNOPSIS...An upper low will remain over Arizona through Sunday
before moving northeast of the region. This system will bring a
chance of precipitation to the White Mountains today and keep
temperatures below normal through Sunday. Freezing low temperatures
will be possible across portions of Cochise and Graham counties this
morning and again Sunday morning. High pressure aloft will then
build back into the desert southwest early next week, with
temperatures warming back up rapidly to well above normal levels.

&&

.DISCUSSION...A strong upper low will drift southward into central
Arizona today and then back into northern Arizona on Sunday before
lifting northeast away from the region Sunday night. High pressure
aloft will build in quickly behind this system from the southwest
early to mid next week.

The upper low will bring a chance of rain/snow showers to the White
Mountains today, with the rest of southeast Arizona remaining dry.
Guidance figures have come up for precipitation chances in the White
Mountains, which makes sense given the upper low`s expected
southward drift today. QPF amounts will generally be less than one-
third of an inch in the Whites, with an additional 1-2 inches of
snowfall. Otherwise, breezy southwest winds of 15-20 mph and gusts
to around 30 mph will persist across portions of Cochise County
today. The rest of the forecast area will have wind speeds of 15 mph
or less. High temperatures will be in the 70s in valley locations
today, or around 10 degrees below normal.

Low temperatures this morning and again Sunday morning will be in
the 40s for most valley locations, with the typical cold spots
dipping down into the 30s. There is the potential (50-80 percent)
for freezing or sub freezing temperatures in the Sulphur Springs
Valley both mornings and a Freeze Warning remains in effect for
those areas. The area is roughly from Klondyke and Fort Grant in
Graham County, southward through Willcox, to Sunizona and Elfrida in
Cochise County. The Freeze Warning is in effect until 9 am MST this
morning and 1 am to 9 am MST Sunday morning. For more information on
this product please refer to PHXNPWTWC.

Behind this system, in the Monday through Thursday time frame, high
pressure aloft builds back across the desert southwest. Temperatures
rebound to above normal levels Monday (2-4 degrees above normal) and
then well above normal levels Tuesday through Thursday (10-14
degrees above normal). There may even be a few lower desert locales
that reach triple digit heat next Wednesday and Thursday. Record to
near record heat will be back on the table mid to late next week.

&&

.AVIATION...Valid through 20/12Z.
SCT-BKN clouds at 7k-10k ft AGL mainly east of a KALK to KSAD line
thru 19/18Z, then FEW-SCT clouds at 9-12k ft AGL most locations
between 19/18Z and 20/02Z, with clear skies/SKC conditions aft
20/02Z. The exception will be in the White Mountains NE of KSAD
where BKN clouds at 6k-10k ft AGL will persist into the evening
hours tonight, along with a chance of -SHRA/-SHSN. SFC wind variable
in direction and less less than 10 kts thru 18/16Z and again aft
20/02Z. Between 18/16Z and 20/02Z, NWLY SFC wind at 12 kts or less
from KTUS westward and SWLY SFC wind at 10-15 kts and gusts to 25
kts across Cochise County in the vicinity of KALK and KDUG. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...There will be chance of rain and snow showers in
the White Mountains today. Otherwise, the rest of southeast Arizona
will remain dry. Below normal temperatures will continue through
Sunday. A strong warming trend will take place the first half of
next week, with high temperatures by Wednesday 10-14 degrees above
normal. Min RH values next week will be in the 8-14 percent range in
the valleys and 10-20 percent in the mountains. Except for breezy
southwest winds at 15-20 mph and gust to around 30 mph today in
Cochise County, 20-foot winds will be less than 15 mph through next
week.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Freeze Warning until 9 AM MST this morning for AZZ508-509.

Freeze Warning from 1 AM to 9 AM MST Sunday for AZZ508-509.

&&

$$

Zell

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