Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 222235

Area Forecast Discussion
National Weather Service Tucson AZ
335 PM MST Fri Feb 22 2019

.SYNOPSIS...A winter storm will continue to bring valley rain and
substantial mountain snow to the area through tonight. Freeze
warnings are in effect for much of the area Saturday morning as very
cold temperatures fill in behind the departing storm. Dry conditions
will prevail this weekend and during the upcoming week. Unseasonably
cold temperatures will continue Saturday followed by a pronounced
warming trend next week.


.DISCUSSION...The winter system which brought a trace to nearly 3
inches of snowfall to the Tucson area will depart the region
tonight. Expect scattered rain and snow showers to continue through
this evening across much of Southeast Arizona, with precip
decreasing from west to east. The majority of precip should be clear
of the area by midnight tonight. Many mountain storm totals are
already in excess of 2 feet, and storm totals of up to 3+ feet may
occur at the highest peaks, including Mount Lemmon and Mount Graham,
through midnight. A Winter Storm Warning continues for most areas
east of Tucson through 8 PM MST this evening.

Clearing behind this system late tonight and early Saturday morning
may result in hazardous driving conditions as untreated wet surfaces
refreeze. Low temperatures across much of the CWA will dip to below
freezing, with lower 20s possible in the valleys of Santa Cruz,
Cochise, Graham and Greenlee Counties. This may also result in a
layer of ice forming on trees and power lines which could cause
isolated power outages. Both Freeze and Hard Freeze Warnings are in
effect for portions of Southeast Arizona from midnight tonight
through 9 am Saturday morning. Please see PHXNPWTWC for more

Zonal flow aloft over the weekend and into early next week will help
keep the storm track well to the north. This will lead to gradually
increasing temperatures and dry conditions. By the middle to end of
next week, slight ridging is expected to result in above normal
daytime temperatures. With the anticipated benign weather over the
next week, surface wind speeds are expected to follow normal diurnal


.AVIATION...Valid through 24/00Z.
BKN-OVC clouds at 2k-5k ft AGL into early this evening with clearing
from west to east. CIGS will then be SCT-OVC at 5k-9k ft AGL into
Saturday morning. Mostly clear or SKC conditions will occur Saturday
afternoon. Expect scattered -SHSN/-SHRA to continue this afternoon,
decreasing from west to east this evening. Precip is likely to be
over by midnight. MVFR conditions likely for most of the period with
IFR/LIFR possible in -SHSN/-SHRA along with mountain obscurations.
SFC wind speeds less than 12 kts this afternoon, except for near
KSAD where NW winds of 10-15 kts and higher gusts will occur into
this evening. Normal diurnal wind trends are expected overnight and
through Saturday with speeds less than 12 kts. Aviation discussion
not updated for TAF amendments.


.FIRE WEATHER...A significant winter storm continues into tonight
with valley rain and heavy mountain snowfall. The storm system exits
the region early Saturday, with dry and warmer conditions into the
middle of next week. Except for some breezy conditions through the
Upper Gila River Valley early this evening, 20-ft winds will
generally be less than 15 mph over the next week.


Winter Storm Warning until 8 PM MST this evening for AZZ506>515.

Hard Freeze Warning from midnight tonight to 9 AM MST Saturday for

Freeze Warning from midnight tonight to 9 AM MST Saturday for AZZ502-




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