Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 231534

Area Forecast Discussion
National Weather Service Tucson AZ
834 AM MST Thu Mar 23 2017

.SYNOPSIS...A storm system will bring a chance of showers and
thunderstorms today mainly from Tucson eastward along with much
cooler temperatures and gusty winds. Dry conditions with somewhat
milder temperatures and gusty winds at times will occur over the
weekend into early next week.


.DISCUSSION...A frontal band with showers and even a few rumbles of
thunder continues to march eastward across the forecast area. Latest
surface observations indicate the cold front is now moving through
Graham and Cochise counties. A 75 mile wide or so band of scattered
showers is now located generally west of a line from Safford-Bisbee
with the western edge now lined up from Kearney-Three Points-Sasabe.
Rainfall amounts have generally been light with most locations under
0.10", however a few spots that have seen heavier convective showers
received up to 0.33". Snow levels are generally above 7000 feet or
so and an inch or two of snow will be possible in the mountains as
well. Once the precipitation with the frontal band moves east out of
the area by early this afternoon, we will be under the influence of
the cold pool under the upper low. Thus, some instability clouds and
even a few lingering showers are possible, especially north and east
of Tucson this afternoon in Graham and Greenlee counties. Otherwise,
the big story is the much cooler temperatures today with highs about
5-10 degrees below normal. Winds will be continue to be gusty as well
making it feel even a bit chillier.

The upper low will push east of the area with any lingering
showers/snow showers across the White Mountains ending tonight.
Shortwave ridging will build in for Friday with mostly sunny skies
and temperatures warming back up to seasonable levels. Heading into
the weekend and early next week, we will see a fairly progressive
pattern take shape. The next system will remain to our north on
Saturday/Saturday night but the gradient will tighten again for some
afternoon breezes. High temperatures will rebound back into the
lower 80`s on Saturday for Tucson. Another shortwave ridge for
Sunday before another system starts digging into the southwest by
late Monday. Still considerable differences in the models by Tuesday
and Wednesday regarding the strength and amplitude of this system
and resulting impacts to our area. At the very least, expect some
increased winds along with cooler temperatures and perhaps some
showers. Will take a closer look at the 12Z guidance and have more
in the afternoon package.

Just made a few tweaks to the grids this morning for the latest
trends. Otherwise, no updates beyond the short term.


.AVIATION...Valid through 24/18Z.
SCT-BKN cloud decks at 6-9k ft AGL thru 23/20Z with isolated to
scattered -TSRA/-SHRA, then clearing skies from west to east.
WLY/NWLY surface wind at 17-25 kts and gusts to 25-33 kts this
afternoon. The strongest wind will be east of KTUS, in the vicinity
of KALK, KDUG and especially KSAD. Diminishing surface wind aft
24/03Z. Aviation discussion not updated for TAF amendments.


.FIRE WEATHER...A Pacific storm system will bring a chance of
showers and thunderstorms today, with the main focus north/northeast
of Tucson. A few snow showers may occur across the  White Mountains
northeast of Safford tonight. Dry conditions will then prevail
Friday into Sunday. There is a slight chance of showers across the
White Mountains Monday.

Expect gusty west to northwest winds today accompanied by higher RH
values, then less wind Friday. Elevated and gusty afternoon winds
are forecast Saturday into the middle of next week.





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