Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 210418

Area Forecast Discussion
National Weather Service Tucson AZ
915 PM MST Fri Apr 20 2018

.SYNOPSIS...A strong low pressure system moving north of the area
will bring a few clouds and wind gusts into this evening. A strong
warming trend will then prevail Saturday into Monday with above
normal temperatures continuing into the middle of next week.


.DISCUSSION...Generally a clear and quiet night across the majority
of Southeast Arizona this evening, as the southern periphery of an
upper low moving through the Rockies slowly tracks through the White
Mountains toward the east. This far south in Northern Graham and
Northern Greenlee counties, just a few breezes and lingering low
clouds that will dissipate shortly after midnight.

Otherwise...a weak shortwave ridge will build into the region the
next few days between the upper low moving the the Rockies and
another weak low spinning out near 27.4N/124.0W. Expect a warm-up in
daytime temperatures the next few days in reflection of this.

Current forecast is on track with no updates necessary.


.AVIATION...Valid through 22/06Z.
FEW clouds at 6k-10k ft AGL northeast of KSAD this evening becoming
clear overnight. Generally clear skies will persist through mid-day
Saturday across the rest of Southeast Arizona...with increasing high
cirrus clouds aoa 20k FT AGL during the afternoon. SFC wind wly/nwly
at 8-12 kts with gusts to 20 kts thru late this evening...
diminishing to less than 12 kts thru the remainder of the forecast
period. Aviation discussion not updated for TAF amendments.


.FIRE WEATHER...Warmer temperatures are expected over the weekend
and through next week, with readings topping out about 10 degrees
above normal by early next week. It will remain dry in most
locations, with just a few showers or sprinkles possible across
portions of Cochise county Sunday. Winds will generally be light and
terrain driven over the weekend and into next week, with the usual
afternoon gustiness due to strong daytime heating.


.PREV DISCUSSION...Abundant sunshine across southeast Arizona with
temperatures running 15 to 20 degrees cooler than yesterday.
Satellite imagery showed a strong upper level low over southwest
Colorado with a fairly strong vort max on back side of system moving
across northeast Arizona. Cloud cover has been increasing across the
White mountains with isolated rain and snow showers across Navajo
and Apache counties. A few light rain/snow(flurries) showers this
evening across far northern Greenlee county. With a cooler air mass
in place, overnight lows will get quite chilly for mid-April with
localized spots in our colder valleys east and south of Tucson
possibly seeing an hour or two of freezing temperatures.

Temperatures rebound quickly tomorrow under building high pressure
aloft. Will see an increase in mainly high level cloud cover late
Saturday afternoon into Sunday morning in advance of an approaching
weak upper level low, currently 600 miles west of the Baja Spur.
Models indicate an increase in mid-level moisture on Sunday as PW
values rise to around a half an inch across Santa Cruz and southern
Cochise counties. Can`t rule out a sprinkle or two put believe that
there will be a lot of virga with this system.

Warm and dry next week with highs running around 10 degrees above
normal. Will need to keep an eye on moisture pushing west mid week
across New Mexico associated with a pair of back door cold fronts.
Could lead to isolated high based storms along AZ/NM border Wed thru





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