Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 220441
Area Forecast Discussion
National Weather Service Tucson AZ
940 PM MST FRI OCT 21 2016
.SYNOPSIS...Dry conditions will prevail into Sunday morning. A
trough of low pressure moving into the western states will then
bring a slight chance of showers Sunday afternoon and Sunday night.
A better chance of showers and thunderstorms exists Monday into
Monday night, then dry conditions return late Tuesday into next
Friday. Above normal daytime temperatures will continue this weekend
and into the upcoming week.
.DISCUSSION...October heat continues with a few spots at or near
record highs. The Tucson airport tied their October 21st record high
at 96 degrees and if the low at midnight is above 66 degrees, a
record high minimum will also be set. Additional climate information
can be found in the climate section below.
Infrared satellite imagery this evening across SE AZ. On water vapor
a plume of moisture was pushing N across Sonora MX. Additionally
there was a small disturbance moving across far southern Chihuahua
MX which popped a few thunderstorms this evening in this area. The
22/00z upper air plot placed the center of the upper high over SE NM
with southerly flow over SE AZ. This southerly flow will continue to
advect moisture, not a whole lot, across the area on Saturday.
22/00z runs of NAM and GFS are showing lifted indexes below zero
along with CAPE values in the 200-700 j/kg mainly from Tucson south.
Day 2 SPC outlook has a portion of the SE AZ in general thunderstorm
risk Saturday afternoon. Hate to yo-yo on the forecast but will run
out an update to include slight chance of high based thunderstorms
tomorrow afternoon, mainly over the mountains from Tucson south.
No break in the October heat on Saturday with a few spots near
record highs again.
.AVIATION...Valid through 23/04Z.
SKC into Saturday morning. Moisture will be on the increase from the
south on Saturday and combined with a bit more unstable atmosphere
across southern areas Saturday afternoon and evening, there is a
slight chance of a high based thunderstorm. At this time, it looks
like the only terminal sites that may be affected will be KOLS and
KDUG. Will add VCNTY TS in the 06z TAFs for those sites.
Surface wind variable in direction less than 12 kts thru the valid
period. Aviation discussion not updated for TAF amendments.
.FIRE WEATHER...Mostly dry conditions through Sunday morning
followed by a slight chance of showers Sunday afternoon and Sunday
night. A chance of showers and thunderstorms exists Monday and
Monday night, and a few lingering showers may occur early Tuesday
across the White Mountains. Dry conditions will then prevail late
Tuesday into next Friday. Otherwise, expect above normal daytime
temperatures and terrain driven winds generally under 15 mph this
weekend and into the upcoming week.
.CLIMATE...Today was the 15th consecutive day of at least 90 degrees
recorded at Tucson International Airport for October 2016. This is
the seventh longest period of 90 degrees or warmer for any October
on record (dating to 1894). The current official forecast indicates
that 90 degrees or warmer should also occur Saturday and Sunday. If
this happens, there will be 17 consecutive days this month of at
least 90 degrees recorded at Tucson International Airport. This 17
consecutive day period would be the sixth longest on record for
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