Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 262137
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
237 PM MST Fri May 26 2017

.SYNOPSIS...Gusty winds will continue into the early evening hours
tonight before slowly diminishing. A warming trend with less wind is
then expected Saturday into Monday. An increase in moisture will
result in a slight chance of showers and thunderstorms, mainly in
the higher terrain east of Tucson, from Memorial Day through next
Friday.

&&

.DISCUSSION...Clear skies and gusty winds continue across southeast
Arizona this afternoon, with the strongest winds (so far) over Santa
Cruz and Cochise counties. Expect elevated winds to continue into
the evening hours tonight before slowly diminishing. Therefore, a
Red Flag Warning remains in the effect through 8 pm MST this evening
for portions of Fire Weather Zones 151 and 152.

A ridge of high pressure will then build across the western United
States late in the weekend into the middle of next week. This will
result in warmer temperatures and less wind. Temperatures will peak
on Monday, with highs in the valley locations of southern Arizona
generally ranging from the mid 90s to the lower 100`s (Tucson will
be right around the century mark). By early to mid next week, the
ridge becomes highly amplified, with the high centered to our north
over the Great Basin. Weaknesses in the flow under this ridge will
allow moisture to push westward into the southern Arizona Monday
through Wednesday of next week. The bulk of this moisture will
remain east of the Tucson Metro area across Cochise, Graham and
Greenlee counties. The latest model runs are not quite as robust
with this moisture (versus 24 hours ago). Therefore, low end slight
chance pops exist for most of the eastern valleys of Cochise and
Graham counties, with a little higher chances in the mountains of
those counties. The highest precipitation chances will be in the
White Mountains/northern half of Graham county where chance to good
chance pops exist Monday through Wednesday of next week.

Forecast confidence is low in the latter periods of the extended
forecast late next week. Not only are the operational GFS and ECMWF
quite different during the Thursday/Friday time frame of next week,
the latest GFS solution differs completely from its prior runs. In
general, the ECMWF has a weak trough to our west with a continued
moisture seep across eastern areas, while the GFS develops a weak
closed low off the southern California coast and shifts this feature
(with a fairly decent Pacific moisture feed) across the state. At
this time, have stuck close to the inherited forecast of slight
chance pops across eastern areas and nearly steady daytime
temperatures.

&&

.AVIATION...Valid thru 27/23Z.
Generally SKC conditions through the period, with some high clouds
AOA 20k ft AGL aft 27/15Z. SFC wind swly/wly at 14-25 kts and gusts
to near 35 kts til 27/03Z, with the strongest wind speeds east of
KTUS. Diminishing SFC wind aft 27/03Z, with SFC wind less than 12
kts between 27/05Z and 27/18Z. Aft 27/18Z, swly/wly SFC wind at 8-15
kts, with the strongest wind speeds in the vicinity of KDUG and
KALK. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...A Red Flag Warning remains in effect until 8 pm this
evening for portions of Fire Weather Zones 151 and 152, mainly south-
to-east of Tucson. The combination of strong and gusty winds, low
relative humidity values and a very high fire danger will continue
to create critical fire weather conditions through the early evening
hours tonight.

Less wind will prevail this weekend and next week. An increase in
moisture will result in a slight chance of afternoon and evening
showers and thunderstorms mainly east of Tucson Monday through next
Friday. Expect erratic and gusty outflow winds with thunderstorms
that do develop.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
  Red Flag Warning remains in effect until 8 PM MST this evening for
   AZZ151-152.

&&

Zell

$$

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