Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 220408

Area Forecast Discussion
National Weather Service Tucson AZ
910 PM MST Tue Feb 21 2017

.SYNOPSIS...Dry conditions will prevail through Sunday. Expect
well above normal high temperatures on Wednesday with a few spots
near record highs. Then a weather system passing by to the north on
Thursday will bring much cooler temperatures to the area Thursday
and Friday. Warmer again this weekend before a strong Pacific storm
brings a chance of precipitation to the area on Monday.


.DISCUSSION...A mild evening for the latter part of February under
clear skies. No changes in that expected tonight thanks to an upper
level ridge that is planted over the area.  This will lead into a
much warmer than normal day tomorrow with plenty of sunshine.  No
need to make any adjustments this evening.  For further detail see
previous discussion below.


.AVIATION...Valid through 23/00Z.
Clear conditions expected through the forecast period. Light surface
winds mainly less than 10 kts thru 22/18z then becoming westerly 10-
15 kts with gusts to 25 kts through the afternoon. Aviation
discussion not updated for TAF amendments.


.FIRE WEATHER...Very warm Wednesday with a light westerly breeze
developing in the afternoon.  A passing dry weather system Wednesday
night into Thursday will bring cooler and much drier air across the
area with gusty west winds Thursday afternoon. It will be dry enough
(low teens RH) and windy enough that the weather part of critical
fire weather conditions may be briefly reached for a few areas of
eastern zone 152 Thursday afternoon. However, overall fuels remain
moist with the exception of the fine dead fuel bed which could allow
for fast moving grass fires. Friday will be another cool and very
dry day however winds will be lighter.

Warmer and dry conditions will continue through the weekend with
afternoon winds picking up again Sunday afternoon.  A storm is
expected to approach the area Monday resulting in rather windy
conditions and depending on how slow the moisture is to arrive we
could have critically low humidity levels again across zone 152 with
the winds before any showers arrive.


.PREV DISCUSSION... /issued 234 PM MST Tue Feb 21 2017/

.DISCUSSION...Warmer today under abundant sunshine thanks to high
pressure ridge over the area. This ridge has kept clouds streaming
northeast across southern California into southern Utah this
afternon. Tonight will start off clear with some of this cloud cover
moving over the area, mostly in thin variety, after midnight as the
upper ridge axis pushes into New Mexico. Afternoon temperatures, as
of 2 pm, were running 4-12 degrees above yesterday values.

Warmer yet tomorrow with highs around 10 or so degrees above mid-
late February normals. A few spots, especially across Cochise
county, will also threaten record highs for February 22nd.

Pressure gradient tightens up on Wednesday night into Thursday in
response to a upper level trof passing by to our north. Gusty
westerly winds Thursday afternoon. Check fire weather section below
for localized fire weather concerns. Can`t rule out a few flakes in
the Whites otherwise this system will be dry for the area. Highs
Thursday will run 10-15 degrees cooler than Wednesday.

Dry zonal flow over the area Friday through much of the weekend
which will result in warmer daytime temperatures.

Flow aloft turns to the southwest late Sunday in advance of our next
weather maker for early next week. ECMWF a little faster than
GFS/CMC in spreading showers across the area on Monday. At this time
will go with a slower timing of showers, mainly Monday night into
Tuesday. Additionally, expect strong gusty southwest winds on Monday
in advance of approaching cold front. Wind advisory type wind gusts
are possible, especially south and east of Tucson. Again check fire
the weather section below for any fire weather concerns. Its coming
up on that time of the year.




FIRE WEATHER...Cerniglia

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