Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 232022

Area Forecast Discussion
National Weather Service Tucson AZ
122 PM MST Tue May 23 2017

.SYNOPSIS...Strong high pressure aloft will bring well above
average daytime temperatures through midweek. Thursday and Friday
will see us between low pressure developing north of the area and
high pressure shifting southward. As a result, expect gusty winds
and several degrees of cooling. Strengthening high pressure next
weekend will once again push temperatures above average.


Early afternoon water vapor imagery continues to show strengthening
high pressure and abundant dry air across the area. Above normal
heights and thicknesses were noted once again on this morning`s 12Z
KTUS sounding when compared to climo and not surprisingly surface
temperatures have already risen above normal values as of 20Z. Most
desert locales were in the mid/upper 90s with a few hours of heating
still to go. Highs at or slightly above 100 seem like a safe bet
although existing records should not be broken by the time all is
said and done.

Much of the same is forecast on Wednesday with afternoon highs
climbing a few more degrees. Some of the better performing guidance
is suggesting highs in the 102-104 range at Tucson and well into the
low/mid 90s across Cochise County and points northward. Again,
records won`t be broken but it will certainly be the warmest day of
the week with the ridge axis squarely overhead.

The ridge will break down on Thursday as weak low pressure (noted on
satellite well west of Baja California as of this afternoon) moves
inland. While the amount of available moisture with this system is
negligible (NAEFS indicating well below normal IVT and PW values and
none of the deterministic models are suggesting significant moisture
transport), gradients will tighten resulting in noticeably breezier
conditions both Thursday and Friday. Areas along the AZ/NM border
will stand to see the strongest winds with 20-30mph speeds common
both days. Given the lack of moisture with this system, this will
more than likely end up as a typical spring wind event. Fire Weather
Watches have already been issued for Thursday and Friday and based
on latest 12z guidance, Wind Advisories may be needed eventually. I
have elected to include a mention of blowing dust near Willcox and
points east near Interstate 10 both Thursday and Friday given strong
winds and low soil moistures in those areas. One bright spot (for
those that aren`t a fan of the heat) is that the upper low will
knock temperatures back into the low to mid 90s through Saturday
although the relief will be short lived as highs will approach the
triple digits by early next week.

Both the deterministic GFS and ECMWF suggest moisture will sneak
into NM next week, possibly making it as far west as the AZ/NM
border. A few GEFS ensemble members are showing a few hundredths of
an inch in the White mtns by the middle of next week, 12Z NBM also
suggesting slight chances of precipitation in that area and I
retained the 10-20 PoPs that we had in place. Even though there
could be enough moisture to generate isolated mountain showers and
storms, the likelihood of a beneficial/wetting rain remains slim.


.AVIATION...Valid thru 24/00Z.
High pressure will mean mostly clear with occasional patches of
thin cirrus. Normal diurnal wind trends, gusty at times in the
afternoon. Aviation discussion not updated for TAF amendments.


.FIRE WEATHER...Dry weather forecast across the region through early
next week. Some breeziness is anticipated on Wednesday although
speeds will really increase Thursday and Friday (especially from
Tucson eastward). With single digit humidities forecast this week,
critical thresholds will likely be realized and Fire Weather Watches
have already been issued. Less wind is forecast Saturday into next
week. There will be some increase in moisture by next
Tuesday/Wednesday along with a slight chance of showers/storms in
the White mtns but wetting rain seems unlikely.


Fire Weather Watch from Thursday morning through Thursday
evening for AZZ151>153.

Fire Weather Watch from Friday morning through Friday evening
for AZZ151-152.




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