Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 261643
Area Forecast Discussion
National Weather Service Tucson AZ
942 AM MST THU MAY 26 2016
.SYNOPSIS...A low pressure system moving north of the area will
bring cooler temperatures today, as well as a slight chance of
thunderstorms across the White Mountains. Dry conditions with a
warming trend will then occur Friday through next Wednesday. High
temperatures by the middle of next week should approach 100 degrees
across the western deserts.
.DISCUSSION...A low pressure system will pass through the state
today with a few showers or thunderstorms possible in the White
Mountains. Otherwise...dry and cooler today across southeast
Arizona. The system will exit the region by tomorrow with dry and
warmer weather over the weekend. The current forecast looked on
track, so no updates necessary this morning.
.AVIATION...VALID THRU 27/18Z.
Clear to mostly clear skies will prevail through the period except
sct cumulus clouds 10-12k ft agl thru 27/03Z over the White Mtns.
Sfc wind wly/nwly at 12-16 kts with higher gusts, with the strongest
winds near the International and New Mexico border areas, including
the KDUG/KSAD/KFHU/KALK terminals. Wind easing to 10 kts or less
again aft 27/03Z. Aviation discussion not updated for TAF
.FIRE WEATHER...Expect weaker westerly winds and a limited threat
for mostly dry thunderstorms over the White Mountains through this
evening, and again Friday afternoon. Then, dry and slightly cooler
than normal conditions are expected this weekend and early next week
with lighter, more typical diurnal 20-ft winds.
.PREV DISCUSSION...The 26/00Z NAM/GFS/ECMWF/CMC depict the bulk
of deeper moisture to remain north of this forecast area
today.However, height falls as well as a slightly more southern
trajectory versus NWP solutions of 24 hours or longer ago suggest
the potential for a few showers/tstms as far south as the White
Mountains. Thus, for continuity with the inherited forecast, have
maintained a slightchance of showers/tstms across the White
Mountains thisafternoon/evening. Dry conditions are then expected
area-wide latetonight and Friday with the belief that any
showers/tstms willremain north of this forecast area.
GFS/ECMWF/CMC were similar to previous solutions with the depiction
of a baggy upper trough over the swrn CONUS Sat-Tue. The 26/00Z GFS
has joined the ECMWF/CMC with also depicting a weak upper low, 5760
meters or such, to meander into the area from srn California by
about next Tue. However, model moisture fields continue to depict a
paucity of moisture across southeast AZ early next week. As such,
have maintained precip-free conditions this weekend and early next
week as deeper moisture ahead of this weak upper low should remain
east of this forecast area.
Thereafter, there were differences between the deterministic GFS/
ECMWF regarding the extent of upper ridge amplification over the
area by next Wed. Have noted that the ECMWF was considerably more
robust versus the GFS regarding the potential of measurable rainfall
next Wed from the Mogollon Rim northward into nrn AZ. At any rate,
dry conditions should continue across southeast AZ underneath some
sort of an amplifying ridge over the area.
The aforementioned height falls today will translate into temps that
will mainly range 5-10 degs cooler versus Wed. Thus, high temps this
afternoon will also average about 8-15 degs below normal, depending
upon location. Expect about 5 degs or so of daily warming Fri-Sat
followed by an additional degree-or-two of daily warming Sun-Wed.
Have generally opted for the higher end of various guidance temps,
especially next Tue-Wed. As such, high temps next week should
approach 100 degs across the western deserts west of Tucson. There
are some solutions that suggest high temps for the Tucson metro area
may approach 100 degs next Thur-Fri. However, those days are beyond
the scope of this forecast package.
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