Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 270300

Area Forecast Discussion
National Weather Service Tucson AZ
800 PM MST Sat May 26 2018

.SYNOPSIS...Dry conditions will continue through next week.
Daytime temperatures will climb back to several degrees above
average Tuesday onward as high pressure strengthens just to our
southeast. We`ll also see gusty winds at times the second half of
next week.


.DISCUSSION...The high clouds are finally thinning over the area but
not before leaving behind a colorful sunset once again. The cloud
cover made for an interesting temperature pattern this afternoon.
The thickest and most persistent clouds were SW to NE across the
Tucson area, and as a result ended up significantly cooler than
locations typically cooler than Tucson. The high in the metro was 92
today while Nogales reached 94 degrees and Douglas hit 97. With a
lack of cloud cover tonight combined with the cooler air mass that
has settled overhead, low temperatures early Sunday morning will
generally be 8-13 degrees cooler than they were Saturday morning but
they will rebound to near average for late May during the afternoon.
I made a few adjustments to overnight temperatures but other than
that no other adjustments were needed this evening.


.AVIATION...Valid through 28/00Z.
Scattered clouds above 20k ft AGL this evening becoming clear
overnight. Surface wind easing late this evening to variable mainly
less than 12 kts. Wind becoming SW-W 8-15 kts with gusts to 25 kts
after 27/19Z. Aviation discussion not updated for TAF amendments.


.FIRE WEATHER...Dry conditions will continue to prevail through next
week and into the following weekend. Typical late May winds are
expected through the early part of the week, with gusty southwest to
west winds returning the second half of the week.


.PREV DISCUSSION... /issued 243 PM MST Sat May 26 2018/
A nice narrow stream of mid and upper level moisture in a
southwesterly flow all the way from the tropics. The subcloud layer
below 500mb remains quite dry though, so just some virga out there
today. Precipitable water remains under 1/2 inch and surface dew
points have cratered into a range from single digits to the lower 20s
this afternoon. Breezy to locally windy as expected, but below
advisory levels with generally isolated fire weather concerns.

We remain in between major features, with a trough over western
portions of the Great Basin northwest of us, and strong high
pressure anchored over western Mexico with a ridge axis through
New Mexico and west Texas. The main low currently associated with
the trough will fill over the next 36 hours as it drifts slowly
eastward, eventually shearing into the northern plains early in
the new week as Alberto complicates the pattern downstream in
southeastern states. We`ll remain dry, however.

The northwestern flank of the Mexico ridge will regain control
late Monday and Tuesday, with temperatures jumping back toward the
century mark around Tucson into the lower western deserts.

There are some signs that western and central Mexico is regaining
some moisture, with Durango and southern portions of Sinaloa
getting convective again next week. Subsidence under the high
center will make it slow going though. For us, still no rain in




FIRE WEATHER...Cerniglia/Rasmussen

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