Excessive Heat in Arizona, June 3 to 6, 2016

Area Forecast Discussion
National Weather Service Tucson AZ
910 AM MST FRI JUN 3 2016

.SYNOPSIS...A strong ridge will bring much hotter temperatures
into early next week. Expect record high temperatures Friday
through Monday, with afternoon temperatures this weekend ranging
from 110 to 115 degrees from Tucson westward across the western
deserts. Some moderation in temperatures will occur by the middle
of next week, but above normal highs will continue.

&&

.DISCUSSION...Clear skies prevail across southeast Arizona at this
time along with light winds. Dewpoints at lower elevations valid 16Z
ranged from the mid 20s-lower 30s, and these temps were about 5-15
degs lower versus 24 hours ago. 03/12Z KTWC sounding total precip
water value of 0.45 inch was 0.15 inch lower versus this time Thur.
03/12Z upper air plots depicted a ridge axis west of Baja California
near 120W extending nwd into the Pacific Northwest. Water vapor and
IR satellite imagery also depicts an upper low centered well west of
the southern Calif coast near 28N/133W. The circulation around the
high pressure ridge is generating light nly/nely flow across
southeast Arizona this morning.

Perhaps a few high-based cumuloform clouds will develop mainly near
the New Mexico border later today. Otherwise, sunny skies will occur
today. High temps this afternoon will be about 5 degs or so warmer
versus Thursday. The Excessive Heat Warning remains in effect until
8 PM MST this evening from Tucson westward across the western
deserts.

There are no updates planned at this time. Please refer to the
additional sections for further detail.

&&

.AVIATION...VALID THRU 04/18Z.
Clear skies into Saturday morning except for a few clouds around 12k-
15k ft msl mainly near the New Mexico border this afternoon. Surface
wind this afternoon nwly at 10-15 kts with gusts to near 20 kts.
Surface wind will be less than 10 kts at other times. Aviation
discussion not updated for TAF ammendments.

&&

.FIRE WEATHER...Dry conditions will prevail through next Thursday.
However, a few mainly dry thunderstorms may occur Sunday and Monday
near the New Mexico border. Expect near-record daytime temperatures
and widespread Haines 6 conditions through Monday. Daytime minimum
relative humidity will be in the single digits to mid teens with
fair to poor overnight recovery. 20-ft winds will be terrain driven
mainly less than 15 mph, with afternoon gusts to 20 mph due to
strong heating. Somewhat stronger southwesterly breezes are possible
early next week, but speeds should remain below critical fire
thresholds.

&&

.PREV DISCUSSION /320 AM MST/...The ridge near the west coast is
increasing both it's amplitude and period as it phases slowly into
the Desert Southwest over the next 48 hours. Near record heat with
values around 10 to 15 degrees above average are expected into early
next week. Considering our average temperatures for early June are
already up there, that means a 4 day period with dangerous heat.
After another 5 or 6 degree jump today, our hottest temperatures are
expected over the weekend. We have modified our Excessive Heat
Warning to include today from near Tucson westward. Saturday and
Sunday still have the previously issued warning, and we have also
added Monday to the heat parade. We have to consider not only
afternoon high temperatures, but also the fact that it's 4
consecutive days with near record temperatures. It also doesn't help
that our first shot of real heat is so strong.

The ridge will dirty up with a decent weakness in the flow near the
western great basin Sunday that will shift slowly through the region
north of us early next week. Heights and thicknesses will fall a
bit, but that won't have much effect on the momentum of the
temperature profile in lower levels. We should see temperatures
start to ease by Tuesday and Wednesday.

Despite what satellite water vapor imagery would have you believe,
there is a modest amount of moisture to be had in portions of Sonora
and Chihuahua. We may see some moisture creeping into far eastern
areas for a few mountain buildups near the New Mexico border early
next week. With a pattern like this, Chihuahua and Sonora are also
going to get busier. By early to mid next week we should be seeing
more activity building north near the Sierra Madres and toward our
area. We'll have to keep an eye out for moisture sneaking in behind
the heat next week.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
    Excessive Heat Warning until 8 PM MST this evening for AZZ501-
      502-504-505.

    Excessive Heat Warning from noon Saturday to 7 PM MST Monday for
      AZZ501>507-509.

&&

Francis/Meyer/French

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