Forecast Discussion

Forecast Discussion for TWC NWS Office
079
FXUS65 KTWC 122314
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
413 PM MST Sat Jun 12 2021

.SYNOPSIS...A strong ridge of high pressure will result in excessive
heat through much of the upcoming week. This high pressure will
become centered over the four corners region by the middle of the
week, allowing mid-level moisture to increase across the area with
the prospects of isolated mainly dry thunderstorms.

&&

.DISCUSSION...The main weather impact for Southeast Arizona over the
next week will be the excessive heat felt across the entire
Desert Southwest. The upper pattern is defined by a ridge of high
pressure extending from central Sonora Mexico into east central New
Mexico. This feature will strengthen the next few days as it
positions itself near the Four Corners region Monday night. High
temperatures will remain 10 to 15 degrees above average, with record
or near record highs likely to persist through the end of the week.
An Excessive Heat Warning is in effect for the majority of Southeast
Arizona through Friday. Please see the climate section of the
forecast discussion for a list of record highs through Monday.

Otherwise, the forecast is actually kinda tricky today, trying to
figure out how much moisture is present to our south and east, and
when/how much of it will work its way northward. Currently there is
an inverted trough across western Mexico moving west. As this feature
continues to move west, it will setup a surface pressure differental
between the lower Deserts of Arizona and the southern Gulf of
California, helping trigger a weak surge up the Gulf. However,
examination of the GOES-17 TPW imagery suggests that immediate
locations to our south are still dry, with deeper moisture residing
way down near Guaymas, southward. So, it will take a while for this
surge to import moisture into our neck of the woods, most likely
Sunday night into Monday morning. the moisture wont be incredibly
deep, but it should be enough fuel mainly dry storms to develop
across the forecast area. In addition, with the upper high being
positioned over the four corners region, we can see a few wiggles in
the upper flow help support storm development this week. In any
event, we still aren`t really wet enough to result in strong storms,
mainly dry thunderstorms with gusty and erratic outflow winds
possible. At this time, the best chance of afternoon and evening
thunderstorms will evolve after Tuesday. The increase in moisture
could help moderate temperatures a bit toward the end of next week.

&&

.AVIATION...Valid through 14/00Z.
SKC-FEW cirrus above 20k ft MSL. Tomorrow afternoon, FEW-SCT cumulus
develops around 15-18k ft MSL east to south of KTUS. Surface winds
WLY/NWLY 8-12 kts with gusts up to 20 kts, decreasing light and
variable this evening. WLY/NWLY winds return tomorrow afternoon 10-
15 kts gusting to 25 kts. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Near record heat will continue each day,
potentially through next Friday. Minimum humidities are woefully
dry, with very poor overnight recoveries until improving Monday
night. This is due to a shift in the weather pattern that attempts
to usher in early monsoon moisture. A slight chance for
thunderstorms develops Monday, persisting each afternoon/evening
through the remainder of the forecast. Rainfall amounts should be on
the lighter side due to the overall dryness of the atmosphere,
increasing the chances for dry lightning and gusty outflows. Winds
will otherwise follow typical diurnal trends, with afternoon
gustiness due to heating.

&&

.CLIMATE...Near record or record high temperatures through much of
the upcoming week.

List of record or near record high temperatures for the next few days.

DATE                     Today         Jun 13        Jun 14
                       FCST RCD/YR   FCST RCD/YR   FCST RCD/YR

TUCSON INTL AIRPORT    109 109/1995  111 110/1924  112 111/1993
AJO                    109 112/1956  110 112/2019  110 112/1940
KITT PEAK               93  89/2013   94  88/1985   94 90/2006
ORGAN PIPE CACTUS      110 111/2019  108 112/1956  108 111/1987
PICACHO PEAK           109 111/1995  112 110/2018  113 111/2000
SAFFORD AG STATION     111 105/1956  113 106/1974  114 106/2006
SIERRA VISTA FD        105 103/2021  105 104/2013  104 101/1974
TOMBSTONE              106 105/1924  107 104/1946  106 106/1993
WILLCOX                105 106/2013  106 106/2013  106 107/2018

&&

.TWC WATCHES/WARNINGS/ADVISORIES...

Excessive Heat Warning until 9 PM MST Friday for AZZ502>506-509.
Excessive Heat Warning from 10 AM Sunday to 9 PM MST Friday for
AZZ501.
Excessive Heat Warning until 8 PM MST Monday for AZZ507-508.

&&

$$

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NWS TWC Office Area Forecast Discussion