572
FXUS65 KTWC 210914
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
214 AM MST Sat Sep 21 2024

.SYNOPSIS...Dry conditions with temperatures near seasonal normal
to below normal today. Temperatures will warm to above normal on
Sunday and into the new week with areas from Tucson westward
possibly seeing 100 degree highs.


&&

.DISCUSSION...Water vapor imagery shows a closed low in west
central Arizona with a few cloud build ups in Pinal County. There
is enough divergence and moisture to help with the cloud build
ups. Radar shows some returns, albeit on the low end of
reflectivity, which may be enough to produce virga this early
morning in eastern Pinal County and into western Graham County.
Rest of Southeastern Arizona has mainly partly cloudy skies that
will clear out by mid morning. The low pressure center will move
eastward to bring westerly to northwesterly winds with a strong
breeze east of Tucson and much cooler temperatures. These
temperatures will be a few degrees below normal.

Ensemble models show a ridge of high pressure building across the
western states starting tomorrow. Temperatures will start to warm
up to a few degrees above normal by Monday. This warming will keep
going through rest of the week as the center axis of the ridge
moves over the region by Wednesday and slowly move east by the end
of the week. Yet, there is fuzziness in the ensembles on the exact
position and strength of the ridge by midweek to the weekend.
Individual ensemble models paint a different picture on the ridge
axis orientation due to a longwave trough downstream over the
midwest and another forming in the Pacific Ocean, depending on the
ensemble model. These troughs will help shape and dictate how the
ridge will play out for Southeast Arizona. Plus, on the position
of the high may result in flow over the eastern part of the state
to produce isolated thunderstorms on Wednesday. Forecaster
confidence is extremely low on this occuring over the White
Mountains and along the New Mexico border, yet it is still a non-
zero chance of occuring-less than 20% chance. However, it is still
over 5 days out and the main story will be warm and above normal
temperatures because of the better signals from all of the model
guidance. With that, most of the region will be in the 90s, except
for higher locations being in the 60s-70s, with areas Tucson west
being in the upper 90s and flirting around the 100 degree mark
for the new week. If the ridge strengthens and or holds, Tucson
and several locations could be near record temperatures. With this
forecast package, Tucson will be within 3-4 degrees of its
records on Thursday and into the weekend.

This weekend is a good time to remember and practice heat safety
tips. Hydrate, cool off in shade or inside with AC, and wear
proper sun protective clothing such as hats. And take breaks!


&&

.AVIATION...valid through 22/12z.
SCT-BKN clouds at or around 08-12K ft AGL this morning and by
21/16Z becoming SKC through rest of the forecast period. SFC winds
will be light and variable this morning and again after 22/04z
for the overnight period. During the day, starting by 21/18z,
westerly to northwesterly winds of 10-15 mph with the occasional
gust to around 20 kts. Terminals east of KTUS can experience the
stronger winds. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Dry conditions with temperatures a few degrees
below normal Saturday. 20-foot winds will generally be 10 to 15
mph with occasional afternoon gust, especially east of Tucson.
Min RHs will generally be 14 to 20 percent in the lower locations
and 20 to 30 percent in the higher locations. Starting Sunday,
high pressure ridge will bring above normal temperatures and
lighter and terrain driven winds through next week.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

Strongman


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