FXUS65 KTWC 220317

Area Forecast Discussion
National Weather Service Tucson AZ
817 PM MST Mon Aug 21 2017

.SYNOPSIS...Limited thunderstorm activity through Tuesday. Better
chances for afternoon and evening thunderstorms Wednesday and
Thursday. Low grade monsoon forecast for Friday and the weekend.
High temperatures this week will be at or above normal.


.DISCUSSION...It was a fairly quiet afternoon across the forecast
area as convection struggled due to a relatively stable atmosphere
as seen on the 00Z KTWC sounding along with reduced moisture values
as PWAT`s are down to near 1 inch. The few showers and thunderstorms
that did develop were across the higher terrain across SW Cochise
County and Northern Greenlee County. Latest radar imagery shows
showers have just about completely dissipated. Skies are mostly clear
across most of the forecast area with the exception of some debris
cloudiness from earlier convection in Sonora moving northeast along
the international border. Things are looking rather quiet for the
overnight period. We already sent an update to reduce PoPs this
evening along with other minor trend updates. Rest of the forecast
remains unchanged, see previous discussion below for additional


.AVIATION...Valid thru 23/06Z.
Mostly clear skies through Tuesday morning, then Isold TSRA/SHRA
developing mainly E and S of KTUS from 22/18Z through about 23/03Z.
Surface wind variable in direction mainly less than 12 kts, although
brief gusts to near 35 kts in vicinity of TSRA are possible.
Aviation discussion not updated for TAF amendments.


.FIRE WEATHER...Expect isolated thunderstorms mainly east and south
of Tucson on Tuesday. Thunderstorm chances increasing again
Wednesday onward. Normal diurnal wind trends will occur through
Wednesday then the flow will become mostly easterly thereafter.
Locally strong and gusty winds expected in the vicinity of
thunderstorms. Daytime temperatures will be warmer than normal
through the week into next weekend with typical humidity levels.


.PREV DISCUSSION...Temperatures cooled a smidge during the partial
eclipse earlier today. It was also fascinating watching the solar
eclipse shadow move across the CONUS using GOES-16 one minute data.

Satellite imagery this afternoon showed scattered cumulus clouds
with some towering CU over the mountains. Held on to slight chance
of a couple of showers/t-storms mainly over the mountains this
evening. Tuesday will also see limited t-storm activity with slight
chances mainly over the mountains east and south of Tucson.

Increasing southerly flow on Wednesday will bring back deeper
moisture across the areas for a more active day versus today and
Tuesday. Depending on which model you look at Thursday could be an
active day or not. Made little change to inherited forecast and see
how models come into better consensus.

Low grade monsoon forecast for Friday thru Sunday.

Temperature wise the highs will be warming up this week and run
about 3 to 5 degrees above normal.






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NWS TWC Office Area Forecast Discussion