FXUS65 KTWC 150340
Area Forecast Discussion
National Weather Service Tucson AZ
840 PM MST Tue Aug 14 2018
.SYNOPSIS...A very moist atmosphere will result in numerous showers
with embedded thunderstorms for the remainder of the week along with
cooler temperatures. More typical monsoon activity and near normal
temperatures will return for the coming weekend.
.DISCUSSION...A few spots of showers and thunderstorms continued
late this evening across southeast Arizona. A cluster of
thunderstorms were tracking westward across Cochise county as of 830
PM MST. The outflow associated with these storms could trigger
additional ones near Tucson by midnight. However, the blowing dust
advisory in effect until 11 PM MST for parts of Pinal and Pima
counties hinges on these storms. That said, will keep the blowing
dust advisory posted along with the rather high POP values for now.
Please refer to the additional sections for more details.
.AVIATION...Valid through 16/00Z.
Isolated to Scattered SHRA/TSRA through 15/10Z, then less coverage
before TSRA coverage increases again Wednesday afternoon. Brief MVFR
conditions possible with the TSRA, otherwise SCT-BKN cloud bases
generally 8-12k ft AGL. Outside of thunderstorm gusts, expect mainly
light SFC winds. Aviation discussion not updated for TAF amendments.
.FIRE WEATHER...The pattern is favorable for decent rain chances
through at least Saturday, but there are hints of drier conditions
Sunday. Near or slightly below normal temperatures will continue
through the forecast period. 20-ft winds will be terrain driven at
less than 15 mph, except for in and around thunderstorms where
strong outflows may occur.
.PREV DISCUSSION...Once the convection ends overnight, there will be
plenty of moisture to work with Wednesday and the next few days.
Wednesday has the potential to be active as well with the weak
inverted trough across the area but much will depend on just how
much cloud cover remains and how worked over the atmosphere is from
convection this evening. The most likely scenario for Wednesday is
considerable shower coverage with some embedded thunderstorms but
with considerably fewer strong thunderstorms. A similar setup is
expected once again for Thursday with continued elevated moisture
levels. If there ends up being enough instability, any potential
thunderstorms both Wednesday and especially Thursday have the
potential to be heavy rain producers as the steering flow slows.
Heading into the weekend, the flow pattern will become more north to
northeasterly with perhaps some drier air working into parts of our
area, especially on Sunday before the flow becomes more easterly
again Monday and Tuesday and deeper moisture tries to make a return.
This scenario in general tends to point to a lower grade monsoon
over the weekend with perhaps some increase in storm coverage early
next week but confidence remains low.
Temperatures will generally remain near to slightly below normal
through the forecast period.
Blowing Dust Advisory until 11 PM MST this evening for
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