Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 202012
Area Forecast Discussion
National Weather Service Tucson AZ
112 PM MST WED JUL 20 2016
.SYNOPSIS...A steady decrease in convection will take place Thursday
into the weekend as the air mass over the region dries out. As a
result temperatures will climb to roughly 10 degrees warmer than
average Friday and Saturday. Monsoon moisture will then gradually
return Sunday onward for an overall increase in convection and a
slight cooling of afternoon temperatures.
.DISCUSSION...Convection beginning to fire up pretty much as expected
to our south with the individual cells moving northward. Expect the
activity to increase over the next few hours, primarily south and
east of Tucson over higher terrain then spreading north. This all
should die off tonight earlier than it has lately with a lack of
significant forcing by that time.
A steady drying trend kicks in Thursday and especially Friday and
Saturday with PWs dropping to around an inch (a bit more south and a
bit less north) by Friday and Saturday. This will result in a
significant decrease in convection despite a wave sliding by just to
our south on Friday. Still carrying some precip chances mainly near
the international border where the highest amount of moisture will
exist. Afternoon high temperatures will climb through this period
peaking Friday and Saturday nearly 10 degrees above normal.
Sunday onward the models are suggesting the the upper level ridge
will shift slightly north allowing the easterlies to have a greater
influence on our area with an increase in moisture. This will help to
put us back into the daily rounds of afternoon/evening convection
especially if it ends up more like what the ECMWF is suggesting.
Will also see a decrease in afternoon high temperatures down a bit
closer to average next week.
.AVIATION...VALID THRU 22/00Z.
Showers and thunderstorms are developing and will continue through
at least 03Z. Storms will be in the vicinity of the terminals,
especially KOLS, KTUS, and KSAD through about 01Z. Heavy rainfall,
gusty winds, and some areas of blowing dust will be the biggest
concerns. The expectation is that storms will begin to wane in
coverage after 03Z. Aviation discussion not updated for TAF
.FIRE WEATHER...Moisture in place will lead to the daily cycle of
mainly afternoon and evening isolated to scattered showers and
thunderstorms through Thursday. A drying trend will then lead to
reduced coverage of showers and thunderstorms Friday into this
weekend. Moisture will remain adequate for isolated to scattered
thunderstorms early next week. Outside of gusty thunderstorm
outflows, 20-foot winds will be terrain driven and mostly less than
.CLIMATE...Record high temperatures will be approached at a few spots
Thursday then most of the area will be at or near record highs
Friday and Saturday.
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