Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 272025
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
125 PM MST Tue Sep 27 2022

.SYNOPSIS...Scattered afternoon and evening showers and
thunderstorms are expected across parts of southern Arizona
through Friday. These are expected primarily from Tucson south and
west and over the White Mountains. Temperatures slide back a few
degrees by the end of the week.

&&

.DISCUSSION...Southeast Arizona is currently under High Pressure
influence via a 500mb ridge. The morning satellite showed clear
skies across the area with the mountainous regions starting to
bubble up with a cumulus cloud field. It has been breezy due to
the High Pressure moving eastward and creating a tight pressure
gradient in the upper levels. The easterly surface winds kept our
morning temperatures a tad warmer than the previous morning. The
moisture is still here in southern Arizona as our 12Z sounding
shows the PWATs at 1.70 inches which provides ample opportunity
for thunderstorms to develop later in the afternoon. Plus, the 15z
850mb mesoanalysis depicted warmer dew point temperatures and a
weak thermal gradient line from Catalina Mountains south to the
International Border. This weakish boundary at the 850mb gives a
clue that thunderstorms could form to the west of the Catalina
Mountain south to the International Border. There is also a weak
stationary boundary draping across our northern part of the CWA.
With these factors, the CAMs do show the thunderstorm activity to
be west of that Catalina Mountain-International Border line, and
the storms will be mainly isolated in nature as the CAPE is fairly
modest in the western part of the CWA.

Tomorrow, ensemble models show a trough moving into the Pacific
Northwest which will bring a change to the synoptic pattern for
the week. Gusty surface winds will return again from the east to
southeast with stronger winds within the Gila River Valley due to
the 500mb ridge influence. Moisture will still hang around along
the International Border and thunderstorms can expected in the
afternoon, mainly south and west of Tucson.

Thursday and through the weekend...The upper level trough will
start to dig into intermountain region of the U.S which will bring
about westerly flow that will help push out the remaining
moisture in southern Arizona. Ensemble guidance shows PWATs and
the dew point temperatures starting its downward trend and drying
the region out to become more align of the typical Fall Season.
But, daily thunderstorms chances will remain through Friday for
areas mainly Tucson west and south, and along the Mogollon Rim.
Temperatures will drop a few degrees to near seasonal normals
through the weekend.

&&

.AVIATION...Valid through 29/00z.
Scattered -SHRA/TSRA expected this afternoon through 28/02Z and
returning again tomorrow afternoon, mainly south and west of
Tucson. SFC winds E-SE at 12-18 kts through the rest of the day
and into the early evening. Winds will diminish to 5-12 kts in the
nighttime hours and then picking up by 28/15Z to 10-12 kts with
the occasional gusts up to 30 kts through the rest of the forecast
period. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Scattered afternoon and evening showers and
thunderstorms are expected through Friday, generally from the Tucson
area south and west and over the Mogollon Rim country. The main
threat from the storms besides lightning will be strong and gusty
outflow winds. Breezy, east to southeast 20 foot winds will continue
through the rest of the day before easing later on Wednesday into
Thursday and generally becoming light and diurnal thereafter.

&&

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

$$

Strongman

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