483
FXUS64 KSJT 221704
AFDSJT

Area Forecast Discussion
National Weather Service San Angelo TX
1204 PM CDT Wed May 22 2024

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 416 AM CDT Wed May 22 2024

...Severe storms expected this afternoon into tonight...

Currently, we have light southeasterly flow to the south of a
cold front that is moving south through the southern plains. This
cold front is expected to move south into our area today, with
most guidance showing the front near or just south of a San Angelo
to San Saba line by mid to late afternoon. Temperatures by mid
afternoon south of the front will climb well into the 90s, while
north of the front, low to mid 80s are likely. Dewpoint values are
expected to remain in the mid 60s to low, and possibly mid 70s,
with increasing moisture the farther east you go. This combination
of warm temps and high dewpoints will yield CAPE values along and
south of the front from 3000 to as high as 4400 J/kg. This
instability, along with ample mid level instability, and deep
layer shear values of 40+ knots will result in any thunderstorms
developing quickly strengthening to severe levels. Not only will
these storms be severe, but hail of 2 inches or larger is likely,
especially with the initial storms that are expected to be
discrete supercells. Along with the very large hail, a few
tornadoes are also possible, particularly any storms that move
along the frontal boundary or any outflow boundaries from
neighboring storms. Individual storm motions are expected to be to
the east/southeast, but some right-moving storms will likely
develop a more southerly direction. As the event evolves, these
discrete storms should grow upscale into a southeastward moving
MCS during the evening hours. As this occurs, there will be a
growing risk for severe wind gusts in addition to large hail, and
a few tornadoes. Expect most of the thunderstorm activity to be
south and east of our area by Midnight or so, although some of the
CAMs do develop additional scattered showers and storms after
midnight, mainly south of I-20. These should be much less intense,
but could offer some marginally severe hail or wind gusts.

Other than the storms, temperatures will be hot south of the
front, and combined with dewpoints in the 60s to lower 70s, there
is a risk for heat-related illnesses for anyone working or
exercising outside. Overnight lows will be in the mid 60s to lower
70s.

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 429 AM CDT Wed May 22 2024

A few strong to severe storms possible in eastern parts of the Big
Country and Heartland on Thursday. Rather hot and mostly dry
conditions expected for the Memorial Day holiday weekend.

Return southerly flow will have already developed by Thursday
morning. Dryline to the west will mix east across at least the
western half of our area. Isolated to scattered showers and
thunderstorms are possible across the area mainly east of a Haskell
to Ballinger to Mason line. May have an weak embedded disturbance
(in west-southwest flow aloft) move across our area during the day.
Although not looking like an organized setup for our area Thursday,
a few strong to severe storms will be possible in the area generally
east of a Haskell to Coleman line, given the forecast strong
instability and effective bulk shear around 50 knots. High
temperatures on Thursday are expected to range from the upper
80s/lower 90s in our eastern counties, to the upper 90s in much of
the Concho Valley and Northern Edwards Plateau, where skies will be
mostly sunny behind the dryline.

On Friday, a weak cold front will move south across the northern
half of our area before stalling in the evening. Some model data
indicates a potential for some shower/thunderstorm development near
this boundary late Friday afternoon over parts of central Texas. At
this time, carrying a slight chance PoP in eastern San Saba County.
Brown and San Saba Counties will be ahead of a dryline and near the
forecast position of the weak frontal boundary. With any outdoor
events taking place Friday evening of the upcoming holiday weekend,
this is something that will need to be monitored. With passage of
the weak cold front across our northern counties, highs will be
limited to 90-94 degrees. The hottest highs Friday in our forecast
area will be ahead of the front and behind the dryline, in the upper
90s to 101 degrees.

Our area will be under quasi-zonal flow aloft Saturday and Sunday,
and situated between a broad upper high over central/southern
Mexico, and upper shortwave troughs moving from the central Rockies
across the central Plains and into the Midwest. After a westward
retreat Friday night, the dryline on Saturday will mix east across
all except some of our far eastern and southeastern counties.
Carrying a low chance (15-20 percent) of thunderstorms Saturday
afternoon/early evening east of a Throckmorton to Coleman to San
Saba line, where a conditional possibility of a strong or severe
storm would exist given the forecast instability and effective bulk
shear. Most of our area, however, will be hot and dry Saturday and
Sunday with the dryline mixing east of our entire area Sunday.
Expect highs Saturday to range from the mid 90s in some of our far
eastern counties, to 100-105 in the Concho Valley south to the I-10
corridor. Highs Sunday should be mostly in the upper 90s in our
northern and eastern counties, to 100-104 in the Concho Valley and
our southern counties.

A little stronger cold frontal passage is progged for early next
week, although the models differ on the timing (Monday vs. Tuesday).
Current consensus is for the cold front to move south across our
area on Monday. Rain chances with the front look too uncertain to
include any mentionable PoPs at this time. Highs Monday look to
range from the lower 90s in the northern and eastern Big Country, to
101-104 in our southern counties along I-10. Temperatures should be
cooler area wide for a couple of days after the cold frontal
passage. Indications at this time suggest highs in the 80s to lower
90s, but the details are uncertain this far out.

&&

.AVIATION...
(18Z TAFS)
Issued at 1203 PM CDT Wed May 22 2024

Storms expected to develop along southward-moving cold front
this afternoon and evening could produce sudden wind shifts and
large hail. MVFR to IFR ceilings late tonight and tomorrow morning
will be very ragged with several breaks likely. Additional showers
and or storms are possible tomorrow morning, but these were left
out of the 12 to 18Z time period due to low confidence.


&&

.PRELIMINARY POINT TEMPS/POPS...
Abilene     68  90  69  92 /  20  20   0   0
San Angelo  70  98  67 100 /  20  10   0   0
Junction    72  98  72 101 /  30  20   0  10
Brownwood   69  88  69  93 /  40  30   0   0
Sweetwater  68  95  67  92 /  10  10   0   0
Ozona       70  98  67  99 /  20  10   0   0
Brady       70  90  71  95 /  40  30   0  10

&&

.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...20
LONG TERM....19
AVIATION...SK