Area Forecast Discussion Issued by NWS Amarillo, TX
000
FXUS64 KAMA 181720
AFDAMA
Area Forecast Discussion
National Weather Service Amarillo TX
1220 PM CDT Sun Jul 18 2021
.AVIATION...
For the 18Z TAFs:
VFR conditions will prevail through most--if not all--of the TAF
cycle. Biggest question will be whether or not "pop-up" summertime
showers/thunderstorms impact the terminals. Leaning against that
at this point based on forecast soundings and subsidence aloft
inhibiting thunderstorms. Will need to watch this and amend if
necessary, but confidence was higher to leave
showers/thunderstorms out of directly impacting the terminals;
however, there could be showers/thunderstorms in the vicinity.
Guerrero
&&
.PREV DISCUSSION... /Issued 407 AM CDT Sun Jul 18 2021/
SHORT TERM...Today through Tonight...
South Florida weather pattern continues to remain in place over
the Panhandles. A humid airmass continues over the Panhandles with
multiple rounds of thunderstorms again throughout the day and
into tonight.
A large anti-cyclonic circulation over the central Rockies
continues to bring a warm and muggy airmass over the Panhandles
with weak winds as well. Any residual boundaries from the
previous few days leftover in this unstable airmass with PWAT
values continuing to be in the +2 to +3 S.D. range should be
enough for storms to develop. We are currently seeing this in the
NE Panhandles early this morning with very heavy rainfall. This
will be the main threat with storms throughout the day. To
accompany the heavy rainfall rates, localized flooding/flash
flooding will also be possible.
Currently a distinct mid level perturbation is rounding the main
H500 high pressure moving south across the Black Hills region.
Later this afternoon and into the evening hours, further north
across the central Plains, this main perturbation will interact
with stronger convergence along the Front Range and a multi-cell
cluster of storms should likely develop in the CO/NE/KS region. In
the main H500 northerly flow of 20-25 kts, with some further
increase in propagation from cold pools, this complex of storms
should move south towards and reach the north central and NE
Panhandles late in the afternoon and into the evening hours. If
cores can hold together, storms in the north central and
northeastern Panhandles later today could be strong to severe with hail
up to 1" in diameter along with damaging wind gusts as this
complex moves southeast. All of the Panhandles today however with
any robust storms and very slow motion will see the chance of
flooding, which may extend through tonight. Check back for updates
as we go throughout the day. High temperatures today will range
from the upper 80s to lower 90s.
Meccariello
LONG TERM...Monday through Saturday.
For Monday and Monday night, the strong upper level ridge of high
pressure remains in place across the north central and northern
plains states down to around the four corners region with northerly
flow aloft continuing across the fcst area, eventually becoming
northeasterly by 12Z Tuesday. This should result in a final
threat for showers and thunderstorms across most of the area
Monday and Monday night before drier weather returns.
For Tuesday through Saturday, the aforementioned upper level
ridge of high pressure is fcst to track slowly east to a position
around the south central Rockies by Saturday afternoon. This
translates to dry weather during this time period due to northeast
to easterly flow aloft, which is unfavorable for bringing storms
into the region from eastern CO, western KS, and eastern NM.
Medium range models except the 00Z ECMWF are in reasonable
agreement with the above scenario and were accepted. The 00Z ECMWF
has its upper level ridge axis further west and is currently the
only model with that solution. For this pckg, have continued to
lean with the model majority solution at this time. That said, NBM
pops and temps were utilized for Monday through Saturday.
02
&&
.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.
&&
$$