NWS Amarillo, TX wrote its last area forecast discussion before the first event at Apr 30, 11:25 PM CST, 35 minutes earlier.
Area forecast discussion, Apr 30, 11:25 PM CST, 35 minutes before
Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
1225 AM CDT Sat May 1 2021
.AVIATION...
VFR conditions are expected to continue through this forecast.
Southerly winds will increase and get gusty by mid to late
morning. Winds will then tend to decrease toward sunset.
&&
.PREV DISCUSSION... /Issued 716 PM CDT Fri Apr 30 2021/
AVIATION...
For the 00Z TAFs, MVFR cigs are expected to develop in the far
southeast TX Panhandle as well as possibly the far southern TX
Panhandle just south of KAMA near sunrise Saturday and persist
until mid to late Saturday morning. Most models keep these MVFR
cigs just south and southeast of KAMA, and have followed the
model majority trend for this fcst cycle. Otherwise, VFR
conditions are forecast to prevail at KGUY, KDHT, and KAMA
through late Saturday afternoon.
02
PREV DISCUSSION... /Issued 244 PM CDT Fri Apr 30 2021/
DISCUSSION...Tonight through Thursday Night...
Latest WV satellite shows an upper low slowly churning eastward over
northern Chihuahua, a northern stream wave over Lake Huron, an upper
ridge over the central and northern Rockies, and a new trough
approaching the Pacific Coast. At the surface, high pressure is
building southeastward in the wake of the northern stream wave,
which has led to easterly and southeasterly winds at the surface
here in the Panhandles. Showers have occasionally approached from
the south through the morning and afternoon, but all have failed to
persist into our CWA, which aligns with the plentiful dry air seen
in the AMA 12z RAOB.
For the remainder of today and tonight, expect the precipitation
free conditions to continue. With a bit more of a pressure gradient
in place compared to last night, expect lows to hold in the 40s.
Saturday, upper low begins to churn northeastward toward the Big
Bend and central TX. As this occurs, with the Pacific Coast trough
advancing over the western CONUS, expect lee troughing to resume
in CO. This will set up a contrast across the Panhandles, with
southwesterly winds, clear skies, and potential fire weather
concerns across the northwestern Panhandles and cloudier
conditions with perhaps some precipitation in the southeastern
Panhandles courtesy of moisture wrapping around the Big Bend upper
low. Moisture profiles in our southeast are only briefly
supportive of precipitation before DNVA-related descent takes
over as the upper low exits to the east, so have kept PoPs fairly
low. These progged skew-Ts also suggest some instability, so have
retained thunder mention in the forecast. Given the skinny CAPE
profiles, do not think any strong or severe storms would be in
cards.
Sunday, aforementioned lee surface trough slides southeastward,
leading to fire weather concerns in the western Panhandles, as
discussed below. Otherwise, expect much warmer conditions as warm
temperatures aloft set up and breezy surface winds help mix this to
the surface.
Sunday night through Monday night, best shot for precipitation in
the entire seven day forecast arrives as the longwave trough
originally off the Pacific Coast slowly slides eastward, with
guidance suggesting this will have a slight positive tilt to it. As
is usually the case with positively tilted longwave troughs, a cold
front will push south Sunday night before the best upper support
arrives during the day Monday. From a precipitation standpoint,
this pattern is usually a recipe for disappointment compared to
what guidance depicts in the medium range, but even this usually
pessimistic forecaster must admit progged moisture quality seems
to be better than what is typically seen in positively tilted
trough scenarios. Given this, and the fact that the trough
possesses only a weak positive tilt, have largely retained likely
NBM PoPs for Monday. Have also largely retained mentions of
thunder given some instability seen in guidance, although severe
thunderstorms look increasingly unlikely given a trend toward a
faster advancing cold front. Otherwise, given the good moisture
seen at 850mb/700mb, have leaned sky cover upward and high
temperatures downward for Monday.
After a cool Tuesday, temperatures should begin to recover by
Thursday as an upper ridge builds over NM. Shortwave disturbance
aloft may lead to some showers and thunderstorms Wednesday, but due
to low confidence in sufficient moisture, have kept mentions out of
the forecast for now.
Ferguson
AVIATION...18Z TAFs...
VFR conditions are likely to prevail at all TAF sites through the
period. Main point of uncertainty is at AMA around 12z Saturday,
when IFR/LIFR stratus may approach from the southeast. At this
time, no available guidance has this reaching the terminal, with
even the most agressive guidance keeping this at least 15 nm away
from AMA. Have thus omitted any mention of stratus from the TAF.
Otherwise, winds are generally light and variable at issuance time
but will become consistent out of the east and southeast this
afternoon, with winds veering to south-southwesterly by the end of
the period.
Ferguson
FIRE WEATHER...
Elevated fire weather conditions may return to the northwestern
Panhandles Saturday as winds across there turn southwesterly, with
resulting warn and dry conditions due to downslope wind component.
Additionally, resumption of surface lee troughing to our northwest
should help tighten the pressure gradient, allowing winds to
increase to 15 to 25 mph as RH values drop below 15 percent,
yielding RFTIs of 1 to 2. In the presence of parched fuels with ERCs
in the 70th to 89th percentile, elevated conditions will likely
occur.
Next fire weather day arrives Sunday as the surface trough shifts
eastward, leading to decidedly downslope westerly winds. As this
occurs, 850mb LLTR impinges on the Panhandles as well. Resulting
warm, dry, and lightly breezy winds should lead to elevated to
perhaps critical conditions, mainly in the southwestern Texas
Panhandle, as RFTI values of 1 to 5 occur.
Ferguson
&&
.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.
&&
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