Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Amarillo Texas
1124 PM CDT Sat Aug 30 2014
southerly surface winds expected to remain above 15 knots overnight with
occasional gustiness. On Sunday...deepening surface trough will cause
southwest surface winds to gust to around 30 knots for much of the day.
Expect that dryline will take shape during the day...and will sharpen
across eastern sections during the heat of the day. Expect that
dryline will lie east of all terminals by 21z Sunday...with isolated
thunderstorms developing along it during the afternoon and evening.
Once formed...thunderstorms will move east...away from terminals.
Previous discussion... /issued 635 PM CDT Sat Aug 30 2014/
for the 00z tafs, VFR conditions are expected.
A 45 knots low-level jet will develop overnight, and could lead to low level wind shear
and kdht. However, did not mention as the core of the low-level jet
may remain just east of the terminal. Surface winds should remain
strong enough at kama and kguy to preclude this threat.
Gusty south-southwest winds are expected after 15z.
Any isolated thunderstorms and rain that may develop Sunday afternoon will stay well
east of the terminals.
Previous discussion... /issued 402 PM CDT Sat Aug 30 2014/
hot temperatures and low thunderstorm chances for parts of the area
will persist through the Holiday weekend.
Isolated thunderstorms have developed across the area this afternoon
as temperatures have climbed into the lower to middle 90s. Expect this
isolated convection to continue into the evening...driven by diurnal
heating along with some weak divergence aloft ahead of the main
western trough and accompanying upper jet and some weak lead middle-
level shortwave energy. Could see a few pulse strong storms through
the evening given 0-1km MLCAPES of 1000-1500 j/kg over parts of the
area. However weak deep layer shear /25 kts or less/ will preclude
any organized severe weather threat. Main concern will be brief wind gusts
to around 50 miles per hour due to the dry sub-cloud layer as low-level moisture
has mixed out...but some small hail can/T be ruled out. Think most of
the activity will dissipate after sunset...but can/T rule out a few
lingering showers or storms overnight given the weak divergent flow
aloft ahead of the upper trough/jet and some 850 mb Theta-E advection
along the low level jet axis. Southerly breezes will stay up
overnight...helping keep overnight lows on the mild side.
Surface low pressure will deepen over southeast Colorado/southwest Kansas on
Sunday ahead of the upper trough ejecting across the northern and
central rockies into the High Plains. This will allow the dryline to
sharpen over the eastern panhandles...and it may serve as a focus for
a couple of isolated storms late Sunday afternoon and evening. Better
dynamics will remain to our north...so it/S still uncertain whether
strong diurnal heating and perhaps some weak glancing upper forcing
to the north will be sufficient to initiate any storms. If storms are
able to develop...strengthening wind profiles promoting deep layer
shear around 40 kts in combination with MLCAPES up to around 2000
j/kg will support supercells capable of producing large hail and
damaging winds. Temperatures will continue to heat up on Sunday...especially
west of the dryline where 850 mb temperatures eclipsing 30c will support
some triple digit highs.
As the upper trough slides east across the northern and Central
Plains...it will push a cold front south into the area Sunday night.
This front now looks to linger in the area on Monday...and may bisect
a diffuse dryline across the eastern panhandles. Thus a few isolated
storms will again be possible in the eastern panhandles late Monday
afternoon and evening. Similar to tomorrow...if a storm is able to
develop...the environment will support a severe threat. Slightly
better thunderstorm prospects may develop Monday night over the
northeast panhandles as the low level jet impinges on the frontal zone.
The front retreats north as a warm front on Tuesday...and the upper
ridge starts to build back north and west. The ridge will continue to
amplify from the Southern Plains across the eastern Continental U.S. Middle to late
next week. The resultant anticyclonic flow may pull in enough
monsoon moisture to bring a return of rain chances to the northwest
panhandles late next week. It also appears that a cold front may
approach the northern panhandles late in the week. However Summer
heat looks to hold on through at least late next week despite the
calendar rolling over to September.
relative humidities will fall below 20 percent across the western and
central panhandles on Sunday...in the presence of breezy southwest
winds /15-25 miles per hour at the 20-foot level/. While these weather
conditions will support elevated fire weather conditions...fuels
still generally remain unsupportive.