Area Forecast Discussion
Issued by NWS Amarillo, TX
FXUS64 KAMA 282331
Area Forecast Discussion
National Weather Service Amarillo TX
631 PM CDT Tue Mar 28 2017
00Z TAF Cycle
VLIFR to IFR or MVFR ceilings and visibilities can be expected at
all three TAF sites through 00Z Thursday. Scattered to numerous
showers and thunderstorms can be expected at all three TAF sites
through 00Z Thursday. Northeast winds 10 to 20 knots will become
north and increase to around 20 to 30 knots with gusts near 35 to
40 knots after 04Z to 06Z Wednesday.
.PREV DISCUSSION... /Issued 458 PM CDT Tue Mar 28 2017/
Current radar indicates showers and thunderstorms across the
eastern TX/OK Panhandle, with strong to marginally severe
thunderstorms possible. Collingsworth County may be an area with
better potential for severe storms as there is the potential for
warmer air to advect into the area. This would increase the threat
for severe weather over the next couple of hours. Otherwise for
short term updates see the Mesoscale Update.
Storms will still be possible overnight, but for now expect that
any storms that occur will not be severe as better dynamic forcing
will be to the east.
With the low overhead tonight and the deformation zone mainly
across the OK and northern TX Panhandles, expected moderate to
heavy rain to continue. Also tracking colder air across the
northwestern TX/OK Panhandles. Latest model soundings are keeping
things very close to the freezing line down to the surface. Air
and ground temperatures will most likely bottom out near freezing
or slightly below. But precipitation aloft has a good chance of
falling as snow. The uncertainty lies with how much snow will
accumulate and the time frame for this snowfall. There is
difficulty in the forecast due to significant QPF expected and
whether temperatures will linger near freezing long enough for
appreciable accumulations. No Winter Weather Advisories will be
issued with this package as confidence is just not high enough.
Cooler and drier air will be in place on Wednesday, with highs in
the upper 40s to lower 50s for the OK Panhandle, and in the 50s to
lower 60s for the TX Panhandle.
Temperatures will rebound on Thursday and Friday as southwest flow
returns ahead of another weather system set to impact the area
next weekend. Right now models are not in good enough agreement to
put certainty into the risk for severe weather. However, the
pattern favors the return of thunderstorms to the Panhandles
starting as early as Friday night. Will iron out the details of
the significance as the weekend approaches the near term.
..Severe weather somewhat possible this afternoon/evening...
* Synoptic Overview: Another in a series of upper level low pressure
systems is again knocking on our door. Substantial height falls
have overspread the area and forcing for ascent has been and
should continue to be plentiful. At the surface, very stable air
has invaded the Panhandles with all convection to this point
certainly of the elevated variety.
* Mesoscale (Eastern Panhandles): Generally about 1000-1500 J/kg of
MUCAPE have been realized through the day, helped along by fairly
steep lapse rates aloft. Model indications though are that lapse
rates may weaken in the ern TX Panhandle this afternoon, with no
significant increase in MUCAPE expected. After having not seen
much more than penny size hail this morning, it`s kind of tough to
believe we`ll be able to see much more than quarters this
afternoon in the line of convection that is moving east.
* Mesoscale (Western Panhandles): Of a bit more interest is the area
of clearing behind the main line of ongoing convection. The low
level stable air mass is shallower in the far west than in the
east, and sunshine could erode enough of it to allow for an
increase in sfc-based convection late this afternoon (something
being seen in NM already). Due to exceptional mid level cooling
associated with the upr low, forecast soundings in Deaf Smith
County from the HRRR and other CAMS show the possibility of around
1200 J/kg MLCAPE with T/Td of only 57/54. Any severe concern that
develops out west will likely be confined to the western 2 tiers
of counties from about 6-9 PM as the thermodynamic environment
will not be supportive any further east. Threats from this
convection will primarily be wind and hail, but again this is all
AVIATION...18Z TAFs...Simply put, flying conditions will be quite
difficult. LIFR to IFR conditions are forecast through the TAF
period for all terminals, with periods of showers and
thunderstorms likely through midday Wednesday. A cold front due to
enter the region will switch winds at KDHT & KGUY to a northerly
direction AFT 29/02Z. Wind speeds behind the front could produce
winds around 20 to 30 kts with gusts up to 40 kts, with the
strongest winds expected at KGUY.