Area Forecast Discussion
Issued by NWS Amarillo, TX

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243
FXUS64 KAMA 282010
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
310 PM CDT Tue Mar 28 2017

.MESOSCALE UPDATE...
...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
  quite conditional.

Simpson
&&

.PREV DISCUSSION... /Issued 1220 PM CDT Tue Mar 28 2017/

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.

Bieda

PREV DISCUSSION... /Issued 1144 AM CDT Tue Mar 28 2017/

UPDATE...

Dense Fog is expected to continue through the early afternoon.
Cloud breaks should follow with improved visibilities by mid
afternoon.

Weber

PREV DISCUSSION... /Issued 1049 AM CDT Tue Mar 28 2017/

UPDATE...

Updated the grids to account for high precipitation chances, as
current satellite and radar has shower/thunderstorm coverage
across most of the CWA. Also due to low level inversion set up
across the Panhandles have included areas of fog, with several
sites reporting 1SM or less for visibility. These storms are not
expected to go severe, but still can`t rule out an isolated strong
to severe thunderstorm.

Weber

PREV DISCUSSION... /Issued 403 AM CDT Tue Mar 28 2017/

DISCUSSION...
Some much needed moisture is expected across the Panhandles over
the next 24 to 48 hours. The upper low which will bring this
moisture is moving across western New Mexico this morning. This
low will help to spark showers across the western portions of the
Panhandles as early as 6 AM. Latest HRRR shows we could see
thunderstorms initiating generally along and west of a Guymon to
Amarillo line around 9AM. While elevated instability will be
fairly limited this morning, deep layer shear of 60kt could be
sufficient for a few storms to become strong. These storms are
anticipated to move northeastward across the Panhandles as the
upper low moves closer to the Panhandles over the course of the
day. recent model runs have shown the track of the upper low to
be slightly further south than previously indicated. This, as
well as morning convection, will help to keep the warm front
further south that previous thought. The result is that the worst
of the severe potential should stay south of the area this
afternoon/evening. With that being said, there is a window for
strong to severe storms to develop this afternoon as MU CAPE
increases to 1000-2000 J/kg across the southern and eastern Texas
Panhandle. These would be primarily elevated storms and would
present a hail threat. Hi-res CAMS for the evening hours show the
potential for storms to transition to a more linear orientation.
This would keep the risk for a severe wind gust possible.

As we go into the overnight hours, the better dynamic forcing will
be pushed east of the area to bring our severe risk to an end.
Storms will still be possible through the day Wednesday into early
Thursday morning, but instability will be far to weak to warrant
any severe risk. Thursday and Friday continue to look dry as our
next upper level low approaches the Panhandles. There is a chance
on Friday that we could see elevated fire weather across the far
southwestern Texas Panhandle, but this threat could easily be
diminished by wetting rains expected Today and Tomorrow.

Over the weekend, the next upper low is anticipated to dive
across the Panhandles. While there remains substantial
differences between medium range models, each model shows precip
getting into at least the northern zones on Saturday. Should the
southern of the solutions verify, it would mean a better coverage
of precip across the area. As of right now, any storms that do
form should remain below severe limits.

&&

.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.

&&

$$

9/89



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