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Area forecast discussion...updated 
National Weather Service Lubbock Texas
1217 PM CDT Thursday Aug 21 2014

Update...
no changes are anticipated to the forecast for the remainder of
this afternoon and evening. The County Warning Area remains situated underneath
the eastern periphery of a gradually thinning subtropical
moisture plume. Middle-level heights are slightly higher than
yesterday with little discernible shortwave energy...so we expect
afternoon and evening convection to be slightly less robust than
yesterday. The development should be concentrated across the western
Southern Plains with activity mainly on The Caprock...but we can/T
completely rule out an isolated storm or two in the rolling plains.

&&

Aviation...
once again...VFR conditions should be the rule...but there is a
slim chance of -tsra at either terminal late this afternoon and
evening...with the better odds at klbb. Amendments for convective
activity are possible. Also...a T-storm outflow boundary may
interfere with the prevailing southerly surface winds for a
period. After the Standard pre-dawn lull...breezy winds will
return Friday morning.

&&

Previous discussion... /issued 628 am CDT Thursday Aug 21 2014/

Aviation...
deep monsoon flow continues just west of klbb today...while kcds
will be enough east to remain dominated by upper level high
pressure ridge. Bulk of short term solutions develop thunderstorms
just west or northwest of klbb but disagree on movement into the
terminal late this afternoon and evening. We will keep mention out
of klbb for now. High clouds that have been blocking lower level
satellite views are now thinning enough to give at least partial
view near the ground...no sign of low clouds south of kcds or
southeast of klbb this morning though still watching. Rmcqueen

Previous discussion... /issued 401 am CDT Thursday Aug 21 2014/

Short term...
a plume of sub-tropical moisture will continue across western zones
today with precipitable water values approaching 1.6 inches near the
New Mexico border. This also is within a weak upper level shear zone
as well as a modest surface trough. Disturbances aloft capable of
producing lift this afternoon and evening are difficult to discern
this morning. A remnant mesoscale convective vorticity near the
extreme southern South Plains potentially could factor in later
today. But if anything...flow suggests slightly more anticyclonic
curvature today versus yesterday favoring less activity...especially
for eastern zones. Solutions on the other hand have been consistent
generating precipitation this afternoon and evening over western
zones very similar to our going forecast. Without convincing
argument to favor either a dry or wet forecast today...we will
retain the gist of the previous forecast tilting best chances
slightly to the model favored areas. Edged todays forecast highs up
a half-notch in line with trends and closer to yesterdays maximums.
Southerly surface winds should again remain moderately breezy for
much of the day. Late afternoon and early evening peak in thunder
chances should be followed by diminishing trend by late evening...
also favoring closer to the New Mexico border. A few storms may
extend just past midnight so added slight chance in the 06z to 12z
period near the state line as well. Rmcqueen

Long term...
precipitation chances still seem to be on track for tomorrow evening across
our western zones...the biggest question is how far east will the
precipitation push. The GFS/NAM keep a thin line of convection associated
with a surface trough along the Texas/nm state line Colorado-located with
forcing at the leading edge of a shortwave trough. Convection that
forms will most likely stay pretty confined to this area as steering
flow in southwest to northeast and is fairly weak. Some storms may
propagate east along an outflow boundary but that scenario is
unknown. Slight chance probability of precipitation were kept from The Caprock Escarpment
westward while chance probability of precipitation were kept along the Texas/nm state line. The
shortwave will push slightly eastward by Saturday afternoon but will
have lost some of its energy as it deamplifies. While weaker...the
shortwave still has the potential to convect along a surface trough
remaining from Friday. With this slight chance probability of precipitation have been
extended eastward to cover the western two thirds of the forecast area. Upper
level flow will turn to the southwest by Sunday but will be rather
light as height gradients are relaxed as we are dominated mainly by
the ridge to our east. A few disturbances move around the western
edge of the ridge through Tuesday which have the potential to
produce some showers across our western zones while continuing to
tap monsoonal moisture.

The forecast by middle week and beyond is fuzzy but somewhat
discernible. The GFS brings a deeper trough eastward towards the Great
Plains keeping our region on the southern edge. The trough is
accompanied by a front which pushes through late Wednesday/early
Thursday as ridging sets up to our west. The European model (ecmwf) GOES by the
philosophy that slow and steady wins The Race and prolongs the frontal passage
till next weekend. Until that time it keeps a closed low over Nevada.
For the time being the forecast will be in the middle of the Road
until a consensus can be made on frontal passage timing.

&&

Preliminary point temps/pops...
Friona 65 90 61 86 61 / 30 30 30 20 20
Tulia 67 92 64 89 63 / 30 20 20 20 20
Plainview 67 91 64 89 63 / 20 20 20 20 20
Levelland 66 90 63 87 63 / 30 20 20 20 20
Lubbock 69 94 67 92 68 / 20 20 20 20 20
Denver City 66 91 64 89 64 / 20 20 20 20 20
Brownfield 67 92 65 91 64 / 20 20 20 20 20
Childress 74 98 70 97 71 / 10 10 10 20 20
spur 68 95 66 94 65 / 10 10 10 10 10
Aspermont 73 98 69 97 70 / 10 0 10 10 10

&&

Lub watches/warnings/advisories...
none.
&&

$$

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