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000
FXUS64 KLUB 261129 AAA
AFDLUB

Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
629 AM CDT THU MAY 26 2016

.AVIATION...
VFR conditions are in place at KLBB and KPVW while KCDS is MVFR
thanks to fog. Both KPVW and KLBB could also see MVFR range
visibilities due to fog around sunrise but confidence is not high
enough to include at this time. VFR conditions are expected by
late morning lasting through tonight. There could be storms near
the KCDS terminal area this afternoon and evening but confidence
on timing is too low to have any mention in the TAFs for now. Any
storms should develop well east of the KLBB/KPVW TAF sites. Storms
will dissipate after sunset with VFR conditions in place. Possibly
could see another round of MVFR conditions Friday morning as well
for all three TAF sites but confidence is too low to include now.

Jordan

&&

.PREV DISCUSSION... /issued 323 AM CDT THU MAY 26 2016/

SHORT TERM...
Water vapor satellite loop shows that there is a weak shortwave
moving out across the Big Bend region of Texas early this morning
which is helping to fire off some thunderstorms around midnight
across the western Permian Basin. These storms have since
dissipated with the lone exception of a thunderstorm moving into
the western Concho Valley. We are also seeing some weak mid-level
reflectivity returns that are likely not reaching the ground
across the western South Plains early his morning as well. 00Z
upper-air analysis shows steep lapse rates across the forecast
area extending west across New Mexico all the way into eastern
California, and model forecast soundings show quite a bit of
elevated CAPE available across the region. The forecast for this
morning is going to be tricky as any lift from the shortwave may
result in additional development of showers or storms. Almost all
of the models do not have any precipitation development this
morning and because the chance for precipitation is highly
conditional, we will leave this out of the forecast for now.

The dryline continues to mix northwestward this morning but should
be stalling out shortly before once again making a march to the east
through the day.  As is usually the case, there are differences in
how far east the dryline will make it but all of the models agree
that it should make it into the eastern Rolling Plains.  Very few of
the high-resolution model runs this morning produce any convection
of significance across our forecast/warning area this afternoon and
this evening but the few that do have some pretty robust storms. The
most favored area will be across the southern Rolling Plains where
the best boundary layer moisture will be and cap strength the
weakest.  Shear profiles are favorable for organized convection and
a few supercells but the better chances appear to be outside of the
forecast area to the east and south.  A likely scenario is for
storms to initiate along the dryline in our forecast area and then
move east and strengthen as they do so.  Confidence is not all that
high that we will see severe storms in our area but will leave
mention in the weather grids for now.

Behind the dryline, a dry southwesterly wind will once again help
to bump temperatures up but not quite as warm as yesterday. The
slightly cooler high temperatures are due in part to heights
falling through the day as an upper level low over western Arizona
continues to slowly push east. Models continue to struggle with
how strong wind speeds will be this afternoon with the GFS MOS
guidance in 25 to 35 MPH range out of the southwest with the NAM
MOS 15 to 25 MPH. Deep mixing will take place behind the dryline
allowing some of the higher wind speeds aloft to transfer to the
surface, but not quite as strong as the GFS is suggesting. Models
do not mix the dryline as far west tonight into Friday morning
which will result in cooler morning low temperatures across the
northwestern South Plains and readings fairly close to what have
been reported the last couple of mornings for the remainder of the
area.

Jordan

LONG TERM...
The extended will start on the quiet side but will trend toward
the unsettled late this weekend into next week. Initially on
Friday dry air will envelop the South Plains region on breezy
westerly winds south of a storm system emerging across the central
High Plains. Temperatures will moderate back down toward average
as the passing trough provides some cooling. There remains a low
threat a little high-based convection originating over the higher
terrain of New Mexico could make a run toward our northwest zones
late in the day but even if it were to make it amounts would be
spotty and light given the deep and dry sub-cloud layer.

A fine start to the holiday weekend will follow with relatively
light winds and dry conditions beneath relatively flat flow and a
progressive low-amplitude upper ridge. The dry conditions and plenty
of insolation will allow highs to peak around the 90 degree mark for
many spots on Saturday.

The upper flow will quickly transition to southwesterly Saturday
night into Sunday as the next storm system digs toward the Desert
Southwest while low-level moisture rapidly returns from the
center of the state. Under this pattern storm chances will quickly
return to West Texas on Sunday. The current round of NWP
advertises a fairly decent embedded disturbance traversing the
region late Sunday into early Monday complete with widespread and
locally heavy QPF generation. Beyond then, models diverge somewhat
on how things will evolve but they do keep relatively weak but
perturbed flow aloft while low-level moisture and instability
remain in the region. So although there will undoubtedly be lulls
in precipitation, there should also be decent periodic chances of
showers and thunderstorms too. Given this we have accepted the
blend guidance that carries solid chance PoPs through the middle
of next week. As alluded too, the dynamics will be on the weaker
side, but with moderate to strong instability present during the
afternoon and evening hours, occasional robust updrafts will
occur. Additionally, slow storm motions and fairly rich moisture
will support locally heavy rainfall at times. To go along with
the increased moisture and rain chances, temperatures will trend
downward to or even a little below average. All said, the overall
forecast remains on track with only minor adjustments made this
iteration.

&&

.LUB Watches/Warnings/Advisories...
None.
&&

$$

14/14/14





000
FXUS64 KLUB 260823
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
323 AM CDT THU MAY 26 2016

.SHORT TERM...
Water vapor satellite loop shows that there is a weak shortwave
moving out across the Big Bend region of Texas early this morning
which is helping to fire off some thunderstorms around midnight
across the western Permian Basin. These storms have since
dissipated with the lone exception of a thunderstorm moving into
the western Concho Valley. We are also seeing some weak mid-level
reflectivity returns that are likely not reaching the ground
across the western South Plains early his morning as well. 00Z
upper-air analysis shows steep lapse rates across the forecast
area extending west across New Mexico all the way into eastern
California, and model forecast soundings show quite a bit of
elevated CAPE available across the region. The forecast for this
morning is going to be tricky as any lift from the shortwave may
result in additional development of showers or storms. Almost all
of the models do not have any precipitation development this
morning and because the chance for precipitation is highly
conditional, we will leave this out of the forecast for now.

The dryline continues to mix northwestward this morning but should
be stalling out shortly before once again making a march to the east
through the day.  As is usually the case, there are differences in
how far east the dryline will make it but all of the models agree
that it should make it into the eastern Rolling Plains.  Very few of
the high-resolution model runs this morning produce any convection
of significance across our forecast/warning area this afternoon and
this evening but the few that do have some pretty robust storms. The
most favored area will be across the southern Rolling Plains where
the best boundary layer moisture will be and cap strength the
weakest.  Shear profiles are favorable for organized convection and
a few supercells but the better chances appear to be outside of the
forecast area to the east and south.  A likely scenario is for
storms to initiate along the dryline in our forecast area and then
move east and strengthen as they do so.  Confidence is not all that
high that we will see severe storms in our area but will leave
mention in the weather grids for now.

Behind the dryline, a dry southwesterly wind will once again help
to bump temperatures up but not quite as warm as yesterday. The
slightly cooler high temperatures are due in part to heights
falling through the day as an upper level low over western Arizona
continues to slowly push east. Models continue to struggle with
how strong wind speeds will be this afternoon with the GFS MOS
guidance in 25 to 35 MPH range out of the southwest with the NAM
MOS 15 to 25 MPH. Deep mixing will take place behind the dryline
allowing some of the higher wind speeds aloft to transfer to the
surface, but not quite as strong as the GFS is suggesting. Models
do not mix the dryline as far west tonight into Friday morning
which will result in cooler morning low temperatures across the
northwestern South Plains and readings fairly close to what have
been reported the last couple of mornings for the remainder of the
area.

Jordan

.LONG TERM...
The extended will start on the quiet side but will trend toward
the unsettled late this weekend into next week. Initially on
Friday dry air will envelop the South Plains region on breezy
westerly winds south of a storm system emerging across the central
High Plains. Temperatures will moderate back down toward average
as the passing trough provides some cooling. There remains a low
threat a little high-based convection originating over the higher
terrain of New Mexico could make a run toward our northwest zones
late in the day but even if it were to make it amounts would be
spotty and light given the deep and dry sub-cloud layer.

A fine start to the holiday weekend will follow with relatively
light winds and dry conditions beneath relatively flat flow and a
progressive low-amplitude upper ridge. The dry conditions and plenty
of insolation will allow highs to peak around the 90 degree mark for
many spots on Saturday.

The upper flow will quickly transition to southwesterly Saturday
night into Sunday as the next storm system digs toward the Desert
Southwest while low-level moisture rapidly returns from the
center of the state. Under this pattern storm chances will quickly
return to West Texas on Sunday. The current round of NWP
advertises a fairly decent embedded disturbance traversing the
region late Sunday into early Monday complete with widespread and
locally heavy QPF generation. Beyond then, models diverge somewhat
on how things will evolve but they do keep relatively weak but
perturbed flow aloft while low-level moisture and instability
remain in the region. So although there will undoubtedly be lulls
in precipitation, there should also be decent periodic chances of
showers and thunderstorms too. Given this we have accepted the
blend guidance that carries solid chance PoPs through the middle
of next week. As alluded too, the dynamics will be on the weaker
side, but with moderate to strong instability present during the
afternoon and evening hours, occasional robust updrafts will
occur. Additionally, slow storm motions and fairly rich moisture
will support locally heavy rainfall at times. To go along with
the increased moisture and rain chances, temperatures will trend
downward to or even a little below average. All said, the overall
forecast remains on track with only minor adjustments made this
iteration.

&&

.LUB Watches/Warnings/Advisories...
None.
&&

$$

14/23





000
FXUS64 KLUB 251125 AAA
AFDLUB

Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
625 AM CDT WED MAY 25 2016

.AVIATION...
VFR conditions in place at both KCDS and KPVW, however KLBB is
already starting to see rapid low cloud and fog development.
Ceilings are bouncing around in the 700 to 1200 foot range and
Gaines County Airport is down into MVFR range visibility wise.
Expect to see MVFR conditions in place right at or shortly before
the 12Z taf issuance goes into effect. Whether or not low clouds
or fog can develop to near Plainview remains highly uncertain and
KCDS should remain clear. Any low clouds and fog will take a while
to burn off but expect to VFR conditions to return by mid-day
today. Then...VFR conditions expected to remain in place until
about the same time tomorrow.

Jordan

&&

.PREV DISCUSSION... /issued 331 AM CDT WED MAY 25 2016/

SHORT TERM...
The dryline has once again sloshed back west early this morning and
was roughly located along a Tatum, NM to Tulia, TX line and was
continuing to slowly mix westward through the first part of our
graveyard shift.  Aloft, 00 UTC Upper-Air analysis shows that we
remain near a strong subtropical jet with 100 knot winds at 250 hPa.
A closed low was initialized well in the 00 UTC models compared to
the hand analysis location, with both showing a closed low over the
west central California Coast.  Water vapor satellite imagery shows
the forecast area being on the northern side of a mid-level moisture
stream associated with the subtropical jet and the 850 hPa analysis
shows the best moisture plume has shifted east across North Texas
with a pretty significant dry punch shown on the Midland sounding.

With the thermal ridge located over the area yesterday, the forecast
area was pretty much shut down for convection save one storm up in
the northeastern part of the forecast area.  The models once again
keep the thermal ridge at 850 hPa centered over the area although
temperatures are forecast to be about 2-4 degrees cooler than
compared to yesterday at the same time.  Winds aloft are also
forecast to remain out of the southwest on the Caprock which should
allow the dryline to once again mix east fairly rapidly through the
day and stall out along or just east of the edge of the Caprock.
Even with weak diffluence flow at the jet level, very little in the
way of synoptic-scale lift will be present over the area and model
soundings for the area around Childress show that strong subsidence
will take place in the mid levels of the atmosphere.  Models keep a
small sliver of SBCAPE values around 2000 J/kg near Childress
down to Aspermont but subsidence and fairly deep mixing should
keep convection at bay again this afternoon. Have opted to keep
rain chances out of the forecast for today and tonight even though
the GFS is hinting at a weak shortwave trying to initiate
convection over the Trans-Pecos and slide it northeast into the
southern Rolling Plains overnight into early Thursday morning.

Only other forecast challenge will be high temperatures today.  With
the dryline pushing east and deep mixing taking place, we could see
some of the warmest temperatures since the first part of May.
Subsidence indicated in the models and a dry airmass on the Caprock
should help to bump highs into the mid to upper 90s for the southern
Rolling Plains. Temperatures in the Rolling Plains will be tricky
as the dryline position will help or hurt temperatures from
warming up depending on how much moisture remains east of the
dryline zone. There could also be a bit of compressional/downslope
warming along/behind the dryline respectively giving a boost to
temperatures. Highs today in the Rolling Plains are also forecast
to be in the mid to upper 90s with the warmest temps in the
southern Rolling Plains. Low temperatures Thursday morning will be
on the mild side once again as the dryline sloshes back west and
low-level moisture helps to keep temps up. Low clouds may also try
to develop as the low-level jet sets up across the eastern half of
the forecast area but how far west any low clouds can develop
remains highly uncertain.

LONG TERM...
The upper low now approaching the southern California coast is on
track to translate across the Four Corners tomorrow before emerging
over the central High Plains Friday. Southwesterly flow aloft will
gradually back and strengthen on Thursday as the low approaches
while surface cyclogenesis occurs across southeast Colorado. An
attendant dryline trailing southward will likely be the focus for
robust convective development Thursday afternoon, though an early
day subtropical disturbance passing to our south through the central
part of the state could provide a period of subsidence and limit
storm coverage. The question then becomes where will the dryline
will reside by late afternoon? The latest NAM and GFS now favor a
more eastern solution near or just east of our eastern CWA
boundary as dry and gusty southwesterly winds overspread most of
the FA. This could happen, but with decent pressure falls to our
northwest it would not be surprising if the dryline were to hold a
little further west than currently progged (as has been the case
with the dryline the past couple of afternoons). Given this we
have maintained low storm chances roughly east of a Memphis to
Spur to Lake Alan Henry line Thursday afternoon. If storms can
form along/east of the dryline, strong instability and good deep
layer shear would definitely support storm organization and a
severe weather threat. Storms chances should briefly expand back
westward toward or even up onto the Caprock Thursday evening/night
as the dryline retreats before it encounters a Pacific front and
increasing upper support.

Breezy and dry west-southwesterly winds will then quickly spread
across the South Plains early Friday with the better storm chances
quickly shifting into the Rolling Plains and then points east.
However, as the upper low passes by to the north we will have to
watch and see if a little high-based convection developing across
northeast New Mexico can make a run toward the western Texas
Panhandle within developing northwest flow aloft. Current mixed
signals in the NWP combined with the very deep and dry sub-cloud
that will be present do not warrant more than about 10 percent
PoPs ATTM.

Weak shortwave ridging aloft will follow on Saturday and with the
deeper moisture likely relegated to our south and east West Texas
should experience a warm and dry day. The pattern is then forecast
to quickly transition back toward an unsettled one as low-level
moisture rapidly returns Saturday night and the western trough
reloads and provides periodic disturbances within renewed southwest
flow aloft. This will set the stage for improving shower and
thunderstorm chances from Sunday through the middle part of next
week. Relatively modest mid-upper level flow may tend to limit storm
organization through much of this stretch, but fairly strong
instability will likely still support some severe storms during
the afternoon and evening hours, while the weaker steering motion
and good moisture levels could lead to locally heavy rainfall.

Regarding temperatures, gusty downsloping winds (sustained at
15-30 mph) will help provide a warm Thursday with highs several
degrees above average. The UA trough passage will bring slight
cooling to close out the week before a quick jump back above
average to start the holiday weekend. Cooler temperatures will
follow through much of the remainder of the extended as increased
cloud cover and rain chances temper readings back toward or even a
little below average.

&&

.LUB Watches/Warnings/Advisories...
None.
&&

$$

14





000
FXUS64 KLUB 250003
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
703 PM CDT TUE MAY 24 2016

.AVIATION...
The surface dryline remains quasi-stationary from near KLBB to
near KPVW, currently has surged through KLBB but may retreat
shortly as well. We are not seeing any thunderstorm development
until far north into Armstrong and Donley counties, but these
cells we will need to watch as they could turn more to the east or
even to the southeast during the mid and late evening potentially
impacting KCDS. For now we have no thunder mentioned at any TAF
site. Low level southerly flow expected through the night. Short
range solutions are not indicating low cloud deck reaching any
site either Wednesday morning, and TAFs are VFR. Low level flow
should veer a bit more to the southwest early Wednesday with
dryline ending up slightly east of todays location. RMcQueen

&&

.PREV DISCUSSION... /issued 324 PM CDT TUE MAY 24 2016/

SHORT TERM...
The dryline is a bit slow to move eastward early this afternoon.
Analysis at 19z indicates it just west of a Dimmitt to Brownfield
line with some localized confluence along it. Immediately to its
east enough mixing has occurred to lower dew point temperatures into
the 50s and lower 60s while not too far to the east of I-27 dew
points linger in the upper 60s to lower 70s. This setup has primed
the pump with plenty of instability waiting to be released. Question
of the day is will it? Multiple hi-resolution models, including the
HRRR, RUC, and TTU-WRF, now showing storms breaking out just east of
the dryline by 22Z but a dearth of precipitation south of about
Plainview. Progged soundings indicate a pretty uniform CAPE and CIN
pattern to the east of the dryline. The difference may be the mid
level jet streak ejecting across Sonora and southern New Mexico,
eventually to cross the South Plains. This may both support storms
to its north and quash them underneath. This still means the focus
for the forecast area will be the northeastern quadrant, and
possibly more specifically Briscoe, Hall, and Childress counties.
Will nudge PoP up a bit there, trim some for areas immediately east
and southeast of Lubbock, and pull back slight mention just a bit to
the west from Plainview northward to account for the slower dryline
progression. Everything still in place for severe potential per
earlier discussions. Any cluster of storms that forms in the
southeastern Panhandle would pose a flooding threat over areas
already hit hard the last two evenings.

The aforementioned mid level jet will exit the region to the east
late tonight. Slim chance that energy from it will interact with
robust low to mid level moisture to result in some convection late
tonight across the southeast. Will keep the slight chance mention
inherited from the midnight shift. More importantly, the egress of
this jet streak will result in veering winds areawide on Wednesday,
mainly from the southwest. This should scour most of the low level
moisture out of the forecast area. The exception could be the
southeast corner of the area where enough low level moisture could
hang on to not completely rule out precip mention. However, with the
veering winds and any low level convergence out of the area will
keep the forecast a dry one at this time. With the drier air in
place temperatures will have a chance to push well into the 90s
Wednesday afternoon.

LONG TERM...
Little change in model depiction and thinking in the long term.
Pattern continues to indicate a persistent trough to the west with
upper level impulses ejecting over an almost daily presence of
a dryline. Trough axis has shifted farther east slightly for the
end of the week resulting in a continuing shift eastward of the
dryline and pushing convection farther east into the Rolling
Plains later Thursday afternoon into early Friday.

Weak ridge passes across West Texas Friday and Saturday providing
a quick respite from convection. Moisture return builds back in
quickly under the exiting ridge late Saturday as upper low
continues to deepen across the dessert southwest. Our next best
chance at widespread rainfall looks to begin in earnest early
Sunday afternoon extending through Memorial Day on Monday. Upper
level flow appears to be similarly anemic with best flow on
northern portion of southern jet late Sunday. Bulk shear would
still support a chance of some severe storms especially given the
time of year across our eastern and southeastern zones. Overall
temperatures remained the same and will be slight warmer than
normal.

&&

.LUB Watches/Warnings/Advisories...
None.
&&

$$

99/99/05





000
FXUS64 KLUB 241624
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
1124 AM CDT TUE MAY 24 2016

.UPDATE...
Will be on convective watch again this afternoon as areas east of
the dryline will have MLCAPE on the order of 3500-4000 J/kg.
Models indicate a weak cap in place with MLCIN generally single
digits and convective temps near or a degree or so above forecast
highs. Modest low level convergence or even confluence in addition
to any topographic effects should winds east of the dryline back a
bit from late morning direction should be enough for convection to
initiate. Models not in terribly good agreement with either
chances of initation or placement of convection, so confidence not
too high at the moment. However, upper support in the form of a
modest mid level speed max is expected to move out of southern New
Mexico to the South Plains late afternoon to early evening. This
would support the most convective converage from the northeastern
quadrant of the forecast area and points to northward. Progged
bulk shear values easily support supercellular storm structure
given the amount of instability expected. It may take a bit of
time for the storms to organize enough to support that structure,
but there is certainly a risk again of large hail and damaging
winds. There is also a tornadic risk across the northeastern
zones, especially if the low level flow is able to back later this
afternoon in response to pressure falls west of the dryline. In
summary, previous forecast handles this scenario well. Grids are
in good shape, with no updated needed late this morning.

&&

.PREV DISCUSSION... /issued 630 AM CDT TUE MAY 24 2016/

AVIATION...
Patchy low stratus will continue in the vicinity of all terminals
through 14 or 15 UTC. Ceilings will be mainly VFR with shorter
periods of MVFR or IFR. Light fog may also reduce surface
visibility through about the same time. Then, VFR conditions
should prevail at all terminals, although there is a chance of
TSRA in the vicinity of KCDS late this afternoon and evening,
which is represented by a TEMPO group.

PREV DISCUSSION... /issued 344 AM CDT TUE MAY 24 2016/

SHORT TERM...
Same song, different verse. We will continue to have southwest flow
overhead today downstream of broad troughing across the western U.S.
It is difficult to pick out any significant embedded impulses in the
water vapor imagery and model guidance seems to confirm by showing
vertical motion remaining largely neutral over West Texas through the
day. At the surface, a small t-storm complex moving from the
southeast TX Panhandle through the Red River Valley early this
morning has laid down an outflow boundary which surged westward as
far as Dimmitt, but which has appeared to stall out recently.
In the near-term, the main forecast issue is to what extent low
stratus will cover the forecast area this morning. The HRRR appears
to have the best handle on the current coverage, and we`ve have
followed it`s forecast closely, showing stratus filling in across
most of the area from now through about 7 am, then eroding from
the edges in pretty quickly during the morning, with ceilings
clearing out by 10-11 am or so. The dryline is forecast to mix a
little farther to the east today, perhaps to around the Caprock edge
by peak heating, 3-4 pm.

We suspect that the current outflow boundary, while gradually washing
out, may hold the dryline`s progress back a little bit to the west -
especially across the northern half of the forecast area, so we have
held PoPs a little farther back to the west than the latest guidance
would support. As for convective initiation, guidance is again
focusing in on our northeast quadrant, generally from eastern Floyd
and Briscoe Counties eastward, with lower chances farther south on
the dryline. This appears reasonable and we have trended PoPs in that
fashion. The overall convective environment has changed little from
previous days, impressive MLCAPES of 3000-4000 J/kg will build up
east of the dryline. Deep-layer shear, while not as impressive,
should be adequate for rotating updrafts and possibly support a long-
lived supercell t-storm or two. The tornado threat appears to hinge
on any outflow boundary interaction and will likely be limited to the
same area as the past two days, namely eastern Briscoe, Hall and
Childress Counties.

Any t-storm activity should track eastward out of our area by 10 or
11 pm. Overnight, the dryline will retreat westward across the
south much more quickly than the north /absent any outflows/. Some
guidance suggests that approaching shortwave energy from southwest
Texas could interact with the returning moisture to bring a
small chance of some early morning t-storm activity across the
southern South Plains and Rolling Plains.

LONG TERM...
The semi-permanent western trough will eject an upper low via the
Desert Southwest later this week. This low is progged to track
from southern California midday Wednesday through the Four Corners
Thursday and then into the Front Range of Colorado on Friday. This
synoptic evolution will maintain southwesterly flow aloft over
West Texas while the dryline continues to roam the region too. It
still does appear there will be a sufficient westerly component to
the flow on Wednesday to push the late day dryline and best storm
chances just east of the CWA. However, the respite from the storms
will be short-lived as backing flow aloft in advance of the
approaching upper low should help maintain the dryline in the
Rolling Plains on Thursday afternoon. Strong instability and
sufficient deep layer shear will mean the risk for additional
severe thunderstorms along and ahead of the dryline late Thursday.
In fact, the retreating dryline could also become active up onto
the Caprock Thursday evening/night as lift from the upper low
glances the area and the moist front meets up with an approaching
Pacific front. Given the magnitude of the instability and the
prospects for increased forcing overnight we did decide to include
a severe mention in the grids where PoPs were carried (roughly
along and east of a Silverton to Lubbock to Brownfield line)
Thursday night. Breezy and dry westerly winds will spread across
the CWA on Friday taking the best opportunity for more robust late
day convection with it.

Low amplitude shortwave ridging will follow on Saturday providing
relatively quiet and warm weather to kick off the holiday weekend.
Moisture should then quickly return on Sunday as southwesterly flow
aloft redevelops overhead downstream of the reloading western
trough. This will set the stage for more rounds of stormy and
potentially severe weather for the remainder of the Memorial Day
weekend. Deep layer wind shear may initially be on the weaker side
Sunday, though instability may overcome that to some degree. This
stormy pattern may persist right into the middle part of next week,
right on schedule for late May and early June which typically
coincides with the peak of severe weather on the South Plains.

Temperatures will remain on the warm side through the extended with
only minor cooling associated with the trough passage late week.
Overall, the blended guidance had a good handle on the forecast
though wind speeds were increased during the day west of the dryline
Wednesday through Friday.

&&

.LUB Watches/Warnings/Advisories...
None.
&&

$$

07





000
FXUS64 KLUB 240844
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
344 AM CDT TUE MAY 24 2016

.SHORT TERM...
Same song, different verse. We will continue to have southwest flow
overhead today downstream of broad troughing across the western U.S.
It is difficult to pick out any significant embedded impulses in the
water vapor imagery and model guidance seems to confirm by showing
vertical motion remaining largely neutral over West Texas through the
day. At the surface, a small t-storm complex moving from the
southeast TX Panhandle through the Red River Valley early this
morning has laid down an outflow boundary which surged westward as
far as Dimmitt, but which has appeared to stall out recently.
In the near-term, the main forecast issue is to what extent low
stratus will cover the forecast area this morning. The HRRR appears
to have the best handle on the current coverage, and we`ve have
followed it`s forecast closely, showing stratus filling in across
most of the area from now through about 7 am, then eroding from
the edges in pretty quickly during the morning, with ceilings
clearing out by 10-11 am or so. The dryline is forecast to mix a
little farther to the east today, perhaps to around the Caprock edge
by peak heating, 3-4 pm.

We suspect that the current outflow boundary, while gradually washing
out, may hold the dryline`s progress back a little bit to the west -
especially across the northern half of the forecast area, so we have
held PoPs a little farther back to the west than the latest guidance
would support. As for convective initiation, guidance is again
focusing in on our northeast quadrant, generally from eastern Floyd
and Briscoe Counties eastward, with lower chances farther south on
the dryline. This appears reasonable and we have trended PoPs in that
fashion. The overall convective environment has changed little from
previous days, impressive MLCAPES of 3000-4000 J/kg will build up
east of the dryline. Deep-layer shear, while not as impressive,
should be adequate for rotating updrafts and possibly support a long-
lived supercell t-storm or two. The tornado threat appears to hinge
on any outflow boundary interaction and will likely be limited to the
same area as the past two days, namely eastern Briscoe, Hall and
Childress Counties.

Any t-storm activity should track eastward out of our area by 10 or
11 pm. Overnight, the dryline will retreat westward across the
south much more quickly than the north /absent any outflows/. Some
guidance suggests that approaching shortwave energy from southwest
Texas could interact with the returning moisture to bring a
small chance of some early morning t-storm activity across the
southern South Plains and Rolling Plains.

.LONG TERM...
The semi-permanent western trough will eject an upper low via the
Desert Southwest later this week. This low is progged to track
from southern California midday Wednesday through the Four Corners
Thursday and then into the Front Range of Colorado on Friday. This
synoptic evolution will maintain southwesterly flow aloft over
West Texas while the dryline continues to roam the region too. It
still does appear there will be a sufficient westerly component to
the flow on Wednesday to push the late day dryline and best storm
chances just east of the CWA. However, the respite from the storms
will be short-lived as backing flow aloft in advance of the
approaching upper low should help maintain the dryline in the
Rolling Plains on Thursday afternoon. Strong instability and
sufficient deep layer shear will mean the risk for additional
severe thunderstorms along and ahead of the dryline late Thursday.
In fact, the retreating dryline could also become active up onto
the Caprock Thursday evening/night as lift from the upper low
glances the area and the moist front meets up with an approaching
Pacific front. Given the magnitude of the instability and the
prospects for increased forcing overnight we did decide to include
a severe mention in the grids where PoPs were carried (roughly
along and east of a Silverton to Lubbock to Brownfield line)
Thursday night. Breezy and dry westerly winds will spread across
the CWA on Friday taking the best opportunity for more robust late
day convection with it.

Low amplitude shortwave ridging will follow on Saturday providing
relatively quiet and warm weather to kick off the holiday weekend.
Moisture should then quickly return on Sunday as southwesterly flow
aloft redevelops overhead downstream of the reloading western
trough. This will set the stage for more rounds of stormy and
potentially severe weather for the remainder of the Memorial Day
weekend. Deep layer wind shear may initially be on the weaker side
Sunday, though instability may overcome that to some degree. This
stormy pattern may persist right into the middle part of next week,
right on schedule for late May and early June which typically
coincides with the peak of severe weather on the South Plains.

Temperatures will remain on the warm side through the extended with
only minor cooling associated with the trough passage late week.
Overall, the blended guidance had a good handle on the forecast
though wind speeds were increased during the day west of the dryline
Wednesday through Friday.

&&

.LUB Watches/Warnings/Advisories...
None.
&&

$$

33/23





000
FXUS64 KLUB 240443
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
1143 PM CDT MON MAY 23 2016

.AVIATION...
Decaying TSRA at CDS before midnight will be replaced by a gradual
onset of MVFR ceilings from east to west affecting all terminals.
Stratus should hold through mid-morning before drier and breezy SW
winds overspread the region behind a dryline. Earlier threat for
afternoon TS at CDS appears greatly diminished at this time, but
later forecasts will adjust this as necessary.

&&

.PREV DISCUSSION... /issued 820 PM CDT MON MAY 23 2016/

UPDATE...
Thunderstorms that were slow to get going earlier in the evening
have cranked up a notch at sunset. We are seeing an increase in
weak energy from northern Mexico into southwest Texas, and a
typical diurnal increase in low level southeasterly flow. The
dryline has retreated a bit further west but is fairly quiet at
the moment. Two zones have become relatively more active as we
anticipated: one around Caprock Canyons now spreading through Hall
towards Childress. And the other in the Southland to Post and just
north of Justiceburg areas. We have updated for a flash flood
watch for Hall and Childress Counties until midnight, as we are
seeing a tendency for some right turning and slowing and this is
the area that received excessive rainfall last evening. RMcQueen

&&

.LUB Watches/Warnings/Advisories...
Flash Flood Watch until midnight CDT tonight for TXZ025-026.

&&

$$

93





000
FXUS64 KLUB 240120
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
820 PM CDT MON MAY 23 2016

.UPDATE...
Thunderstorms that were slow to get going earlier in the evening
have cranked up a notch at sunset. We are seeing an increase in
weak energy from northern Mexico into southwest Texas, and a
typical diurnal increase in low level southeasterly flow. The
dryline has retreated a bit further west but is fairly quiet at
the moment. Two zones have become relatively more active as we
anticipated: one around Caprock Canyons now spreading through Hall
towards Childress. And the other in the Southland to Post and just
north of Justiceburg areas. We have updated for a flash flood
watch for Hall and Childress Counties until midnight, as we are
seeing a tendency for some right turning and slowing and this is
the area that received excessive rainfall last evening. RMcQueen

&&

.PREV DISCUSSION... /issued 626 PM CDT MON MAY 23 2016/

AVIATION...
Thunderstorms have been struggling gaining much traction east of
KLBB and KPVW and west of KCDS. A dryline runs from KLBB to KPVW
and should retreat enough in the evening for low level southeast
flow to remain at both sites. The thunder cluster west of KCDS
does not appear imminent to approach so we are leaving mention out
of this taf forecast. Upper level forcing may yet improve later in
the evening but short range solutions are not indicating any
significant thunder development. Later tonight the low level south
to southeast flow should moisten enough for an MVFR cloud layer
most likely spreading into all sites, and perhaps even an LIFR
cloud layer reaching KCDS towards daybreak Tuesday. Low clouds
should typically break up mid to late morning. RMcQueen

PREV DISCUSSION... /issued 259 PM CDT MON MAY 23 2016/

SHORT TERM...
As in the previous discussion, the atmosphere this afternoon has
become extremely energized over the eastern half of our area for a
risk of very large hail and with enough shear to support at least an
isolated tornado threat. The dryline remains just east of yesterdays
location, but not much. Already seeing bubbling convection over
northern Briscoe and Hall counties, within the convergence zone left
over from last evening. And a more expansive cumulus field lies
across southeast parts of our area. Anyway, a tornado watch has been
issued through 10 pm this evening. We expect a cluster or two,
probably tied closely to the existing low level convergence
boundaries, to move through eastern counties this afternoon into the
early evening. Flooding remains a possible concern but short range
solutions continue to bank on better storm movement today, so still
withholding a flash flood watch at this time. Activity should
progress east by late evening with activity most likely dwindling
later tonight but some solutions support development later tonight
as the dryline retreats west so we will maintain a low chance of
thunder later tonight as well. Otherwise, we expect low clouds to
expand back west to Lubbock as least, as well as over the Rolling
Plains.

Tuesday is appearing as yet another day with potential severe
storms. Southwest flow aloft will remain perhaps slightly more
backed as low pressure moves from central California into the
southwest. Lower atmosphere will remain very moist and energetic. A
dryline once more will mix somewhere over the eastern south plains
during the afternoon with chance severe supported along and to the
east. RMcQueen

LONG TERM...
An active dryline pattern will continue for the area for the rest
of this week. Although, less active for the South Plains and more
likely active for the Rolling Plains. Things may become more
active area wide over the weekend into next week.

We will continue to stay in some form of southwesterly flow aloft
through the week. This will come from a slow moving trough across
the southwestern US this week. Much of the area will see dry
westerly winds west of the dryline with the dryline mixing well to
the east. The upper level trough axis will finally cross the
region on Thursday along with stronger jet level winds. The
dryline may not push east of the Rolling Plains on Thursday
allowing for strong instability to develop over the eastern
Rolling Plains.

The pattern looks to turn more active for a wider area beginning
late this weekend. Westerly flow aloft will back to the southwest
again in advance of additional troughs carving out in the
southwestern US drawing the dryline well back into eastern New
Mexico. Another extended period of thunderstorm activity would
occur through mid week with models showing a deep trough digging
into southern California.

&&

.LUB Watches/Warnings/Advisories...
Flash Flood Watch until midnight CDT tonight for TXZ025-026.

&&

$$

05/99





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