Area Forecast Discussion
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000
FXUS64 KLUB 150534
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
1234 AM CDT Sun Oct 15 2017

.AVIATION...
Fast moving cold front continues to move through the region having
already pushed south of KLBB. Gusty winds will continue with some
risk of light blowing dust through about 10Z when speeds will
start to diminish. Otherwise, VFR through the period.

&&

.PREV DISCUSSION... /issued 937 PM CDT Sat Oct 14 2017/

UPDATE...
Cold front racing south of Amarillo now at about 33 knots/38 mph
with expected arrival through Friona and Happy before 10 PM,
Lubbock 1130-1145, and south of O`Donnell and Aspermont by 1 AM
or so. This is right on schedule with previous forecast - and
forecast winds appear on the mark as well. No changes to any of
the wind part of the forecast.

Flow has remained veered on the Caprock all evening - less so over
southern and eastern Lynn County - so low level moisture is
shallow and limited and convergence fairly weak. A few attempts at
deep convection earlier couldn`t quite make it. Solutions have
persisted through the evening indicating best chances of thunder
as front passes just south of Lubbock and off to the east and
southeast. We have trimmed thunder chances to slight chance most
of southern and eastern South Plains, with still solid chance or
likely across mainly the southern part of the Rolling Plains near
or after midnight where available instability and shear still
might support a few strong to severe thunderstorms. Much drier
air was eroding clouds rapidly behind the front, so not much of a
window for storms. Activity likely to end before daybreak Sunday.
RMcQueen

PREV DISCUSSION... /issued 624 PM CDT Sat Oct 14 2017/

AVIATION...
Winds will make an abrupt shift to the north later this evening as
a strong cold front quickly makes it way through the region. This
will bring very strong northerly winds in its wake. Furthermore, chances
are looking less likely for thunderstorms along this front and
will omit from the TAF at the moment.

PREV DISCUSSION... /issued 346 PM CDT Sat Oct 14 2017/

DISCUSSION...
All of the excitement is in the first 24-36 hours of the forecast
which features the chance of a few strong/severe thunderstorms, a
stout cold front (and associated gusty northerly winds) and a
potential frost or light freeze.

We are in the midst of a another warm fall day with most of the FA
sitting in the middle to upper 80s, aside from a few lower 90s east
and 70s and lower 80s northwest under a thinning sub-tropical
moisture fetch. This mid-level moisture plume has supported
scattered showers and isolated thunderstorms earlier today, though
they have since faded. We could still see isolated convection
attempt to redevelop on the southern fringe of the thinning
moisture plume near a weakly confluent surface trough late this
afternoon into early this evening. However, the better storm
chances will be later this evening into very early Sunday morning
as a strong cold front (associated with an upper trough currently
emerging over the central and northern High Plains) plunges
southward. The veered and drying flow across much of the Caprock
make it less certain that convection will develop here tonight,
though thunderstorms should erupt as they encounter the deeper
moisture and relatively backed flow over the Rolling Plains. Given
this we have trend PoPs downward over much of the Caprock and
southern Texas Panhandle while maintaining likely PoPs in the
Rolling Plains this evening. The best window for convection will
01- 08Z. Shear and instability will be sufficient to support a few
strong to marginally severe storms, though the quick moving cold
front will quick undercut any updrafts. Wind gusts of 50-65 mph
will be the primary risk, though small hail and brief heavy rain
will also be possible with the strongest cores.

In addition to the storm chances tonight, a strong pressure gradient
and associated isallobaric component will result in stout winds
behind the FROPA. Northerly winds will quickly increase to 25 to 35
mph with gusts of 45 to 50 mph immediately behind the front. The
winds should slowly decreasing through early Sunday morning, with
the peak winds likely only persisting 1-3 hours. We have issued a
wind advisory which is in effect from 03-12Z, though the winds
may come down a little quicker than that and we could foresee
portions or all of the advisory being cancelled a little ahead of
schedule.

Northerly breezes will persist at decreasing levels through the
day Sunday, but even with full insolation high will only make it
into the 60s for most spots. A surface ridge will settle over the
South Plains Sunday night and with clear skies, light winds and
relatively dry air this will allow for efficient cooling. It
appears spots north and west of Lubbock could experience a frost
and/or light freeze by early Monday morning. We have continued to
favor the cooler MOS numbers for lows Sunday night given the
favorable pattern for radiational cooling.

Dry northwesterly flow aloft over the first part of next week will
yield to dry quasi-zonal flow later in the week. A weak shortwave
trough may pass through this flow Thursday and Friday, but it
shouldn`t bring anything more than an increase in high clouds.
Eventually, a more significant trough is progged to move into the
western states Friday buckling our flow this weekend. However, it
remains uncertain whether the bulk of the energy with this trough
will pass by to our north or if a portion of it will cutoff across
the Desert Southwest. At minimum this pattern will likely bring a
cold front into the area sometime late next weekend, and if the
upper low materializes to our west rain chances could be on the
rise too. Time will tell. Until then, a warming trend will follow
through the first half of this coming week with highs holding
fairly steady in the middle 70s to middle 80 from mid-week through
Saturday.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 AM CDT this morning for TXZ021>044.

&&

$$

99/99/26


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