Flood and Lightning Strike in Texas, August 31, 2016

Area Forecast Discussion
National Weather Service Lubbock TX
301 PM CDT WED AUG 31 2016

.SHORT TERM...
Once again, precipitation overnight has lingered across the
northwestern South Plains through late afternoon while skies that
have cleared across the rest of the forecast area have destabilized
enough to generate scattered thunderstorms.  Storm motions are
rather chaotic at this time but convergence of outflow boundaries
and long loop of KLBB 88D data show that there is a general
northward motion in activity.  Main issue continues to be moisture
levels in the atmosphere that are well above, if not near-record
that is resulting in efficient rain production.  Storm that
developed and moved over the Plainview West Texas Mesonet site had
15 minutes where the rainfall rate was between 2.0 and 2.5 inches
per hour and current accumulations reflect almost an inch in 35
minutes.  With widespread heavy rainfall and slow storm motions,
localized flooding continues to be a possibility especially in areas
where storms train over the same spot or if activity can become more
organized along outflow boundaries.  However, coverage looks to be
limited enough to not warrant a flash flood watch for the area.
Amount of lightning activity at this time is fairly limited and
remains predominant in the early stages of strong convective growth
so have reworked the weather grids to go with isolated to scattered
thunderstorms with widespread rain showers as this better reflects
current NLDN and ENI lightning trends.  Will also continue mention
of locally heavy rainfall into tomorrow morning.

Biggest uncertainty is how long to carry precipitation chances and
how high to go with PoPs.  All models keep quite a bit of coverage
across the area through tonight before finally starting to taper off
the coverage around midnight.  Difficulty remains how much the
boundary layer will stabilize with ongoing convection and how long
convection can regenerate before the loss of daytime heating.
Another complicating factor is a possible weak cold front/surface
boundary that slides into the northeastern third of the forecast
area by tomorrow morning.  The 00Z models were a bit stronger with
this boundary than the 12Z models but should this actually slide
into the area, it could serve as another focus for convective
development.  Models are not reflecting this however until later
Thursday morning into afternoon.  Will keep drop PoPs back down into
the chance range for Thursday morning into afternoon before bringing
the central part of the forecast area back into the Likely category
for Thursday afternoon.  Temperatures will remain close to what we
have seen the past several days and couldn't see any reason to go
against persistence at this time as it is fairly close to guidance
values.  This means another mild night with a cool day in store for
Thursday.

Jordan

.LONG TERM...
A drying trend is still expected by the weekend across the region.
The axis of the upper level ridge will be to our east by Friday
afternoon and will give way to southwesterly flow aloft as a trof
digs southward across the western CONUS. Organized precip may have
one last hoorah Saturday afternoon along a surface trof aided by an
upper level shortwave. The area that has the best chance to see
afternoon convection will be the Rolling Plains. Precip chances
beyond Saturday are spotty and will dependent upon weaknesses in the
upper level flow to lift moisture. Surface moisture should not be a
problem as the recent heavy rains will help keep dewpoints in the
low to upper 60s. For now pops will be kept below mention as it is
difficult to forecast small upper level flow weaknesses in the long
term.

Saturday through monday could be slightly breezy thanks to a lee
trof. Winds on Saturday and Sunday are expected to be around the 15
knot range. Monday could prove to be a bit breezier as a surface low
is progged to develop around southeastern CO/southwestern KS. The
GFS is more bullish than the ECMWF with the development of a surface
low and in turn has slightly higher winds. For now forecast winds
will be a few knots above blended guidance but slightly lower than
gridded MOS guidance. Temperatures will also be on the rise into
next week and should level out in the upper 80s to mid 90s.

&&

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

14/51

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LUBBOCK TX
523 AM CDT WED AUG 31 2016

TXZ021>044-011030-
PARMER-CASTRO-SWISHER-BRISCOE-HALL-CHILDRESS-BAILEY-LAMB-HALE-
FLOYD-MOTLEY-COTTLE-COCHRAN-HOCKLEY-LUBBOCK-CROSBY-DICKENS-KING-
YOAKUM-TERRY-LYNN-GARZA-KENT-STONEWALL-
523 AM CDT WED AUG 31 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE SOUTH PLAINS...ROLLING
PLAINS AND THE FAR SOUTHERN TEXAS PANHANDLE.

.DAY ONE...TODAY AND TONIGHT

PERIODS OF MODERATE TO HEAVY RAINFALL TODAY AND TONIGHT MAY RESULT
IN LOCALIZED FLOODING...ESPECIALLY OVER THE WESTERN SOUTH PLAINS
TO THE FAR SOUTHERN TEXAS PANHANDLE.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

WIDESPREAD SHOWERS AND THUNDERSTORMS MAY PRODUCE LOCALIZED
FLOODING ON THURSDAY...ESPECIALLY OVER THE WESTERN SOUTH PLAINS.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LUBBOCK TX
341 PM CDT WED AUG 31 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0200 PM     HEAVY RAIN       CROSBYTON               33.64N 101.24W
08/31/2016  E2.00 INCH       CROSBY             TX   TRAINED SPOTTER

            HEAVY RAIN LED TO LOCALIZED FLOODING WITH 18 INCHES OF
            WATER ACROSS THE ROAD...A VEHICLE HYDROPLANED OFF OF
            HIGHWAY 82.

&&

EVENT NUMBER LUB1600325

JM