Severe Thunderstorm Warning 138, NWS Lubbock, TX

Area Forecast Discussion
National Weather Service Lubbock TX
333 PM CDT Tue Jun 13 2017

.DISCUSSION...
The forecast area finds itself between the semi-permanent sub-
tropical upper ridge to our south and a pretty strong closed low
over the northern Rockies. Mid and upper level southwesterly flow
over the southern High Plains is helping the dryline mix eastward
into the western part of the forecast area while east of the
dryline healthy moisture exists indicated by surface dew point
temperatures in the lower to middle 60s across the eastern half of
the forecast area. This set up provides a good potential for large
hail-producing thunderstorms through early to mid evening. Big
CAPE will exist with the rich low level moisture while flow aloft
will provide enough deep layer shear to get the strongest updrafts
spinning. The previous forecast handles well with only some minor
adjustments to the PoP and weather grids.

The northern Rockies upper low will lift northeastward into the
Prairie Provinces Wednesday, allowing the upper ridge to our south
to expand northward. Increasing mid level temps will begin to
quash thunderstorm chances with little low level focus and less
upper level support than seen today and yesterday. Have lower
precip chances slightly, limiting to slight chance range both
Wednesday and Thursday. The ridge will amplify northward across
the desert southwest during the weekend and expand eastward across
Texas. This should effectively shut precip chances down. Of note
is a weak cold front that is still progged into the forecast area
Sunday before stalling. Ideally, this would serve as the focus for
convective initiation. However, the ridge is looking too strong at
this time.

Regarding temperatures, model blend looks good for both lows and
highs. Of note, is the blend came in warmer for daytime highs than
MOS. Given the pattern and recent history this is preferred.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&

07

Hazardous Weather Outlook
National Weather Service Lubbock TX
1110 AM CDT Tue Jun 13 2017

TXZ021>044-141615-
Parmer-Castro-Swisher-Briscoe-Hall-Childress-Bailey-Lamb-Hale-
Floyd-Motley-Cottle-Cochran-Hockley-Lubbock-Crosby-Dickens-King-
Yoakum-Terry-Lynn-Garza-Kent-Stonewall-
1110 AM CDT Tue Jun 13 2017

This Hazardous Weather Outlook is for the South Plains...Rolling
Plains and the far Southern Texas Panhandle.

.DAY ONE...This Afternoon and Tonight
Scattered thunderstorms are expected this afternoon and evening
generally along and east of the I-27 corridor. Large hail in
excess of 2 inches in diameter and wind gusts of 60 mph or greater
can be expected. Movement of the storms will be to the east into
the eastern South Plains and eventually into the Rolling Plains
and southeastern TX Panhandle during the evening.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday
Isolated thunderstorms will be possible Wednesday and Thursday afternoon
and evening along and east of I-27. Some of these storms could
reach marginally severe levels. Rain chances will decrease toward
the weekend.

.SPOTTER INFORMATION STATEMENT...
Spotter activation may be required across the central South Plains
eastward into the Rolling Plains this afternoon and evening.