Mesoscale Precipitation Discussion 0950
NWS Weather Prediction Center College Park MD
1142 PM EDT Mon Oct 08 2018

Areas affected...Southwest to Northwest TX

Concerning...Heavy rainfall...Flash flooding likely

Valid 090340Z - 090900Z

Summary...Widespread showers and thunderstorms are expected
overnight, with flash flooding likely.

Discussion...The latest radar imagery shows multiple clusters of
heavy showers and thunderstorms organizing across areas of
southwest to northwest TX out ahead of a deep layer trough over
the Four Corners region which is edging east out across the
southern High Plains.

The convection is being greatly enhanced by large scale
right-entrance region jet dynamics working in tandem with strong
low level convergence and pooling of a very moist and unstable
airmass across much of western Texas. The latest WV imagery is
also showing a well-defined shortwave trough ejecting across
northern Mexico and into southwest TX around the base of the large
scale trough.

PWATs across the region are running about 2 standard deviations
above normal and much of this is connected to well-defined
low-level east-southeast fetch of moisture in off the Gulf of
Mexico. This will allow for the convection overnight to have
enhanced rainfall rates, with some hourly amounts of up to 2
inches possible within the stronger convective cores.

The aforementioned shortwave trough ejecting across southwest TX
will be a major facilitator of organized convection through the
night as it is expected to take on a negative tilt and interact
with enhanced low-level moisture/instability transport. Widespread
convection with very heavy rainfall is expected.

The latest 00Z hires model suite, including the HRRR guidance,
supports as much as 3 to 5 inches of additional rain. Flash
flooding is likely given these totals and also with such high
short-term rainfall rates.

Orrison

ATTN...WFO...EWX...FWD...LUB...MAF...OUN...SJT...

ATTN...RFC...ABRFC...WGRFC...

LAT...LON   34580019 34439937 34299892 33949832 33299810
            32509847 31189990 30470046 30000101 29800165
            29880275 30200309 30890300 31390304 32250301
            33050280 33650239 34340131