FXUS64 KLUB 232320

Area Forecast Discussion
National Weather Service Lubbock TX
620 PM CDT Wed May 23 2018

Update to raise PoPs to likelies west of Highway 385 this evening,
while lowering values elsewhere. Also inserted heavy rain mention
across our western zones this evening for PWATs of 1 to 1.2
inches collocated with weak steering winds.

Regional radar and satellite reveal a consolidating line of
storms across western Lea County early this evening. Although
favorable storm relative inflow and instability exist, mid level
winds are largely anemic. This will be a major deterrent for
significant eastward propagation of convection, with most of this
process relying on outflow mechanics. Recent iterations of the
HRRR indicate such a scenario this evening with a marked decay of
convection expected after sunset with increasingly hostile CINH
across the eastern South Plains. Window for severe modes should
be small and confined mostly to our counties adjacent to the NM


.PREV DISCUSSION... /issued 550 PM CDT Wed May 23 2018/

Thunderstorm activity across eastern NM has slowly been expanding
eastward toward West Texas. There is a risk of some of this
activity accelerating eastward during the evening hours though
confidence in reaching KPVW/KLBB remains too low for mention at
this time. Otherwise, VFR is expected outside of convection.

PREV DISCUSSION... /issued 223 PM CDT Wed May 23 2018/

Mostly elevated convection has developed across sections of
eastern New Mexico already this afternoon, the southern bit
already petering out as it crosses into the northwestern part of
the forecast area while scattered storms south of Clayton to near
Dalhart are having a better go at it. Hi-res models are again more
generous with QPF this evening than the WRF-NAM and GFS, although
that hasn't been a good thing of late. Favored area for initiation
by the models is Eddy and Lea counties in New Mexico with some
form of eastward movement. That area was populated by stratus this
morning and is taking some time to warm up but do appear to be
nearing convective temperatures. Convection is also developing on
the Sacramentos and Guadalupes and may be a player again for areas
near the state line late tonight. Any storms that form eastern New
Mexico and migrate into the forecast area late afternoon/early
evening will have a chance to become marginally severe. CAPE is
healthier than yesterday, on the order of 2000 J/kg, which may
give that convection a better chance to develop than yesterday's
as well. However, shear remains the limiting factor as far as
severe potential goes with 0-6 km bulk shear values on the order
of 20 kts. Will continue with chance PoP's for the western half of
the forecast area for tonight tapering to slight chance east.

Precip chances take diminish after tonight as upper level ridging
is still progged to develop over the forecast area, the axis being
overhead Friday and Saturday. Could see some isolated storms
develop Thursday afternoon under the building ridge, but a
stronger ridge and veering low level flow should for the most part
squash storm potential Friday and Saturday. Storm chances could
return for Sunday through Tuesday an upper low moves out of the
Great Basin onto the central Plains breaking down the upper ridge
and backing the low level flow across the forecast area.
Temperatures are still expected to push the century mark this
weekend in response to the building upper ridge.




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