Area Forecast Discussion
Issued by NWS Oklahoma City, OK
FXUS64 KOUN 202339
Area Forecast Discussion
National Weather Service Norman OK
639 PM CDT FRI MAY 20 2016
The 00Z aviation discussion follows....
Light southeast winds will help bring increasing moisture into the
region tonight and tomorrow. We expect low clouds to redevelop
tonight, following a similar temporal/spatial pattern as earlier
today. A few showers, maybe even a thunderstorm or two, will
probably be scattered across southern Kansas and far northern
Oklahoma around sunrise, lasting into mid-morning. By late
afternoon a dryline will be established over west Texas, and
combined with supportive conditions aloft, will bring a
possibility of thunderstorms to far western Oklahoma.
.PREV DISCUSSION... /issued 337 PM CDT FRI MAY 20 2016/
Primary forecast concern remains spread over the next several days,
as thunderstorm chances exist daily through mid to late next week
for portions of Oklahoma and western north Texas. This discussion
will focus on details for Saturday and Sunday.
Currently, low level stratus clouds have been very slow to move out
of the southern plains today. Short range guidance has been overly
aggressive with clearing, but current obs and satellite trends have
been the decider, and reflected in the aviation forecast.
Overnight, brief ridging over the plains will increase, with an
associated weak 700mb frontal boundary pushing across portions of
Kansas and Oklahoma. With modest boundary layer and mid-level
moisture residing across the region, this boundary will provide a
focus for scattered shower and thunderstorm development beginning
well after midnight through the morning hours across western/central
Kansas into north central Oklahoma. This activity is not expected to
be severe, but there will be enough instability for some small hail
and lightning development.
Saturday, the remaining convection will continue to push eastward,
likely centered near the OK/KS border through noon before exiting
eastward towards the Ozarks. To the west, through the day, a dryline
will begin to take shape over the western high plains, developing
from southeastern Colorado/southwestern Kansas through the western
Panhandles into the early afternoon. With the continual developing
trough dominating the western United States, the path from the Gulf
will be wide open for persistent moisture return ahead of the
dryline across the Panhandles and western Oklahoma. In response,
surface based CAPE values will result between 1500 and 2500 J/kg
across the Panhandles into southwestern Kansas and western Oklahoma
and western north Texas. As mentioned yesterday, with the lack of
even a modest short wave or similar forcing mechanism outside of the
dryline, mid-level wind fields are not overly strong. Therefore,
deep layer shear is modest, 25 to 35 kts, but more than enough when
coupled with the available instability for decent updraft
development along the dryline over the Panhandles in the afternoon.
Initial convection will likely start out isolated, with supercellular
structures, supportive of large damaging hail development. Storms
will slowly merge into one or more clusters as the low level jet
increases after sunset, propagating eastward through midnight into
western Oklahoma and potentially as far south as western north
Texas. As storms move into western Oklahoma, damaging hail and wind
will remain the primary concerns.
Sunday, lingering convection over central Oklahoma into northern
Texas will be ongoing through early Sunday. The ECMWF/NAM are more
aggressive with the morning activity, persisting a fairly large
complex of storms moving across northern Texas through the morning
hours. This will have an impact on recovery, primarily to the
environment over central Oklahoma into northern Texas. To the west,
over the Panhandles, the dryline will once again strengthen into the
afternoon, with ample amounts of instability pooling ahead of the
boundary. Strengthened wind profiles will promote better deep layer
shear development, which in turn, will support greater chances for
storm development focused along the boundary over the Panhandles.
Once again, storms will propagate eastwards into western Oklahoma
and western north Texas, with additional influence from an
approaching surface front from the north/northwest pushing into
northwestern Oklahoma around midnight. Large hail and damaging wind
gusts will remain the primary concerns with this convection.
However, better low level shear will promote a potential for tornado
development with the strongest updrafts. Overnight, as storms move
into central Oklahoma, gusty winds and hail will be the primary
Monday through late in the week; if there was ever a definition of
an "active pattern," this would be it. The chance for strong to
severe thunderstorms will continue near daily, as the western trough
continues to lumber over the western United States. Sufficient
moisture return will remain in place, with the dryline redeveloping
near daily both Monday and Tuesday, with influence from a few subtle
short wave troughs. Chances for thunderstorms will continue on
Wednesday and more likely on Thursday and Friday as a stronger 500mb
short wave swings eastward from the Four Corners region and across
the central plains.
Be sure to keep up to date with the latest forecasts this weekend
and into next week.
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 58 80 62 80 / 10 20 20 50
Hobart OK 59 83 64 81 / 10 10 40 50
Wichita Falls TX 59 84 63 83 / 0 10 40 50
Gage OK 58 82 63 83 / 10 20 40 40
Ponca City OK 57 77 62 79 / 10 20 20 40
Durant OK 59 83 63 81 / 0 10 10 40