Area Forecast Discussion
Issued by NWS Oklahoma City, OK
FXUS64 KOUN 271746
Area Forecast Discussion
National Weather Service Norman OK
1146 AM CST Mon Feb 27 2017
The February 27-28, 2017 18 UTC TAF discussion follows:
Stratus and fog have dissipated at most terminals this morning
with the exception of KPNC. These VFR conditions are expected to
continue through this afternoon with some improvement at KPNC by
mid-afternoon. MVFR to IFR conditions are expected to redevelop
this evening, primarily near the I-35 corridor (KOKC/KOUN to
KPNC) and may last through mid-morning tomorrow.
Southerly winds are expected to gradually veer to the southwest
tomorrow morning and could become quite gusty toward the end of
the TAF period--especially across western terminals.
.PREV DISCUSSION... /issued 1034 AM CST Mon Feb 27 2017/
Fog that developed earlier this morning has improved over the last
hour or so. However, patchy drizzle and light rain are still
possible across portions of the area this morning. Showers and
storms still remain possible this afternoon and early evening,
mainly along and east of I-35 with the highest chances in
southeast portions of the area. A few of the storms in SE OK may
become strong to severe this afternoon and early evening. Clouds
are also expected to slowly decrease across portions of the area
today with highs climbing into the 60s and 70s.
PREV DISCUSSION... /issued 554 AM CST Mon Feb 27 2017/
AVIATION...27/12z TAF Issuance...
IFR ceilings will maintain through the morning at most sites
across central into southern Oklahoma and north Texas. Overall,
IFR to MVFR ceilings will persist into the afternoon for many
locations across central and eastern Oklahoma. Ceilings are
expected to improve, gradually, across western Oklahoma and
western north Texas through the morning, improving to MVFR to VFR
around noon. Winds will generally remain out of the south through
the period, breezy at times this afternoon across western
Oklahoma. Late in the period, overnight, MVFR to IFR ceilings will
make a return to central and southern Oklahoma.
PREV DISCUSSION... /issued 454 AM CST Mon Feb 27 2017/
Forecast focus remains squarely on rain chances today into Wednesday
and Critical to Extremely Critical fire weather conditions Tuesday.
This morning, an isolated thunderstorm just clipped Bryan county in
southeastern Oklahoma after 100 AM CST. Shower/thunder activity has
remained relatively isolated to southeastern Oklahoma and
northeastern Texas, spurred by the ejecting weak 500mb short wave
trough across the central plains and associated ribbon of isentropic
ascent. Mesoscale guidance is not optimistic this will continue
through sunrise. However, low level moisture advection has continued
to increase and new returns continue to develop on KTLX and KFWS.
Therefore, will continue to mention a slight chance across far
southeastern Oklahoma through the morning hours.
For today, with a developing surface trough down the Panhandles into
western Oklahoma and western north Texas into the afternoon, ahead
of the advancing trough over the Intermountain West. Boundary layer
moisture advection will continue across the eastern half of
Oklahoma. In response, low level stratus deck will continue to build
northward across the region, along with low chances for scattered
showers and thunderstorms persisting east of I-35, with the best
chances in southeastern Oklahoma, through the afternoon and early
evening. Overnight, with the surface low lifting east/northeast
across the northern plains and the associated surface trough
shifting eastward over the central into the southern plains, rain
chances will exit eastward and dry conditions will persist.
Tuesday, "A Tail of Two Warm Air Advection Regimes." The western
trough will dig eastward across the Four Corners, strengthening the
surface trough stretched across the central United States, from the
upper Mississippi Valley to across the Panhandles. Mid-range
guidance, from the traditional suites, remain in good agreement.
With the tightening of the pressure gradient and stout low level
southwesterly flow developing through the morning, surface winds
will be strong, sustained 25 to 35 mph gusting near 50 at times
across western Oklahoma and western north Texas through the
afternoon. At the same time, this hardy dry southwesterly warm air
advection will allow temperatures to push into the low to mid 80s in
western north Texas and southwestern Oklahoma to the upper 70s
elsewhere. Factor in minimum RH values in the teens and you`ve got a
recipe for Critical to Extremely Critical fire weather conditions
across western Oklahoma and western north Texas.
On the flip side, moisture return will be steadily occuring across
southeastern Oklahoma, east of I-35, through the day. Dew points in
the low 60s are more than possible by sunrise from Durant to Atoka.
A steady axis of ascent within the sector of low level moisture
return will result in low clouds through much of the day, which will
have an impact on instability development, one of several factors
impacting potential storm development. With that said, SBCAPE values
are still likely to push 1000-1500 J/Kg by the afternoon given the
strength of the warm air advection. Another limiting factor will be
the capping inversion around 950 to 800mb, which will delay
initiation along the dry line until late in the afternoon and
evening. Once updrafts begin to go, expect isolated thunderstorms,
initially. Low level wind fields are impressive, with effective
shear values pushing 40 to 50 kts. Paired with elevated instability
and steep mid-level lapse rates, damaging hail will be the primary
concern with the strongest storms. The initial activity will likely
quickly merge into a broken line as the cold front finally pushes
southward, across Oklahoma, overnight. Storms will shift eastward,
into eastern Oklahoma and into the ARKLATEX by early Wednesday
Wednesday, gusty northerly winds will exist behind the front,
resulting in Elevated fire weather conditions across western
Oklahoma into western north Texas. This will adversely affect any
containment activities following any fires on Tuesday.
Dry and mild conditions are expected beyond Wednesday, before a
stronger warm up over the weekend and a return of precipitation
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 70 54 78 41 / 10 10 10 10
Hobart OK 71 45 78 37 / 0 0 0 0
Wichita Falls TX 76 55 82 42 / 10 10 10 10
Gage OK 71 45 74 31 / 0 0 10 10
Ponca City OK 66 52 78 37 / 20 10 10 10
Durant OK 70 62 77 49 / 30 20 30 30
OK...Fire Weather Watch from Tuesday afternoon through Tuesday
evening for OKZ004-005-009>011-014>017-021>023-033>038-044.
TX...Fire Weather Watch from Tuesday afternoon through Tuesday
evening for TXZ083>089.