Area forecast discussion...updated
National Weather Service Norman OK
827 PM CDT Tuesday may 21 2013
Update...
quick update to trim probability of precipitation and decrease coverage of fog.
&&
Discussion...
line of storms has exited our forecast area early enough to end probability of precipitation for the
rest of the evening. The vorticity maximum currently over south central OK
will quickly continue eastward overnight and traverse northwest Arkansas around
midnight. A subtle impulse just behind it may result in a shower
or two developing across western OK/North Texas late tonight...but do not
feel confident enough to include any mention at the moment and
will just keep some partly cloudy skies in the grids to reflect
it. Decided to trim fog for tomorrow morning as a much drier
airmass at the surface moves into place especially across west/northwest OK.
Will leave it in across the east/southeast though where boundary layer
moisture (heaviest rain fell) may linger long enough under
clearing skies and light winds. No other significant changes were
made.
Barnes
&&
Previous discussion... /issued 637 PM CDT Tuesday may 21 2013/
Aviation...00z taf issuance...
VFR conditions will prevail through the evening and overnight.
Skies will continue to clear from west to east across western and
central OK this evening as the upper level low continues to shift
eastward this evening. Some scattered to broken middle level clouds will
likely linger across northwestern OK through Wednesday morning
before dry south/southwest flow takes hold through noon Wednesday.
Light and variable winds through the morning hours will result in
possible MVFR to IFR fog at aerodromes across central and southern
Oklahoma. Increasing west/southwest winds Wednesday morning from
southwest OK/western North. Texas into central OK will allow any widespread
fog to lift quickly through sunrise.
Jtk
Previous discussion... /issued 212 PM CDT Tuesday may 21 2013/
Discussion...
the main forecast challenges for this package will be ongoing
convection across Oklahoma and North Texas...and forecasting
shower/storm chances over the coming week...which may hamper
search and Rescue efforts in central Oklahoma.
A strong upper level wave of low pressure is moving across the
Southern Plains. Recent WV imagery shows a well pronounced dry
slot developing west of an eastward moving line of strong to
severe storms extending from just east of Holdenville...southward
to near Tishomingo and Lake Texoma. At times...strong to severe
wind gusts have occurred with this complex...and storms are likely
to remain strong to severe. The threat for severe weather is
expected to continue into the evening. In addition to the severe
threat...persistent heavy rainfall has led to occurrences of
flash flooding and possibly river flooding over parts of south
central and southeast Oklahoma. Do not drive through flood waters
if you come across them on the roadway!
Further north...with cooler and drier air filtering into the
region...and with expansive cloud shield and increasing
stability...expect mainly light to moderate rain over most of
northern and central Oklahoma...with occasional thunder.
By tonight...most activity will have exited the region...with
clouds hanging around southeast Oklahoma. With residual moisture
in place...and surface high pressure moving in behind as passing
front...patchy to widespread fog may develop...especially from
central Oklahoma southeastward. Patchy dense fog may even develop
near sunrise...as winds go calm...causing hazardous driving
conditions.
For the rest of this week...flat middle level ridging will build
into Oklahoma and North Texas. With several small scale impulses
moving along the northern periphery of the ridge...at least
isolated shower and thunderstorm activity will be possible each
day over the coming week. This will mainly be driven by diurnal
heating. Rain chances will increase from this weekend into early
next week...as a large upper storm system emerges into the
Southern Plains. For now...will keep chance probability of precipitation or less through
the entirety of the forecast period.
Regarding search and Rescue operations in the south Oklahoma City
metropolitan area...expect main impacts in the short term to be light
shower activity...which will diminish by this evening. Any fog
development that occurs tonight into tomorrow morning will make
Rescue operations difficult. Cool morning temperatures and patchy
fog will yield to mild temperatures and mostly clear to partly
cloudy skies by early afternoon tomorrow. Again...at least a
slight chance of storms will linger into the weekend...so
personnel involved in cleanup and Rescue activities will need to
monitor the weather situation closely over the coming days.
&&
Preliminary point temps/pops...
Oklahoma City OK 56 80 60 79 / 0 0 20 40
Hobart OK 54 87 60 85 / 10 10 10 30
Wichita Falls Texas 58 89 63 91 / 10 0 10 20
gage OK 49 85 56 78 / 0 10 20 40
Ponca City OK 51 80 57 77 / 0 0 30 40
Durant OK 58 85 64 85 / 10 0 10 20
&&
Oun watches/warnings/advisories...
OK...none.
Texas...none.
&&
$$
04/03
