Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Norman OK
1144 am CST Friday Nov 27 2015
the 18z aviation discussion follows....
relatively little change to current conditions is expected through
the period as a warm...moist flow continues over a cold airmass
at the surface. Freezing rain/pl will be common northwest of klts-klaw-kokc-kswo
this afternoon...with a small shift of about one or two rows of
counties to the east this evening...mainly north of koun. Precipitation
will vary frequently in intensity...in a manner that is not
possible to describe accurately in tafs. Expect occasional
visibility restrictions to roughly 1 sm...but visibilities will
remain in the 4-7 Michigan range the great majority of the time through
tomorrow morning. Some slight warming tomorrow morning should
nudge the freezing line west again...probably by one or two rows of
counties by noon. Precipitation chances will begin to drop in north OK
tomorrow morning...but low ceilings will remain.
Previous discussion... /issued 552 am CST Friday Nov 27 2015/
please see the 12z aviation discussion below.
IFR will apply for most terminals today. Widespread precipitation
and low ceilings will be present through the forecast period. Freezing
rain is expected along and west of i44, with freezing rain/pl also
impacting gag/wwr. North winds around 20 to 25 knots with stronger
gusts will only slowly decrease toward 00z.
Previous discussion... /issued 423 am CST Friday Nov 27 2015/
widespread rainfall...some freezing...continues across the region
early this morning. The freezing line has now moved into west
central OK and will continue to nudge southward during the day as
cold air advection peaks. Decided to include Payne County in the advisory based
on the expected position of the surface 32 degree wet bulb line this
afternoon. We also considered upgrading OK County to a Ice Storm
Warning since it appears a corridor of heavier rainfall will
develop this afternoon along i44/850 mb baroclinic zone. However,
most of the County should only experience a glaze up to one
quarter inch of ice. Western/northwest portions of the County may receive
slightly more. Middle to upper shortwave troughs within the SW flow
aloft will continue to move over the region through early Sunday,
but by this time most of the precipitation will fall where temperatures
are above freezing (se ok).
Flooding will also remain possible through at least early this
evening, especially across portions of central, southern and
southeastern OK as middle level moisture and ascent move out of Texas.
Some elevated instability will also support a few thunderstorms
over the previously mentioned areas through late this morning.
Most of the rain will come to an end Sunday afternoon as the middle
to upper low finally begins to shift northeastward and moisture is
shunted eastward. Another cold front will then move into northwest OK
Monday with the upper low sliding across the Central Plains and
into the Midwest. A surface ridge will setup over west/northwest OK Tuesday am.
Light winds and clear skies under this should drop temperatures into the
low 20s across northwest OK. Temperatures will struggle to climb back to average
through the extended as yet another reinforcing shot of colder and
drier air moves in Wednesday am. Precipitation, however, is not
Preliminary point temps/pops...
Oklahoma City OK 34 31 35 32 / 100 90 80 80
Hobart OK 33 29 33 30 / 100 80 70 70
Wichita Falls Texas 37 33 37 34 / 100 90 80 80
gage OK 26 22 30 25 / 80 60 50 40
Ponca City OK 33 30 35 31 / 90 70 50 50
Durant OK 45 34 40 39 / 100 100 100 90
OK...Winter Weather Advisory until noon CST Saturday for okz013-019-
Ice Storm Warning until noon CST Saturday for okz004>012-014>018-
Flash Flood Watch until 6 PM CST this evening for okz025>032-
Flash Flood Watch through Saturday afternoon for okz043-047-048-
Texas...Winter Weather Advisory until noon CST Saturday for txz085-087-
Ice Storm Warning until noon CST Saturday for txz083-084.
Flash Flood Watch until 6 PM CST this evening for txz085-086-