Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Norman OK
1136 PM CST Wednesday Dec 17 2014
aviation discussion for the 06z tafs is below.
overall...think IFR/LIFR conditions will continue for the next
Airport minimums may be met in a few locations particularly over
western Oklahoma and western North Texas through 18z. Mentioned
these conditions near khbr...kcsm...and kwwr where confidence of
occurrence is moderate.
Some improvement to MVFR may occur at any site after 18z...but
confidence is too low to mention.
-Dz will continue at times north of khbr-kdua. -Rapl may occur
near kgag...kwwr...and kpnc before 18z.
Previous discussion... /issued 721 PM CST Wednesday Dec 17 2014/
the rain has moved out of much of the forecast area early this evening.
Additional precipitation in the panhandles will move into and affect
northern parts of the forecast area this evening with wintry mix possible in
far northern OK. The winter precipitation is still not expected to have a
major impact. Otherwise... drizzle and patchy fog will be the main
factors this evening. Precipitation chances will continue to lower overnight.
Adjusted probability of precipitation to show the quicker ending of precipitation in some areas
and added drizzle/patchy fog wording to weather grids. Updates out
Previous discussion... /issued 538 PM CST Wednesday Dec 17 2014/
visibilities and ceilings will continue to deteriorate through the
night. Sites could approach 100 feet ceilings and 1/2 sm
visibilities toward early morning...however...confidence is not
high enough to mention these vlifr conditions in the tafs.
Conditions should begin to improve late morning to early afternoon
tomorrow. Winds will remain light...shifting from southeasterly to
northeasterly through the taf period.
Previous discussion... /issued 349 PM CST Wednesday Dec 17 2014/
the first upper wave will move into the Central Plains tonight.
Southeasterly/southerly low level winds will keep some degree of
positive temperature and moisture advection in the low levels
which should keep the temperature profile warm enough for liquid
rain through the night... although some of the forecast soundings
have temperatures closer to 0 degrees c in low levels north. With the
temperatures this close to zero... may see a little mix of sleet
or light snow in the far north overnight... but expect rain to be
the dominant precipitation type. We may also still see some sleet
farther south the remainder of the afternoon and early this
evening farther south with the more convective elements in the
precipitation area... but most of the convective elements are expected
to move east out of the area by early evening so will not mention
sleet in the zones except in the far north.
The next wave moves through the plains Friday. A surface boundary
developing near the Texas Gulf Coast will keep low-level
convergence focused well to our south along with the most
widespread precipitation. But with most of the precipitation
during the day Friday...still expect temperatures to be warm
enough for liquid precipitation as well.