Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tulsa OK
709 am CST Friday Dec 13 2013
Forecast updated to insert freezing rain into the northwest Arkansas grids and to issue
Freezing Rain Advisory. See discussion below.
Increasing middle level warm air advection/isentropic lift in advance of the
approaching southwest Continental U.S. Shortwave trough has produced rain
over the region this morning. Unfortunately...the precipitation is
falling as freezing rain over portions of northwest Arkansas this
morning where temperatures were near or slightly below freezing.
Many accidents have been reported so far this morning. A Freezing
Rain Advisory has been issued as a result. Temperatures are
forecast to rise above freezing by mid-morning...thereby ending
this event. Another round of rain is expected later this afternoon
and into the evening as the pv maximum south of The Four Corners
ejects into the Southern Plains. After this system departs...the
middle levels will dry out...leaving saturated conditions in the low
levels below 800mb. Low level warm advection ahead of the front may
produce enough lift to produce dz or possibly fzdz depending on
surface temperatures tonight.
Previous discussion... /issued 522 am CST Friday Dec 13 2013/
concerning taf sites ktul/krvs/kbvo/kmlc/kxna/kfyv/kfsm.
Areal coverage of rain to increase across all the taf sites
through the early portion of the taf period...ceilings and visibilities will
gradually fall to MVFR categories through the afternoon...with IFR
ceilings and visibilities in fog and drizzle possible again
tonight...especially across the northwest Arkansas taf sites.
Previous discussion... /issued 316 am CST Friday Dec 13 2013/
upper low currently moving over Arizona early this morning will
continue shifting east into the Southern Plains today. Scattered
showers have developed ahead of feature in low level jet. Strong
warm air advection is dominating any evaporational cooling taking
place and therefore expect surface temperatures to likely stay or
rise above freezing before onset of any significant precipitation.
Marginal elevated instability could support a few thunderstorms
this afternoon...primarily across southeast Oklahoma and west
central Arkansas. Heavier precipitation will begin to shift east
of the area this evening ahead of strong cold front...which will
move into northeast Oklahoma by midnight. Areas of drizzle will
remain overnight with a brief window for light freezing drizzle
late tonight into early Saturday morning. Again...precipitation is
expected to remain light and do not anticipate any adverse travel
impacts. Cold breezy conditions will continue during the day
Saturday as high pressure builds into the region.
Warming trend will develop on Sunday and continue through the
early to middle part of the work week ahead of next strong Arctic
front which is expected around Friday. Although currently just
beyond the extended periods...very cold conditions expected into
next weekend with at least a limited potential for wintry
precipitation. Stay tuned.
Preliminary point temps/pops...
tul 43 30 38 23 / 80 50 0 0
fsm 39 34 43 24 / 90 80 20 0
mlc 42 32 42 22 / 90 50 0 0
bvo 44 28 37 19 / 70 50 0 0
fyv 43 30 37 17 / 90 80 20 0
byv 43 30 36 18 / 90 90 20 0
mko 42 33 38 20 / 90 60 0 0
Mio 42 29 34 19 / 80 70 10 0
f10 42 32 39 22 / 80 50 0 0
hhw 44 35 44 24 / 90 60 10 0
Arkansas...Freezing Rain Advisory until 10 am Friday for arz001-arz002-