Area forecast discussion
National Weather Service Tulsa OK
617 am CDT Sat may 25 2013
Aviation...
concerning taf sites ktul/krvs/kbvo/kmlc/kxna/kfyv/kfsm.
VFR conditions will prevail through the period...though local MVFR
ceilings are possible this morning through 16z. An upper level
disturbance over North Texas will lift northeast with scattered
thunderstorms impacting areas mainly south of I-40. Will carry a
scattered cumulonimbus at both mlc and fsm through the afternoon.
&&
Previous discussion... /issued 438 am CDT Sat may 25 2013/
Discussion...
Ridging prevails aloft over the Southern Plains today. Stuck
beneath this ridge is an mesoscale convective vortex that formed from the West Texas mesoscale convective system last
night. This feature is centered west of dfw this morning per
radar. The models take it slowly east or east northeast toward
southeast OK later today. Thus...rain/storm chances have been
increased down near the Red River for this afternoon. Outside of
this...most areas will stay dry with temperatures near or slightly warmer
than yesterday.
The pressure gradient will tighten over the region over the coming
days as Lee side low pressure strengthens with increasing SW flow
over The Rockpile. Wind gusts on Memorial Day may come close to 40
miles per hour based on NAM model forecast of near 35 kts at the top of the
mixed layer that afternoon. A Wind Advisory may be needed at some
point for this period. Temperatures will gradually climb as well toward
the middle 80s. Some small precipitation chances were left in for Sunday
before the 700mb warm pool (cap) expands over the region early
next week.
A strong upper level jet /winds 140+kts at 250mb/ is punching across
the Pacific this morning to the north of Hawaii. This jet is
forecast to punch into the western Continental U.S. Early next week...carving
out an upper trough over this region. The nose of this upper jet
will enter the plains Wednesday into Thursday. The exact latitude
that this will occur is still in question...but all of the models
agree that a negative tilt shortwave trough will eject northeast
over the plains during this time. The strengthening wind fields
over very favorable late may thermodynamics will set the stage for
what could be another significant severe weather episode. If the
more southern track of the European model (ecmwf) is correct...Oklahoma will be
under the gun. The GFS and Canadian are a little farther north and
therefore show more capping over Oklahoma and less severe
potential. Regardless...this system bears watching in the coming
days as it does appear that some significant severe weather will
occur somewhere over the central and Southern Plains Wednesday and
Thursday.
The upper jet will eventually collapse and buckle over the
northwest Continental U.S....spinning up a large 500mb height anomaly over
this region. The models differ in the eventual evolution of this
feature. However...it does appear that a front will push south
into the forecast area around next weekend as this system
eventually moves east across the Continental U.S..
Lacy
&&
Tsa watches/warnings/advisories...
OK...none.
Arkansas...none.
&&
$$
Aviation...14
