Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tulsa OK
329 PM CDT Monday Sep 1 2014
A progressive...low amplitude shortwave trough is sliding east
across the north central part of the country today. A pair of
embedded vorticity maxima exist...one lifting quickly northeast
into the Great Lakes...and another moving across Wyoming at this time.
Northeast OK/northwest Arkansas lies on the southern fringe of the
decent westerly flow in the middle levels. At the surface...a more
complex pattern exists due to overnight convection that was more
extensive than forecast. The outflow boundary from that convection
has been retreating north during the afternoon and is
approaching the Kansas border. Meanwhile...the synoptic cold front
has become nearly stationary across central and SW Kansas. The hrrr
has been consistent all day in dvlpng storms between 22-00z in the
zone between the two boundaries. Directional/speed shear should be
great enough to support supercells...especially given available
cape. Low level backed winds in between the two boundaries
suggests...if a supercell can get going...that a large hail/tornado
risk exists before cells gradually congeal into clusters and then
move east/southeast this evening...when the main threat becomes damaging
winds. More development is forecast by the hrrr later tonight
north of the effective boundary. There will be a sharp cutoff as
you go south where rain falls and where it doesn't...given strong
cap in place due to eml.
I backed off some on lows tonight across the NE OK and northwest Arkansas given
potential for convectively cooled outflow...much like last night.
Rain/storm chances will continue into Tuesday mainly across NE
OK/northwest Arkansas near and north of the effective boundary...which will
begin to retreat again tomorrow and especially tomorrow night. The
best chances for rain/storms Tuesday night will be north and east
of Tulsa in the warm advection regime. Precipitation chances come to an
end Wednesday as the boundary lifts north of the region and middle
level heights rise. Gusty southwest winds will push temperatures back
into the upper 90s Wednesday afternoon across NE OK.
The deterministic runs of the GFS/European model (ecmwf) today are slower with the
front toward the end of the week...GFS more so than the European model (ecmwf).
Nevertheless...probability of precipitation will be carried Friday and
Saturday...gradually tapering off Sunday. Temperatures will fall back
into the 80s for highs and 60s for lows.
The rather active pattern across the northern tier of states
continues into next week...as another strong system moves across
the northern part of the country. An even stronger front could be
on the way in about 10 days...a sign of the change in seasons.
Preliminary point temps/pops...
tul 71 91 75 96 / 60 40 20 10
fsm 75 91 73 94 / 30 40 20 10
mlc 77 93 76 93 / 30 30 10 10
bvo 69 90 69 96 / 60 40 30 10
fyv 71 86 69 91 / 60 50 30 20
byv 71 86 69 91 / 60 50 30 20
mko 73 90 72 93 / 50 40 20 10
Mio 71 88 72 94 / 60 40 40 10
f10 74 92 74 93 / 40 30 20 10
hhw 75 94 74 95 / 10 10 10 10