For the Monday to Thursday periods...focus will be on
the weather system in the early part of the week followed by a cool
down and more seasonal conditions with a warmup as we approach later
week.
In a general sense, the system for early week is similar in that
it's a large scale long wave trough with embedded waves. It's these
embedded waves that are driving some of the uncertainty and a bit of
change that we are seeing in the guidance. I mention change in that
there's been a slower shift in the global guidance with the GFS/GEFS
leading the way. The notable feature driving this is the lead wave
lifting more NW/N and thus riding across the SE have a greater
influence. However, the next wave will be close on the heels and
quickly moving through the Big Bend region of S Tx. With more of the
two wave solution, you ultimately slow the frontal progression later
on Monday and help produce a surface wave feature later along the
nearly stalled front which will then allow a more progressive
eastward push of the front later Monday night into the morning hours
Tuesday. Any slower solution would also allow more quality moisture
to make it into the area ahead of the front. This quality moisture
return was a limitation in prev model solutions. Additionally, more
quality moisture will result in higher instability. Overall, this
system has poor lapse rates so there's a low ceiling for any decent
instability. However, having sbcape of 0 to 300 or sbcape of 200-700
will make a difference and with a slower evolution being the
trend...opportunity for the sbcape of 200-700 is more of a
probability than before. Speaking of wind shear and forcing, this
system will have plenty of that so it's really about getting
sufficient instability.
