From RAH (nothing we don't know):
Thu night through Sun: There continues to remain uncertainty in this
timeframe with the deterministic guidance wavering back and forth on
the overall synoptic pattern and timing of mid-level and surface
features. While the GFS/CMC/ECMWF have come into better agreement on
isentropic ascent atop the arctic cold front in the Fri-Sat period
with a surface wave, the previous GFS/ECMWF were dry. To add to
that, the models still disagree on the placement of a potential
Miller-A surface low. The uncertainty likely lies in how the mid-
level pattern will evolve, where guidance indicates a northern
stream shortwave tracking southeast from the upper Midwest Thursday
night into the western Atlantic by late Saturday. At the same time,
the models show a secondary shortwave over the southwest US tracking
east into the lower MS valley Fri. It remains to be seen whether or
not the northern and southern stream shortwaves will merge, which
will impact the downstream pattern and where a resultant surface
wave develops along the arctic front, also influencing precipitation
types (rain, snow, or a mixture). Have kept low chance PoPs as the
suite of ensembles continues to indicate the potential for snow.
Nevertheless, a trend to colder temperatures is forecast. The arctic
airmass will bring some of the coldest air so far this season with
temperatures 10-20 degrees below normal for the upcoming weekend.
&&
Thu night through Sun: There continues to remain uncertainty in this
timeframe with the deterministic guidance wavering back and forth on
the overall synoptic pattern and timing of mid-level and surface
features. While the GFS/CMC/ECMWF have come into better agreement on
isentropic ascent atop the arctic cold front in the Fri-Sat period
with a surface wave, the previous GFS/ECMWF were dry. To add to
that, the models still disagree on the placement of a potential
Miller-A surface low. The uncertainty likely lies in how the mid-
level pattern will evolve, where guidance indicates a northern
stream shortwave tracking southeast from the upper Midwest Thursday
night into the western Atlantic by late Saturday. At the same time,
the models show a secondary shortwave over the southwest US tracking
east into the lower MS valley Fri. It remains to be seen whether or
not the northern and southern stream shortwaves will merge, which
will impact the downstream pattern and where a resultant surface
wave develops along the arctic front, also influencing precipitation
types (rain, snow, or a mixture). Have kept low chance PoPs as the
suite of ensembles continues to indicate the potential for snow.
Nevertheless, a trend to colder temperatures is forecast. The arctic
airmass will bring some of the coldest air so far this season with
temperatures 10-20 degrees below normal for the upcoming weekend.
&&
