Impressive ensemble mean signals regarding coastal storm development
of off S New England. Pivoting impulses through the broader H5 trof
rotating H85 temperature anomalies through the Mid-Atlantic and NE
CONUS. The baroclinic zone sharpening offshore as mid-level energy
is sheared S through the base of the H5 trof, digging cyclonically
with more time given the amplified, slower flow, the trof undergoes
a negative tilt with H5 heights down -2 to -3 standard deviations.
Thermal wind response and conveyor belt motions, a potential latch
into the sub-tropics if the N-stream feature(s) doesn`t flatten /
push out S-stream energy.
Aside, seemingly a Miller-B setup. Clipper low diving S, emerging to
the lee of the Appalachians, riding N/E, deepening and retrograding
back beneath H5-7 negatively tilting features, the surface low bombs
along the coast, a Nor`Easter storm setup sweeping delivering snowy
But still uncertainty giving the timing and speed of features, also
strength and amplitude spatially. Initial cold air damming, question
as to thermal profile with precipitation onset / over-running. Then
how quickly do features evolve with respect to conveyor belt motions
and closing off the H85-5 low, the morphology of the system and how
effectively the comma-head wraps around the deepening low. Parent
lift / deformation rearward within the dendritic growth zone, depth
and quality of moisture mixing back around. Colder, Arctic air will
undoubtedly dig into the backside of the system per the gradient and
isallobaric wind response.
Considerable spread within ensemble members. Certain of a wintry mix
but largely unknown are specifics, both at the surface and up above
within the mid to upper levels when it comes to strength, amplitude,
and timing of features. As alluded to in the OVERVIEW above, simply
need to be patient, be prepared, and be ready to respond in the face
of adverse weather.