STORM2K

srainhoutx wrote:It was an epic November with regard to super Typhoon Nuri transitioning to an exratropical Super Storm that basically changed the entire November pattern on a planetary scale particularly the Northern Hemisphere. The October Eurasia snow led the way with the teleconnection indices responding and Nuri flipped the building cold over Eurasia/Siberia and delivered a record breaking extreme shot of cold air in mid-November across much of the Lower 48. Enjoy the warmup while it lasts. It was sort of fitting to end the Fall discussions with an epic Arctic Outbreak that actually continues today into tomorrow and Thanksgiving to our E as the pattern of a deep Central/Eastern trough pattern finally relaxes. Happy Thanksgiving Everyone!

Although prior studies have established that the extratropical flow pattern often amplifies downstream of recurving tropical cyclones (TCs), the extratropical flow response to recurving TCs has not to the authors' knowledge been systematically examined from a climatological perspective. In this study, a climatology of the extratropical flow response to recurving western North Pacific TCs is constructed from 292 cases of TC recurvature during 1979–2009. The extratropical flow response to TC recurvature is evaluated based on a time-lagged composite time series of an index of the North Pacific meridional flow surrounding TC recurvature. Similar time series are constructed for recurving TCs stratified by characteristics of the large-scale flow pattern, the TC, and the phasing between the TC and the extratropical flow to assess factors influencing the extratropical flow response to TC recurvature. Results reveal that following TC recurvature, significantly amplified flow develops over the North Pacific and persists for ~4 days. The tendency for significantly amplified North Pacific flow to develop following TC recurvature is sensitive to the strength of the TC–extratropical flow interaction (the phasing between the TC and the extratropical flow), which is based on the negative potential vorticity advection by the divergent outflow of the TC. In contrast, the tendency for significantly amplified North Pacific flow to develop following TC recurvature is relatively insensitive to the intensity or size of the recurving TC, or whether it subsequently reintensifies after becoming extratropical.

Albeit recurving and undergoing ET, the downstream impact of Typhoon Jangmi in September 2008 ... was weak. In this study, we explore the physical processes inhibiting the reintensification of Jangmi and governing the forecast uncertainty during ET. The focus is on the relative contribution of the TC and the midlatitude flow. ... Jangmi is located south of and in phase with a midlatitude trough. Jangmi does not couple with the region favourable for reintensification ahead of the trough and subsequently decays. Instead, a weak frontal wave-like cyclone develops. The role of the phasing of Typhoon Jangmi and the midlatitude Rossby wave pattern is tested in sensitivity experiments with the COSMO model in which Jangmi has been relocated. The simulations reveal two contrasting groups of scenarios. The first group reflects the weak actual ET and subsequent decay accompanied by a broad ridge over the Pacific. The second group is characterized by a strong ET with extratropical reintensification, the triggering of a pronounced Rossby wave train and downstream cyclogenesis. The displacement of Jangmi's initial position in the two contrasting groups is less than 1.25° (130 km). In the frame moving with the environmental background flow a critical bifurcation point for the track of Jangmi exists. The relative position to this bifurcation point determines whether Jangmi decays or reintensifies and triggers a Rossby wave train. A simple discrimination parameter is derived that allows for classifying the scenarios....

Texas Snowman wrote::uarrow: Good weather to ride a bicycle in!

Bring it on - we ain't skeered!!!

wxman57 wrote:

Texas Snowman wrote::uarrow: Good weather to ride a bicycle in!

Bring it on - we ain't skeered!!!

I'm having some success in keeping that nasty cold way up north. Should be close to 70 here today. Cool, but sunny. Heading out on the bikes late this morning when it warms up a bit.