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knocker

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knocker last won the day on December 9

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  1. Spare a thought for Iceland and the rapid cyclogenisis with lots of snow with blizzard conditions
  2. And the salient points of the ext mean EPS (those of a nervous disposition look away now) Upstream a high cell over the Arctic; east Pacific ridge and tpv northern Canada Downstream a trough extension from the latter into the NW Atlantic south of the east Greenland ridge A strong westerly upper flow running south of this combination across the Atlantic but backing in the east courtesy of the burgeoning European high. Thus indications of it becoming less unsettled but tending to a NW/SE split with temps rising. The usual caveats apply
  3. The ecm goes through a similar Subtropical zone amplification in the 120-168 period so the charts unnecessary but the Bermuda ridge is soon removed by the rampant energy exiting the eastern seaboard which now hits the block of the intensifying European high resulting in, oh my, south westerly zephyrs
  4. The salient points of the ext mean GEFS this evening Aleutian ridge into the Arctic adjacent to the east Pacific trough Tpv northern Canada with trough extension south east into the NW Atlantic under the high cell over southern Greenland Still a strong westerly upper flow exiting the eastern seaboard across the Atlantic but backing in the east courtesy of the subtropical high amplifying in central Europe This would indicate less unsettled but tending towards a NW/SE split with temps rising nicely. The usual caveat that this is just a broad scale assessment and the det runs need to sort the detail
  5. Between t120-168 the gfs amplifies the subtropical zones thus 'trapping' the upper trough over the UK. All resulting in a continuation of unsettled weather over the latter and Europe swamped by WAA Edit What happens next can only be viewed after the watershed
  6. The gfs still toying with rapid cyclogenisis at the end of the week
  7. The enigma as to why I receive different model outputs to many in the forum remains unresolved.The latest thinking is perhaps interference from Russia?.
  8. The salient points of the ext EPS mean anomaly this morning High cell over the Arctic adjacent the TPV northern Canada Trough extension from the latter into the NW Atlantic beneath the ridge into eastern Greenland which is now just about an extension of the impressive build of heights over Europe. This would still indicate unsettled but perhaps a more NW/SE split with Europe becoming quite toasty
  9. The following is an extract from Synoptic Analysis and Forecasting by Shawn Milrad Temperature Advection Definition In Chapter 7, we discussed two upper-tropospheric mechanisms associated with vertical motion: jet streak divergence/convergence and 500-hPa geostrophic vorticity advection. Here, we introduce the third synoptic-scale mechanism for vertical motion: lower-tropospheric geostrophic temperature advection. Along the same lines as geostrophic vorticity advection (Chapter 7), geostrophic temperature advection is the transport of temperature by the geostrophic wind. Temperature advection tends to be quite small in the upper troposphere, where the isohypses and isotherms are mostly parallel to each other, so we will focus on the lower troposphere. In Chapter 6, we paid special attention to regions on 850-hPa charts where the isohypses and isotherms were nearly perpendicular to each other; this is a key clue to recognize regions of temperature advection. Recall that the geostrophic wind blows parallel to isohypses (on an isobaric chart) and parallel to MSLP isobars on a surface chart. To identify temperature advection, the analyst or forecaster should ask “what type of air is the geostrophic wind transporting into a given region: warm or cold?” Fig. 8.4A shows a schematic of the geostrophic wind parallel to the isotherms (thickness lines); in this case, there is no temperature advection. However, in Fig. 8.4B, the geostrophic wind is perpendicular to the isotherms (thickness lines) and blowing from warm to cold; this is defined as warm-air advection (WM). In contrast, Fig. 8.4C shows the geostrophic wind perpendicular to the isotherms (thickness lines), but blowing from cold to warm; this is defined as cold-air advection (CM). Now that we understand how to recognize WM and CM, let us explore how each relates to vertical motion. During WM, the lower troposphere warms as warm air is advected into a region from somewhere else. This disrupts thermal wind balance, which the atmosphere immediately tries to restore. To do this, the atmosphere must cool adiabatically, which is accomplished through ascent. Through the mass continuity principle, ascent must be accompanied by surface convergence (Chapter 7). In summary, lower-tropospheric WM is associated with ascent and surface convergence During CM, the lower troposphere cools as cold air is advected in from elsewhere. This also disturbs thermal wind balance, which the atmosphere immediately tries to restore through adiabatic warming by descent. Through the mass continuity principle, descent will be accompanied by surface divergence (Chapter 7). In summary, lower-tropospheric CM is associated with descent and surface divergence
  10. Hopefully the wind will ease from now. Gusting 64mph last evening and mid 50s of late.
  11. Hopefully the ecm take on the end of the week will not verify. It has some rapid cyclogenisis along the frontal boundary and a very deep surface low crossing the country
  12. The Chiefs hung on by the skin of their teeth against Sale
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