Forecast
This discussion was last updated at:0:01 am CST
Nov 02, 2005 |
Ridge of high pressure extends from a high near KSAT to KPIT this evening, in the wake of this morning's weak cold front. Upper low over GA shifting steadily eastward with significant 500 mb height rises already over the FA and upstream. Clear skies and light winds across the FA with excellent radiational cooling conditions for most of the FA this evening--just very light SW flow impinging on far western portion. Report from NEMAS forecaster of 1/2SM FG in Dickson TN at 0330Z, and would expect to see more areas of dense fog develop, particularly in the relatively low, outlying spots. Temps showing a rather large range @ 03Z with upper 30s in southern KY to lower 50s middle TN.
Progressive pattern will continue to dominate NH during this period, with the eastern trough shifting offshore, allowing upper ridging to briefly build in for a couple days before heights fall again over the western 2/3 of the CONUS by the end of the work week. The surface high will shift slowly eastward, reaching the NC coast on Thursday. This will keep pleasant fall weather across the FA with very dry air & subsidence. Should see nearly full sun across the area through Thursday with temperatures moderating once WAA kicks in as the ridge shifts farther east.
Difficulties in the longer range determining pattern amplification, with the ECMWF much more amplified and much slower with a central U.S. trough than the GFS runs have been. This creates frontogenesis over the Plains and brings a decent cold front through later in the weekend. GFS had been showing decent run-to-run continuity up until the 00Z run, which suddenly backs way off and keeps the flow very low amplitude, which is probably also an unrealistic extreme. Will go for more of a compromise, leaning on earlier, more consistent runs of the GFS (which agreed well with GGEM and NOGAPS), rather than jumping onto a brand new model idea.
Big question will be moisture return ahead of the front. It appears that the surface ridge will be far enough east to allow a southerly conveyor belt to set up for a time, though dynamics ahead of the front will be lacking. I'm inclined to leave Saturday dry at this point, although it's certainly possible that we'll have to include rain chances later if moisture return is faster than currently anticipated. Better chance for shra/tsra on Sunday, nearer the front, and should be clearing/brisk/cooler for Monday behind the front. |
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