24 Apr 2013
A strong upper ridge of high pressure offshore will gradually flatten over time as disturbances approach from the north. One disturbance crossing White Pass this morning will spread some moisture to the Northwest region late today and then to the northern interior ranges tonight. Mainly sunny skies and mild temperatures will persist over southern regions through Thursday. A strong frontal zone will develop over northern BC tonight and Thursday as a significant upper trough approaches from the far north. Consequently, snow will intensify over White Pass tonight and then the orographic upslope precipitation will increase dramatically over northern regions by Thursday morning as the flow becomes very strong westerly.
This frontal zone will only shift slightly southward on Friday, so precipitation should remain just north of the South Coast region and southern interior ranges until Saturday. This is what the Canadian and ECMWF solutions had yesterday which now appears to be the correct solution. The Canadian ensemble average and the American solutions were misleading. Now all models are similar with the pattern except the QPF bulls-eye is too high Thursday for coastal
sections of the North Coast. This is just a consequence of the model dropping the precip. too quickly on the coast instead of spreading some of it inland.
Posted: 24/04/2013 5:26 AM by Goosen
Lots of QPF overnight and Thursday for Cassiar Mountains, Muncho, and Haines-Skagway Roads. Should be all snow due to higher elevation and being just north of developing arctic front. Snowfall warnings issued for these regions. Quite a bit of QPF near Yukon border today and tonight but prog soundings show snow level rising above valley bottoms by afternoon and for this evening. Lots of QPF for WDL as well but will be mostly rain due to arctic front being just to the north. Not completely certain this will be the case. Amazing how cold it’s remaining over Yukon. Will it be a record cold April?
Posted: 24/04/2013 5:27 AM by Tam
Coast: South coast will see another sunny day will some high cloud. Should stay dry for the next 48 hours. North Coast challenge will be timing and POP of showers as it moves from the north to central coast today. Will need to watch for rain amounts over North Coast-Coastal as bullseye of precip appears to be centered over them on Thursday. GETPCPN may be overdone. For the long range, added POP of showers to the south coast and mentioned “windy” for most north coast regions.
Posted: 24/04/2013 5:29 AM by Tam
Interior: SW Interior and Kootenays will remain mostly sunny and dry today. Cloud cover and timing of precip will be the main issue for the Central Interior and Peace region. Precip will track south into the Columbias tonight and Thursday