Fair Dry Weather Expected Through Wednesday With Warmer Temps…..Gusty Winds Over The Crest Will Continue…..Storm Still Lurking For Next Weekend
Saturday November 13, 2010
Posted at 8:57 am by Howard
Upper ridge at 140west….and mean trof over the central Conus with the upper jet north/south in-between. That’s the dry story through mid week. Outside of strong gusty winds at times over the crest and high clouds on Sunday….not much going on. Expect highs in the low 50s in Mammoth and lows in the 20s. Beautiful Fall Weather!
Medium Range models now beginning to look simular. (GFS-ECMWF) There are timing issues between them. The Global Forecast system has been leading the way with the big weather change and now the EC is following suit.
Both global models initially retrograde the big upper high near 140w midweek. Both models develop a strong upper jet that taps into a vary cold air-mass, then phases it with southern stream energy with plenty of moisture.
Last nights 00z GFS had strong amplification early Tuesday morning near the dateline which taps a very cold air-mass over Alaska while southern stream energy undercuts the strong mid latitude upper ridge that is building northward. Cold arctic air is pulled south from about 80 degrees north between the strong upper high over the Aleutians and the cold upper low developing in the Gulf of AK near 140W.
By Wednesday morning…..the present upper ridge is flattened with the dominant upper ridge back at 170w. This retrogression in the long wave features actually coincides with progression in the long wave features next week. Since there is no blocking down stream at the moment, slow progression should continue into the weekend.
The screeming question is…. Will the cold upper trof tap southern stream energy. Or….will there be southern stream energy to tap into? Allot will depend upon “how far north the upper high builds into the Gulf of AK” If the upper anti cyclone doesn’t get north enough into the gulf, southern stream energy probably won’t be much of a factor and we’ll just have a nice cold storm to deal with.
Strong Blocking is really beginning to show it ugly head over Greenland by the the end of the month. The Dweebs have been waiting for it. The QBO has been growing more and more positive and thus stratospheric winds blowing west to east at the Equator are strengthening. This is pretty common for La Nina Winters. The block and Negative NAO phase has the effect of really deepening the Hudson Bay Low and slowing the progression of storms into the west coast. Lets hope we get a bonanza of precipitation next weekend!
Stay Tuned……The Dweebs have you covered…………………………..:-)
SOME WARMING THIS WEEKEND…..THEN STRONG GUSTY NE WINDS TO RAKE THE CREST…..RETROGRESSION OF THE EASTERN PACIFIC HIGH STILL IN THE CARDS FOR LATER NEXT WEEK
Friday November 12, 2010
Posted at 8:58 am by Howard
Fabulous opener yesterday for Mammoth Mt, on a 1 to 3 foot base. a combination of natural and man made snow is an excellent mix! A very snow warming trend of a degree or two each day is expected as we go through the weekend…….expect highs in Mammoth 45 to 50. lows in the low to mid 20s.
The Eastern Pacific high will remain parked out near 140 west the next 6 to 7 days bringing for the most part, beautiful weather to the Eastern Sierra. The only areas of discomfort will be the very upper elevations where winds will kick up later in the weekend due to short wave energy dropping south through the Great Basin. The Dweebs did notice quite a bit of 700mb moisture coming through early Sunday morning into the late afternoon from the north. Precipitation graphics did not indicate any QPF. With the eastern pacific high strengthening into the weekend, warmer temps should occur aloft while shots of cooling will reach the Eastern Sierra valleys, possibly strengthening inversions.
With the upper high anchored through Wednesday little change is expected between the weekends weather and mid week. High temps will probably push just above the 50 degree mark by Wednesday.
Beyond mid week, the GFS is the most aggressive in bringing in a storm to the west coast by Friday/Saturday, although it does not have enough support of its ensemble members for the big changes touted from the several operational runs of recent days. The ECMWF (Euro) shows a much slower trend to the idea of dropping the upper jet south through the pacific northwest, then into California by the end of the week. However, it still keeps the upper jet core north of the Mammoth area. The Dweebs will say that potentially there are all kinds of possibilities with this pattern change including at some point a subtropical/ tropical tap for the west coast…..and in that there has been little history of this winter so far, the Dweebs will wait until early next week before speculating on the longer term.
GUSTY WINDS OVER THE CREST TODAY…CHILLY WEATHER WILL MODERATE OVER THE WEEKEND….FAIR WEATHER IS LIKELY TO CONTINUE THROUGH NEXT WEDNESDAY…THEN RETROGRESSION OF THE LONG WAVE PATTERN THE 2ND HALF OF NEXT WEEK
Thursday November 11, 2010
Posted at 9:38 am by Howard
It was a chilly morning here in the Eastern Sierra with lows in the mid teens. A building surface high over the Great Basin will keep a NNE flow going over the crest for a few days. Temps will moderate towards Climo by weekend. Mammoth will remain storm free through next Wednesday. High temps will range in the upper 30s today with lows in the teens…then rise into the 40s over the weekend.
It appears that by Friday night…another short wave will drop through the Rockies, rebuilding pressures at the surface and reinforcing the cold air over the great basin. With the mean position of the eastern pacific high at 140west, the storm track will remain well to our north and east.
For the second day now, longer range models were forecasting retrogression of the eastern pacific high back towards 160west. Both ECMWF and the GFS have retrogression in their futures. However, the ECMWF retrogrades the upper high all the way to near the date line, while the GFS has it more toward 160west.
The implications are very significant on which model is correct. If the GFS is correct a major snowstorm would be in our future toward the next weekend while if the EC is correct more of the cold air from that storm along with the upper jet would remain to our north. Obviously more time will be needed in determing the long range outlook. The Dweebs feel that by this weeks end, a better handel on the longer term can be expected. One supporting feature to retrogression is a strong spike in the MJO phase space in phase 7. So retrogression is likely. However, the big question is, how much. If there is too much, will just ridge up and stay dry.