Monsoon Moisture Along with some dynamics to bring an increase in Thunderstorms Sunday into Monday…..Otherwise Fair and dry through Saturday with Seasonal temps….
Thursday July 16, 2015
Posted at 9:40 am by Howard
Will make this as quick and clear as possible this AM:
At the moment, up at 300MB there is a weak WSW/ENE upper trof or boundary that gets pinched off into an upper low off the central coast this afternoon. This boundary has acted as a barrier in the northward movement of moisture. You might have noticed some wind in the afternoon from the west. This has been part of it.
This E/W trof will disappear today. The 12Z NGM creates a lot of CAPE over Mono County and the fact that we are becoming on the NE quad of the upper low off shore will add to the coupling by creating Upper Divergence.
Expect Thunderstorms to develop this afternoon and into this evening mainly south of Bridgeport. The Remains of Dolores will come in adding to the dynamics with additional moisture Monday into Tuesday. If there is plenty of sunshine both days. Heavy wet thunderstorms are possible with flash floor potential…not only during the daytime hours but Monday night and Tuesday as well. Dry weather will return Wednesday into Thursday with an unseasonably cool and breezy trof……
Thursday Night: A quick look to compare the 00z GFS QPF with the 00z ECMWF shows the GFS a lot drier. However, the ECMWF is quite wet with the Combination of Dolores and some dynamics near the area. So at this point, it could go either way as far as heavy rainfall. Odds are good we’ll get some rain. Question is will we get a lot of rain….The IOP is Sunday into Monday. ENSO: A combination of an Atmospheric Kelvin wave that translated east, strong westerly wind bursts late June and early July along with twin cyclones on each side of the equators near 160E, did its magic 3+ weeks ago. This is all being reflective in the further recharge of the Nino Basin and the boost in the CFSv2 indices’. El Nino looks Super! ……. 😉 Update Friday afternoon: ————————————————————————————————————————————————————————————————————————————————————— Last nights GFS Models continue to down play any significant effects from weakening Hurricane Dolores this weekend. Although some remnants are certainly picked up by a weak mid latitude circulation off the central coast of CA, the stronger upper jet over CA that was earlier forecasted by the models for this weekend does not appear in the picture anymore. Looking at the 06 Z GFS from late last night, both the 300MB and 250MB upper winds and jet structure is further east now favoring Arizona and New Mexico. So it is in those areas where you will find the best “Upper Divergence” for precipitation this weekend. Additionally, I did not see any impressive CAPE over the Eastern Sierra in the model as well. So the odds as of this point in time, for major thunderstorm action is greatly reduced. Just possibly some widely scattered action is currently expected Sunday into Monday. With that all said, there will be a big push of Monsoon Moisture from Mexico as well as remnant moisture from Dolores. This may end up a being classic example of lots of moisture but no wide-spread convection because of the lack of significant upper divergence necessary to create a significant thunderstorm pattern over the weekend. The Dweebs will be watching for any sign of a wave or vort max from the SSE flow later this weekend to generate dynamic lift. Additionally, there is some suggestion that Dolores may morf into or become part of a weak mid latitude upper low early next week. If a mid level upper low develops and its NE quad favors Mono County, that would be a localized situation that would make a difference in thunderstorm coverage for Mammoth Lakes about Tuesday of next week. The Dweebs will take another look at it Saturday AM or sooner if necessary. Longer Range: Another potentially strong upper trof for July will descend from the G of AK about Wednesday or Thursday of next week. This would bring a return of a dry air-across the region as well as some cooling with stronger afternoon west or SW winds. There is one more hurricane worth watching for later next week. At the moment, just like this weekend system, the models show the upper trof to the north shifting east before the window of opportunity of the next TS get close enough to CA to make a big difference. That of course is subject to change as we are out in time a long period. ENSO/MJO The transitory convective envelope of the MJO should be out of the Tropical Eastern Pacific “during the 1st week and into the 2nd week of August. So the emphasis of tropical storm action may shift into the Gulf of Mexico if the MJO is strong enough to make a difference. At the same time, the suppressed state of the MJO will have moved into the eastern tropical pacific, with possible destructive interference with the EL Nino Base State. The result would result in less TS action for the tropical eastern pacific developing sometime during the 1st week of August. Again, this is only if the MJO remain strong enough. All systems are go for a strong El Nino event this Fall and Winter for at least the Southern half of the State. Dr Howard and the Dweebs……………………………:-)