Wednesday AM:

With the evolving ENSO state…the Dweebs read the latest discussion from the CPC in regards to weeks 1 and 2.  Based upon the current Wheeler Hedon MJO chart, week 2 shows an emergence of amplitude in the Maritime Continent region suggestive of a weak negative height anomaly over the Pacific Northwest and weak trofing off the CA Coast.  While the GFS week two 500mb heights in the mean hints of this. From the Sierra east, through the great basin shows nothing but above normal temps.  In fact the ECMWF 500mb heights has the continental subtropical high parked more over the Far west with scorching heat for CA with an easterly wave in its underbelly headed for the west coast of Baja later “Week 2”.   From an El Nino-ENSO summer stand point of view, to date, the Dweebs do not see the typical signs anymore of the expected air sea coupling that would promote the cool periods associated with west coast trofing and a displaced eastward, Continental upper high. So the stage is set for both a very hot summer out west, waiting for the other shoe to drop for an enhanced shot of Monsoon moisture and dynamics later next week.

ENSO:  While Nino regions 1 and 2 show strong positive anomalous SSTA’s, as well as subsurface temps,  the Central Pacific is stuck with SSTA’s of only + .05C, barely the threshold of EL Nino. Earlier in the year….A strong Kelvin Wave moved east across the equatorial pacific last winter-Spring, providing warmth to the Nino Basin, its upwelling rear has cooled the subsurface ocean temps in the central pacific region, putting the kibosh on any further warming. “If” another strong Kelvin Wave does not replenish the subsurface heat within the Nino Basin between now and the Fall, you can most likely kiss the wet effects of EL Nino for interior, central and northern CA.   However, Southern CA may still be wet…..  The El Nino would thus be a Modoki type ending up with weakly warm SSTA’s in the central pacific and a cooling eastern tropical pacific.  That kind of winter is known for west coast “Split-flow” patterns.

There is still time for another Strong Kelvin wave to come east…lets keep our fingers crossed!…..


Tuesday PM Update:

Mono Zephyr began earlier then expected today with best Mono County surface convergence well east of Highway 395. Mammoth will now enjoy more afternoon breezes along with slightly cooler daytime highs. A drier air mass in now in place as well. Very pleasant weather will continue with daytime highs in the low 80s cooling to the upper 70s by July 4th. The heat is on again by the end of holiday weekend along with a threat of thunderstorms as early as Sunday…..  More later as SE flow lurking next week….


July 1st Climo wise,  begins a period that is considered the warmest two weeks of the year in Mammoth…..especially up until the 11th. This is because south to south east flow usually has not yet established itself in this region. SE flow contains the ingredients for a greater thunderstorm potential. So unlike like today’s Thunderstorms that are expected, which are high based and are more the result of strong heating of the elevated heat source of the sierra and the shifting area of surface convergence.  Next weeks storms will likely be more associated with the far western flank of the AZ monsoon.

Climo wise, as the continental subtropical high sets up in the Four corners area, odds will increase for the return of South East flow, as we move in time from the 1st week of July to the 2nd. week.  By the end of the 2nd week of July, the western edge of the AZ monsoon should be into full swing bringing both mid level moisture advection as well as the more significant spokes of dynamics. The heat generated early in the month of July will often times help set the stage for when the south east flow returns for greater instability. Especially when thermal trof is anchored just to the West of the Sierra Crest. So in conclusion… out for next week thunderstorm wise…..


Current forecast discussion:

Today Upper Air analysis showed the upper highs axis over Eastern CA. The upper high has peaked in building….a weak trof is approaching the pacific NW.  A small Vt Center has developed on the Northern CA coast between the approaching trof and the upper high over head. Although this small feature will not directly effect us, there will be some slight cooling in the upper levels enough to increase laps rates today with increasing instability. So today is that transition day that thunderstorms will form with lighting and some rain as the lid comes off our local air mass.  Tomorrow will be a slightly cooler, more stable day air-mass wise, with an increasing afternoon and early evening zephyr into the days ahead.

Expect about 5 to 7 degrees of cooling over the next 4 days. A new warm up will begin next Sunday in the high country with the possibility of southeast flow beginning as early next week…..


Dr Howard and the Dweebs……………………..:-)