Archive for August, 2013

Thunderstorms to Redevelop Again today and Wednesday as Upper Cut Off Low Remain West of Santa Barbara Today….Upper Center to begin lifting toward the Bay Area Wednesday…..Drier Air to begin mixing in Wednesday Night…..Fair…Dry Warm Weather expected Thursday Through the Weekend……

Wednesday AM Update:

Few showers dampened the ground at Snowcreek this AM. More on the way.

Wave loop showed Upper cut off just a tad south of Monterrey Bay. I love the way cut offs wobble! Amazing! It was evident that the upper flow has become more south/North orientated as compared to SE/NW which is more of a divergent pattern more conducive to synoptic as compared to meso scale lift. The showers for this AM have already moved north to about Hawthorn, NV.

 

At 9:00am….Mesoscale Analysis this morning showed a weak area of convergence over the crest and a sharper Surface thermal trof west of the Crest then yesterday AM. A strong area of Divergence aloft at 300mb was located along the boarder of Mono county and NV. Lifteds are about -1 to -2. PWAT is higher today over KMMH at .85 and a large pool of PWAT of 1.1 along the Inyo County boarder and NV inc DV. Looks like another day of tsrws with terrain driven Convergence from TSRW outflow aiding further development as well.

In that the Upper Cut off is now on the move…today and this evening will likely be the last of the rainfall for Mammoth for a while. Thursday through Tuesday looks Dry and warm with dry and cooler nights due primarily due to lower dew points rather then any synoptic cooling. However, any existing fires will likely become more active due to the dryer air and gusty winds over the coming days…

 

The only fly in the picture for Sunday will be the northern extent of a Gulf Surge that is expected to be initiated by TS IVO This weekend. Southerly flow looks strong enough to blow up the Gulf of CA where SST are running as warm as 91F and Dewpoints in the high 80s, north into the Southern Deserts of Ca and southern NV east to Western AZ…..Sunday and Monday. This maybe classic Gulf Surge, Flash Flood Pattern for Coachella Valley, Southern NV/Colorado River area. For those in the area, keep weather radios handy and follow NWS advise.

 

Looking at the SPC Mesoscale Analysis page for the NWS, its apparent that the forcing we had yesterday and the day before is not nearly as strong this morning.  Nevertheless, the upper cut off is still churning off the coast of Santa Barbara and the upper flow is still SE. PWAT is a bit lower this morning over Mammoth. But skies are clear and the Sun will heat things up pretty quickly with highs well into the 70s.  So the Cu will pop and thunder will occur this afternoon but rains may not be as wetting as yesterday because of the lack of an, 850mb-250mb couplet.  Yesterdays storms brought .33 of an inch of rain to MammothWeather.com near the Village.

In that the upper cut off will begin to make its move late tonight or Wednesday, there will be another chance of thunderstorms again tonight and Wednesday. By Thursday into Friday the system heads to its grave yard over the pacific Northwest. Thursdays storms will be mainly north of highway 80 and the Northwest.

Outlook:

Dry southwest flow returns this Thursday through next Wednesday. (Warm and Dry) Thereafter, the upper flow backs to the south again for some moisture, extra warmth and possibly some showers or thunderstorm’s later next week. Worth mentioning….Additionally, with the MJO protruding into Phase 8 tropical storm development will increase in the Eastern Pacific with greater chances for warm or hot humid weather and some rainfall for Southern Ca next week.

Beyond Thunderdome………..

Although the longest range guidance is suggesting possibly another cut off 2nd half of next week with moisture advection and air mass modification….another maverick worth keeping an eye on is that the CFS model interseasonally is suggesting another heat spell,  late during the first week of September. There are some ensemble members of the GFX that bring in a 594+ DM upper high from the eastern pacific and progress it into CA. Both 06z and 18z runs as of late included. Other runs develop it more as more of a retrograding upper high, with more hot continental air setting up of over the Inter mountain west.  I think that with tropical storm development in the western pacific increasing because of the MJO then recurring to the NNE, there will be lots of possibilities…..Stay Tuned…September may be wild!!

The following statements/conclusions are my opinion as a hobbyist only……

1. The interseasonal (week 3) shows quite the heat spell for Ca with the long wave upper ridge set up at about 125W and the upstream Trof at 155W.  Several Runs of the GFS has a deep trof  between 160W and 155W.  Additionally, a Tropical storm recurving up toward Japan amping the pattern from upstream……

2. There is a very large warm body of SSTA between Hawaii and 130West. The only really cold water at the surface is from about just north of the Bay Area south along the coast to most of Baja Ca.

“I think” that this could be a prime set up for significant Hot Dry Santana wind system that may develop several times in September into October. The first may be toward the end of the 1st week of September.

If you live in the foothills of SC, like always, take all precautions! IE Clear brush etc….This looks to me like a rough late Summer and Fall.

At this time there looks to be a lot of amplification over the central pacific early next month, but the models will not have a complete handle on it for quite sometime.

Will update later on the possibility of an offshore wind related heat wave for Southern Ca next week….

The Dweeber……………..:-)

 

 

Temperatures to remain normal to above the next week with chances of some summer type rainfall increasing Sunday then into Tuesday……CFS Today has El Nino Beat Picking Up Tempo for California Winter of 2014……

Sunday Am Update:

Offshore weak trof is now a cut-off low. It was located a little SW of Monterrey Bay at Sunrise. It will spin up a bit drift slightly south over the next 36 hours and so its effect upon the Sierra Tomorrow over today will be greater. PWAT is not impressive today. About .65 over Mammoth but will increase Monday into Tuesday. It is estimated by Tuesday, up to 1.00 of PWAT is possible,  as both Air mass Modification and a deeper SE flow runs up the spine of NV/CA to add to the mix.   Yesterday and again today antecedent conditions were/are very warm. That will add to the process as temperatures reached 82 yesterday…..100 in Bishop. So we have plenty of heat from below. Divergence aloft is increasing along with terrain driven convergence…and so the moistening process will be strong.  The tempo should really increase tomorrow as the position of the Upper Low will be more favorable to Mammoth Lakes than today.

Today’s storms will not be as wet as Mondays and Tuesdays or as numerous. Looking at the SPC, the only real area of 300mb divergence today is over the Southern Owens Valley at this time. However at 10:23 Am Sunday, there was a small 850mb-250mb Divergence/Convergence couplet showing up on the SPC over Southern Mono County. Again expect some isolated TSRWS this afternoon including Mammoth Lakes.  But the wetter storms will certainly be Monday/Night!

The only other thing worth mentioning today Sunday is the formation of tropical storm IVO west of Acapulco and yet another depression later in the month. We are getting into that time Climo wise where a tropical storm could pump some moisture into LA…then up into the Sierra there after. Some of the forecast models already track IVO toward Cabo San Lucas, bringing very unsettled weather by or just before next weekend.  Moisture from one of those systems may bring some rain to Southern Ca. if the midlevel and upper flow are favorable.

 

From Friday:

The Dweebs Acknowledge that outside of the few week’s of Smoke this Summer, it has been one of the best Summers weather-wise in memory. Highs have ranged from just a few periods of low 70s during a few cool spells to the low 90s very early in the Summer. We have had a few spells of rainfall as well. I’d say over all we’ve been a bit above normal in temps.

Through this weekend and next week, typical Summer weather will continue while at the sometime, the Polar Vortex continues to strengthen. After all, it is Fall like now through out many areas of Canada.

The weather of the next 5 days will be highlighted by a piece of energy getting pinched off at the bottom of a pacific northwest trough. This little upper cut off low will set up off the coast of Central CA this weekend and into early next week.  The GFS so far has it kicking through Central CA Tuesday while the EC has it lifting more NNE into Northern CA/OR.   Temps will change little the next few days, however, as the cut-off forms, it begins to interact with the upper high over the desert SW by channeling moisture NNW from out of Old MX/AZ. The upper level flow at the mid levels initially back from the south, then deeper SE flow will move into the Sierra Monday and Tuesday for the best chances of Rainfall then. Air-Mass modification and dynamics will work in tandem with moisture advection this weekend.  So we may get some rainfall. Chances of measurable precipitation are:  20% Saturday afternoon and evening; 30% Sunday and Sunday night; 30%-40% Monday through Tuesday Evening. Daytime highs will continue in the mid to upper 70s and lows in the 40s and 50s.

Outlook:

Upper cutoff is expected to kick through Tuesday Night and so remaining moisture will bring a partly cloudy day on Wednesday. At this time the Dweebs are expecting it to be Dry Wednesday and through the remainder of next week. As we go through the rest of the week we go back to a dry southwest flow pattern with weak toughing along the west coast and a stronger Zephyr, especially toward the following weekend and so the last week of August maybe cooler and breezier then normal.

Climate:

As mentioned in the heading>>>>>>>>>>>>>>The El Nino Beat is a bit stronger today…see CFS’s latest update: Remember, that some of our wettest winters were associated when the QBO was in its westerly phase like it is now and ENSO was at least Weak to Moderate…..   SEE: http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/imagesInd3/nino34Mon.gif   This is updated daily and can change as well but the trend has been moving in the direction of at least a Weak El Nino as of late. Weak El Ninos are not as favorable for the Central Sierra as they are for Southern CA, however there has been some wet weak El Ninos in Mammoth as well.

 

The Dweebs will be keeping an eye on ENSO now through the Fall because of the aforementioned…..

 

Dr Howard and the Dweebs…………………………………….:-)

 

Seasonal Temperatures to Rule the High Country the Next 6 days then warmer then normal next week….Expect a Stronger Zephyr along with a few Isolated Thunderstorms Saturday……Perfect Summer Weather to Continue………..

Although the Westerly’s have picked up strength over the Northern Latts….the weather over Mammoth will trend slowly warmer the next 6 to 10 days. A short wave moving briefly through Ca may kick up some extra wind Saturday along with some unstable air for a few isolated TSRWs and bring a few degrees of cooling. (Saturday Only)

Climo suggests that the temps over Mammoth should be slowly coming down as the days grow shorter.  However, the forecast models are trending warmer into next week. The Dweebs expect low 80s to return briefly by Thursday and again next week.  Nighttime lows will continue in the 40s. 

Discussion:

Prind point….    The ECMWF global model shows a pattern the next 6 to 10 days of slow retrogression and amplification. 1st…retrogression of the continental upper high over the desert southwest then eventually more amplification north through the central great Basin next week.  There is also an area of weakness just off the CA coast that is subtropical in nature that may add dynamics and or channeling. This is similar to the pattern we experienced both in June and again in July. Of course this is Mid August now and it is unlikely that heights will get as high.  Nevertheless, 8000 ft. high temps will likely get well into the low, possibly mid 80s next week as the upper long wave low in the Gulf of AK retrogrades westward.

Again….The EC is showing another period of Amplification early next week of both the Continental high northward, with the Gulf of AK low as far west as 150W….north of Hawaii. This looks good for another period of air mass modification preceding a surge of Monsoon moisture into at least Southern NV, Southern California and AZ along with dynamics next week. Will keep an eye out of the possibility of this moisture making its way north into the central sierra as well. An easterly wave may develop along the way. 

Below is an update from the Climatic Forecast System for the month of December, 2013 for precipitation:

This should wet your whistle…………..:-)

http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/imagesInd3/usPrecMonInd4.gif

 

Dr Howard and the Dweebs……………………………………:-)