Weak Upper Low moving on shore tonight will bring some showers today and Saturday……Tetrad Blood Moon Eclipse Begins at 12:07 AM PDT on the 15th…..
Friday April 11, 2014
Posted at 9:00 am by Howard
Sunday Am Update:
An Eastern Great Basin Slider will bring cooling today along with gusty higher elevation Northerly winds. The upper ridge in back of the slider will build in Monday bringing about 10 degrees of warming over today’s highs. The next weather system will move through the pacific NW Tuesday then into the Rockies Wednesday bringing more wind and cooling Tuesday into Wednesday. This too is a dry system for Mammoth Lakes. The NW flow pattern shift east next Thursday with height rises over the far west. This will bring warming back into our area Thursday, into that following weekend. So the week ahead is dry for the Mammoth area.
It will not be until that last week of April that the next opportunity arrives for some precipitation along with unsettled weather. (Sometime between the 21st and the 30th)
Weak upper low off the Southern Coast is spreading high cloudiness over California. Although it is weak, A deformation zone (Surface Convergence) will form to the North and NE of the Low allowing some showers and or TSRWs to form over the Sierra and high deserts of Eastern CA, as well as West Central NV this afternoon and evening. The low is expected to move onshore over the Channel Islands at 09Z Saturday. Another weak short wave will dive into the Rockies Sunday. Although The new WRF is further west in the 12Z Friday Run, I’ll stick with the new 12Z Friday GFS as it takes the cooling well east of our area. There will probably be a few degrees of cooling Sunday with Sunny Skies. The next Stronger system moves in Tuesday with strong gusty winds, cooler temperatures and even the chance of snow showers! Highs on Wednesday will be in the 40s. Another cool short wave may follow on Thursday.
For people in the United States, an extraordinary series of lunar eclipses is about to begin…..ones that have only occurred 3 times in the past 500 years!
The action starts on April 15th when the full Moon passes through the amber shadow of Earth, producing a midnight eclipse visible across North America. So begins a lunar eclipse tetrad—a series of 4 consecutive “Blood Moon” total eclipses occurring at approximately six month intervals. The total eclipse of April 15, 2014, will be followed by another on Oct. 8, 2014, and another on April 4, 2015, and another on Sept. 28 2015.
“The most unusual thing about the 2014-2015 tetrad is that all of them are visible for all or parts of the USA,” says longtime NASA eclipse expert Fred Espenak.
Temperatures will peak out today as Strong Upper Ridge has shifted over the Great Basin…..Weak Upper Low Approaching Southern CA may bring a few showers Friday……Above normal temps to continue into the following week…..
Tuesday April 8, 2014
Posted at 10:31 am by Howard
The High temperature in Bishop was 85 yesterday…Mid 60s in Mammoth. Expect similar highs today with partly cloudy skies this afternoon.
Latest Satellite motion shows quite a subtropical plum developing ahead of a Quasi mid latitude upper low about 31 North – 137W, it is tracking ENE and the latest WRF guidance will take it on shore Friday night about midnight near the channel islands north of Malibu. The upper jet is clearly well south into Southern Ca. A closer look at this system shows mostly high clouds. However there will be a deepening marine layer for Southern Cal so there will be lots of fog and drizzle over the weekend. For the Sierra, it appears that the best diffluence and divergence will be south of Mammoth. However, I still can not rule out the chance of some showers Friday afternoon and evening as well as Saturday as the lapse rates will increase because of cooling aloft. With the higher mid April sun, convection related showers are possible, IE Diurnal. So it is doubtful if any nocturnal percip will happen, given the current track of the upper low, which is now displaced just south of PT Conception. The Dweebs will mention that this is south of the Ensembles. So if the new WRF guidance is wrong and the track remains north of Pt. Conception, that would allow some precip to occur nocturnally as the forcing would be further north as well. Will take another look at it tomorrow AM.
Dr Howard and the Dweebs…………………………..:-)
Spectacular is word for Mammoths weather today…..highs in the mid 60s, lows in the 30s. No Significant wind. Highs 15 degrees above normal….the Bishop temperature forecast is for a high of 84!
Forecast and Discussion:
The west coast upper ridge has shifted into the Great Basin and with a slight southerly flow, temps will peak out today. The upper ridge will weaken a bit Wednesday. The guidance flattens the ridge Wednesday in response to a weak short wave tracking through the Pacific Northwest. Some slight height and 500-1000 thickness falls occurs tomorrow, as well as a slight pick up in breeze. However….temps remain well above normal. Thereafter a closed low develops out over the eastern pacific and shifts towards Southern CA. No doubt So-Cal will see an increased marine layer as well with the possibility of some drizzle or sprinkles Thursday night and Friday.
For Mammoth….The Dweebs expect an increase of mostly high level moisture as it swings SE Friday into Saturday. So lots of clouds Friday in Mammoth and into the night. There may be a few showers in the PM. Because of the cloud cover, expect temps to dip into the upper 50s Friday and remain there through Saturday. Another upper ridge will move through Sunday into Monday and so it may be a few degrees warmer Sunday into Monday as well. Over all, temps running between 5 to 10 above Climo over the weekend so pretty nice.
Next pattern change will be later neat week……IE Cooler WX
Dr Howard and the Dweebs…………………………….:-)
Weak splitting System On the Way for Friday…Then Dry warmer weekend as High Pressure Aloft Builds In through early next week….
Thursday April 3, 2014
Posted at 9:44 am by Howard
Quick Update to reflect that we have a little upslope going on this AM. NE flow coming into the Sierra, a product of both the upper trof exiting into AZ and the upper circulation around the high off shore that will be building in through Monday evening of next week. No measurable precipitation is expected. IE .01 or greater. Winds over the crest will be out of the NE today. They will be in the 40MPH range this morning than increase this afternoon and into the night. These moderate then stronger winds are only significant over the lip of the sierra. Although sierra crest winds will be significant again Sunday, it will be 10 degree warmer. The upper high will peak out over the top of us Monday at 5:00pm. Tuesday will be the warmest day with highs in the low 60s in Mammoth.
We will be storm free through next Wednesday……..
A weakening system is moving through the Bay area this AM is headed toward the Sierra this afternoon and tonight. It looks to be a fair weekend with warmer temps ahead. It will be windy over the “sierra crest” on Saturday, with lighter winds Sunday. Temperatures will be above normal next week with the upper ridge over head, early to mid-week. Mid 60s in Mammoth Wednesday.
The following are some comments from NWSRNO for impacts in regards to area roads….today/tonight:
LIGHT SNOW ACCUMULATIONS OF AN INCH OR TWO ARE POSSIBLE NEAR THE SIERRA GENERALLY ABOVE 6000 FEET THIS AFTERNOON AS SHOWER BANDS MOVE THROUGH, BUT ACCUMULATION ON PAVED SURFACES WILL BE LIMITED
TO ISOLATED LOCATIONS WHERE INTENSITY AND DURATION ARE SUFFICIENT TO OVERCOME TYPICALLY WARM ROAD TEMPERATURES FOR THIS TIME OF YEAR. SOON AFTER THE SHOWERS DIMINISH, ANY SNOW ON ROADS WOULD
MELT QUICKLY. BELOW 6000 FEET, SOME SHOWERS MAY PRODUCE SNOW OR PELLETS THAT WOULD MELT ON CONTACT WITH THE ROADS, RESULTING IN MINIMAL TRAVEL IMPACTS. BY THIS EVENING AS THE TROUGH MOVES EAST
ACROSS NEVADA AND DAYTIME HEATING IS LOST, MOST SHOWER ACTIVITY WILL WIND DOWN QUICKLY FROM WEST TO EAST.
Temperatures will run below normal until Saturday, when upper heights, rise in response to a pretty strong upper height anomaly peaking out over Northern Oregon late Monday Afternoon. Tuesday next week will probably be the warmest day as the upper ridge axis is east of us over the Great basin and a weak southerly flow sets up. Thus, Tuesday’s highs will probably be in the low 80s in Bishop and in Mammoth, low 60s. There is another weather system that may affect our area about Friday the 11th. The ECMWF Ensembles are a bit weaker with it today, and the GFS Ensembles weaker yet. So I am not too excited about it other than it may bring snow showers and cooling. That in itself is good as the days prior will be pretty warm.
More currently, the weather today shows up with a lot of high cloudiness. A quick look at the Satellite motion shows upper level warm air advection type moisture today making it a mostly cloudy day. There was a CAP at about 500MB on the OAK sounding confirming the inversion. Temps today will be tricky with the high clouds, so although the forecast is for highs in the low forties, it may remain colder. Tomorrow will certainly be cooler with the last system expected this week. It is a weak splitting trof with enough moisture and instability to kick up some showers Friday for a dusting to an inch. Otherwise get ready for a fab weekend. Of note there will be gusty NNE winds over the crest Saturday. This will last only long enough for the ridge to get established, so that by Sunday, the gradient’s should have relaxed quite a bit.
NCEPS CFS still insists that we are not done yet. That before the end of this month we are likely to get another foot or possibly two of snowfall, and that May will be similar. In May, there are signs that there may be a period toward mid month of a cold negative upper height anomaly over the Great basin for Freezing Temps as low as the Owens Valley. In that climatically, we usually do not see a lot more big storms capable of several feet beyond early May….. I will follow this, as that is planting season for the Owens Valley as folks are sensitive to hard freezes.
Note: The Climatology of May is quite different then April. The Desert are pretty warm by May and the effects of Continental heating create a stronger gradient on the east sides of digging trofs, pulling them eastward quicker. Thus long wave features have more bias toward a Negative tilt, creating more NW or inside slider type storms. These are usually windy systems with little in the way of preicp. However they can be very cold!!!