Archive for July, 2012

Full On Summer Weather Expected this Upcoming Week with High Temps in the Upper 80s by Wednesday…Thunderstorms Possible with Chance of Additional Moisture Friday for Wetter Storms….Then Drying Trend Saturday into Monday…With Season Temps by Weeks End into the Next Week

Quick Thursday Update:

Dew-points are rising with the temperature this morning an indication of warm moist air advection…..Combined with the daytime heating will allow thunderstorms to form with better areal coverage then yesterday.  Still main focusing is expected along with a lot more moisture Friday.

Temps will be a little cooler today  and cooler Friday with the possibility of wetter storms….

 

Bishop tied record high yesterday of 106  Bishop will be cooler today with the possibility of high based dry thunderstorms

 

Quick Wednesday Update:

1. Today appears to be the warmest day with new 12z WFR showing 500-1000mb thickness isohyet of 594dm protruding west into Eastern Ca.

So  with consideration to both the time of year, current blocked moisture pattern to the south due to the East-West upper ridge axis, upper 80s looks likely for Mammoth at 8000 feet. 88 degree is the average highest Mammoth Lakes temperature normally during the Summer. So today may be the warmest day of the year.   By Thursday, the upper high shifts a bit east opening the door to monsoon moisture. It will be a race during the day for an equally warm day before the skies cloud up.  500-1000mb Thicknesses do not get as high on Thursday for Mammoth so again it may not be as warm. Did not check 700mb temps though.  By Friday the ridge weakens a bit and shifts well into Utah. At the same time a moist SSE flow is well established and most important of all, a vort center at 500mb shifts from south to north over the Sierra. Friday and Friday night look like the best chances for Thunderstorms….  700Rh is in the 60% range from the new 12z Wednesday Run.  It will be humid in the Owens Valley. Expect dew points up into the 50s in Bishop Friday.

Outlook:

Then flow backs to the SW Saturday for a slow drying trend with cooler more seasonal weather on the way by the end of the weekend into the next week. Highs back into the upper 70 with low in the 40s Sunday into Wednesday.

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Monday AM Update:

No real changes the first half of this week. Upper high slowly building west will continue the warm up through Wednesday. Upper levels too warm for any significant TSRWs activity today and most likely Tuesday….although a few may pop. If they do….they will be high based and have little rain.  As we get toward the back side of the warm up about Wednesday/Thursday, some increase in activity will occur Wednesday. Although Wednesdays highs will be warmer in many locations, in upper elevations of the Sierra, it may be a little cooler,  as cloudiness will build a bit quicker in the late Am hours. Some Thunder possible Wednesday, before most models bring in more SE flow Thursday into the weekend with areal coverage increasing for the high country Thursday through Saturday. At this time there is no clear picture on whare the main focus will be or what mechanism will trigger the best activity. However, more instability is expected going into the Weekend as a weak upper Trof interacts with hot and potentially moist air mass. Moisture advection may add to the mix for the possibility of wetter storms Friday-Saturday.   For Mammoth, High temps will be in the 80s this week with lows mostly in the 50s then 40s late in the week.

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The transition to Hot Summer Weather is now complete as compared to 7 to 10 days ago with that chilly negative height anomaly off the coast of the pacific NW. Although there may be weak trofs now and then effecting the pacific northwest and ushering in a dry SW flow aloft, temperatures will be normal to above for sometime to come.

At the moment we have the core of heat building over the great basin. This is expected to strengthen over the next few days. The Thermal trof will apparently jump back and forth between the central valley and western NV and so there will be periods of Zephyr winds that will help deal with the high elevation heat in the late afternoon and early evenings.   There although there will be warming in the upper levels…there will still be enough lift from instability at the surface to pop a few high based thunderstorms until about Wednesday or Thursday when instability increases aloft as some cooling begins in the upper levels. Any added moisture monsoon related would be enough to get the ball rolling to increase areal coverage of TSRWs. Stay tuned on that…..

High temps will reach the upper 80s in Mammoth by Wednesday with the peak of the High pressure system.  There after, some hint of SSE flow may increase moisture with Thunder Thursday into Friday.  High temps will then get cooler from cloud cover if that happens. However, it will remain very hot over the Owens Valley until the end of the week…..Bishop temp forecast is 105 Tuesday and Wednesday.  Some Thunder there after is possible Thursday and Friday for the Owens Valley as well as conditions become potentially more humid with any seasonal wind.

 

 

The Dweeber………………..:-)

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Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.

Upper Flow Pattern Adjusting Westward Now As Upper High North of Hawaii Retrogrades to Near the Dateline Over the Next 48 Hours and Midwest High Backs to Great Basin….Resulting in Very Warm Weather for the High Country……

It looks like one uncomfortable week for the Dweebs next week…..Retrogression in effect now as both the upper high north of Hawaii and the upper high over the Midwest begin backing up today.  Upper ridge according to the latest guidance should be east-west along the Utah/NV border with the axis through the Bay Area by Monday afternoon.  This is a Hot-Dry pattern for the high country with only afternoon cloudiness or high based storms possible. Our warmest temps of the year so far will begin Monday, then continue into Tuesday, Wednesday and beyond. High temps may approach upper 80s at resort levels, dependent upon cloud cover by Thursday.  Unfortunately there will be days of little Zephyr wind and so it will feel uncomfortable into the evening hours for some folks…..We’ll see how the moisture stacks up as we get further into the week.

High based thunderstorms could begin as early as Tuesday afternoon as highs get into the mid 80s at 8000 feet. Then depending upon cloud cover, 87 or even 88 may not be unreasonable by Thursday/Friday depending upon if the ECMWF is correct with its height forecast over Mammoth. Nighttime lows will be in the 50s next week. The 10th of July is usually one of our hottest days of the year historically, with low 90s during some of the hottest years.  However, 90 is not in the forecast at this time on that date.

In the Owens Valley, Bishop is expected to reach 103 to 104 next week. A record high of 110 occurred on July 10th back in year 2002. That was an all time high for Bishop.  That record will remain this year. Coincidentally, Mammoth Lakes had a high of 91 on that same day. The all time record high for Mammoth Lakes as recorded by the Forest Service in town was 93 degrees. The Dweebs do not have the date of that record. However, odds are that it occurred early during the month of July (pre-monsoon) so possibly during the first week of July.

More later…………………………

Dr Howard and the Dweebs…………………:-)

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Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.

Happy 4Th of July!!!!Dry Seasonal Weather to Highlight the 4th…then Above Normal Temps For The Weekend…..Monsoon Moisture To Hold Off For The Time Being……

I will be Brief…..

The last of the chilly trofs is currently moving through the pacific NW. While most of the news has been on the horrid heat across the CONUS…..parts of the Pacific NW has just come though the 3rd coldest June on record with some ski resorts reopening….  Climate extremes is more like what is occurring….

Forecast:

Sunny days and cool nights with some afternoon clouds.

High temperatures in Mammoth will average between the upper 70s and low 80s through Sunday. Nighttime lows will be in the mid 40s to low 50s. Afternoon and early evening Zephyr winds,  “some days”,  will be occasionally moderate with gusts 15 to 30MPH in the late afternoon/early evening.

Looking over the guidance this morning….no surprises.  A dry SW flow will continue to keep monsoon moisture from coming up into Southern Mono County. The moisture currently moving north from old Mexico is being shunted NE well to our south. And although dew points have really come up over Southeast Ca…the Dweebs do not see any of that effecting our area anytime soon.

With that said, you do not need Monsoon moisture to get high based Thunder as recently seen yesterday.  All you need this time of the year is heat, a little cooling aloft and wamo!; a marginally unstable column.  Today and into Friday, it looks pretty stable. Weak SW flow will mostly dominate aloft for the foreseeable future. With that said, further out in time….there will be both periods of instability aloft due to things like the formation of Coll’s off shore and SSE flow at 700mb that we will have to keep our eye on. True SSE flow aloft may not be in the cards until about mid month……

With that said…the Dweebs are extremely concerned about the high based TSRW threat and dry lightning the second half of July and August because of the Tinder dry forest in the Central and Southern Sierra. With the cold water bias over the eastern pacific and the upper atmosphere responding by weak trofing, the Dweebs feel that there is less likelihood of wet thunderstorms then dry.  It would be very wise for locals to take the time now and clear brush, pine needles and small trees under the canopy as prescribed by the local Mammoth Lakes Fire Dept.

 

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

 

 

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Reference Glossary of Weather Terms
Disclaimer: I have been a hobbyist meteorologist for over 30 years here in the Mammoth area and I do this for my personal enjoyment. The National Weather Service saves lives every day . . . I do not. When making important planning decisions please use information provided by the National Weather Service as they are the most knowledgeable and accurate information source available today.