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Archive for September, 2014
An 8 to 14 day Extended Dry period is expected for the High Country with warmer than normal temps by the weekend……Based upon Weeks 1 and 2 Outlook…This should be a beautiful Fall Foliage Season up until Mid October….
Tuesday September 30, 2014
Friday Update:
It appears that the last Subtropical Ridge Building NW from Old Mexico is in Play. This type of Ridge is different than the ones that move in from the pacific. This is usually a late July through early September type pattern, with the exception of the fact that the SW monsoon is over. So the word is, enjoy the last Summer like pattern in Fall!.. We will expect other warm ups, but not the type that will cause this warm up this year. Otherwise expect high temps in the low to mid 70s this weekend and into Monday with the lows in the upper 30s and 40s in town. The upper high breaks down pretty quickly early next week with the return of low to mid 60s by midweek.
At this time…..Other then some cooling next week and some clouds and breezes…the weather will be fair until the middle of October when a system is expected to bring wind and cooling and ?????….;-)
The Dweeber………………………..:-)
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Wednesday AM Update: October 1st.. It will be cooler today Wednesday……
No changes to the previous discussion through the end of next week. However, it is what happens after that, that will be of interest…. Although the GFSX keep the ridge in place through Mid October, the ECMWF is bringing in a storm mid-month. With that said, of all the months of the year, October is probably the worst month for model verification. Nevertheless…the fact that the EC is seeing something for the middle of October is worth noting……..Even though our American counter part is not in agreement at this time………………Stay Tuned!!!!!
Dr Howard and the Dweebs………………………….:-)
After a cool weekend, temperatures recovered nicely Monday with highs back into the mid 60s with little breeze. A weak inside slider is expected to bring about 5 degrees of cooling Wednesday as a dry front moves through the Great Basin Tuesday Night and so high temperatures will briefly return to near 60 degrees Mid Week.
It is nearly October and forecasters must pay special attention to western pacific tropical storm activity. Looking upstream to the western pacific…..Western Pacific tropical storm activity will affect our weather over CA. Tropical storm “PHANFONE” is expected to spin up toward the weekend and become a Super Typhoon by Saturday with a least Cat 4 status. This storm is expected to phase with the westerlies “destructively”. This supports current extended modeling of a strengthening west coast ridge which is expect to get stronger and more amplified the following week. A strong ridge developing over the far west this weekend with result in above to much above normal temps this weekend. This results in highs at least in the low 70s for Mammoth and near 90 for the Bishop area by Saturday. This upper west coast ridge is expected to last through most of next week with beautiful windless Fall Weather in the high country with a resulting “Fab Foliage” season. Temps next week will continue into the 70s……
Intra-Seasonal:
The next change is shown in the ECMWF weeklies. This is in both the control and ensembles….In Weeks 1 through 4
A change to cooler windy weather about the middle of October. This may bring another dusting of snowfall or more. Another period of unsettled weather is expected about the first week of November according to the CFS.
ENSO:
Neutral ENSO conditions still continue over the Enso Basin. Several Kelvin Waves traveling eastward will begin pushing SSTA’s higher over the Central and East Central Nino Basin, over next few weeks then into Fall. This is one hope that at least (weak to moderate El Nino conditions) will develop later this Fall or Winter. Remember, it takes 3 to 5 months of SSTA’s over .05C in the 3.4 region to be classified as an El Nino.
Note:
What seasonal forecasters like about a more significantly positive ENSO signal, is that it gives an increasing bias to long-range forecasting for wetter then normal weather for at least Southern CA What you’re not reading in the news is that you do not always need an El Niño for Wet weather in California. There are other “*Teleconnections” that can do the job as well.
Teleconnections:
We are looking for a winter with some of the teleconnections indicating, -QBO, +PDO, Weak-Moderate ENSO, Low Solar. A -QBO is usually good for higher incidence’s of blocking near Greenland. So a -AO as well as a -NAO are more likely this Winter Season. Additionally, Those three teleconnections along with a positive PDO favor a stronger west coast ridge and thus a northerly displaced upper west coast Jet.
However, even a weak El Nino may provide for enough of a strong split in the southern branch of the polar jet to wet Southern and the Central CA coast. Although Central CA coastal areas in a weak El Nino are more favored for wetness than the more interior areas.
As we all know there is a lot riding on a wet water year this coming Fall, Winter and Spring. “The Cake is still Baking”…..and so this winters weather is still not set in stone.
The Dweebs will be on it…. throughout the Fall and Winter so stay tuned….
Dr Howard and the Dweebs……………………………:-)
Equinox Storm right on time with dry front moving through Mammoth by early Thursday PM followed by Upper Cut-Off like system Saturday…Some Snowfall Accumulation Likely over Higher Terrain…..
Thursday September 25, 2014
8:15AM Saturday:
As indicated Friday afternoon, the later guidance continued the trend of the upper center to move directly over the Mammoth area this morning, thereby setting up the area of deformation to the north of us. Areas like Lake Tahoe picked up about 1.25 inches of water EQ over night while only a few hundreds in the Southern Mono County area. Rain and high elevation snow will continue mainly to our north today with showers lingering into Sunday. The best chance of a few inches of snowfall will be later today and tonight in Mammoth as the main upper center shifts east just across the CA/NV border and wrap around moisture gets pulled down from the north into Southern Mono County. We may still get a couple of inches of snow above 8500 to 9K from that circulation later this afternoon in the Mammoth area.
We will dry out Monday with temperatures warming back to the mid 60s by Thursday.
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Friday late afternoon…6:00pm…..
This afternoons guidance showed up with the deformation zone further north. Meaning that the main band of precip will probably set up between Northern Mono County northward to Reno/North shore Tahoe. That is the big band with the heaviest precipitation not dependent upon daytime heating or any of the sort. So amounts will likely be less here in Southern Mono County now then what the models showed from last nights or even early this AM runs. Typically, the deformation zone, an area typically 70 to 100 miles wide (Surface Convergence) is located to the north of the center of the upper low. If by chance the upper center verifies some 50 miles or so south of Mammoth, that would enhance possibilities for more precip. Based upon the latest guidance…that is unlikely. So some snowfall yes…possibly a few inches over the higher terrain, but no major amounts as indicated by this afternoons guidance. I will update one more time later tonight when the 00z NAM comes in to see if there is any change…..
Dr Howard and the Dweebs……………………:-)
Friday AM Update: 11:40AM
Everything on track this morning with upper trof off shore now split into two centers of circulation. One west of BC, Canada and the other stronger branch digging SSE with the help of a 110 knot upper jet toward the Central CA coast. Over the next 24 hours a portion of the upper jet in the southern branch will round the base, as at the same time, the northern branch pretty much detaches itself and so that this becomes a quasi-cut off upper low as it moves through Central CA Saturday and Sunday. The track of the center should move pretty much right through Mammoth Lakes by 18Z Saturday.
An area of deformation (surface convergence) will develop on the northern portion of the cut off with precipitation developing to our north then shifting SSE over the next 24 hours. The 12z Friday GFS 700RH has draw of moisture up into the desert southwest then up into NV from the Subtropics. Some of this moisture is actually connected to a tropical system off Baja. This moisture looks likely to get entrained in the larger scheme of things this weekend.
Considering 700 mb temps and 500-1000mb thicknesses, it is possible that Mammoth may have snow levels as low as 7500 to 8000 feet as the upper cut off and associated cold pool moves over us Saturday AM. By Saturday night the upper cut off moves east into Western NV and 700 MB temps begin to rise during the late afternoon Saturday into Sunday. The Snow Level will rise up to about 8500 Saturday Night. It is possible that over the upper elevations above 9,000 to 10,000 feet that some 3 to 6 inches of wet snow may fall. The timing is between, late tonight and Sunday Night, as upslope conditions will likely continue through the weekend.
Remember, that the ground is pretty warm from our long warm Summer and so it will take time for the upper elevation pass roads to cool to freezing. However, those that plan on negotiating Tioga Tonight should get an early start Today, as heavier precipitation is expected to begin about Midnight tonight or thereafter………..
Dr Howard and the Dweebs………………………….:-)
A Major Cool down is in play with winds up over the ridges today, as the first cold front of the new season approaches the Sierra. A FROPA is expected by afternoon today Thursday. Although the cold front itself is expected to be dry, the forecast guidance is also showing a slowing of the upper trof as it becomes nearly cut-off over the Sierra Saturday. This closed upper low is expected to remain in the vicinity of the Central Sierra this weekend.
This will have the effect of providing not only a cold pool aloft at 18,000 feet over the Central Sierra, but a upslope component as well. Because of the aforementioned……Upper elevation hunters, back packers, hikers, etc should be prepared for possible winter like weather, if going into the back country, against hypothermia due to cold, wind and……………….The possibly of several inches of snowfall above the elevations of 8500 up to the crest between Friday night and Saturday Night is a significant possibility.
QPF from HPC: http://www.hpc.ncep.noaa.gov/qpf/fill_98qwbg.gif
Judging from the new HPC graphical information above, about 3/4 of an inch of water EQ is possible by Saturday night over the crest….this is mainly along a line from Mono Lake Northward. Amounts for 2 to 4 inches of snow over the crest in the Mammoth area is possible with 1/2 inch of QPF. The Sierra Crest areas from about Tioga (120) northward to Alpine County 3 to 6 according to ECMWF qpf. If the system comes in a little further south of guidance that would make a difference..
Additionally, those that are planning cross travel over the higher elevation passes, should be prepared for the “Possibility” of a temporary road closure of Tioga Pass as early as Friday night into Saturday….
Dr Howard and the Dweebs……………………..:-)
Fall offically here now with more above normal temps expected Tuesday and Wednesday…..The First Fall trof of the season approaches California Thursday with a slow moving cool front expected over Northern Ca Thursday…The Cool Front will Creep through Mono County Early Friday Am as Upper Trof Cuts off over CA Saturday….
Monday September 22, 2014
The upper pattern over the CONUS will be highlighted by amplification, as a good moderate trof for this time of the year builds the upper ridge down stream over the countries mid section.. The upper trof has some chilly air in it as the numerical guidance has 500-1000 thicknesses down to about 558DM Saturday AM. That is good for a potential snow level around 8500K this time of the year with early AM temps well down into the 30s in Mammoth Lakes. The Dweebs note that the RT rear entry region brushes Mono County Friday, and so there may be some showers…especially over the higher terrain. By Saturday…the main energy leaves the upper trof and so what is left cuts off over CA. This sets up some unstable air aloft and so we may have showers….Mainly during the afternoon both Saturday and possibly Sunday.
As the system and WX front approaches Thursday it will be windy. Clouds will increase as well as the chance of showers. Again, this system does not have a lot of moisture with it. However, it may leave a dusting of snow over the higher terrain anytime early Friday into Saturday. Daytime highs on Saturday will be in the 50s…..Stay tuned…..
Dr Howard and the Dweebs……………………….:-)
