It’s Almost Showtime As Moist Subtropical Fetch Heads For The West Coast……
Tuesday January 17, 2012
Posted at 10:52 am by Howard
Wednesday Am Update:
Just a quick update to let the T.O.M know that the models are coming in a bit cooler now for the Friday afternoon and night system. This may be significant for snow instead of a rain event for the Town of Mammoth. It may end up the the upper elevations of town get significant accumulations from this wet system, that has been advertised as more of a rain event then snow…..
The Dweebs are all anxious now as the month long wait for the middle of January is here!
I took a look at the new 12Z GFS analysis and noticed:
1. An impressive surface high over the Bering Straits of 1056MB!
2. To the south at about 170W a 981 Surface Low taping a rich pool of PWAT from near the Hawaiian Islands.
3. A nice cyclonically curved upper jet (300MB) well N and W of Hawaiian Islands
4. Very nice confluence of both the polar and subtropical upper jets near and east of the Dateline.
5. Over the next 24 to 36 hours….The current NW upper flow pattern over the North-Central west coast shifts east as strong mid Lat pacific jet noises into Vancouver Island, Canada, early Wednesday Am….then south to Columbia River by late Wednesday afternoon. At the same time, subtropical ridge builds with increasing heights along central west coast. 700MB 0C line (Freezing Level at 10,000ft) rises to and north of Mammoth By Thursday PM. Meanwhile….a strong upper wave at about 145W heads east toward west coast then on shore into late Thursday afternoon as Main Event of PWAT associated with 160Knot upper jet slams Northern Ca Friday Morning then south throughout the day with Copious Moisture. PWAT forecasts up to 1.50 along the Central West Coast.
6. By Friday night….upper wave moves through….rich PWAT pushes south and drier air along with cooler temps moves in….lowering the snow level below 7000 feet after midnight.
7. There will be a few more waves to come through…..colder and dryer snowfall to follow through the remainder of the weekend and into early next week.
7 Day GFS computer generated QPF has about 4 inches of liquid by Wednesday AM next week storm total. Of course a lot can happen between now and then….IE waves can speed up or slow down in speed……So QPF can very. A snap shot of the guidance for our area would suggest that considering very wet snow in the beginning and dryer snow at the end this Dweebs best guess at this time is about 5 Feet at 10,000ft and above. “First guess” for the Town of Mammoth, @ 8000 ft….up to 24 inches mainly Sunday night into Tuesday Next Week. Will Fine tune later….
8. The pattern is expected to go significantly drier again by Wednesday the 24th as the upper flow shifts more from the north….It will be colder as well. Below normal precip is expected the last week of January.
9. The experimental Climate models are showing dryer then normal the first week of February then wetter the 2nd week of February.
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.