Laura “Diver Laura” James sent that first photo (by the way, you have a few more days to vote for her and help get a grant for Sustainable West Seattle) …Then, Annika got this view as the colors intensified further:
We got a text a few minutes ago saying lightning was visible from Alki. Then, we saw some in the northwest distance from here, just now – nothing in the forecast so far, but as we learned a few days ago, anything can happen, so let us know what you see/hear!
whenever Seattle experiences sunsets this colorful, it’s because there is a disaster elsewhere …
http://blog.seattlepi.com/thebigblog/2012/07/11/thank-russia-for-seattles-gorgeous-sunsets/
Well folks, are we ready for Round 2???
here is my thinking regarding the next 48 hours and this is just my experience forecasting T-storms and severe weather and likely will differ greatly from the NWS as they have a bias for instability and convection, but what follows is my forecast after looking at the models.
We have a somewhat rare situation setting up for us today and Saturday as an ULL ( Upper Level Low ) moves inland from the coast and because of it’s proximity to us and coupled with mid level shear and instability associated with vertical shear at the upper levels we are now entering a very active 48 hours as moisture associated with the ULL moves from East to West as the ULL moves further inland into Eastern Wa, with that said, some of you may have noticed the clouds rolling in last night just before sunset? Those are Altocummulus Castellenus ( an early sign of instability in the mid and upper levels ) and that T-storms are ripe to develop, well that’s exactly what happened last night around 10:30 as a T-storm developed on the leeward side of the Olympics and put on a nice lightning display. and then more T-storms developed near the San Juans and Bellingham areas also putting on a light show.
Now on to the actual specifics for tomorrow and Saturday, I looked at the updated NAM – MM5 for CAPE and LI’s ( Lifted Indicies ) and that model has CAPE values in the 3000 – 5000 kg/j range and LI’s around -3 to -5 This is important because the greater the CAPE number and the more negative the LI # the better chance of T-storms and increased wind shear and convection.
when looking at the 1.14km GFS and the 12 km WRF/GFS I see that both of these models are in line with the NAM MM5 but with weaker CAPE and LI parameters but not enough of a deviation to alter the forecast one way or the other given that we are now entering the prime convective potential for these storms to fire up.
Current NWS thinking is that as we enter the Friday afternoon evening time frame, low level moisture will start to invade the area from the EAST and with LI’s negatively tilted and coupled with the increased CAPE and daytime heating, the expect T-storms to fire along the west crest of the mountains and drift westward throughout the evening and I agree with this assessment as the WRF – GFS shows this well, the other factor to take into account is that because the prime of this event is forecast to occur overnight today ( FRIDAY night/ Saturday morning ) what T-storms do fire up could be strong to severe and long lived and if that weren’t enough, more storms are likely to develop in the overnight period with some if not all of the T-storms that do develop could be SEVERE!!
Stay tuned, Should WSB warrant a specific post about this, I will sure to post there to keep everyone updated.
Patrick, thanks for the info on those clouds.
.
I was wondering if they were an indicator of impending T-storms, as I noticed similar clouds recently, that preceded another thunder boomer.
.
(“Thunder-boomer” is the scientific term, right?)
.
Mike
Sorry, comment time is over.
| 5 COMMENTS