Jump to content
  • Member Statistics

    17,586
    Total Members
    7,904
    Most Online
    23Yankee
    Newest Member
    23Yankee
    Joined

September 17-19 2012 rain and severe weather potential


SNO

Recommended Posts

  • Replies 536
  • Created
  • Last Reply

12z NAM has some pretty nice looking hodos for Tuesday evening into Tuesday night... 12z GFS a bit more alarming with the hodos, but 12z GFS is more centered around Tuesday afternoon. Even though SBCAPE is forecasted just below 1000 J/KG, 0-6km shear is decent to good at 40kts and both 0-3km SRH and 1km SRH are over 350 m2/s2 at 18z TUES at KIAD

Link to comment
Share on other sites

Ian would be going crazy if we had last week's instability juxtaposed with wind profiles like that.

I think we all would no matter where we were.

Anyway, its prob just eye candy... MLCAPE and SBCAPE are 500 J/KG at best, give or take a 100. 0-6km shear is over 50kts and PWATS over 2".... so i see a wind threat with maybe some iso spin-ups in a line or cluster

Link to comment
Share on other sites

I think we all would no matter where we were.

Anyway, its prob just eye candy... MLCAPE and SBCAPE are 500 J/KG at best, give or take a 100. 0-6km shear is over 50kts and PWATS over 2".... so i see a wind threat with maybe some iso spin-ups in a line or cluster

Yeah, I'm thinking the better threat is towards southern VA into the Carolinas.

Link to comment
Share on other sites

I'm mostly worried about a.m. mess tho I think it looks a good deal better than it did. Timing is trying to line up very well and the trough positioning is also falling into a historical place. SREF looks quite nice for this range. We won't need much CAPE.. 500 might suffice.

post-1615-0-63690400-1347851106_thumb.gi

post-1615-0-11406700-1347851110_thumb.gi

post-1615-0-64657800-1347851195_thumb.gi

post-1615-0-40038100-1347851210_thumb.gi

Link to comment
Share on other sites

Wind profiles are nuts ahead of the cold front... even the GFS has surface winds with a bit of an easterly component, which has my confidence up a bit. Still gotta watch out for the instability risks, though.

Here's the Balitmore area just ahead of the front... similar profile that can be found throughout the greater DC area. 55 kt. 925mb jet is serious business... any sort of convection could mix those winds down.

post-96-0-17756500-1347879936_thumb.png

Link to comment
Share on other sites

Wind profiles are nuts ahead of the cold front... even the GFS has surface winds with a bit of an easterly component, which has my confidence up a bit. Still gotta watch out for the instability risks, though.

Here's the Balitmore area just ahead of the front... similar profile that can be found throughout the greater DC area. 55 kt. 925mb jet is serious business... any sort of convection could mix those winds down.

post-96-0-17756500-1347879936_thumb.png

Yeah areas that happen to get any sort of substantial surface based instability (500 J/kg or higher) would certainly have a potential risk for tornadoes. At worst I think the frontally forced squall line will mix down those winds, again though, the higher the instability the better the potential will be.

Link to comment
Share on other sites

Can you explain what all of that means, Mark? Thanks.

The strong jet at 925mb (50-60+ kts depending on the model you look at) is good for damaging wind potential... even weak convection can mix those kind of wind speeds to the surface.

Having a bit of an easterly component to the winds (out of the southeast instead of south or southwest) not only adds more spin to the low-levels of the atmosphere, but it will also help these storms ingest more unstable air and allow storms to have a longer lifespan.

Of course, such high winds throughout the column suggest storms will also be moving pretty quickly... mature storms will have a forward speed of 50-60 mph... perhaps faster in some cases.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...