Jump to content
  • Member Statistics

    17,606
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

Early Winter Banter, Observations & General Discussion 2017


powderfreak

Recommended Posts

  • Replies 3.1k
  • Created
  • Last Reply

I can't really get my grids to spit out as much sleet as we're getting. We just don't have a lot of good tools that know how to turn +7 into sleet. 

My best guess is that this is a shallower layer of very warm air. So the low level cold balances it somewhat. MWN was below freezing for a while, so even though the models said it was warm to almost 10,000 feet that wasn't true.

Link to comment
Share on other sites

4 minutes ago, ORH_wxman said:

Yeah was kind of surprised to encounter a skating rink this morning outside...figured we could flirt with it, but then it would retreat, but it never really did.

Wonder if a huge chunk of the interior N of pike never even warm sectors....front is already near Hudson Valley...prob get 10F spikes everywhere when it mixes out during FROPA.

 

Yeah. I honestly didn’t look much other than knowing NE MA had some ice risk. Once it was rain here, I didn’t really pay attn to those that wedged. But when I saw I was 33 this morning at 5am, I knew we tucked well. Given the nature of the warm front curving north off the coast, I wonder if a little meso low developed offshore.

Link to comment
Share on other sites

4 minutes ago, OceanStWx said:

I can't really get my grids to spit out as much sleet as we're getting. We just don't have a lot of good tools that know how to turn +7 into sleet. 

My best guess is that this is a shallower layer of very warm air. So the low level cold balances it somewhat. MWN was below freezing for a while, so even though the models said it was warm to almost 10,000 feet that wasn't true.

Yeah +7 warm layer into sleet is pretty tough...but you had some temps in the upper teens up there in the low levels. I'm guessing the colder layer is also much thicker where the sleet is happening than further south. Going back to mesoscale class, what do we want, about 400 meters of below freezing to refreeze into ice pellets? I suppose that depth can be trimmed when you have -7C in there.

 

In my presentation at the Amex conference in 2008, I had used -6C as a good gauge for the cold layer turning any ZR into sleet.

Link to comment
Share on other sites

3 minutes ago, ORH_wxman said:

Yeah +7 warm layer into sleet is pretty tough...but you had some temps in the upper teens up there in the low levels. I'm guessing the colder layer is also much thicker where the sleet is happening than further south. Going back to mesoscale class, what do we want, about 400 meters of below freezing to refreeze into ice pellets? I suppose that depth can be trimmed when you have -7C in there.

 

In my presentation at the Amex conference in 2008, I had used -6C as a good gauge for the cold layer turning any ZR into sleet.

I thought it was interesting late last night when it was 19F at the top of the Gondola and grooming was reporting heavy rain.  That warm layer had to be not far above that 875mb layer to have it be so cold and raining... but heavy sleet from 2,500ft and lower.

No doubt that 19F at 875mb was why we saw .5-1" of sleet down here though well under that.

Link to comment
Share on other sites

17 minutes ago, ORH_wxman said:

Yeah +7 warm layer into sleet is pretty tough...but you had some temps in the upper teens up there in the low levels. I'm guessing the colder layer is also much thicker where the sleet is happening than further south. Going back to mesoscale class, what do we want, about 400 meters of below freezing to refreeze into ice pellets? I suppose that depth can be trimmed when you have -7C in there.

In my presentation at the Amex conference in 2008, I had used -6C as a good gauge for the cold layer turning any ZR into sleet.

Yeah 400 meters is about it, especially if you are getting to -6 C like you said.

We're working on getting a wx tool that uses positive and negative area to better capture ptypes. Right now we have a tool that figures out PoP for each ptype, but it uses a climo, where freezing rain dominates above +3 C for instance. So it's good, but not great.

Link to comment
Share on other sites

As Ocean was mentioning ... if the warm layer aloft was thinner, and the coalescence level for hygros was above that layer, than it may not have been long enough to warm through fall rates. 

all kinds of micros sort of physics to consider there.   could be like a plane wreck - it's never a single cause but a series of them that team on a scenario.  error in warm depth, error in cold/viscous bl, ...etc etc.

Link to comment
Share on other sites

49 minutes ago, OceanStWx said:

I can't really get my grids to spit out as much sleet as we're getting. We just don't have a lot of good tools that know how to turn +7 into sleet. 

My best guess is that this is a shallower layer of very warm air. So the low level cold balances it somewhat. MWN was below freezing for a while, so even though the models said it was warm to almost 10,000 feet that wasn't true.

It's been more ZR than IP here at about 120' elev in Augusta, but 10-15 minutes ago I learned that it was mainly IP at home.  Temp there up to mid 20s from 17-18 at 7 AM.

Link to comment
Share on other sites

4 minutes ago, tamarack said:

It's been more ZR than IP here at about 120' elev in Augusta, but 10-15 minutes ago I learned that it was mainly IP at home.  Temp there up to mid 20s from 17-18 at 7 AM.

We were more PL than FZRA about an hour ago, but went to pure FZRA recently. I think the deeper cold air was hugging just up against the foothills.

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...