Jump to content
  • Member Statistics

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

12/26-12/28 Potential Snow Threat


CooL

Recommended Posts

  • Replies 921
  • Created
  • Last Reply

No surprise, the dewpoints came down notably on 12Z MOS guidance for places like LGA/NYC/EWR tomorrow afternoon. NAM shows LGA at 37/27 at 21Z...GFS MOS shows similar dewpoints but 41 on surface temps, thats probably overdone with clouds in place most of the day. The GFS soundings show the entire column other than the surface below freezing at 21Z and no warm layers at LGA til 01Z or so. There is no reason to believe the snow maps showing snows in eastern NJ/NYC and into northern Queens/Southern Bronx are completely out to lunch. I said before this could resemble 12/9/05 a bit, I think eventually everyone goes to more rain near the coast than that event but someone could get hit hard with snow especially if the precip shield comes in with heavy rates.

Link to comment
Share on other sites

What do you guys all think about this potential costal flooding & damaging winds?

Steep lapse rates as others have mentioned means that we can have some high gusts make it to the ground, and easterly winds are quite bad for flooding. Coastal areas that got battered from Sandy definitely have to keep an eye out. I know I will be.

Link to comment
Share on other sites

With a 1030mb sfc high almost ideally placed over SE Canada and the H5, H7, and sfc lows all tracking to our south, I think there might be more of a NELY component at the surface than currently progged. A more NELY wind would essentially eliminate those lower 50mb boundary layer problems near the surface, allowing us to dynamically cool and stick fairly rapidly the first 3-6 hours of the storm.

This is often a problem with strong CAD events, in which we don't see models detect the low level NE wind until < 24 hours from the event. I'd be willing to bet the surface trends cooler on soundings for all stations areawide given a progged 1030-35mb sfc high, plenty strong to hold the low level cold by the way. I can't understand the torching ELY winds at the onset. I see how we eventually torch the boundary layer as the sfc low hugs the coast, but during the hours where the low is traversing well SW of the region in conjunction w/ strong vertical velocities and ageostrophic flow, we should be dammed in pretty good right to NYC.

If the primary was cutting up through OH I could see the torching at the surface, but this again reminds me of VD 07 where we transfered south of the area and a strong sfc high held the NELY winds. No, temps are not as cold to start with, but the airmass is sufficiently cold and dry.

Link to comment
Share on other sites

With a 1030mb sfc high almost ideally placed over SE Canada and the H5, H7, and sfc lows all tracking to our south, I think there might be more of a NELY component at the surface than currently progged. A more NELY wind would essentially eliminate those lower 50mb boundary layer problems near the surface, allowing us to dynamically cool and stick fairly rapidly the first 3-6 hours of the storm.

This is often a problem with strong CAD events, in which we don't see models detect the low level NE wind until < 24 hours from the event. I'd be willing to bet the surface trends cooler on soundings for all stations areawide given a progged 1030-35mb sfc high, plenty strong to hold the low level cold by the way. I can't understand the torching ELY winds at the onset. I see how we eventually torch the boundary layer as the sfc low hugs the coast, but during the hours where the low is traversing well SW of the region in conjunction w/ strong vertical velocities and ageostrophic flow, we should be dammed in pretty good right to NYC.

If the primary was cutting up through OH I could see the torching at the surface, but this again reminds me of VD 07 where we transfered south of the area and a strong sfc high held the NELY winds. No, temps are not as cold to start with, but the airmass is sufficiently cold and dry.

Agreed. A lot of people compare this to 12/9/05 but VD is what comes to mind for me, BTW in Little Rock thunder ZR just reported.

Link to comment
Share on other sites

I think that the coastal flooding threat from this event is significant. Portions of Kings and Queens counties are still recovering from Sandy, and with a 3 to 5 foot surge potential in place, moderate flooding is to be expected. Even moderate coastal flooding will exaserbate the damage already in place. Won't take much to really mess things up. This is my opinion only.

Link to comment
Share on other sites

Agreed. A lot of people compare this to 12/9/05 but VD is what comes to mind for me, BTW in Little Rock thunder ZR just reported.

Another analog that was popping alot on some CIPS was 1/3/03, I think that was a weaker event that was bascially 33-34 rain for the coast but BDR/HVN/HPN basically saw entirely snow or frozen the whole event.

Link to comment
Share on other sites

With a 1030mb sfc high almost ideally placed over SE Canada and the H5, H7, and sfc lows all tracking to our south, I think there might be more of a NELY component at the surface than currently progged. A more NELY wind would essentially eliminate those lower 50mb boundary layer problems near the surface, allowing us to dynamically cool and stick fairly rapidly the first 3-6 hours of the storm.

This is often a problem with strong CAD events, in which we don't see models detect the low level NE wind until < 24 hours from the event. I'd be willing to bet the surface trends cooler on soundings for all stations areawide given a progged 1030-35mb sfc high, plenty strong to hold the low level cold by the way. I can't understand the torching ELY winds at the onset. I see how we eventually torch the boundary layer as the sfc low hugs the coast, but during the hours where the low is traversing well SW of the region in conjunction w/ strong vertical velocities and ageostrophic flow, we should be dammed in pretty good right to NYC.

If the primary was cutting up through OH I could see the torching at the surface, but this again reminds me of VD 07 where we transfered south of the area and a strong sfc high held the NELY winds. No, temps are not as cold to start with, but the airmass is sufficiently cold and dry.

Good post. Many have already mentioned on here that the models tend to underdo CAD, but they also tend to underdo mid-level warming. It will certainly be a battle with that strong high pressure in Canada. If that high pressure was 100 miles further south, this would no doubt be an all out ice event from PHL to BOS.

That being said, the bit you added about the easterly winds is a little perplexing. I haven't thought much about that, but it does make sense to see more of a northeasterly component rather than easterly with the low centered that far to our south and west. This is possibly what the Euro and GGEM have been hinting at, and the American models just haven't caught on. Or maybe, the airmass is really stale and the American models are the correct ones. We won't really know until we wake up tomorrow and see what the dew points are across the region. You can bet that if something like last night happens, where places are sitting at 35/22, then we're in for a front-end dump.

Link to comment
Share on other sites

With a 1030mb sfc high almost ideally placed over SE Canada and the H5, H7, and sfc lows all tracking to our south, I think there might be more of a NELY component at the surface than currently progged. A more NELY wind would essentially eliminate those lower 50mb boundary layer problems near the surface, allowing us to dynamically cool and stick fairly rapidly the first 3-6 hours of the storm.

This is often a problem with strong CAD events, in which we don't see models detect the low level NE wind until < 24 hours from the event. I'd be willing to bet the surface trends cooler on soundings for all stations areawide given a progged 1030-35mb sfc high, plenty strong to hold the low level cold by the way. I can't understand the torching ELY winds at the onset. I see how we eventually torch the boundary layer as the sfc low hugs the coast, but during the hours where the low is traversing well SW of the region in conjunction w/ strong vertical velocities and ageostrophic flow, we should be dammed in pretty good right to NYC.

If the primary was cutting up through OH I could see the torching at the surface, but this again reminds me of VD 07 where we transfered south of the area and a strong sfc high held the NELY winds. No, temps are not as cold to start with, but the airmass is sufficiently cold and dry.

Yep, Feb 1995 comes to mind for me. Although that system had no transfer and our antecedent air mass was much colder, we still had a similar track with center of low tracking right over Philly. Everyone pretty much ended up with a foot or more before changeover to light rn at the end. That one also featured thundersnow.

Link to comment
Share on other sites

With a 1030mb sfc high almost ideally placed over SE Canada and the H5, H7, and sfc lows all tracking to our south, I think there might be more of a NELY component at the surface than currently progged. A more NELY wind would essentially eliminate those lower 50mb boundary layer problems near the surface, allowing us to dynamically cool and stick fairly rapidly the first 3-6 hours of the storm.

This is often a problem with strong CAD events, in which we don't see models detect the low level NE wind until < 24 hours from the event. I'd be willing to bet the surface trends cooler on soundings for all stations areawide given a progged 1030-35mb sfc high, plenty strong to hold the low level cold by the way. I can't understand the torching ELY winds at the onset. I see how we eventually torch the boundary layer as the sfc low hugs the coast, but during the hours where the low is traversing well SW of the region in conjunction w/ strong vertical velocities and ageostrophic flow, we should be dammed in pretty good right to NYC.

If the primary was cutting up through OH I could see the torching at the surface, but this again reminds me of VD 07 where we transfered south of the area and a strong sfc high held the NELY winds. No, temps are not as cold to start with, but the airmass is sufficiently cold and dry.

That VD storm was quite memorable. We had thundersnow in Poughkeepsie shortly after the sleet changed back to snow. Ended up with a little over a foot from what I recall. Regarding the NELY winds, Taunton actually mentioned that in their AFD earlier today, that the models might be underestimating that.

Link to comment
Share on other sites

I think that the coastal flooding threat from this event is significant. Portions of Kings and Queens counties are still recovering from Sandy, and with a 3 to 5 foot surge potential in place, moderate flooding is to be expected. Even moderate coastal flooding will exaserbate the damage already in place. Won't take much to really mess things up. This is my opinion only.

Agreed.

Link to comment
Share on other sites

Yep, Feb 1995 comes to mind for me. Although that system had no transfer and our antecedent air mass was much colder, we still had a similar track with center of low tracking right over Philly. Everyone pretty much ended up with a foot or more before changeover to light rn at the end. That one also featured thundersnow.

February 95 was more the "open trough" coming in from the TN Valley area. Those are notorious for front end snows here because the surface reflection is typically weak and you get less mid-level warm air drawn in til late. The 95 storm the surface low eventually blew up but well after the snow fell. Our problem the last 5-10 years has been this breed of storm going largely extinct because it seems we've been in patterns where everything just wants to amplify and blow up and as a result alot of potential overrunning events have been spoiled because the surface system has just gotten too strong too early.

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...