This is the worst bust I have ever experienced by far

[psuhoffman]

Rhode Island is the New England "DC".  If anyone loops the BOX radar from this storm,  they'll see one of the worst nightmares imaginable happen in RI.

The snowshadow effect has been happening to them all night and now all day.  They still are not getting much as the bands just die over them.  Would suck to be there.

[HM]

The issue of TROWAL-induced convection distorting the cold-sector precipitation has been a long-winded issue in the research world. There was a clear TROWL (trough of warm air aloft) up through about 20K FT with cold temperatures above that. At one point, mid level lapse rates were exceeding 8°C/km over the DELMARVA where the flanking convection along the occluded front developed. Instead of getting banding associated with slantwise convection (CSI) that we are familiar with in the area, the style of instability changed to conditional (CI). Conditional instability is much like regular instability (parcels warmer than environment) with the difference residing in water vapor (the more moist the parcel, the more unstable through latent heat).

CI can be a gift for a small area that happens to be focused in the upward part but can hurt a large area, too, snowfall-wise. Suddenly, the motions are more vertical than slantwise, increasing subsidence zones. At the same time this was happening and increasing, the frontogenesis was beginning to slacken off as the system became vertically stacked (less convergence / tightening gradient and more of a neutral gradient with broader cyclonic wind). So suddenly the entire cool sector has become dominated by more vertical convective processes instead of synoptic-scale, and/or hybrid synoptic-meso (CSI)-scale, processes.

The convection was most favored over the core of the coldest heights along the occluded front where all 3 conditions were met for convection:

1. Coldest temps at say 500mb

2. Strongest Low level convergence

3. Best moisture source

Vertical motions increase the downward motion just as much as upward, producing large gaps in the precip shield. Large gaps, thinner overcast in the DC area during March means more solar input. It increases the melting rate of an already marginal air mass, once the bands move out.

Finally, convection that is 10-20K feet tall along an occluded front in conjunction with CI banding increases latent heat flux / drier pockets into the cool sector throughout (not just in subsidence zones). This likely took a toll on snowflake production (increased temps and less RH are not ideal for snowflake production). Throw in the strong winds and suddenly it became rather difficult to make a decent snow band in the area.

These were my initial thoughts on what happened, bust-wise, in the DC area. I haven't proven anything or done the kind of research that is needed to accept this theory as valid. I was hoping it would spark some input.

[WxUSAF]

HM...interesting post.  So in this case, do you think the CI convection was the W-E oriented band that set up shop down near Salisbury?  And then the TSSN that occurred around RIC was more due to the ULL passing overhead?  

[HM]

 

HM...interesting post.  So in this case, do you think the CI convection was the W-E oriented band that set up shop down near Salisbury?  And then the TSSN that occurred around RIC was more due to the ULL passing overhead?  

I think (and maybe somebody can actually do it to see if I'm on to something haha) if you took a cross section across the area (you need absolute geostrophic momentum/RH/potential temp at least), you would see most of the atmosphere contaminated by "CI" over any other type of instability. Even if CSI showed up, the sheer presence of CI cancels that out anyway (you can't mess with the power of vertical motions). So I think the entire cool sector precip shield was affected by CI; and, the convection along the occluded front was the tallest of the vertical motions/convection that could be sustained the longest (due to the 3 reasons I stated). I believe this would have included the RIC area.

 

I think this could explain the nature of the banding over DC-MD being not so awesome.

[Kevin Druff]

The issue of TROWAL-induced convection distorting the cold-sector precipitation has been a long-winded issue in the research world. There was a clear TROWL (trough of warm air aloft) up through about 20K FT with cold temperatures above that. At one point, mid level lapse rates were exceeding 8°C/km over the DELMARVA where the flanking convection along the occluded front developed. Instead of getting banding associated with slantwise convection (CSI) that we are familiar with in the area, the style of instability changed to conditional (CI). Conditional instability is much like regular instability (parcels warmer than environment) with the difference residing in water vapor (the more moist the parcel, the more unstable through latent heat).

CI can be a gift for a small area that happens to be focused in the upward part but can hurt a large area, too, snowfall-wise. Suddenly, the motions are more vertical than slantwise, increasing subsidence zones. At the same time this was happening and increasing, the frontogenesis was beginning to slacken off as the system became vertically stacked (less convergence / tightening gradient and more of a neutral gradient with broader cyclonic wind). So suddenly the entire cool sector has become dominated by more vertical convective processes instead of synoptic-scale, and/or hybrid synoptic-meso (CSI)-scale, processes.

The convection was most favored over the core of the coldest heights along the occluded front where all 3 conditions were met for convection:

1. Coldest temps at say 500mb

2. Strongest Low level convergence

3. Best moisture source

Vertical motions increase the downward motion just as much as upward, producing large gaps in the precip shield. Large gaps, thinner overcast in the DC area during March means more solar input. It increases the melting rate of an already marginal air mass, once the bands move out.

Finally, convection that is 10-20K feet tall along an occluded front in conjunction with CI banding increases latent heat flux / drier pockets into the cool sector throughout (not just in subsidence zones). This likely took a toll on snowflake production (increased temps and less RH are not ideal for snowflake production). Throw in the strong winds and suddenly it became rather difficult to make a decent snow band in the area.

These were my initial thoughts on what happened, bust-wise, in the DC area. I haven't proven anything or done the kind of research that is needed to accept this theory as valid. I was hoping it would spark some input.

HM -- I understood the English in a lot of this, but not sure I totally understood the concept. However, the bolded above, those of us on the West End of the Richmond metro can certainly attest. We could see the center of the low on radar as it transferred and bombed. Under those bands that formed just to the north east of the center (where it was near 45* at the surface) and pivoted around (to where it was 31-32, just 17 miles away), it snowed as hard as I have ever seen.

[RevWarReenactor]

I really do think we are still paying 09-10.

 

I remember that year a Low did this weird thing where it backed in. We got destroyed. Boston got rain. It has a way of balancing itself out.

 

Still, it blows my mind that something like this could happen. So cruel.

[Bob Chill]

HM, it makes sense. I ran the full storm loop @ dupage site about 20 times. Left a pit everytime of course. It was pretty clear the low intesification and interaction with the ull near ric quickly took the wind out of the sails w/ the waa slug. It just fizzled overhead while things went nuts over ric.

Then the slp took a slow crawl ese for a bit instead of just moving east and then ne. Since the lp in se va didn't get in a more favorable position to help the banded firehose push further east towards us, those bands weakened before they crossed the chesapeake.

It was a game of inches really. It might have been the dc bust of the last 12 years but subtle changes in the evolution of the storm and it's subsequent interaction w/ the waa and ccb precip cost us everything. yay us.

[haudidoody]

I am stuck in this area since my career in in DC and moved from Calvert to Germantown to have better chances, and that has worked out at times.  But damn being such a snow lover just makes me feel real hatred for this area in winter.  We deal with 5-plus months of bare trees and wearing coats, but snow has gotten rarer and rarer.  I just wish we had the means to own a little place in Garrett County that we could run to.  A coworker has that, and his wife also loves snow so they frequently will head out there on a weekend when snow is coming.  I wouldn't have so much hate if I had that.

 

I have told my wife we are GONE when I retire.  Truthfully I'd rather live in a warm climate and travel to CO or UT once or twice a winter for snow and skiing.

 

Similar to what I'd like to do... live somewhere cheaper, that's warm all year, and use the savings to fly to CO a couple times during the winter to go skiing in a real snow climate.

Winter around here is truly miserable!

 

I no longer ski given this regional climate. There's nothing worth my time within 4-5 hours.

[NJwinter23]

Great read. I was thinking that perhaps an interesting comparison to what the Richmond area sat in the other day and lucked out on is Oct 28th, 2008 when I was up at Rutgers.. We saw a very intense and localized band of dynamically cooled heavy snow in the coastal plain with nothing significant going on around it (aside from higher elevations north and west... Here is the radar loop..Notice later in the loop the band of convection moving north through LI and the intense bright band pivoting over Central NJ near the low center. Picked up a very surprise 2" in that.

 

[famartin]

Great read. I was thinking that perhaps an interesting comparison to what the Richmond area sat in the other day and lucked out on is Oct 28th, 2008 when I was up at Rutgers.. We saw a very intense and localized band of dynamically cooled heavy snow in the coastal plain with nothing significant going on around it (aside from higher elevations north and west... Here is the radar loop..Notice later in the loop the band of convection moving north through LI and the intense bright band pivoting over Central NJ near the low center. Picked up a very surprise 2" in that.

Another similar situation was probably April 18, 1997.  A small area directly under the upper low in S/C NJ into far E PA got 1-3" while all areas surrounding them got rain.  I don't have a cool radar loop though

[Amped]

This storm was very similar to 2/10/2010 in SNE. Both featured a strong H5 bowling wall type storm, and both were a huge bust on the northern edge. Both produced more snow than expected on the southern edge

 

I t appears these types of systems behave differently than classic more elongated open wave systems.  Most of the frontal forcing is located to the west and southwest of the low, and the northern part is more isothermal. 

 

Also the PNS for FDK says we got 5"  which is more than Midlo VA got. Someday someone will look back at that number and think the forecast out here actually did okay. Nooo,   It was a car topper, and a "Slushy inch or two on grassy surfaces" would have sufficed.