Jump to content
  • Member Statistics

    17,588
    Total Members
    7,904
    Most Online
    LopezElliana
    Newest Member
    LopezElliana
    Joined

Saint Patrick's Day Snow Event


stormtracker

Recommended Posts

oh wow..yeah, that is definitely an improvement.   3 to 5...holding firm.

 

That's what I would go with... not convinced the cutoff will be as sharp but maybe the HP will be strong enough. 12z NAM is improvement and hopefully the other 12z models follow suit.

Link to comment
Share on other sites

  • Replies 1k
  • Created
  • Last Reply

The 700 mb chart from NAM gives a good idea of onset and cutoff of the precipitation.

This 12 Z run shows precip from hour 33 to hour 48.

 

The suppression is not north to south, it is northwest to southeast suggesting Wes' area

may hold on to the snow a little longer.

 

So lots of people will get precipitating snow but it looks like light snow for 15 hours.

 

:blink:

Link to comment
Share on other sites

The 700 mb chart from NAM gives a good idea of onset and cutoff of the precipitation.

This 12 Z run shows precip from hour 33 to hour 48.

 

The suppression is not north to south, it is northwest to southeast suggesting Wes' area

may hold on to the snow a little longer.

 

So lots of people will get precipitating snow but it looks like light snow for 15 hours.

just like the last storm, hello spring!!

Link to comment
Share on other sites

I would not expect much of a shift from where it is now. If anything a tad north to correct on the NAM and EURO. GFS may come a bit south on its gradient on the 12z run. Still...south of I-70 and especially Loudoun through DC and points south should get in on the good stuff. It will be tight quarters north of I-70 and the area north of the mason Dixon line and northeast through Philly, Central and Northern NJ and NYC metro area will likely get ripped off again. We will make out best on the WAA dump late Sunday evening into the predawn hours Monday. Just my 2 cents... We'll see.

Link to comment
Share on other sites

The NAM shows over 12 hours of precipitation but intensities appear light so in DC you are

going to hope the good stuff occurs late at night.

 

It could happen, NAM shows light to moderate in DC from 9Z to 12Z.  Monday AM rush hour

could be fun even with 2 to 4 if most of it sticks late at night.

 

I know tomorrow it is suppose to be cooler... but road temps will be a problem for stickage

 

http://www.chart.state.md.us/travInfo/weatherStationData.asp

Link to comment
Share on other sites

I dug back a little. The 3/3 event had nearly a 1040 hp pressing in. This one is nearly 10mb weaker. I know it's not that simple because of heights, proximity to the lp, etc but I don't think this setup will be as efficient at squashing the northern edge. Other factors can result in a further south solution with all features of course. But seeing a gradient as tight as the nam raises s flag in my mind.

Link to comment
Share on other sites

At hr 84 it brings light precip back into the DC area. Looks like there's more to come afterwards too.

we may get a bit of light precip partly from interaction with the next wave in the northern stream but i'd be willing to bet the nam is garbage on how it tracks the low.

Link to comment
Share on other sites

total for storm is .42" at BWI and .63" DCA (thru 18Z Monday)

marked improvement from 6Z

 

About 0.16" in Towson, which is better than the essentially 0" for the 06z NAM.  As sharp as the northern gradient is, the southern gradient looks even sharper -- it still looks like someone on the south side of this storm could go from 12" modeled snow to 0" (or vice versa) pretty quick.

Link to comment
Share on other sites

I dug back a little. The 3/3 event had nearly a 1040 hp pressing in. This one is nearly 10mb weaker. I know it's not that simple because of heights, proximity to the lp, etc but I don't think this setup will be as efficient at squashing the northern edge. Other factors can result in a further south solution with all features of course. But seeing a gradient as tight as the nam raises s flag in my mind.

this airmass is definitely less impressive if still impressive. the NAM does a good job modeling the sharpness of an edge which is perhaps legit but location is another story.

Link to comment
Share on other sites

Fine.  Scratch your head over the SREF plume.  This is 3 hour increments of snow at DCA and the event happens during roughly 15 hours.

 

attachicon.gifsref 9Z runtime 3 hr sno_dca.jpg

 

it's usually pretty smart to take an ensemble range of start/stop time -- find a 15 hour duration then divide the mean qpf by 15 hours because you know it's probably going to have a linear precip rate over those 15 hours 

Link to comment
Share on other sites

it's usually pretty smart to take an ensemble range of start/stop time -- find a 15 hour duration then divide the mean qpf by 15 hours because you know it's probably going to have a linear precip rate over those 15 hours 

 

 

0.5" to 17" for me. Those are really useful.

And he used them to make his point.   :lol:

Link to comment
Share on other sites

And he used them to make his point.   :lol:

I've become rabidly anti snow algorithm recently. SREF is a good tool in many ways but not sure the snow plumes are that helpful to most forecasts.

Link to comment
Share on other sites

it's usually pretty smart to take an ensemble range of start/stop time -- find a 15 hour duration then divide the mean qpf by 15 hours because you know it's probably going to have a linear precip rate over those 15 hours 

So...rough math suggests DCA gets 0.5" snow an hour for 15 hours per SREF.  So what accumulates will be the hours

without March high sun angle.

Link to comment
Share on other sites

Archived

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

Guest
This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...