Jump to content
  • Member Statistics

    17,508
    Total Members
    7,904
    Most Online
    joxey
    Newest Member
    joxey
    Joined

March 5 Snow Thread-Model Discussion ONLY


stormtracker

Recommended Posts

LOL it does sound weenie but it's 3 models showing a similar situation. HRRR is at the end of the run showing that outcome and it takes on a look that seems to speed up. Noise id assume. The Lightning probs look to show that this thing will have dynamics in its favor. I'm game either way I just wish this was happening 6 hours earlier so I could ski a powder day.

Link to comment
Share on other sites

  • Replies 1.1k
  • Created
  • Last Reply

rain changing to snow is almost never a favorable pattern for significant accumulations in the Middle Atlantic...except in March! That has been researched. If it's going to happen this would be the time to do it. But...those rates are gonna have to be intense to pile those widespread 6-10 inch amounts. If we lose the rates then the warning level snows will go with it.

Link to comment
Share on other sites

Second wave will have plenty of moisture to tap. Tapping from two oceans and a constant fetch. We are not dealing with a coastal low situation. We have enough moisture to build a rain forest.

The issue is the dense cold dry airmass that comes in and west to northwest flow is a down sloping flow...dry slotting or sharp gradients in precip. I think the nam and gfs are seeing this. PLUS...bands are very difficult to pinpoint even a few hours out let alone days!

We are likely to see intense narrow bands that dump very heavy rates in spots while steady light to moderate snow falls everywhere. Where those bands setup...only God knows!

 

Thanks for explaining. I figured the cold airmass would be the cause. But we need cold for snow!

Link to comment
Share on other sites

My personal forecast would be for a flip to Snow from 4:00am-9:00am NW/SE, DC should be changing over around 7-8am. Light to Moderate Snow through the rest of the day with Heavy Snow in the bands, this should last for 6-9hours. Total Snow in DC will be 2-5", Northern Maryland 4-7".

Link to comment
Share on other sites

My personal forecast would be for a flip to Snow from 4:00am-9:00am NW/SE, DC should be changing over around 7-8am. Light to Moderate Snow through the rest of the day with Heavy Snow in the bands, this should last for 6-9hours. Total Snow in DC will be 2-5", Northern Maryland 4-7".

Conservative. I respect that.

Link to comment
Share on other sites

rain changing to snow is almost never a favorable pattern for significant accumulations in the Middle Atlantic...except in March! That has been researched. If it's going to happen this would be the time to do it. But...those rates are gonna have to be intense to pile those widespread 6-10 inch amounts. If we lose the rates then the warning level snows will go with it.

Yeah I don't see much in terms of rates... I hope it pans out better than what the models are showing.

Link to comment
Share on other sites

Yeah I don't see much in terms of rates... I hope it pans out better than what the models are showing.

 

What models are you talking about.... the 18z NAM gives Washington Baltimore area 4 inches south to as much as 10 inches to the north.  All other models gives at least 4 inches.  Why so down?

 

The RAP has the northern counties up to at least 3 inches by 11 AM

Link to comment
Share on other sites

What models are you talking about.... the 18z NAM gives Washington Baltimore area 4 inches south to as much as 10 inches to the north. All other models gives at least 4 inches. Why so down?

I am still pissed off about the 6z gfs... Sent my entire day in to a tail spin. I think the ten inch totals will verify at around 6 or 7 and the 4 inch totals at like 2 or 3. There is no way we get max potential from qpf... So you gotta shave a little off. 3 or 4 inches really sucks compared to what the two globals were showing yesterday.

Link to comment
Share on other sites

I am still pissed off about the 6z gfs... Sent my entire day in to a tail spin. I think the ten inch totals will verify at around 6 or 7 and the 4 inch totals at like 2 or 3. There is no way we get max potential from qpf... So you gotta shave a little off. 3 or 4 inches really sucks compared to what the two globals were showing yesterday.

 

BWI averages 1.9 inches in March.  So 4 inches would be a major win.  Getting double digits in March is very hard to do.  March like last year comes once in a life time

Link to comment
Share on other sites

What I have for DC.  QPF is amount after the flip to snow.  As much of this as possible is verified, but I had to educated guesstimate for some.  

 

18z GFS - 0.38", 12-13z 

18z NAM - 0.54" - 14z 

18z4kNAM - 0.45" - 14z

18z RGEM - 0.45" - 13z

12z GGEM - 0.60" - 14z

12z EURO - 0.70" - 13z

12z UKMET - 0.60" - 14z

21z RAP - TBD - 14z

Link to comment
Share on other sites

What I have for DC.  QPF is amount after the flip to snow.  As much of this as possible is verified, but I had to educated guesstimate for some.  

 

18z GFS - 0.38", 12-13z 

18z NAM - 0.54" - 14z 

18z4kNAM - 0.45" - 14z

18z RGEM - 0.45" - 13z

12z GGEM - 0.60" - 14z

12z EURO - 0.70" - 13z

12z UKMET - 0.60" - 14z

21z RAP - TBD - 14z

 

Average:  ~.55

Link to comment
Share on other sites

What I have for DC. QPF is amount after the flip to snow. As much of this as possible is verified, but I had to educated guesstimate for some.

18z GFS - 0.38", 12-13z

18z NAM - 0.54" - 14z

18z4kNAM - 0.45" - 14z

18z RGEM - 0.45" - 13z

12z GGEM - 0.60" - 14z

12z EURO - 0.70" - 13z

12z UKMET - 0.60" - 14z

21z RAP - TBD - 14z

Even 0.4" is a good event here. Only concern would be how much of those qpf numbers would be good accumulating snow. Would think it could take an hour after changeover to start piling on all surface but I could be wrong. I guess a period of sleet would help in that regard more than a quick change to from rain to snow.

Link to comment
Share on other sites

What I have for DC.  QPF is amount after the flip to snow.  As much of this as possible is verified, but I had to educated guesstimate for some.  

 

18z GFS - 0.38", 12-13z 

18z NAM - 0.54" - 14z 

18z4kNAM - 0.45" - 14z

18z RGEM - 0.45" - 13z

12z GGEM - 0.60" - 14z

12z EURO - 0.70" - 13z

12z UKMET - 0.60" - 14z

21z RAP - TBD - 14z

If I may ask, when do we flip to IP...earlier the better it would seem

Link to comment
Share on other sites

Even 0.4" is a good event here. Only concern would be how much of those qpf numbers would be good accumulating snow. Would think it could take an hour after changeover to start piling on all surface but I could be wrong. I guess a period of sleet would help in that regard more than a quick change to from rain to snow.

 

I think we'll accumulate right away....It may take a while for the roads to capitulate but that doesnt really matter

Link to comment
Share on other sites

I am not as comfortable with the new GFS yet, but fading the GFS on winter storms coming from the south/southwest when it is an outlier is usually a good idea

Radar sure looks more like something the euro would deliver than the gfs...where would all of that stuff go?

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...