Jump to content
  • Member Statistics

    17,600
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

march 5-7 potential heavy rain event


earthlight

Recommended Posts

Here's a snippet from this mornings discussion which I wrote on the blog

http://nymetrowx.blogspot.com/p/forecast-discussion.html

The front shifts eastward Sunday and the low level jet is forecast to strengthen and develop along the front as a mid level shortwave amplifies eastward. As the trough amplifies later Sunday a southern stream feature will get involved..enhancing the moisture feed as the front slows near our area. This definitely raises the concern for a heavy rain event along the frontal boundary--but the positioning of the front still remains somewhat uncertain. That being said, most models have the area of low pressure strengthening from the TN Valley over the Mid Atlantic to near our area on Monday with a negatively tilted mid level trough and low level flow parallel to the front. We increased probability of precipitation for this time frame with the heavy rain potential. No flood hazards posted yet but they will be issued over the next 24 hours if there are no major changes amongst guidance.

With cold air becoming entrained into the system as this wave develops, northwest locations may see a flip to frozen precipitation before it ends. That being said, not totally sold on this scenario yet, but it is wise to at least consider it given the general signal on the GEFS and ECMWF OP and means.

Link to comment
Share on other sites

  • Replies 317
  • Created
  • Last Reply

I know heavy rain/flooding events are not high topic of conversation around here but this is definitly a real threat. I suspect that the 12z GFS will increase QPF amounts. I was thinking to myself last night, I wonder if the strength of that southern stream energy is not being sampled well yet. If that energy ends up stronger, and tilts the trough sooner than thought, we could end up with a much stronger, more organized wave. The 12z NAM looks like its ready to explode at the end of its run.

Link to comment
Share on other sites

I know flooding is no heavy rain/flooding events are not high topic of conversation around here but this is definitly a real threat. I suspect that the 12z GFS will increase QPF amounts. I was thinking to myself last night, I wonder if the strength of that southern stream energy is not being sampled well yet. If that energy ends up stronger, and tilts the trough sooner than thought, we could end up with a much stronger, more organized wave. The 12z NAM looks like its ready to explode at the end of its run.

I think it becomes a topic of more discussion once it comes to fruition. Lots of people are a bit wary of the high QPF amounts, and rightly so. But still--this is a pretty good setup. The frontal timing is the still up the air, but the mid level trough orientation and low level jet/low level flow is pretty favorable for getting some good moisture along the front.

I'd also watch out for some sleet Friday Night as I noted in my discussion with the onshore flow and the cold wedge holding on.

Link to comment
Share on other sites

I think it becomes a topic of more discussion once it comes to fruition. Lots of people are a bit wary of the high QPF amounts, and rightly so. But still--this is a pretty good setup. The frontal timing is the still up the air, but the mid level trough orientation and low level jet/low level flow is pretty favorable for getting some good moisture along the front.

I'd also watch out for some sleet Friday Night as I noted in my discussion with the onshore flow and the cold wedge holding on.

I think too many people live and die around here with one model. All of the models have been all over the place with this event and with all the events this year in general.

Link to comment
Share on other sites

I think too many people live and die around here with one model. All of the models have been all over the place with this event and with all the events this year in general.

It's more of the fact that rain isn't that exciting, and a little bit of the fact that most of the time the models spit out 2"+ QPF...it's complete rubbish.

Looking past that, this is definitely a good synoptic setup for heavy rains along the front from what we can gather at this range. Still plenty of time to watch it unfold.

Link to comment
Share on other sites

lol.. I've never been weenied before.. should I take this as an accomplishment or total embarassment?

Let's consider it an accomplishment for the sake of metfan's poor soul...he has a trophy case of :weenie:'s which he kisses every morning before going to work slave labor at CVS.

Link to comment
Share on other sites

The models have been all over the place in regard to strength,location,and intensity of the frontal waves.

Once they finally settle down, we should get a good idea of where the heaviest rain will set up.

With PW's going over 1 inch and a slow moving front and a big high offshore,the heavy rain potential

is there.

Link to comment
Share on other sites

The models have been all over the place in regard to strength,location,and intensity of the frontal waves.

Once they finally settle down, we should get a good idea of where the heaviest rain will set up.

With PW's going over 1 inch and a slow moving front and a big high offshore,the heavy rain potential

is there.

Yeah, agreed on all counts. It's still in the medium range so as usual we could still see some significant changes. One thing I have noticed over the past few weeks has been the tendency for models to be way too strong with shortwaves in this range. The progressive flow is not allowing these things to amplify nearly as much as advertised.

You can use the severe weather event in the midwest last week as an example. Around this range (84-102 hrs) most models had a cutoff low with intense PVA ejecting northeast into the Plains and eventually de-amplifying into the MS Valley. In reality, as the event happened, the shortwave was nowhere near closed off at H5 and was very fast..it resulted in a completely different severe weather dynamic. Obviously it was still a strong severe weather event, but the H5 depiction was severely overdone at this range by almost all guidance.

Something to keep in mind.

Link to comment
Share on other sites

It's more of the fact that rain isn't that exciting, and a little bit of the fact that most of the time the models spit out 2"+ QPF...it's complete rubbish.

Looking past that, this is definitely a good synoptic setup for heavy rains along the front from what we can gather at this range. Still plenty of time to watch it unfold.

I remember last year, when the Carolina's were getting crushed with heavy rain and we got hit with that "fire house" the high res were spitting out 10" of rain for our region. Of course I know not to take model QPF too seriously but I love this setup for heavy rain, and lots of it. The system in ten days looks like a very similar setup in alot of ways.

Link to comment
Share on other sites

Yeah, agreed on all counts. It's still in the medium range so as usual we could still see some significant changes. One thing I have noticed over the past few weeks has been the tendency for models to be way too strong with shortwaves in this range. The progressive flow is not allowing these things to amplify nearly as much as advertised.

You can use the severe weather event in the midwest last week as an example. Around this range (84-102 hrs) most models had a cutoff low with intense PVA ejecting northeast into the Plains and eventually de-amplifying into the MS Valley. In reality, as the event happened, the shortwave was nowhere near closed off at H5 and was very fast..it resulted in a completely different severe weather dynamic. Obviously it was still a strong severe weather event, but the H5 depiction was severely overdone at this range by almost all guidance.

Something to keep in mind.

Yeah,and the theme of lows moving up between big areas of high pressure to our east and west.

Link to comment
Share on other sites

10am Thursday and the warmest location I can find on this map is 29 degrees in Woodbine in Cape May county

njwxnet-temperature_midsize.jpg

yep.. cold air is locked in pretty good today.. winds are due north.. perfect trajectory in these parts for keeping temps from rising much. I know in the hudson valley, there is a local affect of cold air draining southward. Surface high also builds in and centers close to us... that will limit the ability to completely mix out.

Link to comment
Share on other sites

Yeah these temps are pretty impressive today. I'm 26.5F with a light NLY wind under full sun in early March. :snowman:

After coming off one of the worse winter febuarys imby for sometimes, this cold weather is def a shock to the system. I really wish we could have cashed in on one of those 3-6 events 2 weekends ago, that was prob our last shot.

Link to comment
Share on other sites

After coming off one of the worse winter febuarys imby for sometimes, this cold weather is def a shock to the system. I really wish we could have cashed in on one of those 3-6 events 2 weekends ago, that was prob our last shot.

February 2009 wasn't anything to write home about, either....there was a Norlun event early in the month but that was basically it except for a SW flow event around the 18th that started as snow in some areas. In fact, only last February stands out as snowy in recent winters.

I'm sure we'll have a couple more chances for accumulating snow, as it's only March 3rd. The 0z ECM has been clinging to the idea of a cut-off low meandering off the Atlantic coastline in the longer range. I think we may see a threat Day 8-10 as we look to get a brief North Atlantic ridge with a rising PNA. Also, you can never rule out a late-season snowstorm in a Niña winter; the famous March 1956 event wasn't until the 18th. I'd definitely like to see a better signal for a -NAO, however.

Link to comment
Share on other sites

February 2009 wasn't anything to write home about, either....there was a Norlun event early in the month but that was basically it except for a SW flow event around the 18th that started as snow in some areas. In fact, only last February stands out as snowy in recent winters.

I'm sure we'll have a couple more chances for accumulating snow, as it's only March 3rd. The 0z ECM has been clinging to the idea of a cut-off low meandering off the Atlantic coastline in the longer range. I think we may see a threat Day 8-10 as we look to get a brief North Atlantic ridge with a rising PNA. Also, you can never rule out a late-season snowstorm in a Niña winter; the famous March 1956 event wasn't until the 18th. I'd definitely like to see a better signal for a -NAO, however.

I got six from that norlun event in 2009, and i remember the bitter cold temps for a few days after that storm. Its been a very long time that i have not seen 2 inches of snow in febuary, in a nut shell this febuary has suck imby. As we go foward into march nate its over, nina has taken over and just pre-pare for a very wet spring....

Link to comment
Share on other sites

12Z NAM through 84hrs before QPF really reaches our region. It's hard to tell how much we would end up with this but the low looks to be in a good position, the trough is already negitive and the simulated radar is impressive.

LOL, really? extrapolating nam precip at 84 hours? this model has a terrible qpf bias as it is, let alone being pretty much a random number generator after 48 hours.

gfs just came in not that wet with its new run.

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...