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Severe weather thread number ...I think X ?


Typhoon Tip

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Pretty much how most smaller scale (and even large ones) tornado events come together. :P

DFW found out firsthand earlier this year.

One of my big concerns is that given the likely position of the surface low, that the models could be underestimating the backing of LL winds somewhat (especially the GFS), which would ramp up helicity values even more (considering instability is already likely to be more than sufficient). I don't think it would be enough to advect a stabilized layer off of the ocean, however.

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Pretty much how most smaller scale (and even large ones) tornado events come together. :P

We're pretty much at the point I think to where not really much more model data we can look at...except of course the models that are more equipped for mesoscale type stuff.

Just have to wake up in the AM, look at satellite/radar to determine when any convection/showers move out, how long it will take to clear, and then figure out where these leftover boundaries are residing.

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I admittedly haven't looked at the GFS much (mostly the NAM) but a cursory glance down in NJ seems to show it lacking the EML that the NAM shows entirely (and hence lower lapse rates and less of a cap). Why would that be?

I've noticed the NAM seems to favor EMLs, you often see them on the NAM soundings but not on the GFS. I don't know why this is. I was actually going to post about this during the run up to tuesday's non-event, when I noticed much the same thing happening, EML on the NAM but not GFS.

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I do think the amount of low level shear, coupled with the forecast LCL heights being so low (despite the warm air mass) will yield a couple storms that have couplets that seemingly appear from nowhere so to speak. You'll see a fairly innocuous meso that jumps to around 100 kts in a volume scan as boundary interaction triggers tornadogenesis.

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Definitely struggling with forecasting the southward extent of the severe weather into Northern NJ/NYC. As HM mentioned you can see the vort coming into better focus now, and the NAM seems to be responding, although its never really smart to take these QPF or simulated radar images too seriously.

The gradient has been jumping around a bit, I've been watching the 582dm height line shift back and forth...I think where that gradient sets up will eventually be a big playmaker in whether or not this MCS takes a southeast turn into N NJ/NYC or not.

http://www.meteo.psu.edu/~gadomski/WRFEAST_18z/f33.gif

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Hopefully this pans out for you guys. Lots of excited weenies in here.

This doesn't look as good as 6/1 last year...but that was kind of exceptional. The clearing is the biggest worry, but SW areas have a better shot at doing it. This potential looks a bit later in the day than 6/1 too.

A lot of the instability on the NAM i sbeing generated by 72-74F dewpoints which you always wonder about. Last year, we actually were able to realize dews in the low 70s. One of the biggest plusses for SW area is it looks like they get a remnant EML in there...most of our biggest problems come from poor ML lapse rates.

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This doesn't look as good as 6/1 last year...but that was kind of exceptional. The clearing is the biggest worry, but SW areas have a better shot at doing it. This potential looks a bit later in the day than 6/1 too.

A lot of the instability on the NAM i sbeing generated by 72-74F dewpoints which you always wonder about. Last year, we actually were able to realize dews in the low 70s. One of the biggest plusses for SW area is it looks like they get a remnant EML in there...most of our biggest problems come from poor ML lapse rates.

Yeah I'm not too confident on any of this northeast of Hartford.

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Can anyone else think of a SWODY2 moderate risk in SNE besides this one?

comparing outlooks is kind of sketchy since it's pretty subjective. how many times have they mentioned a derecho in d2?

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Yeah I'm not too confident on any of this northeast of Hartford.

I'm trying to recall the 6/1/11 set-up, but I thought that the models the day before, or the day of, showed the best chance for tornadoes in CT. However, when it came to fruition, reality shifted North a good 25-50 miles or so. I suppose tomorrow morning will give us a better idea where things set up.

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Are the tornados with the morning warmfront? Surface winds and directional shear look better around that time. The evening looks better for Micro/Macrobursts.

Best shot would probably be early/mid afternoon for tornadoes as the storms would be more discrete and there is still a lot of low level shear.

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7pm Box update on MCS:

7 PM update...

High cloud shield from advancing mesoscale convective system is working its way into

southern New England this evening. Winds have diminished across

most of area and combination of increasing clouds and dry airmass

will prevent fog formation inland tonight.

18z models still uncertain as to where mesoscale convective system will track overnight.

GFS keeps it north across Vermont/New Hampshire while NAM shows more of a southern

track into more of CT/RI/MA. Latest 3km hrrr seems to mirror NAM

and may even be farther S. Should be approaching our area toward

4 am Thursday.

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Beginning of the MCS over MI/WI it appears right now. Our 4km WRF has a good handle on this and brings it across NYS before falling apart around 12z near BGM.

Yeah I'm not sure if that is much of anything for a large part of the state, but it's later on that counts anyways.

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Beginning of the MCS over MI/WI it appears right now. Our 4km WRF has a good handle on this and brings it across NYS before falling apart around 12z near BGM.

Any updates on what the 4km WRF does later in the day? The mesoscale models have been jumping around big time with the MCS track in the early AM.

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Any updates on what the 4km WRF does later in the day? The mesoscale models have been jumping around big time with the MCS track in the early AM.

Yeah I'm not sure if that is much of anything for a large part of the state, but it's later on that counts anyways.

WRF is similar to the HRRR. Dying MCS 12z-14z from NJ to CT. I'm pretty sure this is the way to go. Some showers/rumble of thunder in the morning then we slowly clear out.

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