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Feb 8th Monster Ocean storm obs and hallucinations


Bostonseminole

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Ok yeah if talking about it all as meso-scale then I agree with you.

 

Looking at some BTV 4km WRF maps you can see it to some degree.

 

At the 700mb level you can see the onshore flow causing frontogenesis to develop over SE Mass, likely related to a coastal front or some sort of land-sea speed convergence.  You can see how the isotherm bends there, indicating slightly warmer mid-level temps which is likely indicative of downward sinking air as you move west of that SE Mass lift.  (Also will be interesting to see if that Berkshire band develops more as the BTV 4 really likes the Fronto in that area)

 

attachicon.gifBTV_4_700mb.png

 

A 850mb you can also see it on the low level omega.  Right along the SE Mass coast you have negative UVVs showing low level lift causing precipitation (and with the strong winds, that'll drift inland quite a bit)...but by the time you get back to PVD you are squarely in postive UVVS showing some sinking low level air.  That would easily be off-set by mid-level banding or lift, but when you couple the various levels together, the meso-scale features lead to a general decrease in precipitation rates over Rhode Island.

 

attachicon.gifBTV_4_850mb.png

 

Ekster and I ripped off some images from AWIPS during the last event. The modeling does pick up on it. If you cut a cross section through SE MA into RI, they most definitely have sinking air over RI in the low to mid levels in these set ups.

 

I know Will has mentioned it, but the really curious thing is that this seems like a recent occurrence. This subset of conditions (inversion in the mid levels, NE flow through the boundary layer, etc) should be relatively common and similar for East Coast cyclogenesis, yet we really don't remember seeing this before.

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HRRR has been way too bullish today.

 

Maybe you'll get an extra inch today.

 

Take 'em down as you like to say - though the Farmington Valley is getting it pretty good.

The HRRRX on the other hand was lighter altogether. 

 

Outside of the South Shore and Cape it always really felt more like an advisory event than warning.

 

PWM 4.4" so far, but not sure we get to 6" 

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So I'm done shoveling and I'm going with 4.5" on the bubble here in the Webster Hill neighborhood of West Hartford.......wut a joy that was to shovel compared to the sloppy mashed of Friday......nice pack right now and for once we're looking at a late season pack.....dare I say a Morch pack? Lolz......

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Met hobbyist question. What caused that dry down burst of winds this morning. I saw the pressure drops,all I can imagine is like dropping a rock in a pond the biggest wave is the first. By far way above any other winds we had today.

 

My first thought is this. Overnight your sounding probably looked something like ALY.

 

post-44-0-09851900-1454995394_thumb.gif

 

Shallow nocturnal inversion, well mixed above it. That inversion eliminates the frictional element to winds, and just above it is slightly stronger wind max. As diurnal heating, or CAA mixed out the low level inversion, you get an initial burst of winds stronger than the rest because shortly thereafter mechanical mixing makes the winds in the boundary layer more uniform. That CAA shows up right at the same time as that barograph trough you posted. So a cold front went through the area and helped mix out the nocturnal inversion.

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Just shy of 12:1 ratio here at the office (3.7 off of 0.31")

 

Just goes to show you there are many factors that go into ratios. Not only do you need the depth of the layer, but it needs to be saturated, it needs to have strong lift through it, and you want winds to be on the lighter side.

 

post-44-0-71547700-1454996225_thumb.png

 

The NAM at PWM around this time has a nearly 300 mb deep DGZ. Great for high ratio fluff. But the lift wasn't that strong, and located above the DGZ. If your omega curve looked more like what I drew in there, we could have been talking 20:1.

 

I'm guessing that was our rationale for upgrading parts of our area to warnings on the day shift. 

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