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lilj4425

The snow, sleet, and freezing rain oh my Dec 27-30 thread

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1 minute ago, burrel2 said:

GFS did trend stronger with the vort, even though it didn't translate to the surface on this run.  If we can keep getting the vort to tick stronger and dig more, we would have a chance.  

Looks like the 12z CMC doesn't even have the vort though, so... I dunno.

The vort isn't coming onshore until tomorrow morning. So perhaps we'll get one of those rapid resurgences once the models sample it.

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In the FWIW dept. RAL has taken out any possibilities after a slim one SE of the Triangle tomorrow. 

Looks cold and dry through the period.

...and they were fairly bullish up until yesterday.

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2 minutes ago, WidreMann said:

The vort isn't coming onshore until tomorrow morning. So perhaps we'll get one of those rapid resurgences once the models sample it.

Same thing happened with the Christmas storm in 2010. Not saying that’s applicable here but there’s precedent and not just with that storm.

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Just now, Queencitywx said:

Same thing happened with the Christmas storm in 2010. Not saying that’s applicable here but there’s precedent and not just with that storm.

And January 2003 if I recall. In fact, I've seen plenty of storms come back from the dead. It's just really unlikely for all of these storms that the models have seen to disappear entirely. That's pretty rare. The question now is what configuration will they return in. We probably won't get the Thursday storm exactly as depicted, but it could well be a Wednesday or a Friday storm instead.

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1 minute ago, Queencitywx said:

Same thing happened with the Christmas storm in 2010. Not saying that’s applicable here but there’s precedent and not just with that storm.

Beat me to it. That storm completely vanished only to come back strong. I remember Fischell saying on air it wasn't going to happen.

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GFS just looks late to the show. Has things firing up a good ways off the NC SC coast whereas the NAM gets the show started in South Georgia. One is wrong, obviously 

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Dude, just stop. It may not be a mega CAD situation, but with 1032-1034 down into NC, it's not gone and there won't be WAA at the surface. The GL low is not a strong powerful low. Even with strong lows, we still can see CAD hang out quick hardily before getting scoured as the low approaches. This is not even a scenario like that.

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37 minutes ago, burrel2 said:

Read more post less..... Nam has surface temps around 32 with single digit dew points in the upstate. If any precip makes it there it would drop surface temps in to the low 20's or colder.

Also, your bolded statement is just wrong... look at the wind profiles.

 

36 minutes ago, FLweather said:

Maybe you should take you own advice

Maybe you both should take my advice. KNOCK IT OFF.   

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3 hours ago, cwick20 said:

I'm trying to understand what I'm seeing with the models and how some don't seem to be reconciling the differences they have with each other. The GFS has a 1040+ HP that comes out of Montana and progresses southeast essentially squashing the low pressure. The high pressure seems to make it as far south east as the Kansas, Nebraska, Missouri, Iowa border so the low pressure in the gulf being suppressed makes sense. However, as best I can tell the European takes this high pressure across the great lakes yet for some reason the moisture from the gulf doesn't seem to come any further north. The hi-res models have this same high pressure that meanders within 100 miles of its location for several frames but then move is several hundred miles from one frame to the next. This seems odd as well. Someone help me understand this.

I guess what I'm saying is...with these differences and oddities it seems to me that something exciting could still be on the table for us. It seems to me with some of these differences there should be a wider range of possibilities than what is being shown.

No one has any input on this?

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25 minutes ago, jburns said:

 

Maybe you both should take my advice. KNOCK IT OFF.   

When someone makes a model analysis post that is that far off base, it needs to be called out and/or removed. 

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12 minutes ago, cwick20 said:

No one has any input on this?

The HP doesn't squash the LP. That's not how this works. Weather is happening in a 3d space and a lot of what drives precip and air movement is happening aloft. Precipitation is not generated at the ground.

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6 minutes ago, burrel2 said:

German model didn't back down at 12z.

P1_GZ_D5_PN_066_0000.gif

Since the NAM trended this way and the GFS has a stronger vort, it might be on to something. 

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3 minutes ago, snowlover91 said:

Since the NAM trended this way and the GFS has a stronger vort, it might be on to something. 

The German model did really well last system so I wouldn’t discount it. It is definitely holding its own and being consistent also. 

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Just now, lilj4425 said:

It also did really well last system so I wouldn’t discount it. The German model is definitely holding its own and being consistent. 

It’s incredible to me the completely different handling of the shortwave by the models when we are less than 72 hours out. I have a feeling once this comes ashore we will finally see some agreement. 

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1 minute ago, lilj4425 said:

The German model did really well last system so I wouldn’t discount it. It is definitely holding its own and being consistent also. 

Well, whatever happens, the German model has been very consistent with it's handling of the pattern. Maybe the other globals are more susceptible to small fluctuations in the pattern and it flaws their solutions. I don't know at this point. Just a wild guess. With that being said, if this model is correct, we will give it much more respect through the rest of winter.

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1 minute ago, CAD_Wedge_NC said:

Well, whatever happens, the German model has been very consistent with it's handling of the pattern. Maybe the other globals are more susceptible to small fluctuations in the pattern and it flaws their solutions. I don't know at this point. Just a wild guess. With that being said, if this model is correct, we will give it much more respect through the rest of winter.

The German model uses the ECMWF as its base: https://en.wikipedia.org/wiki/Integrated_Forecast_System.

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6 minutes ago, snowlover91 said:

It’s entirely possible for folks in GA and SC to see sleet and freezing rain in this setup. Evaporation also cooling combined with the HP forcing winds from the NE at the surface will keep the cold air in place. There is little to no warm air advection either. The Great Lakes Low is irrelevant in this scenario because of the existing airmass in place. 

Freezing rain is a self limited process.  WAA always over rides CAA.  Unless  the HP is anchored  providing low level cold air at the surface WAA will over take.  Especially if you have a weak GL low cutting off the CAA by squeezing a HP to the north.If the Nam Euro GFS etc etc etc is right or wrong. It really  doesn't matter. Cause at the end of the day weather right or wrong there is no way GA SC NC gets hit with a freezing rain from a squeezed off modified CAA or CAD.  Even 12z Gfs shows this just more progressive.  Good day. 

 

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7 minutes ago, FLweather said:

Freezing rain is a self limited process.  WAA always over rides CAA.  Unless  the HP is anchored  providing low level cold air at the surface WAA will over take.  Especially if you have a weak GL low cutting off the CAA by squeezing a HP to the north.If the Nam Euro GFS etc etc etc is right or wrong. It really  doesn't matter. Cause at the end of the day weather right or wrong there is no way GA SC NC gets hit with a freezing rain from a squeezed off modified CAA or CAD.  Even 12z Gfs shows this just more progressive.  Good day. 

 

Sure it’s a self-limiting process but when you have the best models like the NAM showing sleet and freezing rain, you can trust it with pretty high confidence as they are great with thermals, CAD, and they do in fact factor in WAA vs CAA and the latent heat release. Inside 48 hours no global model should be relied on as the mesoscale models like the 3km NAM and RGEM are vastly superior. 

Notice on the 12km NAM the winds are NE indicative of the HP still dominating the surface flow. If the GLL was dominant these winds would be out of the SE. Even well to our west there is no SW wind at the surface as the GLL is simply not relevant here. 

namconus_mslp_wind_seus_45.png

Now notice the dewpoints to the NE. Plenty of cold, dry air to advect in and sustain the ice. Again notice winds are NE.

namconus_Td2m_seus_46.png

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3 hours ago, cwick20 said:

I'm trying to understand what I'm seeing with the models and how some don't seem to be reconciling the differences they have with each other. The GFS has a 1040+ HP that comes out of Montana and progresses southeast essentially squashing the low pressure. The high pressure seems to make it as far south east as the Kansas, Nebraska, Missouri, Iowa border so the low pressure in the gulf being suppressed makes sense. However, as best I can tell the European takes this high pressure across the great lakes yet for some reason the moisture from the gulf doesn't seem to come any further north. The hi-res models have this same high pressure that meanders within 100 miles of its location for several frames but then move is several hundred miles from one frame to the next. This seems odd as well. Someone help me understand this.

I guess what I'm saying is...with these differences and oddities it seems to me that something exciting could still be on the table for us. It seems to me with some of these differences there should be a wider range of possibilities than what is being shown.

To go along with what Widre said, processes that produce precipitation mostly occur aloft, above the surface.  The movement of surface highs and lows are also dictated by the flow configuration above the surface.  In a simple view for this 'storm', just look at the direction of the flow at 500mb over the southeast.  If you want to see precip get back into the upstate, you want to see more of a SW to NE orientation to the height lines over the southeast instead of the predominant west to east (see 2 images on the left at 500mb and 700mb) - that would lead to an increase in both the moisture transport and rising motion for precip generation.

c4a8d98.gif

 

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7 minutes ago, FLweather said:

Freezing rain is a self limited process.  WAA always over rides CAA.  Unless  the HP is anchored  providing low level cold air at the surface WAA will over take.  Especially if you have a weak GL low cutting off the CAA by squeezing a HP to the north.If the Nam Euro GFS etc etc etc is right or wrong. It really  doesn't matter. Cause at the end of the day weather right or wrong there is no way GA SC NC gets hit with a freezing rain from a squeezed off modified CAA or CAD.  Even 12z Gfs shows this just more progressive.  Good day. 

 

I do not post but I do read...and I personally think you need to be put in time out....JBurns told you to knock it off.

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5 minutes ago, FLweather said:

Freezing rain is a self limited process.  WAA always over rides CAA.  Unless  the HP is anchored  providing low level cold air at the surface WAA will over take.  Especially if you have a weak GL low cutting off the CAA by squeezing a HP to the north.If the Nam Euro GFS etc etc etc is right or wrong. It really  doesn't matter. Cause at the end of the day weather right or wrong there is no way GA SC NC gets hit with a freezing rain from a squeezed off modified CAA or CAD.  Even 12z Gfs shows this just more progressive.  Good day. 

 

You are correct, freezing rain is a self-limiting process if you don't have a constant feed of low level cold air. In this case, the low-level winds are feeding cold dry air from a very cold source region. I think the disconnect is that you believe this feed will be cut-off by a great lakes low and a retreating high. I understand what you are implying, but I don't think it will happen in this instance.

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14 minutes ago, FLweather said:

Freezing rain is a self limited process.  WAA always over rides CAA.  Unless  the HP is anchored  providing low level cold air at the surface WAA will over take.  Especially if you have a weak GL low cutting off the CAA by squeezing a HP to the north.If the Nam Euro GFS etc etc etc is right or wrong. It really  doesn't matter. Cause at the end of the day weather right or wrong there is no way GA SC NC gets hit with a freezing rain from a squeezed off modified CAA or CAD.  Even 12z Gfs shows this just more progressive.  Good day. 

Ha, it's a Larry Cosgrove flashback.  Issue with this system isn't cold, it's the wretched setup for good precip

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