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1/13, 1/14 - Freezing rain threat


packfan98

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Cold Rain better get his flashlights ready.  This is about 20-30 miles from being a big deal, per the Euro.  Already is a big deal just east of Wake County down 95 corridor.

That would still be winter storm criteria for you and winter weather advisory criteria for me. I'll take that to the bank right now.

 

Edit: Would be winter storm criteria for Cold Rain...

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So does that mean I'm going to get more than a trace of freezing rain?

This -VP burst looks considerably weaker than all other events we've observed to date because the MJO is traveling considerably slower w/ rather high amplitude on the other side of the globe, at least compared to the moist CCKW behavior we've seen over the last few months. This makes sense knowing that MJO amplitude starts to tick upward in the JFM tri-monthly period, coinciding w/ the annual variance & phase cycle in the Equatorial Pacific SSTs & its associated gradient, w/ a lower gradient appearing to coincide w/ higher MJO amplitude & of course higher variance in the ENSO index

 

MJO-amplitude-in-the-year1.gif

 

 

The seasonal cycle in SSTs is partially to blame for the collapse in the Equatorial Pacific SST gardient in the spring. It's amazing transformation actually, in the fall (SON) the gradient is nearly 8C versus ~4C in MAM tri-monthly (which also effects the intensity of the easterly trade winds & bjerknes feedback, both of which are generally weakest in the spring, also in concert w/ the SST gradient collapse. It's no wonder that the ENSO predictability barrier for the climate models is in the spring, when the Eq Pac is most susceptible to intraseasonal Oceanic KW variance.

This collage below shows the tri-monthly NOAA Extended SSTs for the 4 tri-monthlies from DJF (top) thru SON (bottom). I use a SST range from 21.5 to 29.5C w/ an interval of .25C.

Equatorial-Pacific-SSTs-DJF-SON-1948-201

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Cold Rain better get his flashlights ready.  This is about 20-30 miles from being a big deal, per the Euro.  Already is a big deal just east of Wake County down 95 corridor.

Timing would be crucial there ... obviously getting that rain before temps dipped below 0c wouldn't serve any purpose. FWIW, the NAM did push a pulse of moisture through the Sandhills between 6 and 9 a.m. If the EURO is seeing the same thing, that would make for a messy morning.

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This -VP burst looks considerably weaker than all other events we've observed to date because the MJO is traveling considerably slower w/ rather high amplitude on the other side of the globe, at least compared to the moist CCKW behavior we've seen over the last few months. This makes sense knowing that MJO amplitude starts to tick upward in the JFM tri-monthly period, coinciding w/ the annual variance & phase cycle in the Equatorial Pacific SSTs & its associated gradient, w/ a lower gradient appearing to coincide w/ higher MJO amplitude & of course higher variance in the ENSO index

 

 

 

The seasonal cycle in SSTs is partially to blame for the collapse in the Equatorial Pacific SST gardient in the spring. It's amazing transformation actually, in the fall (SON) the gradient is nearly 8C versus ~4C in MAM tri-monthly (which also effects the intensity of the easterly trade winds & bjerknes feedback, both of which are generally weakest in the spring, also in concert w/ the SST gradient collapse. It's no wonder that the ENSO predictability barrier for the climate models is in the spring, when the Eq Pac is most susceptible to intraseasonal Oceanic KW variance.

This collage below shows the tri-monthly NOAA Extended SSTs for the 4 tri-monthlies from DJF (top) thru SON (bottom). I use a SST range from 21.5 to 29.5C w/ an interval of .25C.

So, um, was that a yes?

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How wet?

Looks to be around .1 or so for RDU with perhaps a little more toward GSO. My take-away is that it's in the camp of putting measurable QPF over the eastern Piedmont as opposed to focusing over the coastal plain.

Thanks for the temp info, Pack.

And, I'm just messing with Webber. Although, I'm not 100% sure, it seemed like the implication was that this will be a very light event, consistent with what the models are showing.

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Yeah, looking at it locally, I could see the typical problems on the typical roads. Going to depend on how much QPF can make it back west. 

 

This is interesting. Would the GFS and Euro pick up on the over running drizzle or is the QPF mainly produced from a developing weak LP? Seems like we are awfully close to .2 qpf

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Needless to say the NAM is wetter. Just looking at the 48 hour totals it looks like the .25 line gets almost to Charlotte.

 

RDU looks to be right at .5 liquid. The big story here is how far back the .25 line went - Charlotte to Greensboro

 

http://mag.ncep.noaa.gov/Image.php?image=data%2Fnam%2F18%2Fnam_namer_051_precip_p24.gif&model=nam&area=namer&storm=&cycle=18&param=precip_p24&fhr=051&group=Model+Guidance&imageSize=M&ps=model&use_mins=no&preselected_formatted_cycle_date=20150112+18+UTC&scrollx=0&scrolly=0

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