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Genug Shoyn Mit warm and brown! Is Jan 19-20 a storm to shift the vibe?


mahk_webstah
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I posed this question over on Twitter and I'll pose it here too, but I wonder if the loss of weather balloon launches at both Albany, NY and Chatham, MA contributed to today's precipitation type bust? Albany's is due to the apparent Helium shortage and Chatham's due to beach erosion threatening the launch site. Without this valuable upper air data, I wonder if the warm layer aloft was not adequately sampled prior to data ingestion into the 12z model suite, leading to the models predicting colder p-types than what they should have been. After all, a model is only as good as the data that goes into it; hence the term I learned in NWP class back in the day: "garbage in, garbage out". 

Even today's 12z 3-km NAM (which is usually the warmest among the guidance in these scenarios) had many areas in N MA, S VT, and S NH snowing for a few hours before eventually flipping to sleet and freezing rain. This would've likely led to a few inches before the changeover, but instead it was PL/RA/ZR from the onset. While many places did eventually change to snow briefly due to diabatic cooling eroding the initial warm layer aloft, it took nearly 2 hours here and the WAA won out faster than I had anticipated, flipping my hard earned snow quickly back to PL/RA/ZR after only about 30-40 minutes.

I tend to think that the warm layer aloft that was in place prior to the precipitation beginning was warmer than what the 12z models had expected, leading to the warmer p-types observed and longer changeover times to snow. 

I know that the models often underestimate the WAA aloft with these SWFEs, but usually the high res NAM does a better job than this inside of 12-24 hours to the event. 

In the absence of upper air data from weather balloon launches, how do we know what the actual temperatures aloft are for a given place and time at say the 850 mb level? Satellite data? If it is satellite data, how accurate is it? Just musing over why things transpired the way they did today...

 

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7 minutes ago, wxmanmitch said:

I posed this question over on Twitter and I'll pose it here too, but I wonder if the loss of weather balloon launches at both Albany, NY and Chatham, MA contributed to today's precipitation type bust? Albany's is due to the apparent Helium shortage and Chatham's due to beach erosion threatening the launch site. Without this valuable upper air data, I wonder if the warm layer aloft was not adequately sampled prior to data ingestion into the 12z model suite, leading to the models predicting colder p-types than what they should have been. After all, a model is only as good as the data that goes into it; hence the term I learned in NWP class back in the day: "garbage in, garbage out". 

Even today's 12z 3-km NAM (which is usually the warmest among the guidance in these scenarios) had many areas in N MA, S VT, and S NH snowing for a few hours before eventually flipping to sleet and freezing rain. This would've likely led to a few inches before the changeover, but instead it was PL/RA/ZR from the onset. While many places did eventually change to snow briefly due to diabatic cooling eroding the initial warm layer aloft, it took nearly 2 hours here and the WAA won out faster than I had anticipated, flipping my hard earned snow quickly back to PL/RA/ZR after only about 30-40 minutes.

I tend to think that the warm layer aloft that was in place prior to the precipitation beginning was warmer than what the 12z models had expected, leading to the warmer p-types observed and longer changeover times to snow. 

I know that the models often underestimate the WAA aloft with these SWFEs, but usually the high res NAM does a better job than this inside of 12-24 hours to the event. 

In the absence of upper air data from weather balloon launches, how do we know what the actual temperatures aloft are for a given place and time at say the 850 mb level? Satellite data? If it is satellite data, how accurate is it? Just musing over why things transpired the way they did today...

 

I Dunno, guidance was always borderline and when that happens, I’d always lean conservative. 
 

Besides  the better lift comes in tonight when thicknesses starts to fall. You may see many areas flip. 

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30.7/26  Very light snow  1/4"  Heavier batch incoming..

Interesting post from wxmanmitch about the balloons.  The world is running out of helium.  If balloon launches become unavailable in the future I wonder what will happen?  So stupid that even now helium is wasted with party balloons etc.  

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