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Pattern Fab-February 2020 The dark age

Dawgdaze22 said:
Do we like this?
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Broken024 said:
What does this mean
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Honestly, I'm not 100% sure. When looking at the trend with energy, I feel that it may be a bit worse. We want the energy to be linear and not to trend to northern CA, but really this isn't a bad look. Although I haven't really seen much modeling yet for this setup, so I'm not sure about the rest of the features besides the shortwave.
00z
ecmwf-ensemble-avg-namer-vort500_z500-2135200 (1).png
12z
ecmwf-ensemble-avg-namer-vort500_z500-2135200.png
18z
ecmwf-ensemble-avg-namer-vort500_z500-2135200.png
 
SD said:
Short story first then a longer story below. Basically what little bit of a SER there is, is allowing the sfc front to move south but its delaying the passage of the fronts aloft meaning we keep a warm air advection pattern going inspite of an arctic front moving through. This in a general sense will give you clouds and some light precip but with the STJ in play and the 500mb flow tapped into the Pacific and out of the WSW we are able to funnel low amplitude waves in and enhance precip chances
Longer answer:
In this case the SER is acting like a road block. As the initial trough moves through the lakes and into the NE the sfc front gets propelled south. While its moving south the bc energy in the NE scoots off shore and the flow becomes more west to east. This flow parallel to the front causes it to slow but still inch south, given the fact the models are showing 1040+ building in behind the front you will still get a nice south push even with some SER at 500mb. Now as you go up a couple of levels into the 850 and 700mb levels the fronts and troughs are being slowed and stopped gradually farther north. At 162 on the euro the 850mb front was located along I20 and the 700mb front along I40, this means you are getting moist air moving in at one or both levels. This also gives you convergent boundaries aloft to further aid in lift and focus for precipitation. As you go above this into the 500mb level you have a WSW flow which is tapped into the Pacific and we are able to bring shortwaves embedded in the STJ into the region. Additionally the fight between the SE ridge and the low in the northeast means we have a steep height gradient across the east, this leads to more channeled sheared vorticity and limits amplification so we are having to worry about energy in the flow being too strong and causing things to trend NW. Long story short on H5, you get into a situation where yo could have numerous small impulses moving in the flow and batches of heavier precipitation as these move west to east. Finally as you get into the 300 and 200mb the heart of the STJ is running just to our north so we are able to capitalize on the additional jet dynamics and further enhance the lift.
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.And this is why they call you the Captain
 
Jon said:
That’s not the system, we are looking further ahead in the 2/21-23 time period...


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I gotcha trying to see where the precip is heading upstream since the 18Z doesn't go out that far. The 12z from similar time is below
us_model-en-087-0_modez_2020021312_156_5_155.png
 
Broken024 said:
Isnt that the start if it (over running) or is that after?
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That is overrunning but it’s not the system that produces snow for the SE. It’s just moisture along the frontal boundary, likely all rain for the SE. It has nothing to do with the wave that produces snow. We are waiting for the northern stream energy to rotate around and either go neutral tilt to produce a surface low, or a ULL that is left out west to kick out and move East, producing a low later (around 2/22-23)...

The earliest we can look on the modeling right now to see how things will go downstream is around ~120hours, when we can see if the energy will break off and stall over CA or if the energy will stay with the northern stream and move East.


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Jon said:
That is overrunning but it’s not the system that produces snow for the SE. It’s just moisture along the frontal boundary, likely all rain for the SE. It has nothing to do with the wave that produces snow. We are waiting for the northern stream energy to rotate around and either go neutral tilt to produce a surface low, or a ULL that is left out west to kick out and move East, producing a low later (around 2/22-23)...

The earliest we can look on the modeling right now to see how things will go downstream is around ~120hours, when we can see if the energy will break off and stall over CA or if the energy will stay with the northern stream and move East.


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Yep sorry looked at timing wrong. Thanks buddy
 
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