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3/6-3/7 Last Hurrah Obs


Hvward

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The battle ground is the piedmont of NC. The rates are expected to increase, but will it be enough to counter the WAA.

 

Correlation Coefficient (CC) is by far the best tools to use to show the snow/mix/rain lines. Here its the line that goes from red/yellow-green/red again. Note again that CC tells you the correlation of hydrometers (meaning comparing one drop or snowflake to another to see how well their dimensions correspond to the other). In cases where there is mixing you expect to see low CC where snowflakes (primarily uniform horizontal and vertical axis) have much different dimensions in comparison to raindrops (which typically have a larger horizontal axis than vertical axis). Note that once you get close to the radar in Raleigh, most of the precip is rain again because the drops all have the same ratios.

 

codnexlab.NEXRAD.RAX.N0C.20140307.127.04

 

Regarding the loop you can tell dynamically cooling (due to melting snowflakes) is having an effect on this precipitation type gradient because the area of mixing has increased in size both horizontally and in the vertical (noting we are looking at a 0.5 degree beam that is moving upward in the atmosphere the further away from the radar you go). Thus, dynamical cooling is "fighting" the warm air advection that is causing the mixing line to move northward. It will be fun to watch how this plays out tonight.

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The battle ground is the piedmont of NC. The rates are expected to increase, but will it be enough to counter the WAA.

 

Correlation Coefficient (CC) is by far the best tools to use to show the snow/mix/rain lines. Here its the line that goes from red/yellow-green/red again. Note again that CC tells you the correlation of hydrometers (meaning comparing one drop or snowflake to another to see how well their dimensions correspond to the other). In cases where there is mixing you expect to see low CC where snowflakes (primarily uniform horizontal and vertical axis) have much different dimensions in comparison to raindrops (which typically have a larger horizontal axis than vertical axis). Note that once you get close to the radar in Raleigh, most of the precip is rain again because the drops all have the same ratios.

 

[sNIPPED IMAGE}

 

Regarding the loop you can tell dynamically cooling (due to melting snowflakes) is having an effect on this precipitation type gradient because the area of mixing has increased in size both horizontally and in the vertical (noting we are looking at a 0.5 degree beam that is moving upward in the atmosphere the further away from the radar you go). Thus, dynamical cooling is "fighting" the warm air advection that is causing the mixing line to move northward. It will be fun to watch how this plays out tonight.

 

Yes, it looks to be moving back SE-ward a bit now that rates are finally picking up.  Good news.  I'd at least like to stay IP for awhile. :)

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Not sure what to think but greensboro (georgia), which is south of here,  has gone from reporting unknown precipitation for an hour to light snow now with visibilities dropping to 1.75 miles. There has been a persistent area of heavy precip there for a while. It lies in the heart of the cold 925 to 950mb temps and 850s are between 1 and 2c per meso. Can't tell via radar as it's far enough away to not be able to tell.

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Hopefully the wetbulbs make a surge back like Matthew East said is possible this morning. The high isn't going anywhere soon, and if it keeps driving in cool dry air they can go down. And most of us are only one or two degrees away. The set bulbs have shifted east and you can see that as well in the radar loop if how much is filling back in now.

Not that it will amount to much, but better than 33 and rain.

www.intellicast.com/National/Radar/Current.aspx?location=USNC0121&animate=true

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32.1 currently and it looks like the freezing line is literally less than five miles to both the north and the west of me. Add to that the heavier rates seem to be missing just west as well and this is getting really frustrating. Then again Durham was never really "in" the ballgame.

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Been rain from the get go minus some light sleet mixing in at onset. Getting at and below freezing now starting to glaze on elevated.

Watch the accuweather radar loop and you can see the heavier returns showing snow echoes instead of rain around rock hill and changing up through sporadic areas in southern NC. I'm on a iPad, so I can't pull up all my handy dandy radar sites. There is some truth to getting under the heavier returns and having a shot to see a burst of snow. Neat trend to watch over the next hour or two as those heavy returns come up from our south. I'm trolling looking for any obs to see if what that crappy radar is spewing out has any merit.

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