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stormtracker

February 18/19 Party - STORM MODE

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Total precip while the column supports Snow-ish for us close in...Better North and West.

nam-218-all-ma-total_precip_inch-3660400.png

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2 minutes ago, Ji said:

i think the 6z run was better

I’ll take the 12z in DC... over 1 inch qpf of snow/sleet by 18z.

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1 minute ago, stormtracker said:

Yeah, this runs seems better for us.

look at 17z for 6z vs 12z. Here is 6z. Maybe the 12z has a better front end

namconus_ref_frzn_neus_35.png

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Just now, baltimoreguy said:

Baltimore caught in the crab claw

Just keep in mind that the Super Bowl storm showed the I-95 corridor being the precip max right up until the start.  Meso bands are not well predicted ahead of time.

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16 minutes ago, mdhokie said:

Is the problem still at 700-800mb? Seems like soundings have consistently shown a warm nose and many mets in here have been pointing out southerly winds in the mid levels? This is all above my pay grade but would be interesting to compare the modeled mid level maps to previous storms and see what is different.

Yes, the issue with this storm is almost entirely in the mid-levels. Surface track does matter to an extent, and it is favorable for us, but the upper-level low tracks right over us - you want it to be south and east. Trough axis as a whole is too far west. We end up getting stronger warm air advection at the 700-850 mb level and that's what changes the cities over to sleet and freezing rain. The stronger warm air advection is also what's helping create lift and why you're seeing the intense FGEN bands depicted on the front end. 

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27 minutes ago, psuhoffman said:

*This is NOT a storm cancel or autopsy.  It could break our way. Just wanted to highlight something larger scale going on*

I wanted to illustrate something. 
0D21D6AE-9E49-4B1B-98EF-E016ECE1332E.thumb.jpeg.c85556f08f40b8f1420a40fe5ac5827e.jpeg

look at 6z. This is generally the same across guidance. The primary dies in eastern TN. The coastal takes over and tracks from outer banks to east of Delmarva. Look at where the banding of precip is. That blue area is where it SHOULD be snow. But it’s not. It’s mixed with sleet and freezing rain all the way to the PA line. 
 

Guidance isn’t trending north. It’s trending warmer. And I don’t know why. What are we even rooting for there?  That track is absolutely PERFECT in every way!  We have an Arctic high in place. Cant use the “no cold air” excuse. This keeps happening a lot lately. Tracks that should produce snow in DC find a way not too or produce way less then they SHOULD.  It’s frustrating and troubling. 

The trough axis at that point is in the central Plains.  While we do pop a surface low in the right spot, this is not a good setup for an all-snow event for our region, no matter what the year is.

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16 minutes ago, snowmagnet said:

I don't know if it is relevant, but last week, I was watching it snow and later sleet at my house for many hours, but the weather apps and radar said rain.  And the other day, it was showing snow on radar, while it was definitely raining.  

We were supposed to get a full day of freezing rain with the last storm and instead it was on-and-off and mixed with far more sleet than forecast or modeled..

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16 minutes ago, mdhokie said:

Is the problem still at 700-800mb? Seems like soundings have consistently shown a warm nose and many mets in here have been pointing out southerly winds in the mid levels? This is all above my pay grade but would be interesting to compare the modeled mid level maps to previous storms and see what is different.

It’s mid levels yes but there is usually a mid level warm layer when we have a storm.  I’m going to simplify this but I feel it’s an accurate summary. There almost has to be a warm layer because it’s WAA as the wave approaches that is the primary impetus for precip. The warm air is lifted over the denser cold and that lift creates the precip. But warm is relative to normally very cold air at those levels. Rising air cools and condenses so it’s cooling as it rises. So long as that mid level “warm” layer stays just below freezing it’s ok.  But what happens if EVERYTHING is say 2 degrees warmer then it used to be?  Then a “warm” layer that was -1 is now +1 and the mix line just jumped 50 miles north!  

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2 minutes ago, Winter Wizard said:

Yes, the issue with this storm is almost entirely in the mid-levels. Surface track does matter to an extent, and it is favorable for us, but the upper-level low tracks right over us - you want it to be south and east. Trough axis as a whole is too far west. We end up getting stronger warm air advection at the 700-850 mb level and that's what changes the cities over to sleet and freezing rain. The stronger warm air advection is also what's helping create lift and why you're seeing the intense FGEN bands depicted on the front end. 

I was just looking at the NAM hour 27 700 map. Why would it have winds streaming in from the due south out of Central VA when the prevailing winds are out of the SE? Seems weird to me?

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Interestingly (?) the NAM has dramatically reduced the 700mb warm layer that was showing up yesterday.  Look at the difference between 12z yesterday and today for my area.  

Warm layer now is 800-850mb, which was also present yesterday.  Eventually, the 700mb warm layer does punch in, but several hours slower than shown previously.  

 

1334639815_nam3km_2021021712_fh25_sounding_77.15W76.46W39.05N39_42N.thumb.png.cb634414344fc6dca9607d4d601b7974.png1208232051_nam3km_2021021612_fh49_sounding_77.25W76.49W39.05N39_44N.thumb.png.a076a740d717869bf4dfc8972c5413d0.png

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12 minutes ago, Baltimorewx said:

The 3K NAM isnt nearly as good as reg NAM...sleet much faster

Seems like a precip issue to me than a "warmer" issue.  Its not nearly as wet through 15z as the 12k.  700 winds looked to have backed off quite a bit as well compared to 6z.  has about half the precip as the 3k has during the time when the column is supportive.

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2 minutes ago, MN Transplant said:

The trough axis at that point is in the central Plains.  While we do pop a surface low in the right spot, this is not a good setup for an all-snow event for our region, no matter what the year is.

I see the “flaws”. It’s not perfect. It’s not a hecs setup. But we’ve had snowstorms in this kind of setup before where a cold airmass in front and a perfect track offset that kind of trough axis.  I remember one in 2004 actually that was a 4-8” event across the area that did eventually go to ice but only after the WAA banding ended and we dryslotted. 
 

I guess my point is we keep making excuses for why these little imperfections were the reason it didn’t snow but imo it shouldn’t be this difficult. We shouldn’t need EVERYTHING to be 100% absolutely perfect to get a simple 4-8” snowstorm. I’m taking the 10,000 foot view that it seems pretty good but not perfect setups that used to break our way a decent (not all) amount of the time seem to break bad a lot more recently. 

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Just now, LP08 said:

Seems like a precip issue to me than a "warmer" issue.  Its not nearly as wet through 15z as the 12k.  700 winds looked to have backed off quite a bit as well compared to 6z.  has about have the precip as the 3k has during the time when the column is supportive.

12z 3k is certainly better then 6z was for the metro areas.  Better snow thump before sleet.  3k has been sleetier than the 12k since the get-go as it's usually better at seeing thin warm layers in the vertical column.  

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Just now, WxUSAF said:

12z 3k is certainly better then 6z was for the metro areas.  Better snow thump before sleet.  3k has been sleetier than the 12k since the get-go as it's usually better at seeing thin warm layers in the vertical column.  

Trajectory of the precip from the SW on the 3k was better as well.  It just doesn't send as much through the area before the column issues arise.  6z had it into PA.

1613660400-n9p4EnCfuw8.png

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8 minutes ago, Winter Wizard said:

Yes, the issue with this storm is almost entirely in the mid-levels. Surface track does matter to an extent, and it is favorable for us, but the upper-level low tracks right over us - you want it to be south and east. Trough axis as a whole is too far west. We end up getting stronger warm air advection at the 700-850 mb level and that's what changes the cities over to sleet and freezing rain. The stronger warm air advection is also what's helping create lift and why you're seeing the intense FGEN bands depicted on the front end. 

Yep, the 540 line was never in a great spot. Luckily, we have respectable antecedent cold. This always looked like a classic overrunning event. The only thing I haven’t liked is that ns energy. I would have liked to see it dig more or even be a little further in front of the trough axis (which I think is a bit west due to the pronounced se ridge). Instead, it seems to induce phasing too early and prob doesn’t help the mid levels.

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7 minutes ago, WxUSAF said:

12z 3k is certainly better then 6z was for the metro areas.  Better snow thump before sleet.  3k has been sleetier than the 12k since the get-go as it's usually better at seeing thin warm layers in the vertical column.  

12z 3K and 12K clown maps look great IF they were all snow. Either way, looks like the 12z suite is off to a decent start. 
 

eta: I know it’s the Weather Channel, but they are going with 3-5” in DC. Let’s hope...

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Just a random obs now...supposedly its 28 degrees but it feels damn near 48 degrees lol that sun is blazing right now

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15 minutes ago, Winter Wizard said:

Yes, the issue with this storm is almost entirely in the mid-levels. Surface track does matter to an extent, and it is favorable for us, but the upper-level low tracks right over us - you want it to be south and east. Trough axis as a whole is too far west. We end up getting stronger warm air advection at the 700-850 mb level and that's what changes the cities over to sleet and freezing rain. The stronger warm air advection is also what's helping create lift and why you're seeing the intense FGEN bands depicted on the front end. 

Like my post above said this is 100% but I think I’m coming at this from a different angle. Imo these flaws are good reasons why this isn’t a MECS or HECS. This doesn’t have 8”+ potential in DC. But it’s not a good reason Imo it’s not a regular old 3-6” SECS. Those (at least most of the ones I studied when I looked at all the warming events at BWI) were flawed in some way. Some way more flawed then this setup. It seems like “good but flawed” setups don’t break our way as much anymore and 3-6” becomes 1-2” way too often. 

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Just now, Scraff said:

12z 3K and 12K clown maps look great IF they were all snow. Either way, looks like the 12z suite is off to a decent start. 

Hrrr and the Nam Boyz both have a better thump tomorrow morning than previously advertised at 6z.  Hopefully the globals do the same.  

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16 minutes ago, MN Transplant said:

The trough axis at that point is in the central Plains.  While we do pop a surface low in the right spot, this is not a good setup for an all-snow event for our region, no matter what the year is.

Bingo!! Love your analysis!! So the only conclusion I can draw is the slow bleed of warmth off the Atlantic warm waters further out transport west bound then slowly north bound. 

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I know some give it respect but I have never seen anything regarding winter weather that I respect about the 3k. It’s blotchy precip maps don’t jive well with reality.

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12 minutes ago, WxUSAF said:

12z 3k is certainly better then 6z was for the metro areas.  Better snow thump before sleet.  3k has been sleetier than the 12k since the get-go as it's usually better at seeing thin warm layers in the vertical column.  

It is but it can sometimes be too aggressive.  This was about the range it was showing that crazy 15” solution for the super bowl storm that blasted the 850 warm layer all the way to SE DC. In the end boundary temps sucked but it was way too aggressive with the mid levels. 

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38 minutes ago, snowmagnet said:

I don't know if it is relevant, but last week, I was watching it snow and later sleet at my house for many hours, but the weather apps and radar said rain.  And the other day, it was showing snow on radar, while it was definitely raining.  

It's not relevant. Those ptype radars are notoriously bad and are just estimates (and often poor ones at that). If you want to get an accurate view - use radar and then look at mPING reports to see ground truth. Don't trust consumer weather apps or gimmicky radar apps. 

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4 minutes ago, psuhoffman said:

Like my post above said this is 100% but I think I’m coming at this from a different angle. Imo these flaws are good reasons why this isn’t a MECS or HECS. This doesn’t have 8”+ potential in DC. But it’s not a good reason Imo it’s not a regular old 3-6” SECS. Those (at least most of the ones I studied when I looked at all the warming events at BWI) were flawed in some way. Some way more flawed then this setup. It seems like “good but flawed” setups don’t break our way as much anymore and 3-6” becomes 1-2” way too often. 

This has been some great discussion and I thank you and the red taggers who have engaged. Could it be that the not ideal mid level low track now results in quicker warming than we have seen in the past? Where does the warm air come from, is it from the southern land or does the ocean water come into play here? 

Its almost like typical fall line storms are now fall line + 10 miles storms, meaning you need to be 10+ miles further north/west than in the past to get the same results, and those east of that line get mud.

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9 minutes ago, WinterWxLuvr said:

I know some give it respect but I have never seen anything regarding winter weather that I respect about the 3k. It’s blotchy precip maps don’t jive well with reality.

My 2 cents and that’s more then it’s probably worth...it does a good job showing what the structure of the storm will be. Banding features. Temperatures. Warm layers. But its too ambitious and can’t get the exact placement of those features correct. So if you understand not to rely on exactly where it puts meso scale features but use it as a clue to the structure of the system it’s useful. 

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Just predict climo. Once you already know there is going to be snowfall it's a pretty hard baseline to beat. For Baltimore, that means 2.7 inches (average of all snowfalls occurring in February in last 30 years). I'll take it.

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