Re: March 25th Storm Thread

[Frank_Wx]

What the hell...

Lol

If you read the blog, I said the GGEM is bullish because it shows phasing. NAM just came in, and it shows phasing. If there is going to be a phase, there is going to be a big storm

[Math23x7]

Frank, you should do another live-chat for this storm, even though model runs are an hour later due to Daylight Savings Time.

[Frank_Wx]

Shall we chat tonight?

Eh, lets do it.

9:45pm lets start a chat. We'll do it for NAM and GFS. Spread the word.

[amugs]

Sounds good - Storm Mode time!!

[SNOW MAN]

I'm hearing that the snow ratios won't be that good because of temperatures being in the mid 30's to around 40 and the March sun angle being so high and strong. Maybe 1-3 inches. I have two questions. Will there be accumulating snow in my area (Eastern PA) and how much, and what time does it start any ideas or is it to early at this point to tell ? Thanks !

[Quietace]

RGEM comes in pretty impressive. Similar track to what the NAM takes. 12z GFS was not pretty though.....

[sroc4]

It is becoming more clear, to me at least, that areas from NYC, LI and points north will not see any significant snow totals from this system for Monday. A general 1-3inches is my call. I am 80% for a suppressed soln 20% further north than what I am about to outline. Here is why.
All images are from todays 12z runs.
CMC: hr 48: https://2img.net/r/ihimizer/img818/7914/cmc12z500uvvorteast923.png
This is showing the 500mb chart indicating the position of the Upper level low (ULL). Underneath that ULL is where the primary surface low is located as well and also where the transfer of energy to the coast is taking place(primary is southern Ohio/West Va). At this time the new secondary surface low is being generated just east of the newly generated vort max indicated by the X over the purple area in the south east quadrant of the Long wave trough. The actual beggining of the transfer to the coast begins a few frames before but this is where organization of the secondary on the coast is really starting. Here is the surface map to show where the low is. FYI a surface low will always initially spin up east of a vort max, but a vort max will not always generate a surface low. The reason why is for another time.
CMC surface map hr 48: https://2img.net/r/ihimizer/img145/2226/cmc12zprecipthickeast92.png

Now here is the same thing for the GFS. 500mb first followed by surface map:
https://2img.net/r/ihimizer/img29/2522/gfs12z500uvvorteast1723.png
https://2img.net/r/ihimizer/img594/6863/gfs12zprecipthickeast92.png
Now unfortunately as the new surface low heads NE it quickly runs into the blocking. The first piece of the blocking comes from the strong HP to the north and west of the system. Notice in the next image I have outlined the HP contour fields immediately north into Canada. Notice the down hill appearance of the contours from the domes of HP from Greenland extending south into south central Canada.
https://2img.net/r/ihimizer/img35/9068/ggem0z500mbhghtna06023.gif
The second part of the Block is the ULL to our NE. It too is running into the Greenland block and its large circulation of counterclockwise winds are acting to suppress the heights along the coast. This deflects the storm eastward before it reaches the 40/70 benchmark(BM).

Now both the GFS and CMC are showing the Low track to just south of the BM; whereas the Euro today has it a bit further south and east. One would think that our area (NYC/LI/CT) would still get a good amt of moisture to make it that far north if the low tracked to just south of the BM. But it looks like the the surface low and the ULL become vertically stacked as they move south and east of LI effectively occluding the main surface Low. Vertically stacked means the surface low is directly underneath the ULL. The ULL acts as somewhat like a cap to the surface low inhibiting divergence in the upper levels above the surface low. Divergence in the upper levels triggers air to rise from the surface to take the place of the diverging air in the upper levels. This process is what deepens or strengthens a LP system. This very simply put. If you want to understand this better go here (esp check out the video at the bottom of the page): https://courseware.e-education.psu.edu/public/meteo/meteo101demo/Examples/Section9p05.html
Now look again...this time at hr 60 a mere 12hrs later from the images above. Notice the two feature become vertically stacked in a relatively short time.
CMC:
https://2img.net/r/ihimizer/img10/6363/cmc12z500uvvorteast1150.png
https://2img.net/r/ihimizer/img46/8316/cmc12zprecipthickeast11.png
GFS:
https://2img.net/r/ihimizer/img687/1205/gfs12z500uvvorteast2150.png
https://2img.net/r/ihimizer/img801/8867/gfs12zprecipthickeast11.png
So it looks to me that right as this system want to bomb out it becomes occluded which strings out the precip field preventing any significant QPF from making it into our area. Now the NAM is still being quite bullish bringing the LP further north and much more QPF into the area. If you look at the positioning of the ULL and the surface LP during these same time frames you will see that they do not vertically stack which allows a much healthier system to push its way further north into the blocking vs the CMC, GFS, Euro who system gets occluded and is more influenced by the steering patterns of the upper levels kicking it east.

[Frank_Wx]

Well, after getting home from work and

A) Reading Doc's writeup

B) Seeing the 12z GFS/EURO and

C) Seeing the 18z NAM back off by a lot...

Do you all still wanna chat? Lol

[Quietace]

Well, after getting home from work and

A) Reading Doc's writeup

B) Seeing the 12z GFS/EURO and

C) Seeing the 18z NAM back off by a lot...

Do you all still wanna chat? Lol

Well after the 18z GFS ...im still good... Interseting to see what the 00z put out. The models keep flopping

[Frank_Wx]

Well, after getting home from work and

A) Reading Doc's writeup

B) Seeing the 12z GFS/EURO and

C) Seeing the 18z NAM back off by a lot...

Do you all still wanna chat? Lol

Well after the 18z GFS...im still good... Interseting to see what the 00z put out. The models keep flopping

Yea and RGEM is still nice.

See everyone at 9:45 then

[Quietace]

NAVGEM still looks great

[Frank_Wx]

"Nowcasting" the storm, the radar is blowing up with convection over the southeast. There will definitely be a lot of moisture involved with this system as it moves up the coast. A part of me believes the models are having a difficult time figuring out how close to the coast the secondary low will get because of all this convective blowout to our south. It will be interesting to see what the radar looks like tomorrow morning and where the ULL (upper level low) is located relative to where the models have it (another big factor). Lots to analyze! Sometimes it is best to IGNORE the models.

[Quietace]

12z NAM demolishes CNJ on Southward. Incredible....

[Quietace]

Ouch....the 12z EURO.......

[Frank_Wx]

Radar looks impressive to me.

Secondary storm taking over...

[Frank_Wx]

The WRF does a good job with explaining the current look at the radar. What you are currently seeing now in the Mid-Atlantic is just NOISE and not part of the secondary low that will develop overnight. If you go through the loop, you can see the secondary form and bring a nice thumping of snow to DC/SE PA/NJ/DE

http://hp6.wright-weather.com/wrf_nmmeast-radar-loop_1hour.gif

[Quietace]

Wow, that is really impressive. Heard places down i Virginia extremely out preformed....even during daytime

[Quietace]

Wow, 00z NAM blew it. Very SE and dry

[Frank_Wx]

00z GFS is north still.

[Quietace]

00z GFS is north still.

Heard the RGEM was crap though....Whats with these models???

[Quietace]

WOW, a huge bust. I never saw any accumulations. Nothing. Had heavy heavy snow ALL day, and nothing..lol... at least we are in the 50s by the end of the week....

[Snow88]

Yawn

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