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March 20th White Rain/Slush Event Discussion and Obs


yoda

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After looking at observations, I think we might be dealing with 35-37 degree temps tomorrow morning and any snow over to rain by 9:00am except for the far N/W burbs. 1. We are warmer than March 5th right now and the preceding days have been warm. 2. RAP/RUC was also bullish before that storm. I would go with a GFS/UKMET/Euro blend. We will see though.

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I just looked at the Euro temps and qpf

it keeps 850's below freezing the entire event imby with .65" qpf

unfortunately, the surface gets to a peak of 1.5C

still, it's colder than any previous run, so maybe there's one more tick colder left between this run and reality

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Not looking bad temperature wise either....precip falling at 0.1"+ per hour at this point....

Ifj9Akc.gif

can one of the mets tell me what the diff is between the Mean-Layer Parcel skewt and Surface-Based parcel skewt?

Surface-Based is colder at the surface, but I don't know why.....Thanks

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After looking at observations, I think we might be dealing with 35-37 degree temps tomorrow morning and any snow over to rain by 9:00am except for the far N/W burbs. 1. We are warmer than March 5th right now and the preceding days have been warm. 2. RAP/RUC was also bullish before that storm. I would go with a GFS/UKMET/Euro blend. We will see though.

Preceding days really don't have much to do with it unless you're talking road accums. Even then, if it comes down hard enough and is close to 32, it can and probably will accum on the roads for a time.

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After looking at observations, I think we might be dealing with 35-37 degree temps tomorrow morning and any snow over to rain by 9:00am except for the far N/W burbs. 1. We are warmer than March 5th right now and the preceding days have been warm. 2. RAP/RUC was also bullish before that storm. I would go with a GFS/UKMET/Euro blend. We will see though.

You'll get meteoric temp drops with these dew points.

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can one of the mets tell me what the diff is between the Mean-Layer Parcel skewt and Surface-Based parcel skewt?

Surface-Based is colder at the surface, but I don't know why.....Thanks

 

Well, you are looking at the parcel lapse rate, right?  The blue line, not the actual temperature.  I think the idea is right in the names, the surface-based is literally a "parcel" lifted from the surface, whereas the mean-layer is an average parcel (lowest 100mb?).  I think it is to the right because we are looking at potential temperature.

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Charles Town and C MD need winter storm warnings. NOW.

This is one of those events where that extra 500 feet of elev can make the storm go BOOM, very quickly with WSW amounts on grassy surfaces and possibly even on roads in CharlesTown and in Central MD. Ridgetops near Hillsboro better look out, they could pile on even more. Route 7 bypass has 700 foot elev. Congrats! Easy 6 inches.

You live in that community in those McMansions right near the Rt 9 cutoff, Rack 'em, stack 'em and pack 'em up. The line starts at the Mississippi and everybody better take a number.

My hood. We will see.

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Well, you are looking at the parcel lapse rate, right? The blue line, not the actual temperature. I think the idea is right in the names, the surface-based is literally a "parcel" lifted from the surface, whereas the mean-layer is an average parcel (lowest 100mb?). I think it is to the right because we are looking at potential temperature.

thanks
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Lets do this

You have at least 500 feet elev.

You're gonna get plastered with snow.  :snowing:  :snowing:  :snowing:  :snowing:  :snowing:  :snowing:  :snowing:

I am always jealous of Leesburg. I will be in this storm too, even as my car gets a free car wash tonight.

I have a pleasant 54 degrees with a steady southeast wind. I'll get mostly steady rain and I'll be outright elated as I watch that rain accumulate everywhere in Dale City tonight!!!

Get a snowblower, you're gonna need it in Leesburg!

I dont know whats wrong with the NWS. They need to place you under a Winter Storm WARNING right now for 4 to 7 inches of snow.

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And the kicker, we barely lose the column.  ~0.8" qpf at DCA.

 

 

lol

 

Date: 21 hour NAM valid 15Z FRI 20 MAR 15

Station: KDCA

Latitude: 38.85

Longitude: -77.03

-------------------------------------------------------------------------------

LEV PRES HGHT TEMP DEWP RH DD WETB DIR SPD THETA THE-V THE-W THE-E W

mb m C C % C C deg knt K K K K g/kg

-------------------------------------------------------------------------------

SFC 1017 56 0.5 0.2 98 0.3 0.4 81 4 272.3 273.0 272.6 282.6 3.81

1 1000 190 -0.5 -0.8 98 0.3 -0.6 98 11 272.7 273.3 272.5 282.4 3.61

2 950 599 -1.7 -2.1 97 0.4 -1.9 126 27 275.4 276.0 273.9 284.9 3.43

3 900 1030 -0.9 -1.2 98 0.3 -1.1 161 22 280.5 281.2 277.3 291.3 3.88

4 850 1486 -1.3 -1.6 98 0.3 -1.4 195 13 284.8 285.5 279.6 296.1 3.99

5 800 1968 -2.2 -2.3 99 0.2 -2.3 187 44 288.8 289.5 281.5 300.5 4.03

6 750 2483 -2.1 -2.2 99 0.2 -2.1 214 51 294.3 295.1 284.2 307.1 4.33

7 700 3030 -3.4 -3.6 99 0.2 -3.5 246 39 298.7 299.5 285.8 311.3 4.20

8 650 3615 -4.9 -5.2 98 0.2 -5.0 260 43 303.4 304.1 287.3 315.6 4.00

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You have at least 500 feet elev.

You're gonna get plastered with snow.  :snowing:  :snowing:  :snowing:  :snowing:  :snowing:  :snowing:  :snowing:

I am always jealous of Leesburg. I will be in this storm too, even as my car gets a free car wash tonight.

I have a pleasant 54 degrees with a steady southeast wind. I'll get mostly steady rain and I'll be outright elated as I watch that rain accumulate everywhere in Dale City tonight!!!

Get a snowblower, you're gonna need it in Leesburg!

I dont know whats wrong with the NWS. They need to place you under a Winter Storm WARNING right now for 4 to 7 inches of snow.

Someone took a Xanax   :thumbsup:

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Someone took a Xanax 

only one thing better than a xanax.

 

TWO xanaxes lol

 

You gotta have a good supply of it when you reside in south Maryland like I do. That, and a good supply of BEER. 

Every little bit helps - I expect at least one inch of steady rain here tonight, maybe more if the CSI rain bands develop over my backyard.. March showers bring April flowers. We're a month ahead on temps this spring :axe:

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