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SE snow threat 1-15/16?

Cheeznado

By Cheeznado,
in Southeastern States

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nrgjeff

nrgjeff

Posted
Posted

There is hope east of the mountains! GFS/Euro less robust, but the NAM is the short-term model. I'd fade QPF a bit but agreement is excellent on snow precip type Piedmont west. NAM wants to set up an almost TROWAL like feature over the Piedmont into upstate SC. Current run is okay for Charlotte, less so for Greensboro, but it is nearly a mesoscale feature so too early to get hopes either up or down. Correction: RDU may be too far east. It is not really a TROWAL but good 850 WAA advection with 850 winds out of the northeast, and that WAA goes into lift/precip. Moisture will be limited though. That snowfall map above is probably too aggressive on amounts, but could be decent placement. Just cut amounts in half, except mountains. That still leaves a 2 inch mesocale zone and 1 inch around that in the Piedmont. Good luck Carolina friends!

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mackerel_sky

mackerel_sky

Posted
Posted

There is hope east of the mountains! GFS/Euro less robust, but the NAM is the short-term model. I'd fade QPF a bit but agreement is excellent on snow precip type Piedmont west. NAM wants to set up an almost TROWAL like feature over the Piedmont into upstate SC. Current run is okay for CLT, less so for RDU, but it is nearly a mesoscale feature so too early to get hopes either up or down. It is not really a TROWAL but good 850 WAA advection with 850 winds out of the northeast, and that WAA goes into lift/precip. Moisture will be limited though. That snowfall map above is probably too aggressive on amounts, but could be decent placement. Just cut amounts in half, except mountains. That still leaves a 2 inch mesocale zone and 1 inch around that in the Piedmont. Good luck Carolina friends!

Can someone please explain TROWAL? Sounds like a good thing for upstate?
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FLweather

FLweather

Posted
Posted

If the NAM is correct I would take that with a lot of caution. There will be some surprises that the NAM can't see. Anything is still possible though. Might just be clouds and nothing more. 

 

 

Yeah... I hate to sound like Im wishcasting but depending on how much moisture, how close, weather this thing closes off alot alot alot of other variables. But this brings flashbacks to 2000 I swear.

 

This thing has the potential to go boom once in gets in the se

nam_namer_039_700_rh_ht.gif

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GaWx

GaWx

Posted
Posted

 The 12Z Tue GFS is quite interesting as it isn't too far from producing snow here in Savannah. On Wed. night, the cold front comes through and drops surface temp.'s down to ~31-2 by 7 AM from ~40 at 1 AM with cooling northerly winds. 850's drop to 0C at 7 PM the night before, then fall to just under 0C at 1 AM, and then drop from there. A small area of precip. over FL between 7PM and 1 AM then moves NNE and just misses Savannah and Charleston as 500 mb energy passes nearby, which provides moist SSW 500 mb winds just ahead of it as a 1007 mb surface low develops 300 miles to the east. 0.05" of precip. falls barely offshore with a peak near 0.50" 100 miles offshore. I can't help but wonder what this would do if it were to develop a hair to the west. Would it be cold enough for snow? I give this a very small chance of delivering even flurries (under 5% based on climo), but it will be interesting to follow. MeteoStar should be interesting to see.

 

 This reminds me a little of 2/8/1968, which produced an extremely rare event, just over 3" of snow here in Savannah! At the time it was the heaviest in 100+ years!

 

http://docs.lib.noaa.gov/rescue/dwm/1968/19680208.djvu

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FLweather

FLweather

Posted
Posted

Can someone please explain TROWAL? Sounds like a good thing for upstate

 

I best understand it as wrap around moisture. But maybe a met can explain it better.

TROugh of Warm Air ALoft. Typically used during winter weather, it is a "tongue" of relatively warm/moist air aloft that wraps around to the north and west of a mature cyclone. It is best analyzed between 750-550 mb using equivalent potential temperature (theta-e). 

Areas of intense lift and frontogenesis are commonly associated with TROWALs, hence they are favored regions for heavy and/or prolonged precipitation. During a winter storm, the heaviest snowfall amounts frequently occur along and north of the TROWAL axis.

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burgertime

burgertime

Posted
Posted

Thanks for the explanation on TROWAL! Very interesting ! I thought when we were 24 hrs out or so, the NAM was model of choice? So it may be a flizzard in the upstate area?

 

Typically because of it's higher resolution it is the model of choice but you also can't just throw out the GFS or Euro when still in the 48 hour period as they still have a good handle on the overall "look" so to speak. Once you get around 24 - 12 hours you can start looking at models like the RAP and nowcasting. 

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Lookout

Lookout

Posted
Posted

As larry mentioned, it's VERY close that parts of north florida could get some light snow or a mix a few hours either side of thursday 12z. Depending on which run you look at the nam and gfs hint at the possibility of some precip falling around jacksonville/north florida thur morning. Temps are plenty cold enough aloft...but the boundary layer and surface temps might be too warm in general. However, if there is a heavy enough shower there could be some snow mixed in or maybe even a very brief total changeover.

 

Here is the 42 hour nam sounding for just west of jacksonville.  As you can see, it's plenty cold enough with the exception of surface/near surface temps.   Moisture dries up after this hour but you can see it's pretty cold while nam shows some light precip. Other runs of the nam or gfs differ on just how much precip there is and how cool the boundary layer is but the potential looks to be there in and around north florida.There is even hints of ocean effect mixed showers on the west coast around tampa bay.

 

If this happens and I don't see any flakes with this system, they will get snow before I do...which happened before a few years back. It's really pathetic when florida gets snow before you do :axe:

NAM Text Sounding | 06 UTC Thu 16 Jan 2014 | Latitude: 30.4509 | Longitude: -82.0249
PRES	HGHT	TEMP	DWPT	RELH	MIXR	DRCT	SKNT	TWTB	TVRT	THTA	THTE	THTV
1014.5	26	3.5	0.2	79	3.9	311	10	2.2	4.2	275.6	286.2	276.2
1000.0	142	2.2	-0.3	84	3.8	315	16	1.2	2.8	275.3	285.8	275.9
975.0	346	0.1	-0.8	94	3.7	316	21	-0.2	0.7	275.2	285.6	275.8
950.0	553	-1.9	-2.0	99	3.5	319	26	-1.9	-1.3	275.3	284.9	275.8
925.0	765	-3.1	-4.2	92	3.0	320	32	-3.5	-2.6	276.1	284.7	276.6
900.0	982	-3.9	-5.3	90	2.9	309	29	-4.4	-3.4	277.5	285.6	277.9
875.0	1204	-4.0	-5.2	91	3.0	288	26	-4.4	-3.5	279.6	288.1	280.1
850.0	1433	-3.5	-4.1	96	3.3	264	22	-3.7	-3.0	282.4	292.1	283.0
825.0	1669	-2.8	-2.9	99	3.8	238	20	-2.8	-2.2	285.6	296.5	286.3
800.0	1913	-4.4	-4.6	99	3.4	230	25	-4.5	-3.9	286.4	296.4	287.0
775.0	2162	-6.1	-6.4	98	3.1	228	31	-6.2	-5.6	287.2	296.2	287.7
750.0	2418	-7.3	-8.1	94	2.8	219	37	-7.6	-6.8	288.6	297.0	289.1
725.0	2682	-8.5	-9.1	95	2.7	210	41	-8.7	-8.0	290.1	298.1	290.6
700.0	2953	-10.4	-11.4	93	2.3	212	43	-10.8	-10.1	290.9	297.9	291.3
675.0	3232	-11.4	-12.0	96	2.3	207	44	-11.6	-11.1	292.8	299.8	29
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griteater

griteater

Posted
Posted

Yeah... I hate to sound like Im wishcasting but depending on how much moisture, how close, weather this thing closes off alot alot alot of other variables. But this brings flashbacks to 2000 I swear.

 

I really think this would be a good event in parts of central and eastern NC with a deepening coastal low if we didn't have the big wave moving into the midwest behind our storm.  Just as the SE wave begins to close off and go negative tilt, the trailing midwest wave is kicking it out to sea...there's no time there to allow the SE wave to slow down and deepen

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GaWx

GaWx

Posted
Posted
As larry mentioned, it's VERY close that parts of north florida could get some light snow or a mix a few hours either side of thursday 12z. Depending on which run you look at the nam and gfs hint at the possibility of some precip falling around jacksonville/north florida thur morning. Temps are plenty cold enough aloft...but the boundary layer and surface temps might be too warm in general. However, if there is a heavy enough shower there could be some snow mixed in or maybe even a very brief total changeover.

 

Here is the 42 hour nam sounding for just west of jacksonville.  As you can see, it's plenty cold enough with the exception of surface/near surface temps.   Moisture dries up after this hour but you can see it's pretty cold while nam shows some light precip. Other runs of the nam or gfs differ on just how much precip there is and how cool the boundary layer is but the potential looks to be there in and around north florida.There is even hints of ocean effect mixed showers on the west coast around tampa bay.

 

If this happens and I don't see any flakes with this system, they will get snow before I do...which happened before a few years back. It's really pathetic when florida gets snow before you do :axe:

 

 

Lookout,

 This is the kind of thing the 12Z GFS shows as per my last post. I'm looking forward to MeteoStar's output. Here in Savannah, I'd love to see a very rare snow (even just flurries). But I know climo way too well to get my hopes up. Most years don't even get flurries. Regardless, I'll be following this one closely from here near the beach. ;)

 

Edit: Per 12Z GFS, RDU gets ~6" of snow the last week in Jan. GSP very close to that, too. ATL too warm.

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Jon

Jon

Posted
Posted

FWIW, Here's the top analog for this system w/ 12z NAM guidance. No other analogs come remotely close in the upper air pattern, and there are no real strong analogs for this setup. But nonetheless...

 

12/20/2000

hwskCCP.png

 

 

Today's 12z NAM

ETY8vbD.png

 

AKVnS6A.png

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FLweather

FLweather

Posted
Posted

I really think this would be a good event in parts of central and eastern NC with a deepening coastal low if we didn't have the big wave moving into the midwest behind our storm.  Just as the SE wave begins to close off and go negative tilt, the trailing midwest wave is kicking it out to sea...there's no time there to allow the SE wave to slow down and deepen

I agree I think that it will act as a kicker to limit the duration... but it up the sw really I would think.

 

If it can dive and dig deep enough before the kicker comes in should allow for a wetter system. But I guess that will be the interesting part to watch over the next 12-24 hours. But Im seriously questioning the models view on the amount of moisture already. I still think alot of the models are underdone.

 

Considering how wet its been this year and a couple overperforming rainstorms I bet there will be a fire hose setup and even below the moisture depicted aloft maybe underdone with a setup like that.

 

nam-hires_namer_045_700_rh_ht.gif

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GaWx

GaWx

Posted
Posted

Lookout,

 This is the kind of thing the 12Z GFS shows as per my last post. I'm looking forward to MeteoStar's output. Here in Savannah, I'd love to see a very rare snow (even just flurries). But I know climo way too well to get my hopes up. Most years don't even get flurries. Regardless, I'll be following this one closely from here near the beach. ;)

 

Edit: Per 12Z GFS, RDU gets ~6" of snow the last week in Jan. GSP very close to that, too. ATL too warm.

 

 The 12Z GFS per MeteoStar does have some very light rain that falls at Jacksonville, Brunswick, and Charleston with the atmosphere very close to being cold enough for snow. Also, the 12Z GFS ensemble mean supports some coastal light precip. Interesting.

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BullCityWx

BullCityWx

Posted
Posted 




Date: 39 hour Eta valid 3Z THU 16 JAN 14



Station: KCLT



Latitude: 35.22



Longitude: -80.93



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



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



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



0 1000 126



SFC 990 208 1.3 -0.3 89 1.7 0.6 349 14 275.3 275.9 274.3 285.5 3.76



2 950 537 -2.1 -2.3 98 0.2 -2.2 352 24 275.1 275.6 273.6 284.3 3.39



3 900 965 -2.1 -2.6 96 0.6 -2.3 28 18 279.4 280.0 276.2 289.1 3.50



4 850 1422 -0.7 -1.2 97 0.5 -0.9 162 12 285.4 286.1 280.0 297.1 4.12



5 800 1904 -3.8 -4.9 92 1.1 -4.3 178 21 287.1 287.7 279.8 296.6 3.31



6 750 2409 -7.7 -9.0 90 1.3 -8.1 195 26 288.3 288.7 279.4 295.8 2.58



7 700 2942 -11.7 -13.3 88 1.7 -12.2 201 29 289.5 289.9 279.3 295.4 1.95



8 650 3505 -15.7 -17.7 84 2.0 -16.2 203 35 291.2 291.5 279.4 295.7 1.46



9 600 4103 -20.3 -25.0 66 4.7 -21.2 202 43 292.6 292.8 279.2 295.2 0.83



10 550 4748 -20.3 -45.1 9 24.8 -22.8 207 58 300.0 300.1 281.5 300.5 0.12



11 500 5449 -23.6 -36.3 30 12.7 -25.2 205 68 304.3 304.4 283.6 305.5 0.34



12 450 6211 -28.3 -46.4 16 18.1 -29.8 208 90 307.7 307.7 284.6 308.1 0.13



13 400 7047 -33.3 -49.8 18 16.5 -34.4 206 110 311.7 311.7 286.1 312.0 0.10



14 350 7971 -39.7 -55.0 18 15.3 -40.4 206 126 315.2 315.2 287.2 315.4 0.06



15 300 9012 -44.7 -66.3 7 21.7 -45.2 207 117 322.4 322.4 289.5 322.4 0.02



16 250 10221 -47.4 206 92 335.6



17 200 11688 -49.2 212 88 354.8



18 150 13561 -52.7 215 71 379.3



19 100 16128 -60.3 220 70 411.2



TRP 0



WND 0



Sounding variables and indices



1000-500 mb thick: 5323.09 m



Freezing level: 974.40 mb = 335.58 m = 1100.98 ft



Wetbulb zero: 981.30 mb = 277.54 m = 910.55 ft



Precipitable water: 0.46 inches



Sfc-500 mean rel hum: 72.93 %



Est. max temperature: 11.75 C = 53.15 F



Sfc-Lift cond lev (LCL): 964.25 mb = 417.83 m = 1370.81 ft T: -0.86 C



700-500 lapse rate: 4.73 C/km



ThetaE index: 1.72 C Layer 800.0- 650.0 mb



Conv cond level (CCL): 953.12 mb = 510.76 m = 1675.71 ft



Mean mixing ratio: 3.51 g/kg



Conv temperature: 1.12 C = 34.02 F



Cap Strength: 12.70 C



Lifted Index: 15.41 C Risk: None



Lifted Index @300 mb: 25.55 C



Lifted Index @700 mb: 6.39 C



Showalter Index: 7.47 C Risk: None



Total Totals Index: 45.20 C Risk: Scattered moderate thunderstorms



Vertical Totals Index: 22.84 C



Cross Totals Index: 22.35 C



K Index: 19.98 Risk: < 20 % chance of thunderstorms



Sweat Index: 92.29 Risk: None



Energy Index: 1.65 Risk: None







			
		


		

		
			

		
	


	

	





	
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GaWx
			

			

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 The 12Z GFS per MeteoStar does have some very light rain that falls at Jacksonville, Brunswick, and Charleston with the atmosphere very close to being cold enough for snow. Also, the 12Z GFS ensemble mean supports some coastal light precip. Interesting.


 


 The 12Z Euro, vs. the 0Z Euro, is closer to the coast with that same system for Wed. night. We'll see if this trends even further westward on the next run. It is very close to producing snow on the coast near Jacksonville and at Charleston. There is about .05"+ that falls right on the coast near those two cities (~.08" at Jacksonvile).The Euro's 2 meter temp.'s of 40+ are too warm due to its bias.


 


Stormsfury, I see that you're here. Are you following this for the Charleston area?



			
		


		

		
			

		
	


	

	





	
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