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January 6-8 2014 arctic attack obs thread...


Marion_NC_WX

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Lookout,

 The problem is that I only have 850 temp.'s with which to compare and they're much more readily available. What you say may very well be true, but I don't have other Arctic outbreak 875-900 mb temp.'s. So, I really don't know. Maybe airmasses like 1/85, 12/83, 1/82, 1/77, etc., also had more impressive 875/900 mb? Maybe not? What's the exact coldest you've seen progged for ATL at 875 and at 900? If you have that info, maybe I could dig further and see if I can find some old 875/900 data.

 

 Edit: I'd like to see what 875-900 is on the GFS as the NAM can't be trusted as well if it is colder. I'm not crazy about the NAM at all.

I figured as much. It would be really helpful if we could have that data to compare to this one.  But I was more or less just asking you how much more would you be impressed with sub -20c temps at heights lower than 850mb since you are the by far the most knowledgeable person here with regards to temps aloft on these cold outbreaks.

 

At any rate,  Although we don't know what the temps were at 875 to 925mb during those cold snaps, it really must be rare indeed to have those type of temps at those heights in north ga, atlanta, and the southeast in general.

 

I understand the misgivings about the long range nam but it has been pretty consistent with everything else. The gfs was showing such temperatures at those levels as well before the 06z run. The 06z and 12z gfs  came in a touch warmer but the prior few runs showed temps of -22c to -24c over a lot of north ga, including atlanta. In fact, the -20c isotherm reached down to columbus at 875mb  For atlanta, The 12z gfs has 900mb coming in as the coldest level at -20.5c at hour 66

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I figured as much. It would be really helpful if we could have that data to compare to this one.  But I was more or less just asking you how much more would you be impressed with sub -20c temps at heights lower than 850mb since you are the by far the most knowledgeable person here with regards to temps aloft on these cold outbreaks.

 

At any rate,  Although we don't know what the temps were at 875 to 925mb during those cold snaps, it really must be rare indeed to have those type of temps at those heights in north ga, atlanta, and the southeast in general.

 

I understand the misgivings about the long range nam but it has been pretty consistent with everything else. The gfs was showing such temperatures at those levels as well before the 06z run. The 06z and 12z gfs  came in a touch warmer but the prior few runs showed temps of -22c to -24c over a lot of north ga, including atlanta. In fact, the -20c isotherm reached down to columbus at 875mb  For atlanta, The 12z gfs has 900mb coming in as the coldest level at -20.5c at hour 66

 

Lookout,

 Good news. I just checked and 925 mb data is available for ATL! However, I'd need time to research and compile it. I'd check it for some or all of these: 1/24/03, 2/3-5/96, 1/19/94, 12/22-24/89, 1/27-8/86, 1/20-1/85, 12/24-5/83, 1/10-1, 17/82, 1/9-11, 78, 1/17-9, 29/77, 1/8-9/70, 1/29-30/66, 1/24/63, 12/12-3/62, 2/17/58, 2/2/51, and 11/25/50.

 

 Let me know if you think this would be worthwhile.

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Cross-section. Although not exact it's fun to look at quickly run to run.

 

tempa.png

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This sounds more realistic  ;)   Monday high 49, low 12, Tuesday high 32, low 17. Wednesday high 42, low 26. Thursday high 52, low 37 

 

CAE

 

.LONG TERM /MONDAY THROUGH SATURDAY/...
MODELS ARE SLIGHTLY SLOWER BRINGING THE FRONT ACROSS THE AREA.
IT NOW APPEARS THE COLD FRONT WILL ARRIVE IN THE WESTERN MIDLANDS
AND CSRA AROUND DAYBREAK MONDAY AND REACH THE COAST BY MID-
MORNING. SO..WILL INCLUDE LOW CHANCE POPS ACROSS THE EAST MONDAY
MORNING. A VERY COLD ARCTIC AIR MASS WILL BUILD OVER THE AREA IN
THE WAKE OF THE COLD FRONT. STRONG COLD ADVECTION MONDAY AND
MONDAY NIGHT. HIGH TEMPS MONDAY WILL LIKELY OCCUR IN THE MORNING
WITH TEMPERATURES STEADY OR FALLING THROUGH THE DAY. STILL EXPECT
CLEARING SKIES AND GUSTY WINDS. TEMPERATURES MONDAY NIGHT WILL
BOTTOM OUT NEAR RECORD LOWS IN THE TEENS.

TUESDAY WILL BE THE COLDEST DAY WITH CONTINUING COLD AIR ADVECTION
AS THE SURFACE RIDGE BUILDS INTO THE AREA. HIGHS EXPECTED TO BE
20 TO 25 DEGREES (F) BELOW NORMAL. MANY AREAS MAY NOT GET ABOVE
FREEZING. WITH HIGH PRESSURE OVER THE AREA TUESDAY NIGHT ALONG
WITH DRY AIR AND CLEAR SKIES...TEMPERATURES WILL FALL INTO THE
MIDDLE TO UPPER TEENS. TEMPERATURES BEGIN TO MODERATE WEDNESDAY AS
THE CENTER OF HIGH PRESSURE SLIDES EAST.

AS HIGH PRESSURE SHIFTS OFF THE COAST...MOISTURE WILL INCREASE
WEDNESDAY NIGHT THROUGH SATURDAY. BOTH THE GFS AND ECMWF ARE
INDICATING WEDGE CONDITIONS DEVELOPING FOR THE END OF NEXT WEEK.
CHANCE OF RAIN FOR THURSDAY NIGHT THROUGH SATURDAY. DOES NOT LOOK
LIKE P-TYPE PROBLEMS GIVEN MODEL 1000-850 MB THICKNESSES.

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Lookout,

 Good news. I just checked and 925 mb data is available for ATL! However, I'd need time to research and compile it. I'd check it for some or all of these: 1/24/03, 2/3-5/96, 1/19/94, 12/22-24/89, 1/27-8/86, 1/20-1/85, 12/24-5/83, 1/10-1, 17/82, 1/9-11, 78, 1/17-9, 29/77, 1/8-9/70, 1/29-30/66, 1/24/63, 12/12-3/62, 2/17/58, 2/2/51, and 11/25/50.

 

 Let me know if you think this would be worthwhile.

I think it would larry. Any insight into getting a handle on these airmasses is a plus in my book. 925mb temps would really shed some light on this or some future outbreaks imo since I've heard more than once the coldest air with true arctic outbreaks often will exist below 850mb.

 

The NAM is just unbelievably cold. 

 

http://68.226.77.253/text/MESOSFC/NAM_kakh.txt

You mentioned temp drops a while back, and to add to it..i was just looking at some profiles over ga and al and in many areas temps go from the upper 40s or even 50 degrees to the upper 20s in 3 hours. But the most extreme I can find is around the ga/al line and back into al where it goes from around 55 to 28 in 3 hours. Hard to get any stronger caa than that around here. Of course further east over my way it's a bit slower and then quite a bit slower into sc as the cold air gets temporarily hung up by the mountains.

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Raysweather is now going with -18 F for a period of time Monday evening into early Tuesday in Avery County ABOVE 5000 feet.

Get ready!

wRsFsNf.jpg

Also notice the rapid warm up within 48 hours back to light freezing rain and around 30 degrees.

Nothing in place to anchor the arctic air in with the fast flow.... We need blocking

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I think it would larry. Any insight into getting a handle on these airmasses is a plus in my book. 925mb temps would really shed some light on this or some future outbreaks imo since I've heard more than once the coldest air with true arctic outbreaks often will exist below 850mb.

 

 

Lookout,

 OK, I've started working on it. I'm planning to have the coldest ATL sfc/925/850 for 19 very intense Arctic airmasses since 1950. I'll post it in its own thread so it won't get lost and could be used as an historic reference of sorts since it doesn't just pertain to this upcoming one.

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Raysweather is now going with -18 F for a period of time Monday evening into early Tuesday in Avery County ABOVE 5000 feet.

Get ready!

Also notice the rapid warm up within 48 hours back to light freezing rain and around 30 degrees.

Nothing in place to anchor the arctic air in with the fast flow.... We need blocking

Robert thinks Boone will get to at least -17 so I think Ray is going a little conservative with his +5,000 ft

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Lookout,

 OK, I've started working on it. I'm planning to have the coldest ATL sfc/925/850 for 19 very intense Arctic airmasses since 1950. I'll post it in its own thread so it won't get lost and could be used as an historic reference of sorts since it doesn't just pertain to this upcoming one.

Sounds good larry.

 

Latest nam temps for 12z tue. Looks like close to 0 in gainesville and around 3 or so for atlanta. Looks like it's inching closer  0 in he NC foothills too. Still a good bit of time to get a few degrees colder.

 

temp60.gif

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I've been away from the computer for a good part of today so I'm not sure if the 0z GFS is any different from recent runs...however its looking like the Apps will initially try to block the arctic plunge, temps across the Carolina Mountains/Foothills should be in the 20's to around 30's at daybreak Monday. Temps may hold steady in the Carolina foothills until about noon when the hounds are unleashed. I see the potential of a sudden crash here along the escarpment from 28 or 29 to about 15 in a matter of an hour or two.

 

Meanwhile if you are in North Georgia or Alabama the plunge will begin earllier as the cold will slide under the base of the Apps...teens in North and NW Georgia by noon Monday.

 

Per the GFS everyone in NC/SC should be in the 20's by dark Monday, teens and single digits Western Carolinas, Apps, North GA...

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Sure is dead in here tonight, odd given the rare extreme cold headed this way in less than 24 hours.

Everyone must be getting their homes and pipes ready for the artic express

I was splitting and moving firewood all day... Of course all I do is lurk around here and try to learn what I can...

Sent from my iPad using Tapatalk

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