CAD storms thread.

[dsaur]

Only a light glaze of ZR so far here in Obion County (about 40 miles west of Paris), sleet is coming down heavy with winds gusting to around 20 mph.....still a long way to go though.  Power lines and trees are holding their own, so far.

I've got my fingers crossed for you to get the best of both worlds, and get mostly a great sleet storm with some glaze to make for perfect sledding, and no destruction.  I've seen this so many times.  You guys getting some great sleet totals, whiles south of you it's rain, and east the z monster, if it's not rain.....and because the cold moves slow with no push behind, and banks on the west side of the mtns.  T

[dsaur]

Bottom line. Read more, post less. It seems you only post to take some pot shot at those who are actually posting about the storm (well outside of Brick). The fact is, you live in Waycross GA, your experience with cold air damming probably consists of a visit up to Athens one time. It's very simple experience tells us that typically models do not handle CAD well and often it is colder than what is being depicted. It seems most have taken a very realistic approach to this system with many feeling there won't be anything major. However there are real reasons to take this seriously as it could over perform. Again, read more and please post less. 

Burger, he hails from up Chicago way   Probably knows more about cold than most of us, lol, though his judgement maybe in question as he now lives in Waygone.  And you are right in that that they don't get much cad down there   T

[WestTennWX]

I've got my fingers crossed for you to get the best of both worlds, and get mostly a great sleet storm with some glaze to make for perfect sledding, and no destruction.  I've seen this so many times.  You guys getting some great sleet totals, whiles south of you it's rain, and east the z monster, if it's not rain.....and because the cold moves slow with no push behind, and banks on the west side of the mtns.  T

Thanks..you about summed it up. We have been getting blasted with sleet since about 6 am, (about 2 inches so far) reports about 15 miles to my north of heavy snow, 20 miles to my southeast they are getting slammed with ZR...I am thankful we dodged the z monster this time! Snow line inching ever closer- will post pics when/if there is an obs thread.

[Stovepipe]

Thanks..you about summed it up. We have been getting blasted with sleet since about 6 am, (about 2 inches so far) reports about 15 miles to my north of heavy snow, 20 miles to my southeast they are getting slammed with ZR...I am thankful we dodged the z monster this time! Snow line inching ever closer- will post pics when/if there is an obs thread.

 

Congrats!  I'm hearing of heavy sleet in Paris too.  Post those pics here, powers that be can move em later.

[WxJordan]

According to Meteogram output at the Hickory Regional Airport, the 12Z puts out .46 as freezing rain. Solidly in Ice storm warning criteria 

 

The only problem I see is the temperature will be marginal. It is hard to receive a major ice storm when temperatures are 32, especially when the ground is already warm. I am not saying it is impossible and I am not saying Hickory will not see any ice. I believe that the Hickory area does stand a chance of seeing ice on Sunday morning.

The models are showing the best chance of major ice north of Interstate 40 towards the Lenoir, Winston-Salem, Wilkesboro, and Boone on up into Virginia. In Hickory, Statesville, Morganton areas, there will be a chance of major accumulating ice; however, I think the best chance will be a little farther north.

[dsaur]

Thanks..you about summed it up. We have been getting blasted with sleet since about 6 am, (about 2 inches so far) reports about 15 miles to my north of heavy snow, 20 miles to my southeast they are getting slammed with ZR...I am thankful we dodged the z monster this time! Snow line inching ever closer- will post pics when/if there is an obs thread.

You start it, if it hasn't been started.  Lord knows you got more obs that most of us   If you end up with 4 inches of sleet I'm likely to grind my teeth off from frustration.  That's my sleet storm, lol.  Tony

[CAD_Wedge_NC]

Congrats!  I'm hearing of heavy sleet in Paris too.  Post those pics here, powers that be can move em later.

 

Absolutely...  this is the correct thread for pics of this storm. 

[Stovepipe]

Heads up Amos, icing reported in south west Nashville.

[Stovepipe]

12z Euro Sunday afternoon, virtually no change from 0z with regards to NC/VA border:

 

[NCCatawba]

Heads up Amos, icing reported in south west Nashville.

 

Approaching 80 degrees in Raleigh. Poor Brick.

[POWERSTROKE]

Agreed, I am kind of thinking Winston-Salem and points west and than north from there will be bad, assuming GFS is correct.

Just what I like to hear!!!

[FallsLake]

Approaching 80 degrees in Raleigh. Poor Brick.

No Brick loves this weather. But I hate it; so poor me.

[Yvilleweather]

Agreed, I am kind of thinking Winston-Salem and points west and than north from there will be bad, assuming GFS is correct.

 

This would great with me...I'm ready for some wintry weather regardless of the type.  I'm in Allen's "C" area 

[Blue_Ridge_Escarpment]

Good first call from NWS GSP:

 

 

[NCCatawba]

So here are the areas on the euro who stand the risk of seeing something just shy of 20 hours of freezing rain. Elsewhere gets glazed up too but area below should be the hardest hit...plus or minus the escarpment back toward Boone as well.

 

[CAD_Wedge_NC]

GSP expanding the watch south.......

 

I WILL EXPAND THE
WATCH JUST A LITTLE...TO INCLUDE BURKE...CATAWBA IREDELL AND DAVIE
COUNTIES. I/D SAY MY CONFIDENCE THAT AT LEAST PARTS OF THESE
COUNTIES WILL HIT ICE STORM CRITERIA IS HIGH ENOUGH FOR A
WATCH...

[NCCatawba]

WxSouth is with Brad Panovich on focusing in on the NAM. It's a quick hitting freezing rain AM to mostly a freezing drizzle event through Sunday PM. 

 

WxSouth

4 hours ago

The new NAM continues the trend of pulling the moisture axis up toward northern Virginia and into MD, PA region..seeing the Big High, and going around the Southeast Ridge. I think the models recognize the evolution of this now and we can begin to reduce risks for some areas and focus on areas where it will be a very big deal. 

 

But for southern half of VA to most of NC, the models keep insisting the moisture will be brief there, then focus on northern VA region where it continues as strong overrunning...other words, a brief burst of Wintry precip very near Roanoke to Richmond and points south, then mostly scattered light precip and probably lots of drizzle in a strong C.A.D. environment with not much in the way of totals there. But any ice will be slippery, but there won't be any major totals...

[MillerA]

full gsp disco

Short term /Saturday night through Monday/...

as of 225 PM EST Friday...cold air damming will become established

over the region Saturday night. After midnight...isentropic upglide

will begin to increase with rain expected to break out over most of

the region prior to sunrise. This won't be the type of cold air

damming event where the cold and dry air will already be in place as

the precipitation develops. In fact...it will take a precipitation induced low level

ageostrophic adjustment to really drive the cool air into the region

to the point the surface temperatures drop to freezing. Therefore...I/d expect

precipitation to start as rain and gradually change over to freezing rain

along the Escarpment of the Blue Ridge...the northern mountains and

the foothills north of Interstate 40.

Overall the thinking on this shift has not changed much from the middle

shift. However...there has been an increase in the quantitative precipitation forecast into The

Wedge boundary on the latest GFS while the NAM is lighter. Perhaps this

explains why the GFS BUFKIT soundings now have nearly a half inch of

freezing rain at Hickory while the NAM has nothing. Rather than

Chase individual model runs...I/M going to continue to follow the

sref consensus. I/ll also keep freezing rain confined mainly to

areas on the NAM where the surface wet bulb is freezing or below.

Typically this works well for ME with ice events. I will expand the

watch just a little...to include Burke...Catawba Iredell and Davie

counties. I/d say my confidence that at least parts of these

counties will hit ice storm criteria is high enough for a

watch...that being around 50 percent. At the very least...we can

transition these lower confidence zones to an advisory.

Ground temperatures will be very warm with this event...and the main

impact from freezing rain will be ice accumulations on elevated

surfaces. Fortunately this means that roads should be in good shape.

However...we may see some power outages from ice-laden trees. As the

parent high moves farther away Sunday evening...everyone should see

surface temperatures rise to a few degrees above freezing.

[AirNelson39]

WxSouth is with Brad Panovich on focusing in on the NAM. It's a quick hitting freezing rain AM to mostly a freezing drizzle event through Sunday PM.

WxSouth

4 hours ago

The new NAM continues the trend of pulling the moisture axis up toward northern Virginia and into MD, PA region..seeing the Big High, and going around the Southeast Ridge. I think the models recognize the evolution of this now and we can begin to reduce risks for some areas and focus on areas where it will be a very big deal.

But for southern half of VA to most of NC, the models keep insisting the moisture will be brief there, then focus on northern VA region where it continues as strong overrunning...other words, a brief burst of Wintry precip very near Roanoke to Richmond and points south, then mostly scattered light precip and probably lots of drizzle in a strong C.A.D. environment with not much in the way of totals there. But any ice will be slippery, but there won't be any major totals...

But yet the nam has .7" zr for Boone. How does he not mention that?

[tarheelwx]

18z NAM already much wetter at 36 hours.  has precip oer most of NC by 06z Sunday.  We'll see if it continues in later frames. 

TW

[tarheelwx]

18z NAM looks colder at the surface at 06z Sunday as well.

TW

[Brick Tamland]

anymore on the NAM?

[tarheelwx]

On the 18z NAM about the northern 2/3 of NC has over .25 in the 24 hrs up to 10 pm Sunday. On the 12z run, most all of the state was in the .10+ range.
TW

 

From the maps, I'd think many places might be pushing .50.

[CAD_Wedge_NC]

Well...... there you have it folks. The NAM has fallen in line with the other guidance and it now showing a much wetter solution. This looks reasonable to me and I think that by tonight's 0z suite we will have a solution that will be very close to what we can expect. The temps are going to be tricky for many folks in NC and 1-2 degrees can be a very big deal. As it is in most cases, it will come down to how the lower dewpoints are advected into the area and where the 32 degree wet-bulb line sets up shop. Going from past experience, that line should end up somewhere from just east of AVL to Lincolnton to Concord and northeast to GSO. That's my call.

[SN_Lover]

Well...... there you have it folks. The NAM has fallen in line with the other guidance and it now showing a much wetter solution. This looks reasonable to me and I think that by tonight's 0z suite we will have a solution that will be very close to what we can expect. The temps are going to be tricky for many folks in NC and 1-2 degrees can be a very big deal. As it is in most cases, it will come down to how the lower dewpoints are advected into the area and where the 32 degree wet-bulb line sets up shop. Going from past experience, that line should end up somewhere from just east of AVL to Lincolnton to Concord and northeast to GSO. That's my call.

Adding on to that, I think the NAM was also having trouble seeing the vertical forcing associated with the warm front and inversion. Looking at the model details i would not be surprised to see western NC overpreform.

[superjames1992]

RAH just pulled the trigger on Winter Storm Watches.

 

http://forecast.weather.gov/product.php?site=NWS&issuedby=RAH&product=AFD&format=CI&version=1&glossary=1&highlight=off

 

 

 

A WINTER STORM WATCH HAS BEEN ISSUED FOR FORSYTH...GUILFORD...
ALAMANCE...AND PERSON COUNTIES. A FREEZING RAIN ADVISORY MAY BE
NEEDED FOR A TIER OR TWO OF COUNTIES SOUTHEAST OF THERE AS THE EVENT
DRAWS NEARER.

[ncskywarn]

per NWS Raleigh Winter storm watch NW piedmont thru Person County Freezing Rain Advisory may be needed further South and East

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 335 PM FRIDAY... A QUICK HITTING ARCTIC HIGH...BUT FAVORABLY STRONG AND LOCATED WHEN THE PRECIPITATION IS EXPECTED TO OCCUR...WITH AN ASSOCIATED LIKELY PROBABILITY OF NEARLY ALL-DAY FREEZING RAIN OVER MUCH OF THE NW PIEDMONT ON SUN...AND A BRIEF PERIOD OF FREEZING RAIN POSSIBLE AS FAR SOUTHEAST AS A WARRENTON TO RDU TO ALBEMARLE LINE. A WINTER STORM WATCH HAS BEEN ISSUED FOR FORSYTH...GUILFORD... ALAMANCE...AND PERSON COUNTIES. A FREEZING RAIN ADVISORY MAY BE NEEDED FOR A TIER OR TWO OF COUNTIES SOUTHEAST OF THERE AS THE EVENT DRAWS NEARER. SATURDAY NIGHT: COLD AND DRY ADVECTION WILL CONTINUE THROUGH THE NIGHT...AS 1035-1040 MB ARCTIC HIGH PRESSURE BUILDS FROM THE UPPER MIDWEST TO THE NORTHERN MIDDLE ATLANTIC AND NORTHEAST AND SUBSEQUENTLY RIDGES SOUTHWARD EAST OF THE APPALACHIANS - ALL IN A FAVORABLE POSITION FOR STRONG COLD AIR DAMMING. AT THE SAME TIME...WARM AND MOIST AIR WILL BE TRANSPORTED NORTH NORTHEASTWARD IN STRENGTHENING LOW LEVEL FLOW FROM THE GOM...WHICH WILL CONSEQUENTLY CAUSE ISENTROPIC UPGLIDE TO RAPIDLY INCREASE AND PROMOTE THE DEVELOPMENT OF RAIN FROM SOUTH TO NORTH...WITH TEMPERATURES FALLING THROUGH THE 40S AND 30S...OVERNIGHT. BY DAYBREAK...TEMPERATURES ACROSS THE NORTHERN PIEDMONT WILL BE FLIRTING WITH THE FREEZING MARK...AS THE SUPPLY OF COLD AND DRY AIR IN THE LOW LEVELS CONTINUES FROM THE PARENT HIGH...RESULTING IN A TRANSITION TO FREEZING RAIN WITHIN A COUPLE HOURS EITHER SIDE OF 7 AM. BOTH THE (LIMITED) DEPTH OF SATURATION AND RAPIDLY WARMING TEMPERATURES ALOFT WILL PRECLUDE ANY CONCERN FOR FROZEN PRECIPITATION...ASIDE FROM A TYPICAL BRIEF NUISANCE MIX OF GRAUPEL/"SLEET" NEAR ONSET. SUNDAY AND SUNDAY NIGHT: ISENTROPIC LIFT...HOWEVER SHALLOW/BELOW THE EFFICIENT MIXED PHASE PRECIPITATION PRODUCTION ZONE...WILL CONTINUE THROUGH SUN EVE - STRONGEST AND LONGEST FROM NORTHERN NC TO VA. THIS WILL SUPPORT THE HIGHEST PRECIPITATION AMOUNTS OVER THE NW PIEDMONT - AROUND A THIRD TO HALF INCH - AND LESSER AMOUNTS OF AROUND A COUPLE TENTHS OVER THE EASTERN SANDHILLS AND SOUTHERN COASTAL PLAIN. THE ARCTIC HIGH WILL BECOME INCREASINGLY ESTABLISHED EAST OF THE APPALACHIANS DURING THE DAY SUNDAY...SO TEMPERATURES MAY ACTUALLY FALL A DEGREE OR THREE THROUGH SUNDAY AFTERNOON IN THE HEART OF THE WEDGE - TO 30 OR 31 DEGREES OVER THE WATCH AREA. ELSEWHERE... TEMPERATURES WILL CREEP THROUGH THE 30S...TO NEAR 40 DEGREES TOWARD KFAY TO KCTZ AND KGSB. WITH TEMPERATURES HOLDING AT OR BELOW FREEZING OVER THE NW PIEDMONT...75% OF THE PRECIPITATION WILL LIKELY FALL IN THE FORM OF FREEZING RAIN...THEREBY NECESSITATING THE WINTER STORM WATCH ISSUANCE. THE GREATEST IMPACTS ARE EXPECTED TO OCCUR ON ELEVATED SURFACES (ESPECIALLY TREES AND POWER LINES). THE PRECIPITATION WILL TAPER TO DRIZZLE...AND FREEZING DRIZZLE OR LIGHT FREEZING RAIN OVER THE NW PIEDMONT...AS THE LLJ AND ASSOCIATED ISENTROPIC LIFT WELL NORTH OF OUR REGION SUN NIGHT. TEMPERATURES WILL GRADUALLY WARM OVERNIGHT AS THE ARCTIC RIDGE SHIFTS OFFSHORE...WITH WARMING TO THE MIDDLE 30S NW PIEDMONT TO MIDDLE 40S SE BY DAYBREAK MON.

[Brick Tamland]

if the models keep coming in wetter there might be more places further south and east with more ice.

[FallsLake]

if the models keep coming in wetter there might be more places further south and east with more ice.

I think we will get something more like what Allen has posted. RAH is basically saying the same thing. The one difference is Allen's map has us with .25 which would be boarder line Winter Storm criteria. RAH is only saying brief period of Freezing rain. 

[NCCatawba]

Well...... there you have it folks. The NAM has fallen in line with the other guidance and it now showing a much wetter solution. This looks reasonable to me and I think that by tonight's 0z suite we will have a solution that will be very close to what we can expect. The temps are going to be tricky for many folks in NC and 1-2 degrees can be a very big deal. As it is in most cases, it will come down to how the lower dewpoints are advected into the area and where the 32 degree wet-bulb line sets up shop. Going from past experience, that line should end up somewhere from just east of AVL to Lincolnton to Concord and northeast to GSO. That's my call.

 

Interesting. However, I'm not to sure if it will even be mentioned by the people riding the 12z nam (Brad Panovich/WxSouth/Raysweather/others) because its a drastic change to just make a call on it right away. I think it would be smart to wait and see at least (1) run (0z suit you mentioned) match it. Even with that said, the other models are fairly wet. Bares watching the 0z tonight.