Christmas Storm VII

[ncskywarn]

NWS Chat out of Raleigh

https://nwschat.weat.../my/monitor.php

Too bad that is not open to certified spotters and new NWS Raleigh discussion is out

[/url]

000

FXUS62 KRAH 260402

AFDRAH

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE RALEIGH NC

1100 PM EST SAT DEC 25 2010

.SYNOPSIS...

-- Changed Discussion --A STRENGTHENING AREA OF LOW PRESSURE WILL TRACK FROM FLORIDA

NORTHEAST OFF THE NORTH CAROLINA COAST TONIGHT AND SUNDAY... THEN

REACH ALONG THE NEW ENGLAND COAST MONDAY. VERY COLD AIR WILL FOLLOW

THE STORM. A WARM-UP WILL BEGIN THURSDAY LASTING WELL INTO NEXT

WEEKEND.-- End Changed Discussion --

&&

.NEAR TERM /THROUGH SUNDAY/...

-- Changed Discussion --AS OF 11 PM SATURDAY...

...WINTER STORM WARNING CONTINUES FOR CENTRAL NC...

NOT AN EASY UPDATE WITH COMPLEX INTERACTION AND TRANSITION WITH THE

NORTHERN STREAM TROUGH AND STRENGTHENING SURFACE LOW LIFTING UP THE

SOUTHEAST COAST.

EARLIER THIS EVENING:

A 3.0-3.5" SWATH OF SNOW EXTENDING SOUTHWEST TO NORTHEAST

FROM WINSTON SALEM TO ROXBORO HAS ALREADY FELL EARLIER THIS

AFTERNOON AND INTO THE EVENING. THIS WAS IN RESPONSE TO THE

DIGGING NORTHERN STREAM TROUGH INTO THE LOWER MS VALLEY...

WITH STRONGLY BACKED FLOW RESULTING IN GOOD ISENTROPIC UPGLIDE

UNDERNEATH THE DIVERGENCE REGION OF A 110KT JET STREAK EXTENDING

SOUTH DOWN THE MID-ATLANTIC STATES. WARM AFTERNOON SURFACE

TEMPERATURES(MID TO UPPER 40S)ALONG AND EAST OF A PSEUDO WEDGE

BOUNDARY ATTENDANT TO THE SOUTHERN STREAM SURFACE LOW OVER THE

NORTHERN GULF...DELAYED THE LATE AFTERNOON/EARLY EVENING RAIN TO SNOW

CHANGEOVER...AND PREVENTED SIGNIFICANT SNOW ACCUMULATIONS SOUTH AND

EAST OF THE AFOREMENTIONED AREA. HOWEVER AFTER A HEAVIER BAND OF

PRECIP MOVED THROUGH THE...EVAPORATIVE COOLING FINALLY SHIFTED THE

TO SURFACE WET-BULB/RAIN-SNOW LINE SOUTHWARD TOWARDS THE TRIANGLE.

TONIGHT:

DEEPENING SURFACE LOW OVER FLORIDA WILL TRACK UP THE SOUTHEAST COAST

WILL...WHILE THE UPPER TROUGH PUSHES EAST ACROSS THE SOUTHERN

APPALACHIANS.

LATEST SATELLITE IMAGERY SHOWS SHEARED SOUTHERN STREAM VORT AND

DEEPER MOISTURE PLUME HAS SHIFTED EAST OFF THE SOUTHEAST COAST.

PRECIPITATION RATES/AMOUNTS ACROSS THE CAROLINAS HAVE REALLY LESSEN

OVER THE PAST HOUR WITH THE LOSS OF THIS SATURATION/MOISTURE ALOFT.

HOWEVER...THE EASTERN HALF OF NORTH CAROLINA WILL SEE RENEWED LIFT/FORCING

AND MOISTURE TRANSPORT INTO THE AREA BETWEEN 06 TO 12Z...THIS TIME

IN THE DEFORMATION BAND ASSOCIATED WITH DEEPENING SURFACE LOW

LIFTING UP THE SOUTHEAST COAST. MODELS SUGGEST A QUARTER TO HALF

INCH OF LIQUID QPF WITH THE NORTHERN SURGE OF MOISTURE INTO THE

EASTERN HALF OF NORTH CAROLINA WITH THE FREEZING SURFACE WET-BULB

SHIFTING SOUTH OF THE AREA BY 12Z. THIS WILL RESULT IN SNOWFALL

AMOUNTS OF 2 TO 4 INCHES FROM US 1 EAST. THE WESTERN PIEDMONT WILL

BE TOO FAR REMOVED FROM THE COASTAL BOMB...BUT COULD STILL SEE

ANOTHER INCH...MAYBE TWO... AS THE STRONG DPVA WITH THE UPPER TROUGH

SWINGS THROUGH THE AREA...HOWEVER SNOWFALL RATES WILL BE ON THE

LIGHT SIDE. -MWS

SUNDAY: THE MAJOR WINTER STORM WILL CONTINUE TO TRACK ALONG THE NC

TO MIDDLE ATLANTIC COASTS... SO WE EXPECT THE WIDESPREAD... HIGHER

INTENSITY SNOW TO COME TO AN END FROM WEST TO EAST THROUGH THE

MIDDAY HOURS... LINGERING LONGEST OVER THE NORTHERN COASTAL PLAIN

INTO THE MID-LATE AFTERNOON. COULD SEE AN ADDITIONAL 1 TO 3 INCHES

FROM THE TRIANGLE EAST BEFORE THE SNOW CHANGES OVER THE FLURRIES.

WILL HOLD ONTO A SLIGHT TO SMALL CHANCE OF LIGHT SNOW OR FLURRIES

FOR MOST OF THE DAY AREAWIDE... HOWEVER... AS THE CLOSED MID LEVEL

LOW PIVOTS EASTWARD ACROSS THE REGION. HIGH TEMPERATURES WITH A

PROJECTED FRESH SNOWPACK OVER THE REGION WILL STRUGGLE TO CLIMB INTO

THE LOWER TO MIDDLE 30S. BLUSTERY WITH A GUSTY NORTHWEST WIND BEHIND

THE DEPARTING CYCLONE. -MWS-- End Changed Discussion --

[DopplerWx]

The heavy rain making its way here should help to lower the temp a good bit.

[burgertime]

Radar shows a gap over me but it let up for maybe 5 minutes then started right back up with the moderate snow.

[fig]

The heavy rain making its way here should help to lower the temp a good bit.

I'm in Wilmington and hoping the same thing!!!

[SnowDeac]

I'm going to take back my bummer talk for the Triangle temporarily as this precip rolling up north/northwest from about Florence down to Augusta over to Charleston up to Wilmington looks serious. It's rain down there, but it's moving this way.

I am too. This has been such a long day, spending Christmas in intensive care of Duke Hospital, I don't have too much positive energy left. There are also more important things than snow.

[WidreMann]

RaleighWx, Foothills, eyewall, et al.: thoughts on RAH's discussion? It's pretty disappointing and seems slightly off from reality as the low does look to be cranking and not terribly sheared.

[augustagaweather]

I'm going to take back my bummer talk for the Triangle temporarily as this precip rolling up north/northwest from about Florence down to Augusta over to Charleston up to Wilmington looks serious. It's rain down there, but it's moving this way.

Hey Watch it buddy! Sure its Rain now but.....I think a change over is just around the corner. Currently 35 with light rain off an on.

[RaleighWx]

RaleighWx, Foothills, eyewall, et al.: thoughts on RAH's discussion? It's pretty disappointing and seems slightly off from reality as the low does look to be cranking and not terribly sheared.

The deep moisture plume did shift off shore, but I think we knew that would happen. I think they were counting on 1-2 before the coastal cranked and for many that wasn realized, So now the 2-4 from their perspective comes from the coastal storm and deformation band.

It could end up being a good call certainly anything more than 6 in the Triangle is going to be a reach now unless things really slow down and wrap up. However , we shoudl still get a 4-6 or 8 hour period of moderate to heavy snow possib.y commencing as early as 1am or so.

[DopplerWx]

SLP just exiting the coast of FL. Should really get cranking now.

http://www.spc.noaa.gov/exper/mesoanalysis/new/viewsector.php?sector=18&parm=pmsl&underlay=1

[CaryWx]

Thanks RaleighWx. Sure has been a disappointment from the higher totals called for as late as 6pm this evening.

[nchighcountrywx]

For Down in Charlotte Area:

Reports that boundary layer issues still exist with the 925mb 32 degree line literally bisecting Mecklenburg county. This is causing a lot of the wet snow to melt without accumulating.

Need to get the lower temperatures down several degrees to help things out.

The backing of the precipitation shield starting to move north up the coast may clip the eastern parts of Mecklenburg.

For folks down into the Piedmont and east, I was disappointed to just see this from KRAH:

LATEST SATELLITE IMAGERY SHOWS SHEARED SOUTHERN STREAM VORT AND

DEEPER MOISTURE PLUME HAS SHIFTED EAST OFF THE SOUTHEAST COAST.

PRECIPITATION RATES/AMOUNTS ACROSS THE CAROLINAS HAVE REALLY LESSEN

OVER THE PAST HOUR WITH THE LOSS OF THIS SATURATION/MOISTURE ALOFT.

In January 2000, the exact opposite was occurring as the moisture plume, saturation and lift was being driven back of the North Carolina US1 corridor that evening.

Updates 1137pm: I just see that a Mesoscale Discussion for up to 1" per Hour Rates East and NE of Charlotte up through the Coastal Plain was just issued. Looks like things are coming together in that area for what moves up the coast.

When all is said in done, in WNC it appears the Hickory - Morganton - Lenoir area gets the prize on this one (exclusive of upcoming upslope in the HIgh Country)

[Pilotwx]

I'm no Met but if you look on the WV you can see the best lift going off shore. But, wait a minute look at the last few frames and you can see the Low getting ready to go off the coast near FL. GA east coast. Now take a look @ the flow now turning north northwest the last few frames also. I think they are changing their forecast a little too early. We will see? Also there is going to be a lull, or dry slot during this change from Gulf to Atlantic, remember it's source of moisture has been temp. interrupted by crossing land, and it is a delayed effect.

http://www.goes.noaa.gov/GSSLOOPS/ecwv.html

RaleighWx, Foothills, eyewall, et al.: thoughts on RAH's discussion? It's pretty disappointing and seems slightly off from reality as the low does look to be cranking and not terribly sheared.

[DeepSouthSC]

WLTX weatherman (during the 11pm news), Jim Gandy, feels we should see some snow within the next couple of hours. He also mentioned (paraphrase), snow should be heavy in NE Richland County, Kershaw County and Winnsboro County.

I'm still on the fence how this thing is gonna shape up, but I'm not sure I can wait a couple more hours. I feel sleep hitting me on the head shortly. LOL

He just said, "When it does change.... It should change dramatically." By the way, he predicted 1-4 inches in the area. Higher amounts in the areas where he said it would be the "heaviest."

[DopplerWx]

I'm no Met but if you look on the WV you can see the best lift going off shore. But, wait a minute look at the last few frames and you can see the Low getting ready to go off the coast near FL. GA east coast. Now take a look @ the flow now turning north northwest the last few frames also. I think they are changing their forecast a little too early. We will see? Also there is going to be a lull, or dry slot during this change from Gulf to Atlantic, remember it's source of moisture has been temp. interrupted by crossing land, and it is a delayed effect.

http://www.goes.noaa...LOOPS/ecwv.html

No doubt. The radar is exploding in the lowcountry of SC and it is just the beginning. Once the temps crash I think central and eastern SC and NC will be under a band of moderate to heavy snow for quite a while.

[NCWeSU]

RaleighWx, Foothills, eyewall, et al.: thoughts on RAH's discussion? It's pretty disappointing and seems slightly off from reality as the low does look to be cranking and not terribly sheared.

I don't have any issues with RAH's discussion, and I still don't see a reason to change the forecast. It's not really an exact science when they paint their totals into the grid forecast.

MWS is just talking about the energy transferring over from the gulf to the Atlantic.

This low will travel up the east coast and the associated deformation band will likely drop 3-7 inches from the triangle eastward.

[Triad SKYWARN]

SPC issues MCD for Central and Eastern N.C..

[Triad SKYWARN]

http://www.spc.noaa.gov/products/md/md2134.html

[JQPublic]

Looks to be filling in nicely in much of central and eastern SC. The triangle are is prime to get in on the action early in the morning! I hope I can make it back tomorrow to check it out

[DopplerWx]

http://www.spc.noaa..../md/md2134.html

Nice! Just as I thought, we will be under some heavy snow soon guys!

[Jet Stream Rider]

http://www.spc.noaa..../md/md2134.html

Thats an outstanding mesoscale discussion. Interesting.

[superjames1992]

http://www.spc.noaa..../md/md2134.html

That's BOOM GOES THE DYNAMITE stuff to spread it all the way out west to us. E NC would get pounded.

[DopplerWx]

Dang...the radar is just exploding right now as the low moves offshore, it will only get better. Man what a night and morning this will be!

[NCWeSU]

Weak elevated instability?

Thundersnow?

[AJF0602]

I was just thinking the same thing... many mets mentioned it yesterday but focused on the western parts of SC.

Weak elevated instability?

Thundersnow?

[burgertime]

For Down in Charlotte Area:

Reports that boundary layer issues still exist with the 925mb 32 degree line literally bisecting Mecklenburg county. This is causing a lot of the wet snow to melt without accumulating.

Need to get the lower temperatures down several degrees to help things out.

The backing of the precipitation shield starting to move north up the coast may clip the eastern parts of Mecklenburg.

Yea for how much has falling it has amounted to what it should have. We should be sitting at around 2 inches but seem to be capped at one inch. I'm on the eastern side so I'm hoping to get clipped by those one inch an hour rates.

[DopplerWx]

Well, we saw western nc and sc have their fun, now its our time boys and girls. Once we changeover it is going to be an insane night, heavy snow plus a deepening low just offshore...wow.

[burgertime]

That's BOOM GOES THE DYNAMITE stuff to spread it all the way out west to us. E NC would get pounded.

This may or may not be the case but if that low over performs and is a little west it makes all the difference, however I GSP and RAH.

[tazaroo]

For Down in Charlotte Area:

Updates 1137pm: I just see that a Mesoscale Discussion for up to 1" per Hour Rates East and NE of Charlotte up through the Coastal Plain was just issued. Looks like things are coming together in that area for what moves up the coast.

When all is said in done, in WNC it appears the Hickory - Morganton - Lenoir area gets the prize on this one (exclusive of upcoming upslope in the HIgh Country)

Good find and somewhat encouraging. It even has part of the triad area in this area.

[crossthread]

I'm in Wilmington and hoping the same thing!!!

Fig since you last replied, (NOT this Quote), it's raining lightly, getting lil more moderate, AND the temps have dropped 4 degrees from 44.7 degress to 43.4 with-in the last 45 minutes or so...w/a couple ip's mixed in every once in awhile... (edit falling again as I type---> 43.1)

Current obs

43.3, (dropped another 10th as I'm typing this..

Humidity back up from 77% to 100 % now

dew point @ 44F

Wind now picking up from theNorth/NNE @ 8.8 with gusts to 11.4

Pressure fell from 30.09 now to 29.82...since 6pm

KILM AFD Valid 8:15 this evening....

Near term /through tonight/...

as of 8 PM Saturday...low pressure is now across the extreme

northeast Gulf of Mexico...nearing the Florida coast with 3 hourly

pressure falls currently increasing off the southeast coast of the

United States. Low pressure is expected to intensify significantly

off the southeast coast through tonight given the favorable

pre-conditioning. The regional radar mosaic and surface observations

indicate -ra is occurring just west of the Pee Dee zones and -sn

farther upstream. Meanwhile the initial weak targets falling across

the Pee Dee and Lumberton areas are virga...with some sprinkles a

good bet.

Once -ra begins to fall within the hour or two across the western

zones expect to see temperatures lowering a category or two as a

result of evaporative cooling. Meanwhile increasing low-level cold

air advection overnight into Sunday morning will finally allow the

changeover to snow to occur. Currently think the changeover is on

target to occur across the far inland zones around midnight...and at

the coast around daybreak. Since the 00z models are not in

yet...will not be making any significant changes with the 9 PM

issuance. Instead...will make any adjustments based on radar and

trends in the surface observations.

&&

Short term /Sunday through Sunday night/...

as of 3 PM Saturday...rapidly deepening low pressure should pass

about 125 miles east of Cape Fear early Sunday morning on its way up

the middle-Atlantic and New England coast over the next couple of days.

This track is significantly closer to shore than climatology

suggests for significant snow in the eastern Carolinas...but given

the below normal heights and temperatures both ahead of and

especially behind the storm...snow should still be the result. The

12z model suite finally has excellent internal agreement within the

various members and also with the 00z models from last night.

Confidence is much higher than yesterday at this time...although

there are still some questions regarding the timing of the

changeover from rain to snow along the coast and its impact on

ultimate snowfall accumulations.

At daybreak Sunday...moderate snow should be ongoing across all the

area except within ~20 miles of the coast where rain will still be

falling. As colder air slams in during the morning precipitation

should go to all snow down to the beaches. Temperatures here at the

surface will be marginal for significant accumulations unless

snow rates are high. And this is actually expected...especially

after reviewing the 12z NAM that shows mesoscale banding of

moderate to perhaps heavy snow Sunday morning within a region of

middle-level frontogenesis and enhanced dendritic Crystal growth.

This feature moves from the Pee Dee region around daybreak to near

Wilmington by noon...then out to the northeast by 1-2 PM. Our

snowfall forecasts have increased as a result...with storm totals

now in the 3-4 inch range from Darlington to Dillon...Lumberton

and Elizabethtown. Locations from Florence...to Marion...

Whiteville...Wilmington and Burgaw should see around 2 inches. One

to two inches are forecast across Kingstree...Conway...and the

Brunswick County beaches...with around an inch from Georgetown to

the Myrtle Beach area. (I bet We may get more)

As synoptic and mesoscale ascent pushes out to the north and east

Sunday afternoon snow should taper down to flurries...which may last

into Sunday evening as wrap around low cloud tops chill down to

around -12c...temperatures suitable for efficient snow Crystal

growth. Clouds should diminish from west to east after midnight with

mostly clear skies expected by daybreak Monday.

As I just typed/pasted this, in the last 10 minutes temps fell another Whole degree, now @ 42.0 F even)

Light rain

[wakeforest22890]

Still getting a constant rate of snow here in NW Forsyth (Winston), hoping maybe it stretches out just a bit more to the west and gets us included, but if not we've had our time. Hope everyone gets some snow in the eastern parts as well.

Snow is melting off the roofs here though as the temperature still sits slightly above freezing.