Christmas Eve/Day Winter WX Event - Midsouth

[breeze]

What? The Snow Fairy might be coming? Of course, 1" accumulations
here are...... Let's see what evolves!

~Annette~



Special Weather Statement
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NASHVILLE TN
320 PM CST SAT DEC 23 2006

TNZ005>011-022>034-056>066-075-077>080-093>095-240900-
BEDFORD-BENTON-CANNON-CHEATHAM-CLAY-COFFEE-CUMBERLAND-DAVIDSON-
DEKALB-DICKSON-FENTRESS-GILES-GRUNDY-HICKMAN-HOUSTON-HUMPHREYS-
JACKSON-LAWRENCE-LEWIS-MACON-MARSHALL-MAURY-MONTGOMERY-OVERTON-PERRY-
PICKETT-PUTNAM-ROBERTSON-RUTHERFORD-SMITH-STEWART-SUMNER-TROUSDALE-
VAN BUREN-WARREN-WAYNE-WHITE-WILLIAMSON-WILSON-
320 PM CST SAT DEC 23 2006

...ACCUMULATING SNOWS POSSIBLE OVER CHRISTMAS NIGHT AND TUESDAY...


A SIGNIFICANT STORM SYSTEM WILL BEGIN TO DEVELOP JUST SOUTH OF NEW
ORLEANS IN THE GULF OF MEXICO SUNDAY NIGHT OR CHRISTMAS EVE NIGHT...
THEN TRACK NORTHEAST TO CENTRAL ALABAMA CHRISTMAS MORNING. RAIN
WILL OVERSPREAD OUR REGION LATE SUNDAY NIGHT AND CONTINUE INTO
MONDAY.

THE STORM WILL CONTINUE TO INTENSIFY AS IT REACHES NORTHEAST
TENNESSEE MONDAY NIGHT...AND EASTERN PENNSYLVANIA TUESDAY
MORNING. A COLD BLAST OF AIR WILL INVADE OUR AREA MONDAY NIGHT BEHIND
THE LOW AND CHANGE THE RAIN TO SNOW. AT THE PRESENT TIME...WE EXPECT
THE RAIN TO CHANGE TO SNOW FROM ALONG THE TENNESSEE RIVER TO THE I-65
CORRIDOR DURING THE EVENING HOURS...AND ALONG THE CUMBERLAND
PLATEAU LATE IN THE EVENING MONDAY...BEFORE MIDNIGHT.

THE SNOW SHOWERS WILL CONTINUE THROUGH TUESDAY MORNING AND TAPER OFF
TO FLURRIES TUESDAY AFTERNOON...LEAVING ABOUT AN INCH FOR MOST
PLACES...BUT POSSIBLY 3 INCHES ALONG THE PLATEAU.

COLD BRISK WINDS TUESDAY WILL KEEP TEMPERATURES IN THE MID TO
UPPER 30S AND WITH A NORTHWEST WIND AROUND 15 MPH...IT WILL PRODUCE
WIND CHILLS VALUES OF 25 TO 30 DEGREES.

CHRISTMAS HOLIDAY TRAVELERS ARE ADVISED TO STAY TUNED TO THE LATEST
WEATHER UPDATES TO THIS POTENTIALLY SIGNIFICANT WINTER STORM.


$$

END/ORCHANIAN

[Brent]

The 0z NAM is more in line with the GFS now...

I actually think someone might get a decent snow out of this.

It's almost too good to be true.

[JonathanBelles]

is the first blue line the 32 degree line or is it just were snow will fall.

[cheezyWXguy]

its just a thickness line...its really not that important to either of what you suggested...it just shows exactly what it says: the thickness of the atmosphere...its a basis of what to look at...look at it to a general idea, then look at atmosphere profile and other things to get it exact to tell whether its snow or what temp...it may very well be where its 32 degrees or snowing, but thats not exactly what its supposed to show. Im pretty sure AFM gave a big explanation of all that good stuff the other night

[Janie2006]

Yep, yep, yep.

I think of the 540 line as a good starting point, then you go from there. You have to examine the Skew-T and things of that sort.

[JonathanBelles]

Yep, yep, yep.

I think of the 540 line as a good starting point, then you go from there. You have to examine the Skew-T and things of that sort.

skew-T?

[Janie2006]

Yep, yep, yep.

I think of the 540 line as a good starting point, then you go from there. You have to examine the Skew-T and things of that sort.

skew-T?

Yah. It gives you an atmospheric profile at a given location. Its based on "parcel theory". You send up a wx balloon and the sensors relay information about the temperature, etcetera of the atmosphere at that location at that particular point in time. For example, I think the soundings for our stretch of the Gulf Coast are taken at Slidell, La.

Mets take the information from the skew-t and use it in forecasting. In this situation, the skew-t can tell you what the temperature might be at, say, 500 MB. This is important right now because we could then guess at the type of precipitation that you might eventually see at the surface. If the atmosphere is below freezing just above the surface (or all the way to the surface), you would likely see a snow event. If the temp at the surface is 32* or below and the atmosphere above it is warmer, you might see freezing rain, so on and so forth. The skew-t is pretty handy.

[Janie2006]

Actually, I'm growing more concerned about this situation. The estimated pressure of the system is currently 1009 mb, and I think the low pressure may deepen as time goes by. There is a strong pressure gradient between the high pressure system to the north and the low, giving rise to wind advisories over coastal Texas and presumably, Louisiana as Christmas Eve progresses. There is a real potential for severe wx along the coast, that is, if the warm front crosses the coastline....

Question: Is there a potential for explosive cyclogenesis here? I wonder if the pieces are coming into place?

[Brent]

My zone forecast!!!

Tuesday...Mostly cloudy. Chance of rain and snow through the day. Highs around 42. West winds 10 to 15 mph with gusts to around 25 mph. Chance of precipitation 50 percent.

[HarlequinBoy]

Yay!! Hope you get some!!!

--
Monday Night...Showers early in the evening...Then rain or snow late in the evening. A chance of light snow after midnight. Less than an inch snow accumulation. Cloudy. Lows in the lower 30s. Northwest winds 10 to 15 mph. Wind gusts to near 25 mph in the evening. Chance of precipitation 80 percent.
--

That looks somewhat promising.

Although, they don't seem quite as confident with the snow changeover here now as well as they did last night, so I really wouldn't be surprised to see nothing but a cold rain tomorrow.

But hey, at least it will feel very Christmas-like and there's a chance.

[Janie2006]

Keep hope alive, snow peeps!

It doesn't look good for the Coast. Ah well, at least there's some cooler air coming in.

[HarlequinBoy]

Reports are coming in of snow across Northern Arkansas!

Still very little accumulation expected.. minor and on grassy surfaces.

[Brent]

Snow cancel here. It is freaking 66 degrees out!!! UGH!!!

BMX has given up. Blah.

THERE IS STILL SOME QUESTION ON WHETHER SOME SNOW COULD MIX IN
WITH THE RAIN LATE TONIGHT. LOOKING AT 12Z MODEL SOUNDINGS...THE
PROSPECTS OF SNOW IN OUR FORECAST SEEM PRETTY SLIM. THE BULK OF
THE DEEP MOISTURE ASSOCIATED WITH THE UPPER LOW IS FORECAST TO
STAY NORTH OF HERE...WITH SATURATED CONDITIONS LIMITED TO THE
LOWEST FEW THOUSAND FEET. THE LOWEST TEMPERATURES IN THE
SATURATED LAYER ONLY GET AS LOW -5C OR SO...WHICH IS NOT QUITE
COLD ENOUGH FOR SIGNIFICANT ICE CRYSTAL FORMATION. GROUND
TEMPERATURES ARE ALSO FORECAST TO STAY ABOVE FREEZING OVERNIGHT.
AND SINCE THE PRECIP SHOULD STAY FAIRLY LIGHT...MELTATIVE COOLING
WILL NOT BE SUFFICIENT ENOUGH TO BRING COLD AIR DOWN TO THE
GROUND. ASSUMING THAT ANY ICE CRYSTALS ARE ABLE TO FORM IN THE
CLOUDS IN THE FIRST PLACE...THE LOWEST THE SNOW LEVEL GETS IS
AROUND 1500 FEET. THAT PRETTY MUCH JUST LEAVES MOUNT CHEAHA --
WHICH IS EVEN FARTHER REMOVED (SOUTH) OF THE BETTER TEMPS AND
MOISTURE. SO...I PLAN ON TAKING OUT THE MENTION OF SNOW
TONIGHT...IN THE INTEREST OF HAVING A MORE SUCCINCT FORECAST.

[Portastorm]

Unfortunately Brent ... Heat Miser won out again and we all ended up with rain and/or warm for Christmas. Same thing in Tejas.

[Lowpressure]

Same thing in Charlotte, rain all day and 44 degrees.

[breeze]

...LITTLE OR N0 SNOW ACCUMULATIONS FOR MOST AREAS IN MIDDLE
TENNESSEE...

OHX in Nashville has went from 1", yesterday, to 1/2", this morning, to "little or NO
accumulation" by this afternoon. BLAH! BUST, again, maties!

~Annette~


A LOW PRESSURE SYSTEM WAS TRACKING THROUGH THE MID STATE THIS
AFTERNOON...AND WILL RACE TOWARD NORTH CENTRAL PENNSYLVANIA
TUESDAY MORNING. WRAP AROUND MOISTURE FROM THE LOW WILL CONTINUE TO
BRING RAIN ACROSS OUR REGION TONIGHT. THE COLD AIR BEHIND THE LOW
WILL NOT BE AS STRONG AS WE PREVIOUSLY THOUGHT...THUS THE RAIN
WILL MIX WITH SNOW FOR AREAS WEST OF I-65 AFTER MIDNIGHT...AND
THIS MIXTURE WILL REACH THE CUMBERLAND PLATEAU BY SUNRISE
TUESDAY. SCATTERED SNOW SHOWERS OR FLURRIES WILL BE THE RULE
THROUGH TUESDAY MORNING RESULTING IN LITTLE OR SNOW ACCUMULATIONS.

IF ANY ACCUMULATIONS OCCUR...IT WILL BE ON GRASSY AREAS. THE HIGHER
ELEVATIONS OF THE CUMBERLAND PLATEAU MAY SEE UP TO AN INCH OF
SNOW.

SINCE GROUND TEMPERATURES WILL BE ABOVE FREEZING TONIGHT AND
TUESDAY...NO ROAD PROBLEMS ARE EXPECTED.

$$

END/JAO

[HarlequinBoy]

Well, it's just drizzle here now. I didn't see any snow or flurries, just quite a bit of rain.

Temps were around 40 almost all day.

[Brent]

...LITTLE OR N0 SNOW ACCUMULATIONS FOR MOST AREAS IN MIDDLE
TENNESSEE...

OHX in Nashville has went from 1", yesterday, to 1/2", this morning, to "little or NO
accumulation" by this afternoon. BLAH! BUST, again, maties!

As usual. Winter in the South sucks.