December 16th event

[dsaur]

This run gave me sprinkles

Thumbs up for sprinkles As long as you have moisture you have a chance. There is a lot of cold air to scour out. Just need the systems crossing Fla. and not Ga. T

[dsaur]

So this thought is running around in my head and I have read back a ways and still not seeing anyone address it. So here goes.

With dewpoints and wetbulbs being what they are at the onset of this precip (assuming we get any precip worth talking about) Because this is not the typical CAD situation, and given the cold air at the surface today and tonight. If / when the precip starts falling is there a chance that with EVAP cooling we never get very much above freezing or will the warm advection from the south be that great?

Anyone is welcome to fire away.

My experience has been that with insitu your good bet is zrain if you can get even a reinforcing zepher to push against the waa. Otherwise, the waa just eats into the cold ...working up the state. Dewpoints and wetbulbs are in your favor, but you need something to keep the cold pool from being eroded away over time. That is why I think NeGa. wins out this season with some icing where he will be slower to warm up there when there is no reinforcing, and no big scouring out either. Down here I might see some pellets or light zrain if the virga finds the ground, but quickly the waa will win unless there is some breeze from the n or ne at some level.

The weekend would look promising if that low were back in Fla. like it was before. T

[NEGa]

My experience has been that with insitu your good bet is zrain if you can get even a reinforcing zepher to push against the waa. Otherwise, the waa just eats into the cold ...working up the state. Dewpoints and wetbulbs are in your favor, but you need something to keep the cold pool from being eroded away over time. That is why I think NeGa. wins out this season with some icing where he will be slower to warm up there when there is no reinforcing, and no big scouring out either. Down here I might see some pellets or light zrain if the virga finds the ground, but quickly the waa will win unless there is some breeze from the n or ne at some level.

The weekend would look promising if that low were back in Fla. like it was before. T

until today, i was thinking tomorrow/tomorrow night might be the zr time in ne ga....but not looking too good now. the precip has been delayed a bit, and is also still so light i doubt it will reach the ground before it evaporates nothing like a last minute fizzle sigh.

[tazaroo]

May be grasping at straws at this point but the GFS indvidual ensembles look cooler, further south, more moisture and quicker for the Thurs "event". May be just a function of the lowere resolution they are run at and I don't know how to read them correctly I don't know.

[eyewall]

Treating the roads here already.

[MotoWeatherman]

So this thought is running around in my head and I have read back a ways and still not seeing anyone address it. So here goes.

With dewpoints and wetbulbs being what they are at the onset of this precip (assuming we get any precip worth talking about) Because this is not the typical CAD situation, and given the cold air at the surface today and tonight. If / when the precip starts falling is there a chance that with EVAP cooling we never get very much above freezing or will the warm advection from the south be that great?

Anyone is welcome to fire away.

Pretending there is no CAD you could get wetbulbed to freezing and get a period off freezing rain but then the latent heat release of the freezing rain would likely slowly warm you up back over freezing. Not only that but the rain is falling thru warmer air aloft which would slowly warm the surface also in a situation where their is no sort of CAD to sustain the cold at the surface.

[NEGa]

well this sucks, yet again. after a couple of days with snow to sleet to frz rain in the forecast and the models tending to show a better system, now a day out and the precip is slower, cold air retreating, warm air coming in and now maybe an hour or so of sleet followed by rain and, yep 33 or 34. of course probably very little qpf at this point. bah humbug

and this after a couple of days of frigid temps apparently i will never learn lol

[burgertime]

15z SREF has CLT mainly ZR for a few hours then rain. RDU and I 40 are snow for a few hours then ZR then plain rain. RDU would win with the snow if it were to verify.

[eyewall]

FAIL!

RAH disco:

TIMING:

PRECIP WILL INITIALLY BEGIN AS SNOW AS ANTECEDENT COLD AND DRY

ARCTIC AIRMASS WILL PRODUCE MIN TEMPERATURES IN THE LOWER TO MID 20S

NORTH TO MID TO UPPER 20S SOUTH. HOWEVER...THE AFOREMENTIONED 850

WARM FRONT/LLJ WILL PUNCH EAST THROUGH THE MID MORNING

HOURS...RESULTING IN A SUBSTANTIAL WARM NOSE ALOFT AND BRINGING

A QUICK TRANSITION TO A COLD RAIN WITH A BRIEF PERIOD OF FREEZING

RAIN IN BETWEEN. AREAS ALONG AND NORTH OF US 64...AND MORE

SPECIFICALLY NEAR THE NC/VA BORDER WILL HAVE THE POTENTIAL TO SEE

THE LONGEST DURATION FOR FREEZING RAIN...POSSIBLY LASTING INTO THE

EARLY TO MID AFTERNOON HOURS.

PRECIP AMOUNTS:

LIQUID QPF AMOUNTS LOOK TO AVERAGE FROM AROUND TWO TENTHS NEAR THE

NC/VA BORDER TO ONLY SEVERAL HUNDREDTHS ACROSS THE SOUTH. COULD SEE

A QUICK DUSTING(A HALF INCH OR LESS) WITH EARLY ONSET OF SNOW...

BUT MAIN CONCERN IS ICE. CURRENT THINKING IS AREAS ALONG AND NORTH

OF US 64 AND 70 WILL SEE NUISANCE ICING IN THE MORNING (TRACE

AMOUNTS)...WITH THE CHANGEOVER TO RAIN MELTING IN LIGHT ACCRUAL. THE

COUNTIES ALONG THE NC/VA BORDER COULD SEE AS MUCH AS A TENTH OF AN

INCH OF ICE ACCRUAL....WITH A LOW...10% PROBABILITY...OF UP TO

AROUND 0.25" OF ICE (WARNING CRITERIA). WILL ISSUE A STRONGLY WORDED

HAZARDOUS WEATHER OUTLOOK...ALLOWING US TO INTERROGATE

ONE MORE MODEL ITERATION BEFORE MAKING A DECISION ON ANY WINTER

ADVISORIES/WATCHES/WARNINGS.

MODEL FORECAST SOUNDINGS SHOW ABRUPT DRYING IN THE MID AND UPPER

LEVELS THURSDAY EVENING...WITH MEAN FLOW BECOMING WESTERLY. BUT

COULD SEE SOME SOME PATCHY/OCCASIONAL DRIZZLE LINGER THROUGH THE

OVERNIGHT HOURS.

TEMPERATURES...HIGHS THURSDAY WILL RANGE FROM LOWER TO MID 30 ACROSS

THE NORTH TO LOWER 40S SOUTH. NEAR STEADY TEMPERATURES THURSDAY NIGHT

WITH LOWS IN THE LOWER 30S TO AROUND 40.-- End Changed Discussion --

[Brick Tamland]

Doesn't seem like a fail for areas north of 40. And RAH has been wrong abount the amount of icing before. You never know here until it actually starts how much you will see.

[eyewall]

Doesn't seem like a fail for areas north of 40. And RAH has been wrong abount the amount of icing before. You never know here until it actually starts how much you will see.

I meant fail down this way Looks alright north of 40 for a little something based on their reasoning.

[rduwx]

18z nam looks a little better than 12z. It still has the heaviest precip up at the Va/NC border and up into Va. For the RDU area it looks to be a light snow to light ip/zr. Overall it doesn't look like much.

[chapelhillwx]

I was just thinking.... it's been quite a long time since the last real ZR event around here. December 2005 was the closest date I found in RAH's case studies that had significant icing... 1/10" here, but more just west of the Triangle. Some icy shenanigans would be fun, as I haven't seen them in forever.

[Brick Tamland]

May not be a big amount, but it doesn't take much on the roads here for there to be chaos.

[NEGa]

I was just thinking.... it's been quite a long time since the last real ZR event around here. December 2005 was the closest date I found in RAH's case studies that had significant icing... 1/10" here, but more just west of the Triangle. Some icy shenanigans would be fun, as I haven't seen them in forever.

that was the last one in ne ga as well. 5 years is a long to wait - esp since we used to seem to have several icing events each winter, and usually one was at least .25 or more

ah memories, that was one fun storm to track (esp with all the naysayers) and to experience.

[DaculaWeather]

All of our good weather disappeared years ago.

[rduwx]

May not be a big amount, but it doesn't take much on the roads here for there to be chaos.

Yea but you need it to come down hard enough for a short period of time to cause problems. According to what the models are showing it might not come down hard enough. Also you are going to have temps rising during the precip. It just doesn't look like much to me.

[chapelhillwx]

that was the last one in ne ga as well. 5 years is a long to wait - esp since we used to seem to have several icing events each winter, and usually one was at least .25 or more

ah memories, that was one fun storm to track (esp with all the naysayers) and to experience.

I'm sure it was fun to track, but I was 11, and I don't even remember it. I do remember the December 4-5 2002 storm very, very vividly!

[wake4est]

The Town of Cary (Wake County) put down brine on the roads this afternoon.

[rduwx]

The Town of Cary (Wake County) put down brine on the roads this afternoon.

Yea, and more to come. My brother is one of the drivers that puts the brine out and they have a crew coming in a 10pm tonight. I also work for the Town of Cary and from what I understand they will continue tomorrow.

[Isopycnic]

FAIL!

RAH disco:

TIMING:

PRECIP WILL INITIALLY BEGIN AS SNOW AS ANTECEDENT COLD AND DRY

ARCTIC AIRMASS WILL PRODUCE MIN TEMPERATURES IN THE LOWER TO MID 20S

NORTH TO MID TO UPPER 20S SOUTH. HOWEVER...THE AFOREMENTIONED 850

WARM FRONT/LLJ WILL PUNCH EAST THROUGH THE MID MORNING

HOURS...RESULTING IN A SUBSTANTIAL WARM NOSE ALOFT AND BRINGING

A QUICK TRANSITION TO A COLD RAIN WITH A BRIEF PERIOD OF FREEZING

RAIN IN BETWEEN. AREAS ALONG AND NORTH OF US 64...AND MORE

SPECIFICALLY NEAR THE NC/VA BORDER WILL HAVE THE POTENTIAL TO SEE

THE LONGEST DURATION FOR FREEZING RAIN...POSSIBLY LASTING INTO THE

EARLY TO MID AFTERNOON HOURS.

PRECIP AMOUNTS:

LIQUID QPF AMOUNTS LOOK TO AVERAGE FROM AROUND TWO TENTHS NEAR THE

NC/VA BORDER TO ONLY SEVERAL HUNDREDTHS ACROSS THE SOUTH. COULD SEE

A QUICK DUSTING(A HALF INCH OR LESS) WITH EARLY ONSET OF SNOW...

BUT MAIN CONCERN IS ICE. CURRENT THINKING IS AREAS ALONG AND NORTH

OF US 64 AND 70 WILL SEE NUISANCE ICING IN THE MORNING (TRACE

AMOUNTS)...WITH THE CHANGEOVER TO RAIN MELTING IN LIGHT ACCRUAL. THE

COUNTIES ALONG THE NC/VA BORDER COULD SEE AS MUCH AS A TENTH OF AN

INCH OF ICE ACCRUAL....WITH A LOW...10% PROBABILITY...OF UP TO

AROUND 0.25" OF ICE (WARNING CRITERIA). WILL ISSUE A STRONGLY WORDED

HAZARDOUS WEATHER OUTLOOK...ALLOWING US TO INTERROGATE

ONE MORE MODEL ITERATION BEFORE MAKING A DECISION ON ANY WINTER

ADVISORIES/WATCHES/WARNINGS.

MODEL FORECAST SOUNDINGS SHOW ABRUPT DRYING IN THE MID AND UPPER

LEVELS THURSDAY EVENING...WITH MEAN FLOW BECOMING WESTERLY. BUT

COULD SEE SOME SOME PATCHY/OCCASIONAL DRIZZLE LINGER THROUGH THE

OVERNIGHT HOURS.

TEMPERATURES...HIGHS THURSDAY WILL RANGE FROM LOWER TO MID 30 ACROSS

THE NORTH TO LOWER 40S SOUTH. NEAR STEADY TEMPERATURES THURSDAY NIGHT

WITH LOWS IN THE LOWER 30S TO AROUND 40.-- End Changed Discussion --

When in doubt, follow long term climate data.

[audioguy3107]

Wow, very interesting description of the impending "event" from the Birmingham WFO....check this out:

THE PRECIP SHOULD START OUT AS A MIXTURE OF FREEZING SPRINKLES (FRINKLES?) AND SLEET SPRINKLES ( SLINKLES?) IN THE NORTHWEST.

Is someone over there drinking?

[NEGa]

Wow, very interesting description of the impending "event" from the Birmingham WFO....check this out:

THE PRECIP SHOULD START OUT AS A MIXTURE OF FREEZING SPRINKLES (FRINKLES?) AND SLEET SPRINKLES ( SLINKLES?) IN THE NORTHWEST.

Is someone over there drinking?

no way, is that really in there i want some of what they are having

[eyewall]

I was just thinking.... it's been quite a long time since the last real ZR event around here. December 2005 was the closest date I found in RAH's case studies that had significant icing... 1/10" here, but more just west of the Triangle. Some icy shenanigans would be fun, as I haven't seen them in forever.

Yeah this was the last time I remember seeing any decent ZR. 1/10 is about right for Moore County.

[Isopycnic]

Wow, very interesting description of the impending "event" from the Birmingham WFO....check this out:

THE PRECIP SHOULD START OUT AS A MIXTURE OF FREEZING SPRINKLES (FRINKLES?) AND SLEET SPRINKLES ( SLINKLES?) IN THE NORTHWEST.

Is someone over there drinking?

That is almost as good as a met's dare/mention of DBM in an GSP AFD. I think there was some 'splaing to do the next day and a "Diffluent Buoyancy Momentum" pulled out of an oriface.

[audioguy3107]

no way, is that really in there i want some of what they are having

It really is in there! I will say this.....everyone gives FFC such a hard time (most of the time deserved I might add)...it's amazing the contrast between the discos. between those two offices. I usually read the BHM since whatever happens out west usually affects us in some way and they really seem to enjoy their job with their in depth discussions.

[AirNelson39]

Is it possible a band sets up somewhere and someone gets a few inches or an equivalent amount of IP or zr? I know there have been plenty of times where it wasn't looking like much for anyone but a few bands set up. Or is this system that unlikely to produce much?

Just hoping for a little something here in Caldwell County

[superjames1992]

Someone posted this forecast discussion on another forum:

http://forecast.weat...on=1&glossary=1

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE BIRMINGHAM AL

530 PM CST TUE DEC 14 2010

.UPDATE...AVIATION DISCUSSION.

&&

.DISCUSSION...

NO LARGE CHANGES IN THE FORECAST REASONING OR OUTCOMES FROM THE

PREVIOUS PACKAGE. OVERRUNNING EVENT STILL PROGGED TO COMMENCE

WEDNESDAY MORNING ACROSS OUR AREA...WITH LIGHT PRECIPITATION

EXPECTED TO BREAK OUT AROUND SUNRISE IN THE NORTHWESTERN COUNTIES

AND SPREAD WESTWARD FROM THERE. WE`VE BEEN LOOKING AT FORECAST

SOUNDINGS FROM JUST ABOUT EVERY ANGLE OVER THE LAST COUPLE DAYS...

AND WE JUST DON`T SEE ANY REASON TO DEVIATE FROM WHAT WE HAVE BEEN

THINKING ALL ALONG.

WE WILL BE ON THE SOUTHERN FRINGE OF WHAT COULD BE A MUCH MORE

SIGNIFICANT ICING EVENT TO OUR NORTH. THE PRECIP SHOULD START OUT

AS A MIXTURE OF FREEZING SPRINKLES AND SLEET SPRINKLES

IN THE NORTHWEST. A SLOW WARMUP WILL HELP PUSH THE

SURFACE FREEZING LINE NORTHWARD THROUGH THE DAY...AS THE PRECIP

INCREASES A BIT IN INTENSITY AND SPREADS WEST. IF IT DOES REACH

SUFFICIENT INTENSITY TO BE MORE THAN JUST A TRACE AMOUNT...I STILL

DON`T SEE ANY MORE THAN A FEW HUNDREDTHS OF AN INCH AT MOST IN OUR

CWA.

I`VE ALSO TRIED TO COME AT THIS FROM ANOTHER ANGLE...AND INSTEAD

OF TAKING THE MODELS AT FACE VALUE...TRYING TO FIGURE OUT IN WHAT

WAYS THE MODEL FORECASTS COULD BE WRONG (AND WHAT IMPACT THAT

WOULD HAVE ON SENSIBLE WEATHER). THE MODELS COULD BE INDICATING

TOO MUCH WARMING...WHICH WOULD MEAN MORE FREEZING TEMPERATURES

LONGER THAN CURRENTLY FORECAST. SCENARIOS THAT CAUSE THE MODELS

TO BE TOO WARM TYPICALLY INVOLVE EASTERLY WINDS AND A COLD AIR

DAMMING WEDGE. I DON`T SEE THAT COMING INTO PLAY HERE. THERE`S NO

BIG SURFACE HIGH IN THE NORTHEAST SENDING COLD/DRY AIR DOWN THE

EAST SIDE OF THE MOUNTAINS...AND THE PRECIP RAIN IS NO WHERE NEAR

HEAVY ENOUGH TO LOCK IN A WETBULBING/IN SITU TYPE EVENT. SO...WHEN

THE SURFACE WARM ADVECTION KICKS IN ON WEDNESDAY...IT SHOULD NOT

HAVE TOO HARD A TIME PUSHING OUT THE SURFACE COLD. AND SINCE THE

WINDS WILL BE OUT OF THE SOUTH...THE SNOW PACK TO OUR NORTH WILL

ALSO NOT HAVE AN IMPACT IN KEEPING OUR TEMPERATURES DOWN. SO...I

THINK THE MODELS DO HAVE A PRETTY GOOD HANDLE ON THE SITUATION.

SO LETS BREAK THINGS DOWN THIS WAY: DRAW A LINE FROM PICKENS

COUNTY WESTWARD TO RANDOLPH COUNTY. ANYTHING NEAR AND NORTH OF

THAT LINE COULD GET SOME LIGHT FREEZING RAIN. NOW DRAW A LINE FROM

SULLIGENT TO PIEDMONT. ANYTHING ALONG AND NORTH OF THAT LINE HAS

THE BEST CHANCE OF SEEING SOME FREEZING RAIN. IN BOTH CASES...THE

BEST CHANCES WILL BE IN THE WESTERN PORTIONS PRIMARILY BEFORE NOON

AND IN THE EASTERN PORTIONS PRIMARILY AFTER NOON. NOW...THOSE

LINES AREN`T MAGICAL. OBVIOUSLY THE SURFACE FREEZING LINE IS NEVER

A STRAIGHT LINE. SO...DON`T FOCUS ON THE FORECAST-TO-FORECAST

TWEAKS OF WHERE THE FREEZING LINE IS PLACED.

HAVING SAID ALL THAT...MY CONFIDENCE LEVEL IN HAVING ENOUGH FREEZING

RAIN TO CAUSE AN IMPACT ON TRAVEL IS STILL NOT HIGH ENOUGH TO TRY TO

PIN DOWN A FREEZING RAIN ADVISORY AREA.

EVERYTHING STILL ON SCHEDULE TO CHANGE OVER TO ALL RAIN BY 9 PM

WEDNESDAY. SEVERAL MORE ROUNDS OF RAIN AFTER THAT THROUGH AT LEAST

FRIDAY NIGHT. SOME MODEL DIFFERENCES ON WHEN THE LAST VORT MAX

ROTATES ACROSS THE NORTHERN GULF AND CAUSES A LOW PRESSURE TO FORM

AND MOVE NORTHEAST AND ULTIMATELY TAKE THE LAST OF THE PRECIP WITH

IT. WILL ALSO NEED TO TAKE A CLOSER LOOK AT THERMAL PROFILES ON

LATER MODEL RUNS...WITH RESPECT TO THE TAIL END OF THE PRECIP AND

WHETHER OR NOT CONDITIONS WILL BE COLD ENOUGH FOR A BRIEF PERIOD

OF WINTRY WEATHER FRIDAY NIGHT OR SATURDAY MORNING.

THATS QUITE ENOUGH.

Freezing sprinkles and sleet sprinkles, oh my!!!

[burgertime]

Here comes the NAM

[Wow]

Hoping to catch a good viewing of snow falling from the sky, but I'm still not really seeing much accumulation per the models yet.