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Late December Discussion and Christmas um Event

Cold Rain

By Cold Rain,
in Southeastern States

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burgertime

burgertime

Posted
Posted

Calm Down. Besides, I was right about this last storm days in advance with where the real snow would be. You werent. Remember the GFS was closer with the storm in the 168 to 180 hour range than the md range before it switched back. The euro only had real consensus when the GFS did, too.

Besides, you always talk about the euro but never post anything to back it up. Then when people like me look it up and find the euros different you chew them out. I won't forget you claiming the euro was way east when it wasn't. Or giving the entire I40 corridor snow when it didn't and that's not what happened.

Anyway, there s a little light snow here and the mountains will pick up a few inches tonight perhaps. I'll know from the report tomorrow.

This wraps up anything major for December here methinks.

Wait a minute...you and Wilkesborodude are the same person? :blink:

As for the bolded. Except I didn't say way east and it did show that.

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SN_Lover

SN_Lover

Posted
Posted

Calm Down. Besides, I was right about this last storm days in advance with where the real snow would be. You werent. Remember the GFS was closer with the storm in the 168 to 180 hour range than the md range before it switched back. The euro only had real consensus when the GFS did, too.

Besides, you always talk about the euro but never post anything to back it up. Then when people like me look it up and find the euros different you chew them out. I won't forget you claiming the euro was way east when it wasn't. Or giving the entire I40 corridor snow when it didn't and that's not what happened.

Anyway, there s a little light snow here and the mountains will pick up a few inches tonight perhaps. I'll know from the report tomorrow.

This wraps up anything major for December here methinks.

even though i think the model runs are a crapshoot for winter precip for the south, i think he puts more weight on the euro because it's been the top preforming model thus far.

monthly_ts_rmse_GZ500_NA_24.png

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ColdRainsStr8cashhomey

ColdRainsStr8cashhomey

Posted
Posted

A slight cold trend on forecast models and projected soundings overnight for Western NC folks, but that's all it has taken to flip the script on this system from all rain to some mixture of rain/sleet and snow. The problem is that with the timing (evening), roads like Highway 64 near Cashiers and Highlands could have problems tonight with some heavy snow/sleet in a few places for a short time.

It looks like a front-end thump (probably 3-6 hour window) sleet/snow and poss. frz rain (less likely) is going to happen IN A FEW AREAS west and *edit:(southwest) of Asheville, especially along the Balsam Mountain area in and around the counties of Macon (Franklin), southern Jackson (Highlands, Glenville Mtns, Cashiers), Haywood (Clyde, Waynesville, Cataloochee Mtn, Canton areas) and even possibly in Buncombe in Western NC this evening/overnight between the hours of 6pm and 3am...

Checked forecast soundings and there is a decent cold layer sufficient for frozen for a time (probably 3-6 hour window) and some evap. cooling will cause temperatures to hover between 31 & 33 in the low-levels for the areas mentioned above. Also, a the warm layer above 5,000ft could keep most places liquid or at least inconsistent frozen. Both NAM and GFS thermal profiles are similar on the 6z runs and both are marginal at 5000ft with 0.5C, 0C to -0.5C (0.5C at the lowest). 0z model runs were only slightly warmer, but they were close enough in the mid-levels to mention this possibility as well, especially once some evaporative cooling is realized. One thing that's important to remember about this system is that the system will be too weak to cause a lot of warm air to overwhelm the column completely. Also, precip. falling in areas where mid-level to low-level cold air gets trapped (could be around the Balsams) may be the wildcard for more sleet or snow than is expected in other forecasts. On the flip of that, heavy precip rates will eventually lead to a dynamic warming situation where the warm layer is eventually pulled down to the surface bullying the cold layer and using the moderate to heavy precip to make that happen.

The interesting part is that, due to southwest flow where the moisture is coming from, this could create sizable snowflakes for a time, especially if the mid-level to low-level cold gets trapped and doesn't get over-powered very quickly. I've seen this exact thing happen in the past for the areas/towns mentioned in Jackson, Transylvania, Haywood and Buncombe counties.

Since the layer of cold won't be all that established or widespread, there will be many areas of all rain as well (no surprise of course)... then, the warm will most likely win the battle by late night or very early Saturday in most Western NC towns. Watch out on some of the highways in Western NC this evening and overnight, but rain will probably melt whatever falls early on in the evening.

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NavarreDon

NavarreDon

Posted
Posted

A slight cold trend on forecast models and projected soundings overnight for Western NC folks, but that's all it has taken to flip the script on this system from all rain to some mixture of rain/sleet and snow. The problem is that with the timing (evening), roads like Highway 64 near Cashiers and Highlands could have problems tonight with some heavy snow/sleet in a few places for a short time.

It looks like a front-end thump (probably 3-6 hour window) sleet/snow and poss. frz rain (less likely) is going to happen IN A FEW AREAS west and southeast of Asheville, especially along the Balsam Mountain area in and around the counties of Macon (Franklin), southern Jackson (Highlands, Glenville Mtns, Cashiers), Haywood (Clyde, Waynesville, Cataloochee Mtn, Canton areas) and even possibly in Buncombe in Western NC this evening/overnight between the hours of 6pm and 3am...

Checked forecast soundings and there is a decent cold layer sufficient for frozen for a time (probably 3-6 hour window) and some evap. cooling will cause temperatures to hover between 31 & 33 in the low-levels for the areas mentioned above. Also, a the warm layer above 5,000ft could keep most places liquid or at least inconsistent frozen. Both NAM and GFS thermal profiles are similar on the 6z runs and both are marginal at 5000ft with 0.5C, 0C to -0.5C (0.5C at the lowest). 0z model runs were only slightly warmer, but they were close enough in the mid-levels to mention this possibility as well, especially once some evaporative cooling is realized. One thing that's important to remember about this system is that the system will be too weak to cause a lot of warm air to overwhelm the column completely. Also, heavy precip. rates falling in areas where mid-level to low-level cold air gets trapped (could be around the Balsams) may be the wildcard for more sleet or snow than is expected in other forecasts.

Also, due to southwest flow where the moisture is coming from, this could create sizable snowflakes for a short timew (have seen this exact thing happen in the past for the areas/towns mentioned) in Jackson/Transylvania/Haywood/Buncombe counties.

Since the layer of cold won't be all that established, there will probably be some sleet as well... then, the warm will most likely win the battle by early Saturday in most Western NC towns. Watch out on some of the highways in Western NC this evening and overnight, but rain will probably melt whatever falls early on in the evening.

Thanks Andy! Looks like you are on top of it this am.

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ColdRainsStr8cashhomey

ColdRainsStr8cashhomey

Posted
Posted

12z NAM trended slightly colder and more widespread in Western NC with the 5,000ft layer

but, it's the NAM........ which is akin to AshevilleDon, FranklinNCWx or Bevo throwing darts blind-folded at a dart board with possible precip solutions attached to it

again, precip. falling into dry air leading to some evap.cooling... and then in areas where mid-level to low-level cold air gets trapped (for a brief time at least - which will probably be around the Balsams)

this may be the wildcard for more sleet or snow than is expected in other forecasts... on the flip of that, heavy precip rates will eventually lead to a dynamic warming situation where the warm layer is eventually pulled to the surface bullying the cold layer and using the moderate to heavy precip to make that happen...

this one should be interesting to watch unfold

post-8747-0-45984400-1356705432_thumb.jp

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Met1985

Met1985

Posted
Posted

A slight cold trend on forecast models and projected soundings overnight for Western NC folks, but that's all it has taken to flip the script on this system from all rain to some mixture of rain/sleet and snow. The problem is that with the timing (evening), roads like Highway 64 near Cashiers and Highlands could have problems tonight with some heavy snow/sleet in a few places for a short time.

It looks like a front-end thump (probably 3-6 hour window) sleet/snow and poss. frz rain (less likely) is going to happen IN A FEW AREAS west and *edit:(southwest) of Asheville, especially along the Balsam Mountain area in and around the counties of Macon (Franklin), southern Jackson (Highlands, Glenville Mtns, Cashiers), Haywood (Clyde, Waynesville, Cataloochee Mtn, Canton areas) and even possibly in Buncombe in Western NC this evening/overnight between the hours of 6pm and 3am...

Checked forecast soundings and there is a decent cold layer sufficient for frozen for a time (probably 3-6 hour window) and some evap. cooling will cause temperatures to hover between 31 & 33 in the low-levels for the areas mentioned above. Also, a the warm layer above 5,000ft could keep most places liquid or at least inconsistent frozen. Both NAM and GFS thermal profiles are similar on the 6z runs and both are marginal at 5000ft with 0.5C, 0C to -0.5C (0.5C at the lowest). 0z model runs were only slightly warmer, but they were close enough in the mid-levels to mention this possibility as well, especially once some evaporative cooling is realized. One thing that's important to remember about this system is that the system will be too weak to cause a lot of warm air to overwhelm the column completely. Also, precip. falling in areas where mid-level to low-level cold air gets trapped (could be around the Balsams) may be the wildcard for more sleet or snow than is expected in other forecasts. On the flip of that, heavy precip rates will eventually lead to a dynamic warming situation where the warm layer is eventually pulled down to the surface bullying the cold layer and using the moderate to heavy precip to make that happen.

The interesting part is that, due to southwest flow where the moisture is coming from, this could create sizable snowflakes for a time, especially if the mid-level to low-level cold gets trapped and doesn't get over-powered very quickly. I've seen this exact thing happen in the past for the areas/towns mentioned in Jackson, Transylvania, Haywood and Buncombe counties.

Since the layer of cold won't be all that established, there will be some sleet/rain as well (big surprise)... then, the warm will most likely win the battle by early Saturday in most Western NC towns. Watch out on some of the highways in Western NC this evening and overnight, but rain will probably melt whatever falls early on in the evening.

Andy same sentiments as Don. Thanks for taking the time and posting on this storm. From Haywood County here and I am getting pretty stoked about this little event.

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ColdRainsStr8cashhomey

ColdRainsStr8cashhomey

Posted
Posted

Andy same sentiments as Don. Thanks for taking the time and posting on this storm. From Haywood County here and I am getting pretty stoked about this little event.

you got it buddy & happy to follow along... hope to see Haywood Co., Macon Co. and Jackson Co. areas get at least a one to three-hour window of some snow, sleet or ice... wait, let me re-phrase: sleet or ice

since systems have been over-producing on rainfall lately with the subtrop jet as energetic as we have seen in a year or more, there's more validity in the thinking that this system will over-produce with moisture (interestingly, the 12z NAM shows this and also shows that large area of 0C air at 850mb hanging around until 1am in some western NC towns).... but, who trusts the NAM outside of 18 to 24 hours in advance these days? :banned:

ultimately, the heavier precip rates will likely drag down that warm column above the colder column at 3,000-5,000ft a bit quicker than is forecast on the GFS and NAM this morning... but, I have seen that cold air be harder to scour out in these southwestern areas before and it wouldn't surprise me if that happens again with this system

if nothing else, the token flakes on the front end of this thing could be pancakes before the rain/warmer air ultimately wins the battle late (aside from the high elevation NW flow areas)

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Met1985

Met1985

Posted
Posted

you got it buddy & happy to follow along... hope to see Haywood Co., Macon Co. and Jackson Co. areas get at least a one to three-hour window of some snow, sleet or ice... wait, let me re-phrase: sleet or ice

since systems have been over-producing on rainfall lately with the subtrop jet as energetic as we have seen in a year or more, there's more validity in the thinking that this system will over-produce with moisture (interestingly, the 12z NAM shows this and also shows that large area of 0C air at 850mb hanging around until 1am in some western NC towns

ultimately, the heavier precip rates will drag down that warm column up air above the colder column a 3,000-5,000ft a bit quicker than is forecast on the GFS and NAM this morning... but, I have seen that cold air be much harder to scour out in these southwestern areas before and it wouldn't surprise me if that happens again with this

if nothing else, the token flakes on the front end of this thing could be pancakes before the rain/warmer air ultimately wins the battle late (oaside from the high elevation NW flow areas)

Yep we have had some nice surprises with these types of storms in the past. Always calling to change to rain then it never changes or it changes to ice after it has snowed. Again thanks Andy and looking forward to seeing this unfold later tonight.

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Tacoma

Tacoma

Posted
Posted

Yep we have had some nice surprises with these types of storms in the past. Always calling to change to rain then it never changes or it changes to ice after it has snowed. Again thanks Andy and looking forward to seeing this unfold later tonight.

Yes even in Buncombe county (Asheville) I have seen storms like this predicted to start as snow and turn to rain after a couple of inches of snow but it never changed to rain and I remember about 2008 Asheville had like 10 inches of snow and was predicted only 2 to 3. Snow never changed to rain and I mean it snowed hard all day long.

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iceman

iceman

Posted
Posted

I can't believe there is not more chatter going on in regards to this system tonight in the mountains of NC, this seems to have the chance to be a significant system with snow and ice.

I agree and also think the foothills and triad could see some frozen stuff overnight/early morning if these temps continue to stay lower than forcasted. Could be interesting.

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SN_Lover

SN_Lover

Posted
Posted

GSP's discussion sounds nasty

AT 2 PM FRIDAY...THE LATEST RUNS OF THE GFS AND ECMWF CONTINUE TO

INDICATE THAT THE EXTENDED RANGE WILL BE DOMINATED BY A POSITIVELY

TILTED CENTRAL CONUS MID LEVEL TROF. TWO WAVES OF QG FORCING IS

EXPECTED TO TRACK ACROSS THE REGION DURING THE PERIOD...THE FIRST

WAVE SHOULD OCCUR ON TUESDAY AND THE SECOND WAVE EXPECTED TO PEAK

THURSDAY AFTERNOON. WITH EACH ROUND OF MID LEVEL QG FORCING...SFC

LOW PRESSURE SHOULD FORM OVER THE NRN GULF OF MEXICO AND TRACK NE

ACROSS SOUTHERN GA AND NRN FL. I WILL CONTINUE TO INDICATE CHC POPS

FOR TUESDAY AND THURSDAY. HOWEVER...GIVEN MODEL DIFFERENCES AND RUN

TO RUN CONSISTENCY...CONFIDENCE REMAINS LOW CONCERNING THE LLVL

THICKNESS AND TEMPERATURE PROFILES. USING A BLEND OF HPC TEMPERATURE

GUIDANCE AND MEX MOS...IT APPEARS THAT MORNING LOWS WILL REMAIN

SEVERAL DEGREES ABOVE NORMAL WITH NEAR NORMAL HIGH TEMPERATURES.

DIURNAL TEMPERATURE CHANGES WILL FAVOR SN ACROSS THE MTNS AT

NIGHT...MIXING OVER TO RAIN DURING THE DAY. EACH EVENT WILL LIKELY

RESULT IN QPF LESS THAN A HALF INCH.

-- End Changed Discussion --

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ColdRainsStr8cashhomey

ColdRainsStr8cashhomey

Posted
Posted

Yes even in Buncombe county (Asheville) I have seen storms like this predicted to start as snow and turn to rain after a couple of inches of snow but it never changed to rain and I remember about 2008 Asheville had like 10 inches of snow and was predicted only 2 to 3. Snow never changed to rain and I mean it snowed hard all day long.

yep, have seen that also... thanks for the feedback on past storms... always good to hear about similar situations even though some of the variables and players on the field were probably slightly different

one thing I know for sure is that when copious moisture rides in on a weak low pressure (a weak low unable to pump a lot of warm air advection ahead of it)... trouble is coming as temperatures wet-bulb down to cause some angry, white locusts to come flying... January 10th, 2011 comes to mind as a weak low with a lot of upper-level driven moiusture content without much warm air advection (not that I'm comparing the January 10th system to this one because that was a MUCH larger, dynamic system)

I can't believe there is not more chatter going on in regards to this system tonight in the mountains of NC, this seems to have the chance to be a significant system with snow and ice.

absolutely should be getting more attention... radar blossoming back west in Alabama without many breaks in precip

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SN_Lover

SN_Lover

Posted
Posted

CAE's discussion is a tad more optimistic

MODELS ARE CONSISTENT IN UPPER RIDGING AND SURFACE HIGH PRESSURE

OVER THE REGION ON MONDAY RESULTING IN DRY CONDITIONS. HIGH PRESSURE

WILL MOVE OFFSHORE LATE MONDAY/EARLY TUESDAY AS A COLD FRONT PUSHES IN

FROM THE NORTHWEST. RAINFALL WILL MOVE INTO THE AREA BY 18Z ON

TUESDAY AND TAPER OFF EARLY WEDNESDAY. ANOTHER ROUND OF

PRECIPITATION WILL MOVE IN LATE WEDNESDAY/EARLY THURSDAY AS A SYSTEM

MOVES UP FROM THE GULF. MORE DISCREPENCY BETWEEN GFS AND ECMWF WITH

THIS SYSTEM ESPECIALLY WITH TIMING. DECIDED TO GO WITH A BLEND OF

HPC GUIDANCE. GIVEN THE GFS TRACK OF THE SECOND SYSTEM LATER NEXT

WEEK... SOME POTENTIAL WINTER WEATHER ISSUES MAY NEED TO BE

ADDRESSED ESPECIALLY OVER THE NORTHERN COUNTIES OF THE FORECAST

AREA...BUT CONFIDENCE IS RATHER LOW THIS FAR IN ADVANCE. THE GFS HAS

850 MB TEMPS MUCH LOWER THAN THE ECMWF THURSDAY EVENING. MODELS SHOW

AN UPPER TROUGH ADVANCING FROM THE WEST AND STRETCHED ACROSS THE

OHIO AND TENNESSEE VALLEYS BY EARLY FRIDAY.

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griteater

griteater

Posted
Posted

I'm pretty sure this loop is from the RPM model, but for NC, it's showing a wintry mix in the mountains and central/northern foothills. It has a bit of a mix along I-40 out to Hickory and just north of Statesville, and north of there. It's also showing a bit of snow in the northern foothills, just east of the mountains. The loop runs fast once it gets going, so just restart it to let it cycle through and you can see it in 'slow motion' - http://www.wdef.com/content/weather/mapsRegionalFutureCast.aspx

Also, this shows the snow in the northern foothills - this may also be from the RPM, as it matches up well with the above loop - http://www.wral.com/weather/page/9748768/

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