October 2013 pattern and discussion

[FLweather]

Bring it on!!

SPECIAL WEATHER STATEMENT

NATIONAL WEATHER SERVICE RALEIGH NC

410 PM EDT SUN OCT 20 2013

 

Did you catch what else they had in their afternoon discussion?  Which I already knew it would be cold and the potential for the mid 20s(hard freeze).

 

 

 

WHEN LL THICKNESSES ARE STILL PROGGED TO

DIP INTO THE 1305-1310 METER RANGE. THESE THICKNESS VALUES...WITH

EXCELLENT RADIATION COOLING CONDITIONS AS THE SFC RIDGE AXIS DRIFTS

EAST OF THE APPALACHIANS...WOULD SUPPORT LOWS OF 22-28. WILL TAKE A

MORE CONSERVATIVE APPROACH GIVEN THE INHERENT UNCERTAINTY AT THIS

TIME RANGE AND AN OFTEN COOL BIAS IN THE MEDIUM RANGE MODELS...AND

ADVERTISE LOWS OF 26 TO 33 - WITHIN REACH OF THE RECORD LOW OF 27 AT

RDU FOR THE 26TH. THE RECORD OF 23 AT GSO FOR THE DATEWOULD SEEM

SAFE.

[Met1985]

Frost for much of the mountains tonight and for good reason. Temp already down to 45 degrees. Looking at upper 20s here tonight.

AVERY-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-GRAHAM-NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-CALDWELL MOUNTAINS-BURKE MOUNTAINS-MCDOWELL MOUNTAINS-INCLUDING THE CITIES OF...NEWLAND...SPRUCE PINE...BRYSON CITY...WAYNESVILLE...ASHEVILLE...SYLVA...FRANKLIN...BREVARD...HENDERSONVILLE1056 AM EDT SUN OCT 20 2013...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM EDTMONDAY...THE NATIONAL WEATHER SERVICE IN GREENVILLE-SPARTANBURG HAS ISSUEDA FROST ADVISORY...WHICH IS IN EFFECT FROM MIDNIGHT TONIGHT TO9 AM EDT MONDAY.* LOCATIONS...MOUNTAIN VALLEY LOCATIONS OF WESTERN NORTH CAROLINA.* TEMPERATURES...LOWS IN THE MID 30S.* WINDS...SOUTH 5 MPH OR LESS.* IMPACTS...AREAS OF FROST MAY DAMAGE SENSITIVE OUTDOOR  VEGETATION.

[DCMetroWinston]

Looks like the forecasts are trending colder than previously thought for late week

[strongwxnc]

wow. Thanks for posting these maps!!

 

Larry, these are monthly snowfall accumulation maps from 1935/1936 that I posted some time ago at Easternuswx.  Nearly thirty inches of snow fell that winter southeast of Charlotte.

 

[FLweather]

Sounds like cold rain possible next weekend. We don't need a lot of cold yet because we know it will warm back up and we want it to in November not December and January

Where did you hear or see that at if you dont mind me asking?

[FallsLake]

RAH long range discussing the possibility that lows Friday night might drop further than currently forecasted.

 

THURSDAY THROUGH SUNDAY: A SHORTWAVE TROUGH AND SUBSEQUENT THIRD
COLD FRONT WILL MOVE THROUGH CENTRAL NC THURSDAY NIGHT...WITH AND
INCREASE IN LOW TO MID LEVEL MOISTURE...MAY BRING AN INCREASE IN
CLOUD COVER AND KEEP TEMPS FROM DROPPING BELOW THE MID 30S IN THE NW
THURSDAY NIGHT. WITH THE COLD AIR IN PLACE...HIGHS ON THURSDAY
EXPECTED TO BE IN THE UPPER 50S TO LOW 60S. BEHIND THE LATEST COLD
FRONT...POLAR HIGH PRESSURE WILL BUILD INTO THE AREA...BRINGING WITH
IT CLEARING SKIES...LIGHT OVERNIGHT WINDS (ALLOWING FOR IDEAL
RADIATIONAL COOLING CONDITIONS) AND THE COLDEST TEMPERATURES OF THE
SEASON. THE HIGHLIGHT OF THIS PERIOD WILL BE THE LOWS FRIDAY
NIGHT/SATURDAY MORNING AS THE HIGH IS CENTERED OVERHEAD...WITH THE
POTENTIAL FOR SOME UPPER 20S OVER THE NORTHWEST HALF OF THE AREA TO
MID 30S SE. WITH THESE TEMPS COMES AN INCREASING PROBABILITY OF THE
FIRST FREEZE OF THE SEASON FOR AREAS ALONG AND WEST OF I-95.
INTERESTING TO NOTE...MODEL FORECASTED LOW LEVEL THICKNESS VALUES
ARE IN THE 1310 METER RANGE...WHICH WOULD SUGGEST LOWS IN THE LOW TO
MID 20S...BUT WITH MODEL UNCERTAINTY THIS FAR OUT WILL WAIT A BIT TO
SEE HOW THAT FORECAST EVOLVES WITH TIME. AS WAS MENTIONED IN THE
PREVIOUS DISCUSSION...THE RECORD LOW AT RDU FOR THE 26TH IS 27...
AND AT GSO IS 23 DEGREES. HIGH TEMPS FRIDAY AND SATURDAY EXPECTED TO
BE IN THE MID TO UPPER 50S ACROSS THE NORTHERN TWO-THIRDS OF THE
AREA...TO LOW 60S ACROSS THE SOUTH...INCREASING TO THE LOW TO MID
60S FOR SUNDAY. OVERNIGHT LOWS SHOULD GRADUALLY REBOUND THROUGH
SUNDAY NIGHT...TO THE MID 30S NW TO LOW 40S SE.

 

[Snowless in Carrollton]

Glenn Burns says that according to the latest Arctic Oscilllation Index, things are really going to heat up by the first of November. Temps in the 80s for Atlanta !

[FallsLake]

Glenn Burns says that according to the latest Arctic Oscilllation Index, things are really going to heat up by the first of November. Temps in the 80s for Atlanta !

I say bring it.... seesaw to warm in November and then seesaw back to cold by late November.  

[FallsLake]

NAO also looks to go positive by November 1st; this should allow for a warmer pattern. Indian Summer(??)

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/new.nao_index_ensm.html

[Met1985]

NAO also looks to go positive by November 1st; this should allow for a warmer pattern. Indian Summer(??)

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/new.nao_index_ensm.html

 

NAO also looks to go positive by November 1st; this should allow for a warmer pattern. Indian Summer(??)

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/new.nao_index_ensm.html

Not so sure about the NAO going that positive or positive at all. They have a great thread on re-curving tropical systems affecting blocking and the models doing poorly to forecast it. Although I would not mind the pattern relaxing through November just to come back to a cold pattern in December. Really wish we were in January seeing this pattern we are in know.

[Marion_NC_WX]

Not so sure about the NAO going that positive or positive at all. They have a great thread on re-curving tropical systems affecting blocking and the models doing poorly to forecast it. Although I would not mind the pattern relaxing through November just to come back to a cold pattern in December. Really wish we were in January seeing this pattern we are in know.

Would agree for sure...

The models always miscalculate exactly when the NAO switches over from negative to positive and vise versa. Also...there seems to be a reason to believe the models could break down the + PNA too quickly in the Day 10-14 range.

[FLweather]

Not so sure about the NAO going that positive or positive at all. They have a great thread on re-curving tropical systems affecting blocking and the models doing poorly to forecast it. Although I would not mind the pattern relaxing through November just to come back to a cold pattern in December. Really wish we were in January seeing this pattern we are in know.

 

That has been an interesting thread to read.

 

 

 

 

 

[Met1985]

Would agree for sure...

The models always miscalculate exactly when the NAO switches over from negative to positive and vise versa. Also...there seems to be a reason to believe the models could break down the + PNA too quickly in the Day 10-14 range.

This to. Ya I agree on this also. I both models are breaking this pattern down to fast right know. Especially bringing in that system in the SW out of know where.

 

That has been an interesting thread to read.

Yep there has been some great information past around by the mets in that thread.

[Cold Rain]

I'm not so sure what's great about the current pattern...unless it's just the thrill of early season cold, which, don't get me wrong, is awesome. But cold and dry, while better than warm in the winter (IMO), still doesn't yield snow.

We will need to see some southern stream energy once we get into winter in order for it to be a truly exciting pattern.

[metalicwx366]

I'm not so sure what's great about the current pattern...unless it's just the thrill of early season cold, which, don't get me wrong, is awesome. But cold and dry, while better than warm in the winter (IMO), still doesn't yield snow.

We will need to see some southern stream energy once we get into winter in order for it to be a truly exciting pattern.

Yeah not sure what is so exciting about cold and dry. Well it is one step closer to getting snow if it was the winter.

[FLweather]

I'm not so sure what's great about the current pattern...unless it's just the thrill of early season cold, which, don't get me wrong, is awesome. But cold and dry, while better than warm in the winter (IMO), still doesn't yield snow.

We will need to see some southern stream energy once we get into winter in order for it to be a truly exciting pattern.

But its still only Oct.  We have till atleast mid April to go before winter is officially over. As long as the enso remains neutral shouldn't be too hard to get an active stj to cooperate with hopefully the pattern we're seeing now... -ao-nao+pna. Usually the first flakes don't start falling in the piedmont till early Dec on a good year so there is still time.

[DaculaWeather]

The AO is forecast to go pretty positive though. http://www.daculaweather.com/4_teleconnections_graphs.php

It no big deal now, at least for us, maybe a slight warm up for a little while

[metalicwx366]

The AO is forecast to go pretty positive though. http://www.daculaweather.com/4_teleconnections_graphs.php

It no big deal now, at least for us, maybe a slight warm up for a little while

Hmm.. Funny how the OPI, which can predict the DJF AO with 83% variability says we should have a ++AO winter according to that thread. It's only October though.

[Cold Rain]

But its still only Oct. We have till atleast mid April to go before winter is officially over. As long as the enso remains neutral shouldn't be too hard to get an active stj to cooperate with hopefully the pattern we're seeing now... -ao-nao+pna. Usually the first flakes don't start falling in the piedmont till early Dec on a good year so there is still time.

Oh yeah, totally. I mean the upcoming pattern as-is isn't terrible -- it's just dry. So like you said, if ENSO doesn't screw us, maybe we can get lucky and add a STJ along with the rest of it, and then we'll be in business.

So if, in winter, we get a similar pattern to the one that's modeled, it'll be ok -- certainly better than what we had last year -- but it won't be great until we add some STJ energy in the mix. If we don't, then there will probably be a lot of posts bathed in frustration, some of which I will likely write.

[Met1985]

Oh yeah, totally. I mean the upcoming pattern as-is isn't terrible -- it's just dry. So like you said, if ENSO doesn't screw us, maybe we can get lucky and add a STJ along with the rest of it, and then we'll be in business.

So if, in winter, we get a similar pattern to the one that's modeled, it'll be ok -- certainly better than what we had last year -- but it won't be great until we add some STJ energy in the mix. If we don't, then there will probably be a lot of posts bathed in frustration, some of which I will likely write.

Ya Cold Rain I think the one thing I am taking from this current pattern is the break in the persistent Negative PNA which we have seen though winter over the past several winter. If we can periodically get a ridge out West and some blocking this winter I think we will be in business because by winter snow pack will be better and I think that these lows rolling down the trough will dive further south kind of like what Roger Smith has predicted but we shall see. Hoping for the best but trying not to expect much.

[Jon]

Ya Cold Rain I think the one thing I am taking from this current pattern is the break in the persistent Negative PNA which we have seen though winter over the past several winter. If we can periodically get a ridge out West and some blocking this winter I think we will be in business because by winter snow pack will be better and I think that these lows rolling down the trough will dive further south kind of like what Roger Smith has predicted but we shall see. Hoping for the best but trying not to expect much.

Was it last year that the +PNA really never set up and was more neutral and even with decent blocking in place we still got screwed? Let's hope that doesn't happen again...I'm optimistic and I don't mind the fluctuating teleconnections at least until Dec 1 then I'd prefer them be favorable...Having perfect Greenland blocking and nothing to show for it is like a dagger.

[Cold Rain]

Ya Cold Rain I think the one thing I am taking from this current pattern is the break in the persistent Negative PNA which we have seen though winter over the past several winter. If we can periodically get a ridge out West and some blocking this winter I think we will be in business because by winter snow pack will be better and I think that these lows rolling down the trough will dive further south kind of like what Roger Smith has predicted but we shall see. Hoping for the best but trying not to expect much.

Yeah, if nothing else, we should start to see some nice snow build-up in Canada, which is never a bad thing. Hopefully, the +PNA won't be a stranger all winter like it has been. It will be interesting to see how things evolve as we head into winter. There are mixed signals for sure, which may actually be a good thing, given how many cold forecasts there were last year. It certainly doesn't look wall to wall cold or warm to me, so we'll see (I do have a better feeling this year though), but now we're getting a little beyond the October Pattern discussion....

[FLweather]

Ya Cold Rain I think the one thing I am taking from this current pattern is the break in the persistent Negative PNA which we have seen though winter over the past several winter. If we can periodically get a ridge out West and some blocking this winter I think we will be in business because by winter snow pack will be better and I think that these lows rolling down the trough will dive further south kind of like what Roger Smith has predicted but we shall see. Hoping for the best but trying not to expect much.

Thats the reason why Im optismistic about this coming winter. Nothing like that is presently dominating the pattern. Espeically like 11-12 with -enso -pdo along with a deep deep GOA vortex. I just hope that enso remains neutral to positive along with the current -nao -ao +pna.... that should allow cold and wet  winter pattern over the east. If enso doesn't remain neutral then cold and dry may be the rule.

[Cold Rain]

How did the PNA look last fall before it went abysmal in winter?

[Jon]

How did the PNA look last fall before it went abysmal in winter?

It was jumping between -1 and basically neutral

[GaWx]

 In places like Atlanta and much of the SE US, it usually only takes one significant winter storm to put them well over the average annual S/IP or ZR. So, even without a persistent subtropical jet or a cold winter, much of the SE US can still get lucky and do well vs. averages with just one freak storm. More often than not, places like Atlanta will get only one sig winter storm, if any, in a typical winter although on occasion they get two and in very rare cases 3-4.

[dsaur]

 In places like Atlanta and much of the SE US, it usually only takes one significant winter storm to put them well over the average annual S/IP or ZR. So, even without a persistent subtropical jet or a cold winter, much of the SE US can still get lucky and do well vs. averages with just one freak storm. More often than not, places like Atlanta will get only one sig winter storm, if any, in a typical winter although on occasion they get two and in very rare cases 3-4.

 

In my experience it takes a persistent pattern most times to get a multiple.  I.E. split flow with blocking and a wet southern stream.  Getting a big event in Jan. then a mild Feb. and another event in March is harder to do, lol.  I like the two or three in a week to 10 days play, where it's cold the whole time, and you get frozen precip on top of old ice.

  I'd be curious how many multiple storm year storms came in clusters as opposed to spread over months.   Whatever, I'm ready for my long awaited back to back sleet extravaganzas.

  But I need rain first..... it won't sleet, if it won't rain. T

 

[Met1985]

Was it last year that the +PNA really never set up and was more neutral and even with decent blocking in place we still got screwed? Let's hope that doesn't happen again...I'm optimistic and I don't mind the fluctuating teleconnections at least until Dec 1 then I'd prefer them be favorable...Having perfect Greenland blocking and nothing to show for it is like a dagger.

Lol Ya we had blocking but the NPAC completely screws us.  We had a negative NAO and negative AO but could not get the pattern to set up.

[Cold Rain]

It was jumping between -1 and basically neutral

Ok, good deal. Thanks man. Then I guess that's maybe a good sign.

[HKY_WX]

Noticed the euro is close to a weak nino by early winter. This will be interesting to watch unfold. This combined with cold and snow bulid up over the NH in October usually means good things. There are some unfavorable things to consider as well, such as the QBO. Overall, I think the SST's over october have trended much more favorably in the atlantic and pacific (specifically the PDO regions and NAO regions). One thing I have noticed through several years of researching winter forecast analogs, is the trends over the late fall are much more important than the snapshot of a global SST map in early fall, which is what is commonly used in winter forecasts.