February Pattern and Storm Discussion

[packbacker]

That is usually not a good sign...

 

216 on precip, not far from something big, origin still looks to be from development of that front draped across FL at day 7, map below is day 9.

 

Why on the NoGaps?  It's a progressive model, usually to far SE at day 7 range.  I thought it was actually a good sign, but I guess not.

[Cold Rain]

0z 2/24 CMC and NCEP ensembles, 120-240hrs, CMC pretty bullish with development inside 35N -70W

Needs to get to about 83 and 30, then game on?

[WeatherNC]

Why on the NoGaps?  It's a progressive model, usually to far SE at day 7 range.  I thought it was actually a good sign, but I guess not.

I always thought the NOGAPS tended to flatten things out as t is stepped, hence the usual SE OTS bias we often see, this run develops a low over SVH and while weak, rides it very close to the coast.  That could be a concern since one would expect it to be more suppressed than the actual guidance envelope.  12z GFS ens are likely taking another step, 0 and 12z means below.

 

0

12

 

Doc is out to 72, gotta like this ots look 7 days out though, much easier to get it west as we get closer than to move it further east.  May also be able to get development sooner depending on how the actual wave shapes up along and in to the Gulf day 6-7.

[griteater]

EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD

1059 AM EST SUN FEB 24 2013

 

VALID 12Z WED FEB 27 2013 - 12Z SUN MAR 03 2013

 

WINTER STORM SYSTEM WILL BE IN FULL SWING AND TRACKING

EAST-NORTHEASTWARD ACROSS THE MIDWEST AND NORTHEAST DAYS 3/4.

ALONG/AHEAD OF THE SYSTEM'S COLD FRONT...A WET PATTERN IS

ANTICIPATED...WITH SIGNIFICANTLY DRIER AND COLDER CANADIAN AIR

SURGING INTO THE GULF OF MEXICO.

 

BETWEEN THE ECMWF AND GFS MODEL PACKAGES...THE MANUAL GRAPHICS DID

FIND THE 24/00Z EC ENSEMBLE MEANS CONSISTENT WITH ITS PREVIOUS 4-5

00Z CYCLE RUNS...WITH THE 24/06Z GEFS MEAN IN LOCKSTEP WITH THE

KEY FEATURES OF THE FLOW PATTERN. THERE WERE SOME DIFFERENCES IN

THE CENTRAL AND EASTERN PACIFIC BEYOND DAY 5...TO TREND AWAY FROM

THE GFS PACKAGE.

 

FOR DAY 5-7...THE OVERALL THEME IN THE FLOW PATTERN FOR NORTH

AMERICA IS FOR A SPLIT-FLOW PATTERN TO BECOME A MAINSTAY ALONG THE

WEST COAST...WITH THE 'SPLIT' OCCURRING INVOF 45N-50N 140W AND

DOWNSTREAM CONFLUENT FLOW REAPPEARING ALONG 40N LATITUDE FROM THE

LOWER MO VALLEY EASTWARD TO THE DELMARVA. ALONG THE BASE OF THE

UPPER-LEVEL TROUGH...THE NORTHERN STREAM ENERGY ORIGINATING IN

WEST CENTRAL CANADA WILL LIKELY BE A SERIES OF ALBERTA CLIPPERS.

THIS WILL PROVIDE THE LIGHT PRECIPITATION FOR THE NORTHEAST

QUARTER OF THE NATION. THE ONE CHALLENGE AND WITH LITTLE DETAIL AT

THE MOMENT...WILL BE THE ESTABLISHMENT OF AN ENERGETIC  SOUTHERN

STREAM...WHICH INVARIABLY DEVELOPS ONCE THE SPLIT-FLOW PATTERN

BECOMES MORE OF A QUASI-STATIONARY FEATURE IN THE EAST PACIFIC.

 

WHAT HAS BEEN A CONSISTENT PRECURSOR THIS SEASON...TO THE

TRANSITION PATTERN AND SOUTHERN STREAM INFLUENCES THAT THE

MAINLAND WILL BE OBSERVING AROUND THE END OF THIS FORECAST

PERIOD...IS A DEEP SYSTEM AND VORTEX IN THE WESTERN ALEUTIANS AND

OFF THE KAMCHATKA PENINSULA SHEARING OUT A MODERATE CUTOFF/CLOSED

MID-LEVEL TO THE NORTHEAST OF HAWAI'I. IN THE EXTENDED...MAINLY

DAYS 6-7...WE ARE SEEING MORE OF THIS PATTERN EMERGING IN THE

WESTERN PACIFIC.

[weatherlover]

^wow sounds like they are expecting the southern stream to stay active as well...that is definitely a great sign

[packbacker]

Euro looks much better at day 6/7. Low off the NC coast.

[WeatherNC]

The 0z Euro looked great at H5 up until 156hrs, it really looked like these two pieces were going to hook and turn the trough quick, however, at 168 it's as if the tail from the energy diving down amplifies over Mexico and severely holds the axis back left. At 204 it has a full latitude trough extending from the Bay of Campeche all the way to extreme SE Canada.

[rduwx]

12z euro looking better.  Actually has some moisture back into NC.

[WeatherNC]

12z euro looking better.  Actually has some moisture back into NC.

 

It closes off ~530dm over DC at 168, my precip maps have not updated yet, but it looks like even more energy diving down through the middle MS River Valley, timing likely not going to work out this run.  

[WeatherNC]

Correction, it is closed off, albeit barely detached, at 144, also acts like it wants to develop something SE of ILM.  Axis stinks, but still about a week out.

 

 

168 has the double barrel 

[GaWx]

Meanwhile, for those further west in the SE US who have felt left out on recent Doc runs, there is a Miller A bringing snow to S TN/N MS/N AL/N GA 3/4-5 fwiw on the 12Z Doc.

 

Edit: snow into upstate SC 3/6. Clown maps suggest major snow (4-6") parts of N AL and N GA 3/5 and probably eventually into Carolinas after end of run!

[jaxjagman]

Meanwhile, for those further west in the SE US who have felt left out on recent Doc runs, there is a Miller A bringing snow to S TN/N MS/N AL/N GA 3/4-5 fwiw on the 12Z Doc.

Euro is bringing a train of ULL's around this time,i think alot of people will see some sn in the SE during this time,it's also trying to bring another slug of cold air at the end of the run,not as warm as it was

[LithiaWx]

Euro is bringing a train of ULL's around this time,i think alot of people will see some sn in the SE during this time,it's also trying to bring another slug of cold air at the end of the run,not as warm as it was

Jacksonville is worse than waycross for a snow lover.

[metalicwx366]

Jacksonville is worse than waycross for a snow lover.

LMAO!

[GaWx]

Meanwhile, for those further west in the SE US who have felt left out on recent Doc runs, there is a Miller A bringing snow to S TN/N MS/N AL/N GA 3/4-5 fwiw on the 12Z Doc.

 

Edit: snow into upstate SC 3/6. Clown maps suggest major snow (4-6") parts of N AL and N GA 3/5 and probably eventually into Carolinas after end of run!

 

 The 12Z Sun Euro is a great lesson in climo for snows in the inland SE US: the best snows are often from very weak lows. This one is down to only ~1012 mb along the Gulf coast and deepens only to ~1010 mb once it gets to near Brunswick. Yet, it gives a major hit (4-7") to some (yes, that's definitely big for N GA and N AL as this occurs only once every 4-5 years or so in many of these areas on average) and 1-4" to many others in the northern Gulf coastal states from up to as much as ~0.70" of liquid and with 0.50"+ covering a 200 mile wide swath. It is often better for the low to stay weak to limit warm air advection and help keep the track far enough south. I know this from studying the tracks of dozens of Miller A snows that have occurred since the 1870's, many of which were weak. As long as it taps into the Gulf, the moisture will often be ample enough for a sig. storm. Phasing is often more of a detriment in this area. The bigger key is a track from the western GOM E or ENEward along the N GOM or right along the Gulf coast and then across N FL or far SE GA as well as a good cold air source to the north. There is normally WSWish 500 mb flow to allow for good moisture. I have no doubt about the 12Z Euro's result IF there would actually be a track like this since there'd likely be enough cold air to the north in this case. The harder thing as always is to actually get this kind of thing to occur!

 

Edit: per my memory, this is only the 2nd Euro run this winter to show a major snow like this in the northern Gulf coast states. The only other one was that incredible run from January (at ~forecast day 7) that then disappeared to never return.

[DixieBlizzard]

Larry. Great pattern recognition by you this season. There is indeed method to your madness. Even if we don't get the snow, the pattern recognition was still outstanding because "the players" seem to really be on the field.

[oconeexman]

 The 12Z Sun Euro is a great lesson in climo for snows in the inland SE US: the best snows are often from very weak lows. This one is down to only ~1012 mb along the Gulf coast and deepens only to ~1010 mb once it gets to near Brunswick. Yet, it gives a major hit (4-7") to some (yes, that's definitely big for N GA and N AL as this occurs only once every 4-5 years or so in many of these areas on average) and 1-4" to many others in the northern Gulf coastal states from up to as much as ~0.70" of liquid and with 0.50"+ covering a 200 mile wide swath. It is often better for the low to stay weak to limit warm air advection and help keep the track far enough south. I know this from studying the tracks of dozens of Miller A snows that have occurred since the 1870's, many of which were weak. As long as it taps into the Gulf, the moisture will often be ample enough for a sig. storm. Phasing is often more of a detriment in this area. The bigger key is a track from the western GOM E or ENEward along the N GOM or right along the Gulf coast and then across N FL or far SE GA as well as a good cold air source to the north. There is normally WSWish 500 mb flow to allow for good moisture. I have no doubt about the 12Z Euro's result IF there would actually be a track like this since there'd likely be enough cold air to the north in this case. The harder thing as always is to actually get this kind of thing to occur!

 

Edit: per my memory, this is only the 2nd Euro run this winter to show a major snow like this in the northern Gulf coast states. The only other one was that incredible run from January (at ~forecast day 7) that then disappeared to never return.

Larry, reading your disco is like watching a Hardees commercial! Pure bliss! Im seeing some real potential in the 3/3-3/6 time frame. Established cold air mass with re-enforcing shot at the time of a weak gulf low is possibly the best/most realistic set up we snowless folks in western

SC and Ga could ask for imo!

[GaWx]

Larry. Great pattern recognition by you this season. There is indeed method to your madness. Even if we don't get the snow, the pattern recognition was still outstanding because "the players" seem to really be on the field.

 

 Thanks, Greg. It is fascinating how past seasons can be so helpful due to their tendency to repeat in somewhat similar fashion. Analog seasons can't be used as crystal balls, of course, but certainly can be used as excellent tools. Now it is time to sit back and see what exactly comes out of this.

 

 Wouldn't it be great if a Miller A similar to what the 12Z Doc has were to materialize? By the way, you'd get ~5" from it from 0.50" of liquid! A snow like that has a return period of only ~4-5 years on average! Note how weak it is pressurewise...that's actually pretty typical for big snows in our area based on looking at old maps since the 1870's. I don't think a lot of people realize this since it is sort of counterintuitive. This run is a good climo lesson imo.

[GaWx]

Larry, reading your disco is like watching a Hardees commercial! Pure bliss! Im seeing some real potential in the 3/3-3/6 time frame. Established cold air mass with re-enforcing shot at the time of a weak gulf low is possibly the best/most realistic set up we snowless folks in western

SC and Ga could ask for imo!

 

 Thanks! Wow, comparing my disco to a Hardees commercial is the ultimate compliment lol. It is going to be fun to follow regardless of what actually materializes.

[DixieBlizzard]

 Thanks, Greg. It is fascinating how past seasons can be so helpful due to their tendency to repeat in somewhat similar fashion. Analog seasons can't be used as crystal balls, of course, but certainly can be used as excellent tools. Now it is time to sit back and see what exactly comes out of this.

 

 Wouldn't it be great if a Miller A similar to what the 12Z Doc has were to materialize? By the way, you'd get ~5" from it from 0.50" of liquid! A snow like that has a return period of only ~4-5 years on average! Note how weak it is pressurewise...that's actually pretty typical for big snows in our area based on looking at old maps since the 1870's. I don't think a lot of people realize this since it is sort of counterintuitive. This run is a good climo lesson imo.

 

A snow like that would be a nice finish to a rather eventful winter. I know some may disagree but to me, this winter was anything but boring. Snow very close by, tornado too close by and the rain has been so good this year for areas that really could use it. I think summers are better after rainy winters but I am going by memory alone. 

 

This run was a good climo lesson.

[superjames1992]

Our vortex in the NE is scooting out a lot faster on the 18z GFS.  It was centered over New England on March 2nd on the 12z GFS and now it's south of Newfoundland in the Atlantic.

[WhiteoutWX]

Our vortex in the NE is scooting out a lot faster on the 18z GFS.  It was centered over New England on March 2nd on the 12z GFS and now it's south of Newfoundland in the Atlantic.

Wave goodbye as the trough scoots off the coast.

[AbsolutZero]

I just saw this looking at ffc's homepage and they now have weekly web briefings videos on youtube. Maybe I missed this being mentioned but I  had no idea they have been doing this and I'm sure I'm the only one. 

 

Anyway, they started. apparently. not too long with 13 videos uploaded dating back a month or so.  Maybe other offices have been doing this for a while, I don't know...but I think it's cool they are doing it.

 

Here is this weeks link to the flooding/rainfall potential in the coming days. Now it is a day old  but still good (nice graphics alone make it worth it)

 

The only the thing I would wish for is it would be awesome if they would update these videos every day when facing severe weather, winter weather, heavy rains, etc as needed. For example, uploading one today after this mornings rainfall reports and new model runs. I know though they are real busy but maybe they can make it happen. (you ffc forecasters that visit or post here...hint hint lol )

 

Still can't complain too much though and glad they are doing it.

 

 

Hey Lookout, we'll be using youtube from now on for our weekly briefing and big events, now that permission has been given to use it and accounts set up.  Before youtube, we used to post mp4 videos on our web page and Facebook for the big events, however our thresholds for what constitutes a "big" event is subjective and probably higher than other WFOs (>2" snow, high-end Slight or higher severe risk, moderate or record flooding).  That might explain why many people haven't seen them.  Before we recorded briefings, we did them live for state and county government and other safety agencies and only the slides were put online for a short time. 

 

If you or anyone have suggestions, let us know.  Feedback so far has been good.

 

Steve

[burgertime]

Remember when folks were punting winter for Feb and then Charlotte got three inches? I'm not saying it will happen but all I know is I'm half drunk and getting car service to the Men's Club tonight. You hardly know about the day before life brings let alone weather.

Sent from my EVO using Tapatalk 2

[Cold Rain]

Remember when folks were punting winter for Feb and then Charlotte got three inches? I'm not saying it will happen but all I know is I'm half drunk and getting car service to the Men's Club tonight. You hardly know about the day before life brings let alone weather.

Sent from my EVO using Tapatalk 2

Before you do all that, could you tell us about the EPS control run? I'm sure it was a swing and a miss since nobody's posted anything about it.

[packbacker]

Before you do all that, could you tell us about the EPS control run? I'm sure it was a swing and a miss since nobody's posted anything about it.

It had a closed 500mb low over CLT day 7/8 but the surface low was 100 miles east of Hilton Head, it tracked over Jacksonville. Looking more closely at it, it had a two contour closed low over the GA/TN border with a weak low over the pan handle.

[Cold Rain]

It had a closed 500mb low over CLT day 7/8 but the surface low was 100 miles east of Hilton Head, it tracked over Jacksonville. Looking more closely at it, it had a two contour closed low over the GA/TN border with a weak low over the pan handle.

That sounds good to me from an upper air perspective. Maybe it sucks. I can't see it. But I would think a closed upper low in the SE would be a good thing here. Am I wrong?

[Dr. Steve Brule]

Well its Feb 24th still nothing really to track on the gfs or euro, yea it might get a little chilly but thats not snow. So if u ask me our chance for a significant snowstorm are gone, could be wrong but im probably right.

[Poimen]

Well its Feb 24th still nothing really to track on the gfs or euro, yea it might get a little chilly but thats not snow. So if u ask me our chance for a significant snowstorm are gone, could be wrong but im probably right.

 

Dr. No has an alias! 

 

All kidding aside, I tend to agree with you but I still have a glimmer of hope for something to occur in the next 7-10 days.

[WeatherNC]

eps is pretty close to if not a Miller A, system comes out of the eastern gulf through Central FL, comma head taking shape just a little too far offshore the SE this run.

 

Edit: and by far I mean 100-150 miles to get in to the heavier >0.25" axis