Texas Winter 2013-2014

[wxman57]

Just looked at the 2m temp predictions from the 12Z Euro. Above freezing Austin to Houston Friday and down to 31-32 in the Dallas area for the coldest.

[Snowman67]

Wxman - quick question on the meteograms. If you are doing an extended model run that shows the temps in 12hr intervals, and say it is a runtime that will graph the 12AM and 12PM, does the graph not show how low the temp gets say at 6am? On the 0-192 hr I can see the temps at 3hr intervals, but on the extended only at 12hr, so if I have a 12AM/12PM interval, I don't see how high the temp would be say at 3pm or how low at 6am. Thanks in advance for the explanations.

If you want to see 6am (CST) temps on the extended GFS then you need to plot the 00Z or 12Z GFS run. The 06Z and 18Z runs depict temps at 12am and 12pm only. It's difficult to estimate the low or high for the day using the 06Z and 18Z extended GFS. For the 00Z and 12Z, the 6am temp will be pretty close to the morning low. The 6PM temp on the extended won't capture the high at 3PM - you may need to add 3-5 degrees to the 6PM temp to get the day's high.

Thank you Wxman 57. Now here's hoping to a nice cold spell late next week I'll be in Chicago Tuesday-Thursday and just took a look at their forecast- brr

[wxman57]

I'll be in LA, MS, AL and the FL panhandle Wed-Fri. Maybe it'll be warm there.

[gboudx]

Steve McCauleys latest FB post says his stat method is still rejecting any wintry precip and is only showing very minimal rain. You can read his full post if you Google Steve McCauley Facebook.

[Ntxw]

Steve McCauleys latest FB post says his stat method is still rejecting any wintry precip and is only showing very minimal rain. You can read his full post if you Google Steve McCauley Facebook.

I'm curious as to what his stat method consists of? Is it a composite of model(s) run(s)? I mean everything we forecast is pretty much reliant as to what the models show (since none of us realistically has the ability to mathematically calculate the entire globe) so I'm curious what he uses.

Edit: I looked at some of his posts and appears it's looking at it (hence the name) statistically. Meaning likely he's calculating based on many runs and includes climatology, and based on how far it deviates from the "norm" likely shows how confident it is on an outcome in lay man terms. I may be wrong but that's what I get from it the same way NWS uses MOS which is why they never put a strong forecast unless it is very out of the typical. So it is correct to show a low statistic since it's only been shown in one or two runs out of many before that had nothing (add in multiple models) and thus far mostly been dry

[Ntxw]

I'll be in LA, MS, AL and the FL panhandle Wed-Fri. Maybe it'll be warm there.

Take it with you sir! We, the cold mongers, will temporarily hold down the fort for you in Texas and run the weather machine in your absence

[gboudx]

Ntxw I see you read some of his posts. The only post I saw where he sorta explains it is below. I'm not on FB so I don't actively follow his posts. But he seems very engaging with his followers so maybe he can explain it more if asked.

From Steve:
The Stat Method is a forecasting technique I have been trying to develop for the past 5 years. It is certainly not perfect and never will be, but it is becoming more reliable especially for those 10-day forecasts
47 · December 4, 2013 at 11:23am · Edited

[MississippiWx]

I'll be in LA, MS, AL and the FL panhandle Wed-Fri. Maybe it'll be warm there.

Not much chance of that here, Heat Miser. Temps in upper 40s to low 50s for highs and lows in the 20s.

[CYCLONE MIKE]

I'll be in LA, MS, AL and the FL panhandle Wed-Fri. Maybe it'll be warm there.

Pffftt, i know we will be seeing warm temps and rain now. Sure liked the look of this mornings gfs run

[DonWrk]

Here is what Steve says the stat method is. He posted this a few minutes ago.

The stat method is essentially a 2-week running statistical analysis (including a linear least square regression of probability) of all the numerical weather prediction models, each one weighted anisotropically according to their maximum forecast projections and their strengths and weaknesses in various atmospheric setups.

[Portastorm]

I'll be in LA, MS, AL and the FL panhandle Wed-Fri. Maybe it'll be warm there.

Pffftt, i know we will be seeing warm temps and rain now. Sure liked the look of this mornings gfs run

Yeah Cyclone Mike, I'm sorry about that. Heat Miser brings pain and misery wherever he goes for those in the South who love cold weather and snow/ice. You can be he'll have that same impact as he moves through your area.

[Portastorm]

Lots of interest from Texas-Louisiana NWSFOs in the late-week weather for obvious reasons. Here are the relevant snippets from the afternoon AFDs, for your reading pleasure:

Austin/San Antonio:
MODELS ARE COMING INTO BETTER ALIGNMENT ON THE INCREASE OF PACIFIC
AND GULF MOISTURE AND THE ARRIVAL OF AN ARCTIC FRONT EARLY
THURSDAY. THE TEMPERATURE TRENDS ARE HEADING LOWER WITH EACH
RUN...BUT SOUNDING DATA FROM THE GFS INDICATES A DEEP AND WARM
LAYER CAPABLE OF MODIFYING THE INVERSION FROM PERSISTENT SHOWERS
TO HOLD TEMPERATURES ABOVE FREEZING THROUGH FRIDAY MORNING. LATER
SHIFTS WILL NEED TO WATCH THE TRENDS AND POSSIBLY ACCOUNT FOR
MIXED PRECIPITATION CHANCES FOR EARLY FRIDAY. POPS AND QPF AS WELL
AS WARMER THURSDAY MIN TEMPS FAVOR THE ECMWF MODEL THROUGH THIS
COLD AND DAMP PERIOD. RAIN CHANCES ARE EXPECTED TO DIMINISH
SATURDAY WITH A WARMING TREND EXPECTED FOR NEXT SUNDAY.

Dallas/Fort Worth:
THE THURSDAY FRONT WILL BE FAIRLY STRONG...AS THE HIGH PRESSURE
SYSTEM WILL ORIGINATE IN THE ARCTIC AND DROP RAPIDLY SOUTH INTO
THE NORTHERN PLAINS BY WEDNESDAY. THE COLDEST OF THE AIR WILL HEAD
PRIMARILY INTO THE MIDWEST AND EASTERN PART OF THE CONTINENT AS
THE MAIN UPPER TROUGH PULLS OFF TO THE EAST. BUT NORTH TEXAS WILL
STILL SEE TEMPS TUMBLE THURSDAY TO BELOW NORMAL AS WE GET A
GLANCING BLOW OF THIS SHALLOW ARCTIC AIRMASS. THE FRONT SHOULD
CROSS THE RED RIVER AROUND SUNRISE THURSDAY MORNING. THIS WONT BE
ONE OF THOSE FRONTS WITH A SHARP TEMPERATURE GRADIENT...BUT RATHER
A SUSTAINED BOUT OF STRONG COLD ADVECTION THAT WILL SEND TEMPS
INTO THE 20S BY THURSDAY NIGHT. MEANWHILE WE WILL BE EXPERIENCING
A SUBTLE SHIFT IN THE UPPER LEVEL PATTERN BY THURSDAY AS A PIECE
OF UPPER LEVEL ENERGY FROM THE PACIFIC RIDES OVER THE TOP OF THE
WEST COAST RIDGE AND DROPS INTO THE WESTERN US. WINDS IN THE MID
AND UPPER LEVELS WILL BACK FROM NORTHWEST TO WEST...WHICH WILL
HAVE THE EFFECT OF BRINGING IN MORE PACIFIC MOISTURE ALOFT IN THE
FORM OF MID TO HIGH LEVEL CLOUDS THURSDAY. THESE CLOUDS WILL LIMIT
MODIFICATION OF THE SHALLOW ARCTIC AIRMASS...BUT ALSO HELP KEEP
OVERNIGHT LOWS FROM GETTING TOO COLD.

THE MAIN FORECAST UNCERTAINTY IS JUST HOW STRONG THIS PIECE OF
PACIFIC ENERGY IS...AND THE EXACT TRACK IT WILL TAKE. THE 12Z GFS
MADE A SUDDEN CHANGE BY DIGGING THIS UPPER SYSTEM SOUTH OF LAS
VEGAS BEFORE EJECTING IT EASTWARD TOWARD TEXAS. THE ECMWF...UKMET
AND CANADIAN KEEP THIS SYSTEM FARTHER NORTH AND MUCH WEAKER. THE
12Z GFS ENSEMBLE SHOWS ABOUT HALF OF THE MEMBERS INDICATING THE
DEEPER/STRONGER TRACK. ALL FORECAST MODELS SHOW THIS SYSTEM
ENTERING A REGION OF CONFLUENT FLOW ALOFT WHICH WILL HAVE THE
AFFECT OF SQUASHING/SHEARING OUT THE SYSTEM...WHICH MEANS THE
SYSTEM WILL WEAKENING AS IT APPROACHES THE REGION.

THE QUESTION WILL BE JUST HOW MUCH RETURN FLOW NEAR 850MB THE
SYSTEM CAN GENERATE OVER THE REGION. THE STRONGER THIS RETURN FLOW
IS...THE BETTER THE LOW LEVEL MOISTURE/ISENTROPIC LIFT WILL BE
FOR PRECIPITATION. THE LOW LEVEL AIRMASS WILL CERTAINLY BE COLD
ENOUGH FOR FREEZING RAIN OR SLEET BY THURSDAY NIGHT AND FRIDAY
MORNING...AND THE MAIN UNCERTAINTY IS THE PRECIPITATION COVERAGE
WHICH HINGES ON AN ACCURATE 500MB FORECAST OF A SMALL SCALE
FEATURE 100 HOURS OUT. WHAT WE CAN SAY IS THAT THE BEST CHANCE OF
PRECIP IS ACROSS CENTRAL AND SOUTHEAST TEXAS...WHERE GULF MOISTURE
IS MOST LIKELY TO RETURN EVEN WITH A WEAKER SYSTEM. RIGHT NOW WE
WOULD ESTIMATE BASED ON ALL MODEL FORECASTS THERE IS ABOUT A 1 IN
5 CHANCE OF WINTER PRECIP IN OUR CWA THURSDAY NIGHT AND FRIDAY
MORNING. UNFORTUNATELY THE PUBLIC RESPONSE TO A MERE MENTION OF A
20 PERCENT CHANCE OF WINTER PRECIP ON DAY 5 SEEMS TO IGNORE THE
FACT THAT IT MEANS THERE IS AN 80 PERCENT CHANCE OF NOTHING
OCCURRING. THEREFORE...THERE IS JUST NOT ENOUGH CONFIDENCE YET TO
ADVERTISE FREEZING RAIN IN THE OFFICIAL FORECAST...AND WE WILL
NEED TO SEE SOME RUN TO RUN CONSISTENCY FROM THE GFS AND/OR
ANOTHER MODEL TO JUMP ON BOARD BEFORE FIRING UP THE WINTER WEATHER
PANIC MACHINE. HOWEVER...WILL ADD IN A 20 PERCENT CHANCE OF LIQUID
RAIN THURSDAY AFTERNOON AND EVENING OVER THE SOUTHERN PARTS OF
THE AREA...BUT END PRECIP CHANCES BEFORE TEMPS DROP BELOW FREEZING
TO AVOID THE ISSUE. HIGHS FRIDAY LOOK TO BE COLD WITH CLOUD COVER
AND POSSIBLE PRECIPITATION AND HAVE UNDERCUT GUIDANCE BY SHOWING
MOST OF THE ENTIRE AREA ONLY IN THE LOW 40S. AGAIN THIS PART OF
THE FORECAST BEARS CLOSE WATCH.

CLEARING SKIES SHOULD OCCUR BY FRIDAY NIGHT AS NORTHWEST FLOW
ALOFT RETURNS. WESTERLY LOW LEVEL FLOW WILL RESULT IN A RAPID
MODERATION OF TEMPS SATURDAY AND SUNDAY WITH HIGHS REBOUNDING INTO
THE MID 50S TO MID 60S.

Houston/Galveston:
THE LAST HAZARD OF CONCERN WILL BE ASSOCIATED WITH A COASTAL
TROUGH THAT WILL FORM LATE IN THE WEEK. THE GFS AND ECMWF DIFFER
A BIT...BUT BOTH SHOW INCREASING ISENTROPIC LIFT LEADING TO LIGHT
RAIN OVER SPREADING THE FORECAST AREA ON THURSDAY. A VERY COLD
AIRMASS WILL THEN PUSH INTO THE PLAINS ON FRIDAY AND SATURDAY. THE
COLD AIR MAY ARRIVE IN TIME FOR FREEZING RAIN EARLY FRIDAY MORNING
AND THEN AGAIN EARLY SATURDAY MORNING OVER THE FAR NORTHERN
COUNTIES...MAINLY NORTH OF A LINE FROM MADISONVILLE TO COLDSPRING.
THERE IS A LOT OF UNCERTAINTY WITH TIMING AND WILL ONLY GO WITH A
SLIGHT CHANCE OF FREEZING RAIN MIXED WITH RAIN IN THESE LOCATIONS
FRIDAY AND SATURDAY MORNINGS. ONSHORE WINDS WILL THEN HELP BRING
WARMER CONDITIONS OVER THE WEEKEND AS THE COASTAL SYSTEM PUSHES
OFF TO THE EAST.

San Angelo:
END OF THE WEEK CONTINUES TO LOOK MUCH COLDER. HAVE CONTINUED TO
TREND DOWN TEMPERATURES.

BOTH THE GFS AND THE ECMWF SURGE A VERY COLD AIR MASS THROUGH THE
CENTRAL PLAINS AND INTO WEST CENTRAL TEXAS ON THURSDAY, AS A NEARLY
1050MB SURFACE HIGH PRESSURE MOVES INTO THE AREA. THE GFS IS NOW THE
COLDER OF THE MODELS FOR THURSDAY AND FRIDAY, AND ALTHOUGH GIVEN THE
MODEL UNCERTAINTY ON TEMPERATURES, WILL OP TO TAKE THE READINGS DOWN
FOR THURSDAY AND FRIDAY ANOTHER 5 DEGREES OR SO. STAYING SOMEWHERE
IN BETWEEN THE GFS AND ECMWF SEEMS TO HAVE BEEN A DECENT SOLUTION.

GFS IS ALSO BREAKING OUT SOME DECENT PRECIPITATION TOTALS, AS A WEAK
DISTURBANCE PASSES AND COMBINES WITH ISENTROPIC LIFT OVER THE
FRONTAL BOUNDARY. ECMWF IS DRIER, SURGING THE COLD AIR THROUGH THE
AREA QUICKER AND THUS ENDS UP WITH LESS CLOUDCOVER AND SLIGHTLY
WARMER TEMPERATURES. AT THIS POINT, OPTED TO INCLUDE A MENTION OF
LIGHT RAIN ACROSS THE I-10 CORRIDOR FOR THURSDAY ALONG AND JUST
BEHIND THE FRONT. KEPT IT DRY FARTHER NORTH FOR NOW, BUT WILL NEED
TO MONITOR AS ANY PRECIPITATION FARTHER NORTH COULD BE IN THE FORM
OF FREEZING RAIN. EXPERIENCE HERE SUGGESTS THAT WITHOUT A
SIGNIFICANT DISTURBANCE TO THE WEST, COLD AIR WILL SURGE SIMILARLY
TO WHAT THE ECMWF SHOWS AND MORE LIKELY TO CUT THE PRECIPITATION OFF
BEFORE THE FREEZING TEMPERATURES ARRIVE. WILL WATCH VERY CLOSELY
THOUGH.

Shreveport:
ARCTIC AIRMASS WILL DEFINITELY FOLLOW THE THURSDAY FRONT...WHICH
OPENS UP THE POSSIBILITY FOR WINTRY PRECIP THURSDAY NIGHT AND
AGAIN FRIDAY NIGHT. CURRENT THINKING IS THAT RAIN SHOULD END PRIOR
TO LOCATIONS FALLING BELOW FREEZING AS THE BEST CHANCES FOR PRECIP
SHOULD REMAIN ACROSS THE SRN ZONES. THUS...GRIDS DO DEPICT PRECIP
CHANCES WITH BELOW FREEZING MIN TEMPS...BUT POPS/WX TYPES MATCH
BETTER WITH THE HOURLY TRENDS. DO NOT HAVE VERY HIGH CONFIDENCE
FOR WINTRY PRECIP OCCURRING. HOWEVER...IT IS TOO CLOSE TO CALL
GIVEN THE TIME FRAME SO THE SITUATION WILL NEED TO BE MONITORED
CLOSELY. /09/

[gboudx]

Here is what Steve says the stat method is. He posted this a few minutes ago.

The stat method is essentially a 2-week running statistical analysis (including a linear least square regression of probability) of all the numerical weather prediction models, each one weighted anisotropically according to their maximum forecast projections and their strengths and weaknesses in various atmospheric setups.

I wonder if he can explain it in Pig Latin to make it more clear?

[srainhoutx]

Portastorm can add NWS Midland/Odessa and NWS Lake Charles to the list of afternoon 'chatter' regarding the late week potential.

[CYCLONE MIKE]

Well don't worry about adding baton rouge/new Orleans to that list. Their riveting long range discussion is as follows

MODELS ARE IN AGREEMENT ON ANOTHER FRONTAL PASSAGE THURSDAY
NIGHT...BUT NOT PROGRESSING VERY FAR SOUTH OF THE AREA. MODELS
HINTING AT MOISTURE RIDING OVER THE SHALLOW COLD AIR DURING THE
WEEKEND...AND WILL CARRY SMALL RAIN CHANCES FOR THE WEEKEND.
CLOUDS WILL HOLD LOW TEMPERATURES UP SOMEWHAT BUT SUPPRESS HIGH
TEMPERATURES BELOW NORMAL. 12Z GFS MOS NUMBERS ARE PRETTY CLOSE TO
THE 00Z ECMWF NUMBERS...AND HAVE USED A BLEND OF THE TWO FOR THE
TEMPERATURE FORECAST.

[Ntxw]

So you're probably wondering where is this said storm? Where does it come from? Well, the mother system is the Aleutian low, and the feature we are watching is that huge blob of energy to the west/south diving underneath and will undercut the PNA ridge far left of the globe.

[gpsnowman]

Here is what Steve says the stat method is. He posted this a few minutes ago.

The stat method is essentially a 2-week running statistical analysis (including a linear least square regression of probability) of all the numerical weather prediction models, each one weighted anisotropically according to their maximum forecast projections and their strengths and weaknesses in various atmospheric setups.

There is one thing I don't understand......and that is everything he just said.

[Ntxw]

Here is what Steve says the stat method is. He posted this a few minutes ago.

The stat method is essentially a 2-week running statistical analysis (including a linear least square regression of probability) of all the numerical weather prediction models, each one weighted anisotropically according to their maximum forecast projections and their strengths and weaknesses in various atmospheric setups.

There is one thing I don't understand......and that is everthing he just said.

His method essentially in simple terms is to take all computer models and give out percentage of the likely outcomes each with their own strengths and weaknesses. The greatest percentage is the consensus of what is likely to occur. His method currently has low chances of frozen precip because essentially only the GFS and a few ensembles show anything of significance while most other models is dry at this time. Example if 1/10 models show snow then that's a 10% vs 90% no snow, of course it's much more complex but that's an example. If more models latch on to the idea then his SM will likely increase in percentage chance of X.

[TheProfessor]

Does any one have the statistics on the 18:00 GFS? It looks like it is showing all snow instead of ice on the wundermap. (I was looking around DFW airport.)

[Tireman4]

Here is what Steve says the stat method is. He posted this a few minutes ago.

The stat method is essentially a 2-week running statistical analysis (including a linear least square regression of probability) of all the numerical weather prediction models, each one weighted anisotropically according to their maximum forecast projections and their strengths and weaknesses in various atmospheric setups.

There is one thing I don't understand......and that is everthing he just said.[/quote]