Texas Winter 2015-2016

[orangeblood]

The question now is how far south will the Arctic air penetrate. Many of the models are showing a trend of cold air being held up.

My instincts tell me everything with plow southward. EPO is negative and may reach 3 SD's below normal That's a solid signal for Arctic attack. It's nothing to joke about the blocking that is going to occur up there. We just saw the same kind of idea happen in the Kara Sea and the intense cold that blasted the Black sea region below. There are very few cases where you will see Alaska/Yukon block sit like that. Nearly all of them plunged the lower 48 into a deep freeze.

Yep, we seem to have this same discussion almost every year with these type synoptic setups....they almost always deliver! PNA is forecast under +2, this air should have no issue making it down into the southern plains.

[weatherdude1108]

Eye-catching conclusion to the EWX discussion this afternoon.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
505 PM CST SUN JAN 3 2016

.PREV DISCUSSION... /ISSUED 234 PM CST SUN JAN 3 2016/

SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
DRIER AIR AND ISENTROPIC DOWNGLIDE WILL CONTINUE TO ERODE
CLOUDCOVER OVER THE EDWARDS PLATEAU AND RIO GRANDE PLAINS THIS
AFTERNOON...WITH MOST LOCATIONS IN OUR AREA CLEAR BY MID-EVENING.
THE CLEAR SKIES WILL ALLOW FOR FAVORABLE RADIATIONAL COOLING AND
THUS EXPECT LOW TEMPS FROM THE UPPER 20S IN THE HILL COUNTRY TO
THE MID 30S SOUTH. ALL AREAS EXPECTED TO REACH FREEZING OR BELOW
HAVE ALREADY HAD A FREEZE THIS YEAR...SO NO NEED FOR A FREEZE
WARNING. MONDAY WILL HAVE SIMILAR TEMPS TO TODAY DESPITE CLEAR
SKIES...AS WEAK COLD AIR ADVECTION CONTINUES. MONDAY NIGHT WILL
HAVE SIMILAR TEMPS TO TONIGHT.

LONG TERM (TUESDAY THROUGH SUNDAY)...
THE LONGWAVE PATTERN CHANGE OVER NORTH AMERICA DURING THE NEXT
WEEK...INITIALLY RESULTING IN FAST ZONAL FLOW ALONG THE
SUBTROPICAL JET THROUGH THE SOUTHERN HALF OF THE CONUS...RESULTING
A SERIES OF SHORTWAVE TROUGHS MOVING ACROSS TEXAS. NONE OF THESE
ARE DEEP...AND THEY ARE MOVING SO FAST THAT NEITHER EXTENSIVE
WARM OR COLD ADVECTION IS EXPECTED. A SLOW WARMING AND MOISTENING
WILL BRING MILDER OVERNIGHT LOWS BY THE END OF THE WEEK...BUT
HIGHS WILL REMAIN ABOUT THE SAME. WHILE SOME CHANCE FOR SHOWERS
BEGINS TUESDAY...THE BEST CHANCE FOR RAIN WILL BE WEDNESDAY NIGHT
AS THE DEEPEST TROUGH PASSES THROUGH. MODEL SOUNDINGS HAVE SMALL
AREAS OF CAPE...SO WE INCLUDED MENTION OF ISOLATED THUNDERSTORMS
WEDNESDAY NIGHT. RAIN SHOULD END EARLY THURSDAY...WITH THE REST
OF THE DAY AND FRIDAY REMAINING DRY. A WEAKER SHORTWAVE TROUGH
WILL BRING LOW POPS ON SATURDAY...BUT SUNDAY SHOULD BE DRY.

LOOKING FURTHER AHEAD...LONGER RANGE MODELS AND PATTERN
RECOGNITION INDICATORS SUCH AS CROSS-POLAR FLOW ARE ALIGNING FOR
AN ARCTIC AIR OUTBREAK IN THE JANUARY 12-16TH PERIOD. AT THIS
FORECAST RANGE...THE BEST ADVICE IS TO TAKE CARE OF OUTDOOR WORK
THIS COMING WEEK AND EARLY THE FOLLOWING WEEK.

[Ptarmigan]

My instincts tell me everything with plow southward. EPO is negative and may reach 3 SD's below normal That's a solid signal for Arctic attack. It's nothing to joke about the blocking that is going to occur up there. We just saw the same kind of idea happen in the Kara Sea and the intense cold that blasted the Black sea region below. There are very few cases where you will see Alaska/Yukon block sit like that. Nearly all of them plunged the lower 48 into a deep freeze.

Anyone who wants to understand what is 1 standard deviation (SD) or 3 SD.

68–95–99.7 rule
https://en.wikipedia.org/wiki/68–95–99.7_rule

68%-1 SD
95%-2 SD
99.7%-3 SD

[TeamPlayersBlue]

Are there any daily analogs we can look at to compare a blocking scenario like this? Such a rare event. ALso, is there a better archives site than the PSU site? Thanks!

[Ntxw]

Another run, and another flip for the GFS. Back to sending down some cold again. At 5h it is all over the place run to run.

[Ntxw]

Are there any daily analogs we can look at to compare a blocking scenario like this? Such a rare event. ALso, is there a better archives site than the PSU site? Thanks!

It's not a crazy rare event. 4-5 SD's (1983 type stuff) is the off the charts crazy. 3 SD's for the EPO occurs once a winter or every other. The past two winters we've seen a few more occurrences than typical.

ftp://ftp.cdc.noaa.gov/Public/gbates/teleconn/epo.reanalysis.t10trunc.1948-present.txt

[Texas Snowman]

30 degrees in Denison, chalk another freeze up.

[wxman57]

Eye-catching conclusion to the EWX discussion this afternoon.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
505 PM CST SUN JAN 3 2016

...snip...THE BEST ADVICE IS TO TAKE CARE OF OUTDOOR WORK
THIS COMING WEEK AND EARLY THE FOLLOWING WEEK[/b].

Does that mean it won't be safe to go outdoors next week? Let's see, the 06Z GFS has north Houston dropping into the mid 20s next Wednesday. Yep, not safe for me to go outdoors...

I just remembered - I'll be in New Orleans for the annual AMS meeting next week. Surely Lake Pontchartrain will modify the cold air for me.

[ThunderSleetDreams]

Gulf cruiser over cold air... I'm sure it will disappear/reappear 6 times over the next 11 days.

[orangeblood]

Classic Upper Level Setup for an Arctic Outbreak into the Lower 48....PV crashing into Minnesota with Cross-Polar Flow straight out of Siberia up and over the Pole into North America. Polar HPs coming down one after the other on most all models at this point, along with an active southern jet. Very interesting next few weeks coming up!!!

[aggiecutter]

The reaction of Austin, Texas commuters (IF-WHEN) A snowflake EVER falls in the city itself.

[Ralph's Weather]

Classic Upper Level Setup for an Arctic Outbreak into the Lower 48....PV crashing into Minnesota with Cross-Polar Flow straight out of Siberia up and over the Pole into North America. Polar HPs coming down one after the other on most all models at this point, along with an active southern jet. Very interesting next few weeks coming up!!!

That is a very cold look for all but the West Coast. This is right on schedule from what was expected by many months ago. The Great Lakes will be the epicenter for the cold and Texas is where the STJ and the Polar jet meet which means we should be in line for multiple winter precip chances over the Jan. 12-25 period.

[aggiecutter]

Classic Upper Level Setup for an Arctic Outbreak into the Lower 48....PV crashing into Minnesota with Cross-Polar Flow straight out of Siberia up and over the Pole into North America. Polar HPs coming down one after the other on most all models at this point, along with an active southern jet. Very interesting next few weeks coming up!!!

That is a very cold look for all but the West Coast. This is right on schedule from what was expected by many months ago. The Great Lakes will be the epicenter for the cold and Texas is where the STJ and the Polar jet meet which means we should be in line for multiple winter precip chances over the Jan. 12-25 period.

Just need the SOI to crash to get something major.

[Ntxw]

06z GFS has dfw down to 9F next it will have a low of 29...

Seriously though the pattern is ripe for deep conus cold

[orangeblood]

Classic Upper Level Setup for an Arctic Outbreak into the Lower 48....PV crashing into Minnesota with Cross-Polar Flow straight out of Siberia up and over the Pole into North America. Polar HPs coming down one after the other on most all models at this point, along with an active southern jet. Very interesting next few weeks coming up!!!

That is a very cold look for all but the West Coast. This is right on schedule from what was expected by many months ago. The Great Lakes will be the epicenter for the cold and Texas is where the STJ and the Polar jet meet which means we should be in line for multiple winter precip chances over the Jan. 12-25 period.

Just need the SOI to crash to get something major.

Ask and you shall receive......

SOI values for 04 Jan 2016

Average for last 30 days -9.82
Average for last 90 days -11.06
Daily contribution to SOI calculation -30.66

[Ntxw]

El Nino this week held steady at 2.7C. NINO 1+2 fell dramatically which means tropical forcing will center near the dateline. This is favorable for conus cold and roaring stj

[Ralph's Weather]

SHV throws in chance for changeover Saturday night in their discussion this morning. I will have to start model watching again to see if we can hold onto moisture long enough for the cold to build in.

[perk]

The reaction of Austin, Texas commuters (IF-WHEN) A snowflake EVER falls in the city itself.

That's funny and i think that's the same reaction we would have in the Houston/Galveston area.

[srainhoutx]

SHV throws in chance for changeover Saturday night in their discussion this morning. I will have to start model watching again to see if we can hold onto moisture long enough for the cold to build in.

The 12Z GFS is in agreement with the 00Z Euro suggesting a robust shortwave and surface low moves across Texas Saturday into early Sunday.

[gboudx]

DFW made some mention of wintry precip this weekend as well.

THE WEEKEND SYSTEM HAS THE POTENTIAL TO BRING WINTRY WEATHER TO THE
REGION...BUT AT THIS TIME...IT LOOKS LIKE TEMPERATURES WILL NOT
BOTTOM OUT UNTIL AFTER THE RAINFALL HAS COME TO AN END.