Texas Winter 2013-2014

[South Texas Storms]

The latest trends are looking pretty good for at least a dusting of snow in DFW tomorrow morning.

[orangeblood]

That sounding is about as good as it gets, this far south, for beautiful powdery white stuff (get your minds out of the 60's) Temps in the mid 20's, dendritic growth zone > 100mb with atmosphere saturated from surface up through 500 mb. Not to mention ground temps already below freezing so no melting on contact this time around

[dhweather]

BETA PROGRAM


A coworker and I have been working to make a better spreadsheet for creating meteograms. All you need is Excel with macros enabled. This is incredibly easy to use, click the create a chart button, select state and city from the drop down menus, then click create chart. The spreadsheet does the rest! No more cut and paste, and all that jazz.

A couple of kinks we're working out, it's saying 21Z for the 18Z GFS, but the data is correct. Give it a shot, download it here: http://www.heathweather.com/GFS_Chart_Creator.xlsm

This is really cool of you to make. When I click Create Chart I get an error saying, "Compile error in hidden module: UserForm1". I can help you debug any issues if you need help, but we should take it to PM before Porta lays down the hammer.

What version of Excel?

[DougNTexas]

Tyler/Longview?

[SnowintheFalls]

Wichita falls is a little earlier in the morning, similar to DFW's soundings. The precip isn't as heavy on that model as areas just to the south and not as saturated but would be efficient at producing powdery snow.

http://i59.tinypic.com/10zxqh3.png

We still have snow on the ground from the last bout so I will be happy with whatever we get here! I'm more concerned with travel tomorrow. Thanks for all the insight!

[Ntxw]

:uarrow: That sounding is about as good as it gets, this far south, for beautiful powdery white stuff (get your minds out of the 70's) Temps in the mid 20's, dendritic growth zone > 100mb with atmosphere saturated from surface up through 500 mb. Not to mention ground temps already below freezing so no melting on contact this time around

The superbowl snowstorm sounding was an equal. It too snowed starting in the teens warming up to the lower 20s. I found it odd because when following the radar it didn't snow under the heavy bands, or any band at all really but it started coming down behind the shield, it was weird and interesting at the same time. iorange55 and myself thought we were losing our minds.

[Wntrwthrguy]

In austin, is there a chance that the atmosphere saturates from the top down to get more than just drizzle or flurries?

[Ntxw]

This is NOT a live radar. It is radar from the superbowl storm. I think the HRRR is teasing us.

[GRAYSONCO.WX]

This is NOT a live radar. It is radar from the superbowl storm. I think the HRRR is teasing us.

I was thinking the same thing at the end of the HRRR run.
Déjà Vu?!

[TheProfessor]

I wish that was a live radar.

[Rgv20]

Possible Sleet for Northern parts of Deep South Texas!



A reinforcing surge of cold air will continue to push cold north winds across the Rio Grande Valley and Deep South Texas through the overnight hours. The low wind chill readings after midnight will feel like 25 to 35 degrees. A Wind Chill Advisory may be needed later. Temperatures will hover in the mid to upper 30s in the northern ranch lands...low to mid 40s elsewhere. Under cloudy skies, light rain and sleet will be possible as unsettled moisture moves across the Region. Winds will remain north at 10 to 15 mph.-Martinez-



NWS Brownsville afternoon discussion..

DISCUSSION...A FEW ADDITIONS TO THE AFTERNOON PACKAGE. WITH CAA
ADVECTION CONTINUING TO AFFECT THE REGION FOR THE NEXT 24-36 HOURS
AND THE UPPER TROUGH MOVING INTO NW MEXICO EXPECTED TO MOVE FARTHER
SOUTH THEN FORECAST MODELS TEMPERATURES COULD TREND A FEW DEGREE
COLDER IN THE MID LAYERS OF THE ATMOSPHERE. FORECAST SOUNDINGS
INDICATE TEMPERATURES PROFILES BECOMING COLDER BY THURSDAY MORNING
AND NOT WARMING SUBSTANTIALLY UNTIL AFTER 6 AM FRIDAY. THE MENTION
OF LIGHT SLEET ACROSS THE NORTHERN RANCH LANDS AND WIND CHILL
TEMPERATURES APPROACHING ADVISORY LEVELS 20-30 DEGREES FOR ALL
AREAS INCLUDING THE RIO GRANDE VALLEY IS APPROPRIATE AT THIS TIME.
LATER SHIFTS WILL CONTINUE TO MONITOR THE COLD AIR ADVECTION
ADJUSTING THE FORECAST ACCORDINGLY. DO NOT BELIEVE SLEET WILL BE
MUCH OF AN IMPACT AT THIS TIME HOWEVER SOME MODELS HAVE SURFACE
TEMPERATURES REACHING OR DIPPING BELOW FREEZING FOR A FEW HOURS
ACROSS THE FAR NORTHERN RANCH LANDS THURSDAY AND FRIDAY MORNINGS.
CONFIDENCE IS LOW FOR ANY SIGNIFICANT TRAVEL/ROAD IMPACTS BUT HIGH
ENOUGH TO WARRANT THE MENTION OF THESE WINTER WEATHER CONDITIONS.

[orangeblood]

In austin, is there a chance that the atmosphere saturates from the top down to get more than just drizzle or flurries?

In order to get decent snow growth in the atmosphere, you need the saturated layer (red and green line very close together) in the -12 to -18 deg C range....this is normally where you find the dendritic growth zone, the region of the atmosphere (when saturated) where you'll find the most rapid snow crystal growth.

Notice in the Austin sounding, the saturated layer only goes up to around 700 mb (top of the cloud layer) where the temp is only - 4 to - 5 deg C - very inefficient for snow growth. But if you look at the DFW sounding, you'll find the saturated layer up through 500 mb, which also includes the saturated layer going through the coveted -12 to -18 C dendritic growth zone - approximately 625 mb to 525 mb (around 100 mb thick, which is considered fairly productive for sufficient snow crystal growth). Just looking at the current soundings, I'd only expect light drizzle or flurries in Austin tomorrow unless that saturated layer would rise higher up in the atmosphere.


The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.

[Ntxw]

Very well explained. Lots of dendritic crystals definitely will be made up in the cloud decks. The key will be to saturate the lower level of the atmosphere. Ratio's look quite high, this is how places further north seemingly gets more snow out of the very little moisture they get. Even 0.05 QPF can equate to a few inches of snow especially with a frozen ground.

[Wntrwthrguy]

Thank you for the great explanations orangeblood and ntwx. What needs to happen for the saturated layer to rise in the atmosphere, or is it not that simple?

[katheria]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
945 PM CST WED FEB 5 2014

.UPDATE...
CLOUDS AND MOISTURE WILL GRADUALLY INCREASE OVERNIGHT AS A
PRONOUNCED SHORTWAVE OVER NORTHERN MEXICO MOVES EAST INTO WEST-
CENTRAL TEXAS. MOISTURE LEVELS WILL REMAIN LIMITED WITH THIS
SYSTEM...BUT SUFFICIENT FOR LIGHT PRECIPITATION TO DEVELOP OVER
WESTERN COUNTIES OF NORTH TEXAS EARLY THURSDAY MORNING...THEN
SWEEP NORTHEAST ACROSS THE CENTRAL AND NORTHEASTERN COUNTIES LATE
MORNING THROUGH EARLY AFTERNOON. SUB-FREEZING TEMPERATURES AT ALL
ALTITUDES INDICATES THAT PRECIPITATION WILL FALL AS SNOW. THE MOST
RECENT MODEL OUTPUT FROM THIS EVENING REMAINS FAIRLY CONSISTENT
WITH EARLIER RUNS...INDICATING 1-2 INCHES OVER THE WESTERN-MOST
LOCALES...TAPERING OFF TO AROUND A QUARTER OR HALF AN INCH IN THE
DALLAS-FORT WORTH METROPLEX...TO A DUSTING FARTHER EAST. A WINTER
WEATHER ADVISORY WILL REMAIN IN EFFECT FROM 3 AM UNTIL 2 PM
THURSDAY FOR AREAS GENERALLY WEST OF AN EASTLAND TO JACKSBORO TO
BOWIE LINE. PRECIPITATION WILL COME TO AN END THURSDAY AFTERNOON AS
THE SHORTWAVE ACCELERATES EASTWARD INTO THE MISSISSIPPI VALLEY. AT
THIS TIME...IT APPEARS THAT MEASURABLE SNOWFALL WILL BE LIMITED TO
AREAS GENERALLY ALONG AND NORTHWEST OF A LINE FROM PARIS TO
COMANCHE...WHILE AREAS FARTHER SOUTH AND EAST MAY BE TOO FAR REMOVED
FROM THE UPPER LEVEL FEATURE TO RECEIVE MEASURABLE PRECIPITATION.

EITHER WAY...BITTER COLD CONDITIONS WILL BE EXPERIENCED AREA-WIDE
THROUGH TOMORROW AS TEMPERATURES PLUMMET INTO THE TEENS. A WIND CHILL
ADVISORY WILL REMAIN IN PLACE OVERNIGHT FOR AREAS ALONG AND NORTH
OF A LINE FROM CISCO TO WEATHERFORD TO MCKINNEY TO BONHAM. WE
WILL KEEP AN EYE ON PRECIPITATION TRENDS AS ACTIVITY UNFOLDS LATER
TONIGHT...AND ADJUST THE AREAS OF THE WINTER WEATHER ADVISORY IF
NEEDED. AT THIS TIME...THE FORECAST REMAINS IN GREAT SHAPE WITH NO
SIGNIFICANT UPDATES NEEDED.

[Meteorcane]

00z GFS still pointing to a potential high precipitation event next Tuesday, has a warm-conveyor belt set up for parts of north Texas/southern OK. Also has PVA at upper levels, these two factors are a ripe combination for lift and precipitation. The question though looking at the thermal profiles is what the precip.type will be, would likely begin as rain for North Texas but then could transition to sleet and snow as the event continues. All that said it is still 5 days out and the GFS could completely lose it in a few runs, or be way off with the temps.

[katheria]

have a good night everyone,
see what tomorrow brings

[stormywaves]

There is a Winter Weather Advisory for the Houston area.

[ravyrn]

BETA PROGRAM


A coworker and I have been working to make a better spreadsheet for creating meteograms. All you need is Excel with macros enabled. This is incredibly easy to use, click the create a chart button, select state and city from the drop down menus, then click create chart. The spreadsheet does the rest! No more cut and paste, and all that jazz.

A couple of kinks we're working out, it's saying 21Z for the 18Z GFS, but the data is correct. Give it a shot, download it here: http://www.heathweather.com/GFS_Chart_Creator.xlsm

I have spreadsheets for meteograms for the 0-192 GFS, 192-384 GFS, and 0-84 NAM that includes 850mb temps if you're interested.

[orangeblood]

00z GFS still pointing to a potential high precipitation event next Tuesday, has a warm-conveyor belt set up for parts of north Texas/southern OK. Also as PVA at upper levels, these two factors are a ripe combination for lift and precipitation. The question though looking at the thermal profiles is what the precip.type will be, would likely begin as rain for North Texas but then could transition to sleet and snow as the event continues. All that said it is still 5 days out and the GFS could completely lose it in a few runs, or be way off with the temps.

Given the GFS track record this winter, it is very difficult to ignore. Even with this current cold snap, compared to all other models, it was the one to follow most accurately for temp output (even though it was still off by 4-5 deg F)....seemed to handle the snowcover across central plains better. This one is to be followed very closely due it being a potential high impact event across a fairly wide area