Texas Fall-2015

[weatherdude1108]

Once we get past Tuesday's stuff, looking forward to cooler weather, freezing drizzle or no freezing drizzle.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
250 PM CST FRI NOV 13 2015

.LONG TERM (SUNDAY THROUGH FRIDAY)...
MOISTURE AND INSTABILITY INCREASES A LITTLE SUNDAY INTO MONDAY AS
IMPULSES CONTINUE TO FLOW THROUGH THE SUBTROPICAL JET AND HAVE
MAINTAINED THE SHOWERS AND THUNDERSTORMS. THE PATTERN BECOMES
SIGNIFICANTLY MORE ACTIVE MONDAY NIGHT INTO TUESDAY. AN UPPER
LEVEL TROUGH DEVELOPING OVER THE GREAT BASIN INTO THE DESERT
SOUTHWEST THIS WEEKEND SHIFTS EAST TO THE FOUR CORNERS REGION ON
MONDAY AND THEN TO THE SOUTHERN HIGH PLAINS ON TUESDAY. A COLD
FRONT DEVELOPS WEST OF OUR AREA ON MONDAY AND THEN MOVES ACROSS
SOUTH CENTRAL TEXAS LATE MONDAY NIGHT INTO TUESDAY. STRONG UPWARD
FORCING DUE TO DIFFLUENCE ALOFT FROM A 130 KT SUBTROPICAL JET
ALONG WITH A 50 KT LOW LEVEL JET AND THE COLD FRONT WILL INCREASE
SHOWER AND THUNDERSTORM ACTIVITY. NUMEROUS CONVECTIVE PARAMETERS
INDICATE STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE WITH FORECAST
CAPES OF 1000 TO 2000...HELICITY OF 200 AND GOOD LOWER-MID LEVEL
SHEAR. EXPECT THE SEVERE WEATHER MODE WILL BE A SQUALL LINE WITH
A FEW INDIVIDUAL STORMS AHEAD OF THE LINE. PWS PEAKING NEAR 2
INCHES ALONG THE FRONT INDICATES BRIEF MODERATE TO HEAVY RAINS
WITH THE LINE. SHOWERS AND THUNDERSTORMS END FROM WEST TO EAST
WITH THE PASSAGE OF THE LINE. UP UNTIL THE LATEST MODEL RUNS...
THE MODELS WERE IN GENERAL AGREEMENT FOR MID TO LATE NEXT WEEK.
HOWEVER...THE LATEST ECMWF KEEPS THE TROUGH MOVING AS A BROAD
UPPER TROUGH DEVELOPS OVER MOST OF THE UNITED STATES. THE OTHER
MODELS STILL KEEP THE TROUGH OVER THE CENTRAL/SOUTHERN PLAINS INTO
WEDNESDAY AND THEN MOVE IT NORTHEAST THURSDAY INTO FRIDAY. HAVE
FAVORED THE MODEL CONSENSUS BASED ON ITS CONSISTENCY. THERE MAY BE
SOME SHOWERS EAST OF I-35 TUESDAY NIGHT AHEAD OF THE LINGERING
TROUGH. THE AIRMASS DRIES SIGNIFICANTLY ON A WESTERLY MID LEVEL
FLOW. THE COOLEST NIGHTTIME TEMPERATURES OF THE SEASON ARE
EXPECTED THURSDAY MORNING WITH 40S MOST AREAS...EXCEPT SOME UPPER
30S IN SOME LOW LYING SPOTS IN THE HILL COUNTRY

[weatherdude1108]

For next week the ensemble shows 3 inches of rain for E TX and over an inch across just about the whole state. 4 of 21 12Z GFS Ensembles are showing some snow across N and E Texas for Thanksgiving week.

We may be visiting relatives in southeast Texas TG week. Could make for an interesting drive(?).

[Ralph's Weather]

18Z GFS going insane with a historic snowstorm on TDay.

[vbhoutex]

Evening update from Jeff:

Powerful storm system to affect TX early-mid next week…with potential widespread tornado/severe weather outbreak and flash flooding.

Sub-tropical jet continues over TX with mid and high level clouds in place. Dry low levels will keep any radar returns from reaching the ground on Saturday with temperatures on the cool side.

Big changes come Sunday into Monday as an intensifying upper level storm system ejects eastward out of the southern Rockies and into the southern plains. Surface pressure falls over NW TX will rapidly develop into an intense surface cyclone by late Monday with an impressive 40-55kt low level jet developing inland over coastal and east TX. Tremendous moisture advection will occur with dewpoints rising into the lower 70’s by late Monday. Embedded disturbances in the sub-tropical flow and increasing diffluent upper level winds on the east side of the trough will result in a gradual increase in showers and thunderstorms Monday afternoon and evening. May see enough instability and shear for a few severe thunderstorms by Monday afternoon… and this would be the start of a prolonged severe weather and potential tornado outbreak.

Tuesday:

Significant weather day possible with widespread severe/tornado threats and flash flooding.

Surface low really deepens over the plains with pressure falling toward 990mb (near category 1 hurricane intensity). Powerful upper level jet core will carve into central and SE TX early Tuesday upwards of 120kts overtop of the 40-50kt low level jet. This will lead to tremendous speed and directional wind shear. Air mass will be warm and very moist and position of the upper level trough will likely advect a cold pool aloft over this warm surface air mass resulting in increasing instability. Forecasted CAPE values of 1000-2000 J/kg will be possible and when combined with the load wind profiles…is very concerning with respect to the tornado threat. Upper jet goes into a strong split structure overtop of the warm sector air mass and this may be the catalyst for discrete supercell formation by early Tuesday. Given the shear profiles any discrete supercells rooted near the surface will be rotating and have an enhanced tornado risk especially when coupled with very low LCL’s (cloud bases). Forecasted low level hodographs are strongly curved suggesting a good environment for tornado formation. Need to get closer to the event to see some of the other tornado indices, but what is available now is looking pretty rough.

Cold front comes slicing into the juicy air mass during the day and expect more severe weather with a squall line and possible supercells within the line. Damaging wind threat appears likely with any squall line as mid level wind energy gets transported toward the surface.

Increasing concern with the flash flood threat also as wind fields will support repeat cell training of potential HP supercells. Moisture values rise to 1.8-2.0 in PWS by early Monday which is +2 SD above normal for November. Saturated profile will result in very efficient rainfall production with hourly rates of 2-3 inches possible. Potential for training bands and repeat supercells impacts is certainly raising the flash flood threat. Will go 2-3 inches widespread for now with isolated 5 inches. Models trying to slow the upper level system down some and maintain a an excessive rainfall threat into Tuesday night and even Wednesday which would be very concerning. Not overly confident in the slower solution nor being able to maintain excessive moisture as expect a strong dry slot to round the base of the trough and some point Tuesday helping to end the rainfall. Will have to watch this potential very closely over the weekend.

Residents should be prepared for active weather from late Monday afternoon-early Wednesday morning with Tuesday likely being the worst day. Potential for tornadoes, damaging winds, large hail, and flash flooding during that time period.

[Brent]

Happy Thanksgiving!

[texas1836]

Looks good. I'll be in Ruidoso New Mexico during Thanksgiving. Could be an adventurous drive home the next day.

[Ntxw]

:double:

Happy Thanksgiving!

http://www.tropicaltidbits.com/analysis ... _us_47.png

18z GFS thinks DFW shatters the November lowest temperature record

I doubt it gets that cold, but -EPO supports an Arctic blast at the very least.

[TheProfessor]

I will be in Kansas on Thanksgiving, would miss both the Snow in Ohio and Texas Unless it came a day earlier.

[asd123]

:double:

Happy Thanksgiving!

http://www.tropicaltidbits.com/analysis ... _us_47.png

18z GFS thinks DFW shatters the November lowest temperature record

I doubt it gets that cold, but -EPO supports an Arctic blast at the very least.

I saw the temperature minimums for the Dallas area on instantweathermaps. 20s for highs, single digit lows, up to 3 inches of snow the day before???? Record low for Dallas on the 29th is 28 degrees

[Ntxw]

I saw the temperature minimums for the Dallas area on instantweathermaps. 20s for highs, single digit lows, up to 3 inches of snow the day before???? Record low for Dallas on the 29th is 28 degrees

The November low all time is 19F. Even last year with an extreme -EPO block it managed about 21F I doubt we get to single digits. The models are not showing that kind of blocking as of yet, the -EPO signal would have to poke into Alaska and up to the arctic for that to happen I think. The model is nuts but a hard freeze is a real probability, though freeze climo is approaching anyway. As for snow, that's definitely not unheard of in November.

[TarrantWx]

I would guess that the GFS was showing temperatures that low because of snow cover

[Brent]

I would guess that the GFS was showing temperatures that low because of snow cover

Yep, exactly...

It has 70s on the night before Thanksgiving and then temps crash on Thanksgiving Day into Friday.

[Lagreeneyes03]

I would guess that the GFS was showing temperatures that low because of snow cover

Yep, exactly...

It has 70s on the night before Thanksgiving and then temps crash on Thanksgiving Day into Friday.

Ice bowl 93 anyone? I was in school and I remember going to the store with my mom in the am . By 3pm it was sleeting hard.

[Ntxw]

0Z GFS came to it's senses and just a big cold front, for now. But that is the nature of la la land I guess. Still though the signal for significant cold intrusion into the conus is still a good bet imo.

[NDG]

I think the GFS is on drugs on its long range forecast when ensembles show the NAO & AO staying in the mostly positive territory and PNA either neutral or slightly negative.

[Ntxw]

I think the GFS is on drugs on its long range forecast when ensembles show the NAO & AO staying in the mostly positive territory and PNA either neutral or slightly negative.

Probably with the extremes. Surface cold signal here in Texas is the -EPO. -PNA/-EPO is our cold signal vs +PNA/-NAO. the latter combo shunts cold to our east with a deep EC trof .

The colder air mass will probably come down the western US and bleed into the plains, then modify east'



The NAO really does very little for us Texans aside from clogging the pattern downstream for storms to go over us vs to our north. The Atlantic ridge often drains western Canada of cold and dumps it over into Europe and the east coast.

[NDG]

I think the GFS is on drugs on its long range forecast when ensembles show the NAO & AO staying in the mostly positive territory and PNA either neutral or slightly negative.

Probably with the extremes. Surface cold signal here in Texas is the -EPO. -PNA/-EPO is our cold signal vs +PNA/-NAO. the latter combo shunts cold to our east with a deep EC trof .

The colder air mass will probably come down the western US and bleed into the plains, then modify east'

http://i65.tinypic.com/214xmjr.jpg

The NAO really does very little for us Texans aside from clogging the pattern downstream for storms to go over us vs to our north. The Atlantic ridge often drains western Canada of cold and dumps it over into Europe and the east coast.

I keep forgetting that you guys in TX benefit more from a -PNA & -EPO for colder wx

[Ntxw]

Courtesy of JB on twitter from the GFS, consistent with -EPO

[gpsnowman]

https://youtu.be/umDDzdA6V2g
I think I have posted this before but still get a kick out of it mostly because I remember the cold and snow associated with the forecast. Living in Highland Village Texas at the time as a 10 year old with a dog running around the snow on a winter holiday from school. Good memories. The weather report starts about 8 minutes 40 seconds. An arctic front with snow and temps that low today would be an all news breaker.
Back in 1985, news and especially weather events were reported, just without all the hype and superlatives like you see today. Quality stuff from WFAA 8 back in the day.

[Ralph's Weather]

18Z GFS ensembles still look stormy with an Arctic front around Thanksgiving. A good snow shows up on a number of the individual charts, but still almost two weeks out so details will fluctuate.