December 2015 -Year Ends As One Of Wettest On Record

[John Rogers]

Merry Christmas everyone! Looks like we have a very interesting week ahead with the weather.

Does anyone have a driving route suggestion from Montana back to the Houston area that could perhaps bypass the blizzard conditions that are forecast for the Rockies into North Texas? I am leaving tomorrow morning to return home and this looks bleak for road travel. Every weather site's travel forecast has me a wee bit queezy.

Have a great Christmas day everybody!!!

Back at ya!

[djjordan]

What a beautiful July night we are having tonight...... (laying on the sarcasm pretty heavy here)

Current SGR Wx

Overcast
77°F
25°C
Humidity 90%
Wind Speed S 15 mph
Barometer 29.91 in (1012.9 mb)
Dewpoint 74°F (23°C)
Visibility 8.00 mi
Heat Index 78°F (26°C)
Last update 25 Dec 7:53 pm CST

This is air you can wear outside..... Sheesh!!!!

[DoctorMu]

What a beautiful July night we are having tonight...... (laying on the sarcasm pretty heavy here)

Current SGR Wx

Overcast
77°F
25°C
Humidity 90%
Wind Speed S 15 mph
Barometer 29.91 in (1012.9 mb)
Dewpoint 74°F (23°C)
Visibility 8.00 mi
Heat Index 78°F (26°C)
Last update 25 Dec 7:53 pm CST

This is air you can wear outside..... Sheesh!!!!

It's incredible. A soggy 72°F dew point in College Station on Christmas night. Wow.

[Andrew]

Models continue to show a record setting event for much of the state tomorrow (Saturday) into Monday. Mid-level heights continue to drop off over the four corners region as an unusually strong upper level low approaches West Texas. This will spark a strong pressure gradient with an associated FROPA that will bring a sharp drop in temperatures. Over the Panhandle of Texas, Oklahoma, and parts of Kansas blizzard conditions will be seen as the mid level low tracks directly over the region. 00z models are painting multiple areas of 20+ inches of snow with strong winds making conditions that much worst. Further to the south and east over central, northern, and SE Texas severe weather will be a real threat. A surface low should develop over parts of central Texas and as it pushes through Texas it will help usher in even more moisture from the gulf and help to create a vertical wind profile that will support multiple modes of severe weather. NAM4k suggests that storm updraft helicities could reach the 20-40 m^2/s^2 range across multiple parts of the state tomorrow and Sunday. This would suggest that not only would strong winds be a threat, the tornado potential is there. Biggest conflict will be how fast the line of storms becomes linear and cloud cover. Any storms that do develop tomorrow around the region would present signs of turning severe (SPC slight risk was issued). Overall it looks to be a very active couple of days.

[srainhoutx]

The Storm Prediction Center issues Enhanced Risk for Severe Storms for today across potions of Central, N Central Texas and a small area of Southern Oklahoma. The Texas Cities included in this Enhanced Risk are Austin, Dallas/Ft Worth/Arlington and Plano.

[srainhoutx]

Morning briefing from Jeff:

High Impact Storm System Heading for TX.

Severe weather and tornadoes increasing likely over much of central and east TX tonight/Sunday

Crippling/life threatening blizzard over W/NW TX tonight-Monday AM

Discussion:
Much advertised upper air storm system is digging into the SW US this morning with high impact potential track across the state of TX the next 48 hours. Incredible warmth continues to spread northward ahead of this powerful system setting the stage for a major clash of the seasons over TX on Sunday. Tremendous height falls are starting to spread into W/SW TX this morning and this will induce rapidly deepening surface low pressure over SW TX this afternoon. Very strong low level jet stream of 50-60kts will develop transporting a summer time air mass across much of eastern and central TX today. Dewpoints already in the mid 70’s with temperatures at 700am only 3 degrees from the daily record high show just how hot and humid the air mass is. SW TX surface low will deepen rapidly as it shift ENE toward SC and then SE TX Sunday. Surface pressure fall toward the upper 990mb’s…so the wind is really going to howl with this event. Impressive lift overspread the large unstable warm sector late tonight into Sunday with all severe modes likely in the warm sector. Very cold air mass surges southward on the backside of the deepening upper level and surface storm systems. Jet on the backside of the surface low really cranks Sunday with likely sustained winds of 40-50mph with gusts of 60-65mph over much of west TX. Cold core upper low transitions to heavy snow in the backside comma precipitation shield with extremely large amounts being forecasted in the blizzard warning areas. All-time and December monthly snowfall records may be challenged with this event over W/NW TX.

Simply stated the next 48 hours will bring major weather impacts to the state of TX.

Severe Threat:

SPC “enhanced” or cat 3 out of 5 severe risk was issued for Day 1 (today) along the I-35 corridor northward across all of N TX. Main reason for the upgrade was to add 10% tornado probabilities into this region for this afternoon and tonight as extremely humid and increasingly unstable air mass moves NW today. Current risk appears to be the most significant tornado threat in the “enhanced area” for the month of December since December 2006. Shear profiles are getting fairly intense with 50-60kt low level jet by this afternoon howling inland off the Gulf of Mexico overlaid with a powerful 120kt mid level jet stream intruding over the region tonight into Sunday. Low level shear profiles are maximized over SE TX Sunday morning with low level helicity values of 200-400 m^2/S^2. Dewpoints in the low to mid 70’s support very low LCL’s (cloud bases). Capping appears to keep a lid on things for most of today…luckily, but formation and track of intense SW TX surface low near/just west of SE TX late tonight/Sunday will place out region very near the “triple point” location and help to maximize the severe threat as this will help back low level winds to the SE increasing low level shear and storm rotation.

Discrete cells early this evening will have a concerning tornado threat along the I-35 corridor…potential is certainly there for fast moving tornadoes this evening with the threat increasing after dark tonight as large scale lift overspreads the warm sector air mass. Think this threat will remain NW of SE TX this evening, but will have to watch for any cells that deepen over SE TX late this afternoon and take advantage of the high shear values.

Upper trough takes on a slight negative tilt early Sunday allowing the cold front and surface low to punch ENE toward the NW parts of SE TX. High resolution models develop a broken line of strong to sever supercells along this boundary Sunday morning and cross SE TX. Forecasted wind shear is concerning for tornado production, but instability is looking a bit weak (800-1500 J/kg). Tremendous wind energy aloft can certainly be transported to the surface in the updrafts and downdrafts with damaging gusts. I am a bit worried with the models showing more of a broken line versus a solid squall line which would point more toward a tornado threat than widespread wind damage. Either way will go with all severe modes (wind damage, tornadoes, and may a few reports of hail).

SPC Day 2 outline has all of SE TX outlooked for slight chances (2 out of 5) risk for severe thunderstorms.

Will update this threat again this afternoon as additional high resolution model data becomes available.

Heavy Rainfall:

Moisture levels are already high and will only deepen more today as Pacific moisture arrives from the SW and we continue the Gulf feed. PWS progged to max out in the 1.7-1.9 inch range with surface dewpoints in the mid 70’s and nearly saturated air column. Simply put this is mid summer moisture getting ready to be squeezed by winter dynamics. Storms will be excellent rainfall producers, but fast forward motions (on the order of 30-50mph) should help to cut back on overall storm totals. Still expecting a solid 1-2 inches over SE TX with higher amounts of 3-5 inches over E/NE TX with isolated totals of 5-10 inches possible especially NE TX where period of cell training is possible. Think the threat for cell training over SE TX will be limited to tonight and early Sunday and mainly focus over the Huntsville to Liberty region.

Such rainfall especially on saturated grounds and already swollen/flooded rivers is only going to cause more issues. Latest QPF forecast ingested in RFC hydro models result in rises to flood stage on the Navasota River and worsen ongoing flooding on the entire Trinity River Basin. Significant rises are noted on the Brazos River basin.

Blizzard:

***Life threatening crippling blizzard to affect much of W/NW TX***

Intensifying upper level low will move across the Hilly Country Sunday with intense surface low tracking from SW to NE TX. Very impressive pressure gradient will develop with this surface low leading to very strong surface winds. Air column will rapidly cool, yet tremendous moisture advection will load the mid levels of the NW side of the mid/upper level low leading to significant snowfall rates. Models show extensive meso scale banding and instability which could lead to 1-3 inch per hour snowfall rates. Looking at some very impressive accumulations of anywhere from 6-18 inches and some locations could see over 20 inches of actual snow. 40-60mph will result in major blowing and drifting with potential for some drifts of 8-10ft high in location from Lubbock to Amarillo. Travel across W/NW TX will be impossible during this blizzard along with the ability for rescue personnel to respond. Expect some areas to have “white-out” conditions for many hours and potential for “ground blizzard” conditions with the howling winds.

Motorists not sheltered in place by this evening stand a high chance of being stranded on local highways and interstates until Monday.

Temperatures:

BUSH IAH, Hobby Airport, and Galveston all record their hottest Christmas Day in history yesterday. The previous record at BUSH IAH was 82 and yesterday reached 83. The warmest overnight low on Christmas morning broken the previous record by 6 degrees at IAH…old record was 67 and the low yesterday was 73! This low so far this morning also breaks the daily record and the record high of 78 (currently 75) will likely fall with a few breaks of sun today.

Record warmth will be ended on Sunday as cold Canadian air mass surges across the region with temperatures tumbling from the 70’s into the 40’s. Cold air will remain in place for the next several days with multiple fronts crossing the area.

SPC Day 1 Severe Weather Outlook:

SPC Day 2 (Sunday) Severe Weather Outlook

[/i]

[srainhoutx]

Midday briefing from Jeff:

SPC has upgraded a large portion of SE TX into an “enhanced” risk (category 3 out of 5) for severe weather on Sunday.

Strongly dynamic storm system approaching TX will bring a round of strong to severe thunderstorms including tornadoes to eastern TX tonight-Sunday. Latest high resolution model guidance is suggesting somewhat greater instability will be present on Sunday as deepening surface low tracks near/just NW of SE TX during midday time period. 120kt jet streak will overspread 60kt low level jet with air mass extremely moist. Low level hodographs are showing long and strongly curved profiles suggesting an enhanced tornado threat including a few high end tornado events.

Outbreak of severe weather/tornadoes appears to begin shortly as strong lift ahead of deep upper level trough begins to overspread the NW moving warm sector. Tornado Watch will be issued shortly for NW TX. Outbreak will continue all night and into much of Sunday.

Day 2 (Sunday) Severe Weather Outlook:

[/i]

[Andrew]

Timing and updraft helicities are looking more and more favorable for a greater chance of tornadoes for both later tonight and tomorrow. Later this afternoon should be key for northern Texas. Any discrete cells that form ahead of the line need to be watched.

[Rip76]

Curious...

I don't know if I've just never paid attention before, but it seems that over say the last 3 to 4 months that everytime a front comes down from the NW, there is a "Coastal Flood Watch" in Galveston County.

Is this an El Nino/Jet Stream set up/scenario?
IKE Beach erosion?

I really have never paid attention to this before.

[Ptarmigan]

Curious...

I don't know if I've just never paid attention before, but it seems that over say the last 3 to 4 months that everytime a front comes down from the NW, there is a "Coastal Flood Watch" in Galveston County.

Is this an El Nino/Jet Stream set up/scenario?
IKE Beach erosion?

I really have never paid attention to this before.

I am thinking Ike Beach erosion.

[DoctorMu]

Saw small vortex/funnel cloud just W of Bryan headed NNE with little descent below a modest wall cloud and weak. Spin barely noticeable. Radar up though.

Fear the shear.

[unome]

quite a few tornado warnings out of NWS Fort Worth/Dallas

http://www.srh.noaa.gov/fwd/

[srainhoutx]

Cold front has passed San Angelo and Abilene. Winds gusting into the 50"s in the Panhandle. Saw a gust to 65 MPH in Clovis, NM

[djjordan]

Large Tornado on the ground near DeSoto, Tx .... (DFW area)


SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
614 PM CST SAT DEC 26 2015

TXC113-139-270045-
/O.CON.KFWD.TO.W.0146.000000T0000Z-151227T0045Z/
ELLIS TX-DALLAS TX-
614 PM CST SAT DEC 26 2015

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 645 PM CST FOR NORTH
CENTRAL ELLIS AND CENTRAL DALLAS COUNTIES...

AT 612 PM CST...A CONFIRMED LARGE AND EXTREMELY DANGEROUS TORNADO WAS
LOCATED OVER DESOTO...MOVING NORTH AT 40 MPH.

THIS IS A PARTICULARLY DANGEROUS SITUATION.

HAZARD...DAMAGING TORNADO.

SOURCE...WEATHER SPOTTERS CONFIRMED TORNADO.

IMPACT...YOU ARE IN A LIFE THREATENING SITUATION. FLYING DEBRIS MAY
BE DEADLY TO THOSE CAUGHT WITHOUT SHELTER. MOBILE HOMES
WILL BE DESTROYED. CONSIDERABLE DAMAGE TO
HOMES...BUSINESSES AND VEHICLES IS LIKELY AND COMPLETE
DESTRUCTION IS POSSIBLE. THIS DESTRUCTIVE TORNADO IS MOVING INTO
DESOTO AND LANCASTER. IF YOU ARE NEAR THIS STORM...TAKE COVER
IMMEDIATELY TO PROTECT YOUR LIFE!

THE TORNADO WILL BE NEAR...
WILMER AROUND 620 PM CST.
HUTCHINS AND COCKRELL HILL AROUND 625 PM CST.
BALCH SPRINGS AROUND 635 PM CST.
UNIVERSITY PARK AND HIGHLAND PARK AROUND 640 PM CST.
GARLAND AND MESQUITE AROUND 645 PM CST.

THIS INCLUDES THE FOLLOWING INTERSTATES...
INTERSTATE 35E BETWEEN MILE MARKERS 410 AND 436.
INTERSTATE 20 BETWEEN MILE MARKERS 457 AND 477.
INTERSTATE 30 BETWEEN MILE MARKERS 34 AND 63.
INTERSTATE 45 BETWEEN MILE MARKERS 272 AND 284.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPEAT...A LARGE...EXTREMELY DANGEROUS AND POTENTIALLY DEADLY
TORNADO IS ON THE GROUND. TO PROTECT YOUR LIFE...TAKE COVER NOW! MOVE
TO A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST FLOOR OF A STURDY
BUILDING. AVOID WINDOWS. IF YOU ARE OUTDOORS OR IN A VEHICLE...MOVE
TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT YOURSELF FROM FLYING
DEBRIS.

[srainhoutx]

Large tornado on the ground currently ENE of DT Dallas.

[unome]

https://tvnweather.com/live/chasers/847783629

[unome]

from http://alerts.weather.gov/cap/tx.php?x=1 crazy amount of alerts

Message: NOAA-NWS-ALERTS-TX1253D2BA3A3C.SevereWeatherStatement.1253D2BA72E0TX.FWDSVSFWD.7ef6d8841ee92024544b281e05a46c9c from w-nws.webmaster@noaa.gov
Sent: 18:55 CST on 12-26-2015
Effective: 18:55 CST on 12-26-2015
Expires: 20:00 CST on 12-26-2015
Event: Severe Weather Statement
Alert:

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 730 PM CST FOR SOUTHERN
COLLIN...NORTHEASTERN DALLAS AND WESTERN ROCKWALL COUNTIES...

AT 654 PM CST...A CONFIRMED LARGE AND EXTREMELY DANGEROUS TORNADO WAS
LOCATED OVER ROWLETT...MOVING NORTHEAST AT 40 MPH.
THIS IS A PARTICULARLY DANGEROUS SITUATION.
HAZARD...DAMAGING TORNADO.
SOURCE...RADAR CONFIRMED TORNADO.
IMPACT...YOU ARE IN A LIFE THREATENING SITUATION. FLYING DEBRIS MAY
BE DEADLY TO THOSE CAUGHT WITHOUT SHELTER. MOBILE HOMES
WILL BE DESTROYED. CONSIDERABLE DAMAGE TO
HOMES...BUSINESSES AND VEHICLES IS LIKELY AND COMPLETE
DESTRUCTION IS POSSIBLE. RADAR CONFIRMED DEBRIS WAS BEING LOFTED
OVER 1 MILE IN THE AIR. THIS IS AN EXTREMELY DANGEROUS SITUATION. IF
YOU ARE NEAR ROWLETT...TAKE COVER IMMEDIATELY TO PROTECT YOUR LIFE!
THE TORNADO WILL BE NEAR...
ROCKWALL AROUND 705 PM CST.
WYLIE AROUND 715 PM CST.
FARMERSVILLE AROUND 730 PM CST.
OTHER LOCATIONS IMPACTED BY THIS TORNADIC THUNDERSTORM INCLUDE ST.
PAUL...BUCKINGHAM...NEVADA AND LAVON.
THIS INCLUDES THE FOLLOWING INTERSTATES...
INTERSTATE 35E BETWEEN MILE MARKERS 425 AND 435.
INTERSTATE 30 BETWEEN MILE MARKERS 41 AND 69.
INTERSTATE 45 BETWEEN MILE MARKERS 280 AND 284.
TORNADO...OBSERVED
TORNADO DAMAGE THREAT...CONSIDERABLE
HAIL...1.00IN

Instructions: A LARGE AND EXTREMELY DANGEROUS TORNADO IS ON THE GROUND. TAKE IMMEDIATE TORNADO PRECAUTIONS. THIS IS AN EMERGENCY SITUATION.
Target Area:
Collin
Rockwall
Forecast Office: NWS Dallas-Fort Worth (Dallas - Forth Worth)

[srainhoutx]

Andrew and I have been chatting about our severe potential for SE Texas tomorrow morning/midday. The latest HRRR is getting a bit worrisome for our local Houston and Bryan/College Station area.

[Poltracker]

My cousin is there. She just posted that the patrons in the restaurant she is at are sheltering in a storage room.

[srainhoutx]

Update from Jeff:

Significant tornado outbreak underway over N TX.

Cluster of supercells have produced several damaging tornadoes across N TX with current double supercells producing tornadoes within the City of Dallas. Extensive damage has been reported in the suburb of Lancaster. Supercells have developed in uncapped and unstable warm sector ahead of main strong cold front surging now into NW TX. Radar shows extensive debris circulation on dual pol reflectivity’s near Rowlett, TX with large damaging tornado moving along I-30 corridor. Images from TXDOT cameras show at least ¼ mile wide tornado approaching Rowlett Rapidly from the south.

Second extremely dangerous tornado moving toward Garland and Rockwall…tornado at least ¼ mile wide.

Attention will quickly shift to SW TX between Del Rio and San Antonio where strong height falls and developing surface low in region of strong instability will foster rapid severe thunderstorms develop the next few hours. Significant bowing segments and supercells will be possible with damaging winds. SPC has outlooked this area with an “enhanced risk” and expect a tornado watch to be issued within the next few hours as strong forcing ejects out of NE MX and into this air mass.

Severe threat remains for SE TX Sunday including tornadoes.