Texas/New Mexico/Louisiana/Mexico Obs And Discussion Thread Part 7

[bubba hotep]

Mike Ventrice has been pushing a svr wx index and says that orange roughly equates to SPC mod. This is what it is showing for tomorrow:

 

[bubba hotep]

FWD AFD on tomorrow:

 

 

AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
334 PM CDT THU APR 28 2016

...POTENTIALLY SIGNIFICANT SEVERE WEATHER POSSIBLE FRIDAY...

.DISCUSSION...
IT HAS BEEN A NICE DAY ACROSS NORTH AND CENTRAL TEXAS BUT CHANGES
ARE ON THE WAY AS A VERY MOIST AND UNSTABLE AIR MASS HEADS BACK
INTO THE REGION TONIGHT IN THE WAKE OF A WARM FRONT MOVING UP FROM
THE SOUTH. THIS WILL SET THE STAGE FOR AN ACTIVE DAY TOMORROW WITH
A NOTEWORTHY SEVERE WEATHER POTENTIAL THAT COULD END UP BEING
SIGNIFICANT IF MESOSCALE FEATURES EVOLVE AS DISCUSSED BELOW.

SATELLITE AND SURFACE OBSERVATIONS DEPICT THE RICH MOISTURE WITH
DEWPOINTS IN THE LOW TO MID 70S IN SOUTH AND SOUTHEAST TEXAS THAT
WILL ENTER THE SOUTHERN ZONES THIS EVENING. WARM FRONTS ARE NOT
SURPRISINGLY ASSOCIATED WITH WARM ADVECTION...AND WARM ADVECTION
IS OFTEN SYNONYMOUS WITH LIFTING OR RISING AIR. AS THIS WARM AND
MOIST AIR ENTERS THE CWA...IT WILL BE UNDERCUTTING A COLDER
AIRMASS ALOFT WHICH WILL YIELD HIGH AMOUNTS OF INSTABILITY THAT
WILL BE UNCAPPED. THE WARM ADVECTION ITSELF WILL BE PROVIDING THE
LIFT FOR SCATTERED STORMS TO BLOSSOM. THESE STORMS SHOULD BE
SLIGHTLY ELEVATED ABOVE THE BOUNDARY LAYER WHICH SHOULD LIMIT THE
WIND OR TORNADO POTENTIAL DESPITE WELL ORGANIZED AND IMPRESSIVE
SHEAR PROFILES. HOWEVER THESE STORMS WILL STILL BE CAPABLE OF
LARGE HAIL...PERHAPS UP TO THE SIZE OF GOLFBALLS FOR THE STRONGEST
CELLS. THE ISOLATED TO SCATTERED ACTIVITY IS EXPECTED TO DEVELOP
IN THE SOUTHERN ZONES AROUND MID EVENING...WITH STORMS MOVING
NORTHWARD AND INCREASING IN COVERAGE AND INTENSITY BY THE TIME
THEY REACH THE I-20 CORRIDOR AROUND MIDNIGHT. HIGHEST POPS OF
60-70 PERCENT WILL BE LOCATED OVER THE NORTHERN HALF OF THE
REGION...WITH POPS JUST 30 PERCENT IN THE SOUTHERN ZONES.

WHILE MODEL GUIDANCE IS SOMEWHAT SPLIT ON WHETHER THE OVERNIGHT
ACTIVITY WILL CONTINUE TO REDEVELOP/PERSIST OVER THE CWA LATE
TONIGHT AND INTO FRIDAY MORNING...AM SIDING WITH THE RAP/HRRR/TTU
WRF FORECASTS WHICH KICK THE WARM FRONT AND STORMS NORTH OF THE
RED RIVER BY DAY BREAK. THIS IS BECAUSE THE SOUTHERLY WINDS IN
THE LOW-MID LEVELS SHOULD ALSO PULL SOME WARMER AIR IN FROM SOUTH
TEXAS WHICH SHOULD EFFECTIVELY CAP THE CWA FOR ADDITIONAL
CONVECTION WELL SOUTH OF THE WARM FRONT BY DAYBREAK FRIDAY. THIS
CAP IS NOT FORECAST TO BE VERY STRONG BY ANY OF THE MODELS...AND
AS TEMPS REACH THE UPPER 70S TO LOWER 80S BY MIDDAY FRIDAY IT
SHOULD BREAK.

WHILE A DRY LINE WILL BE APPROACHING FROM THE WEST AND REACHES OUR
WESTERN CWA BORDER FRIDAY AFTERNOON...IT IS MORE LIKELY THAT
CONVECTION WILL SPONTANEOUSLY DEVELOP WELL EAST OF THE DRY LINE IN
AN AXIS OF WARM ADVECTION AND MOISTURE CONVERGENCE ALONG THE I-35
CORRIDOR AROUND OR JUST AFTER MIDDAY. THIS IS ADVERTISED BY
SEVERAL OF THE HIGH-RES MODELS...AND ALL OF THE GLOBAL MODELS ARE
DROPPING THE HIGHEST QPF AND UPWARD MOTIONS EAST OF I-35 BETWEEN
18Z-00Z. THUS THERE IS HIGH CONFIDENCE THAT STORMS WILL NOT NEED
THE DRY LINE OR PEAK DAY TIME HEATING TO DEVELOP. IN SHORT THIS
EVENT DOES NOT LOOK LIKE IT IS GOING TO BE THE TYPICAL DRYLINE DAY
WHERE WE WAIT UNTIL LATE AFTERNOON FOR STORMS TO FIRE OUT WEST.

INSTEAD THE INITIATION OVER THE I-35 CORRIDOR COULD LEAD TO
NUMEROUS STORMS IF THE CAP IS TOO WEAK AND PERHAPS A MESSY
CONVECTIVE EVOLUTION THAT DOES NOT LET ANY ONE STORM HAVE ALL OF
THE INSTABILITY TO THEMSELVES. THIS WOULD LOWER THE OVERALL SEVERE
WEATHER POTENTIAL. HOWEVER IF CONVECTION IS NOT AS NUMEROUS THERE
IS A GREATER POTENTIAL FOR SIGNIFICANT SEVERE WEATHER OCCURRING
GIVEN SURFACE BASED CAPE VALUES INCREASING TO 2500 TO 3500 J/KG
BY EARLY AFTERNOON. THIS INSTABILITY WILL ALSO BE OCCURRING IN THE
PRESENCE OF WELL ORGANIZED SHEAR PROFILES...MORE THAN ENOUGH TO
SUPPORT SUPERCELLS AND ENOUGH LOW LEVEL SHEAR TO BE CONCERNED
ABOUT TORNADOES...ESPECIALLY GIVEN THE UNUSUALLY HIGH LOW LEVEL
INSTABILITY COMPLEMENTS OF LOWER 70S DEWPOINTS. FURTHERMORE IF
ACTIVITY DOES DEVELOP ALONG THE I-35 CORRIDOR BY MIDDAY AS
EXPECTED...IT IS LIKELY TO TRAIN OVER THE SAME REGION WITH JUST A
GRADUAL EASTWARD SHIFT. THIS COULD LEAD TO EXCESSIVE MULTI-INCH
RAINFALL IN LOCALIZED AREAS. SINCE THIS FLOODING POTENTIAL IS
HIGHLY DEPENDENT ON MESOSCALE FEATURES DEVELOPING IN THE RIGHT
PLACE AND TIME...WE THOUGHT IT WOULD BE BEST TO LET LATER SHIFTS
MAKE THE CALL WHETHER TO INCLUDE PART OF THE AREA IN A WATCH.

[NTXYankee]

Biggest concerns for tomorrow is convection east of us instead of here and messy mode if storms develop around these parts and then move east. An outflow boundary moving down from the north killing us for chances. Finally convection blowing up south of us and cutting off moisture feed.

[weatherextreme]

Mike Ventrice has been pushing a svr wx index and says that orange roughly equates to SPC mod. This is what it is showing for tomorrow:

 

 

 

 

Looks like the index is calling for a moderate to high risk.  

 

 

 

Michael Ventrice ‏@MJVentrice  5h5 hours ago

My experimental severe wx index pushing a moderate to high risk of severe thunderstorms o/the S. Plains tomorrow PM

[bubba hotep]

Big storms over the Panhandle and first signs of towers going up down south

 

[Quixotic1]

Serious DPs in south and SE Texas.

[jhamps10]

Looks like our cells getting going good between Austin and Temple.. Probably reaches dfw about 1am I'd guess

[jojo762]

Serious DPs in south and SE Texas.

No kidding... Low-mid 70's dews are pretty prevalent, with ~17C DP's at H85 per KCRP 00Z RAOB... 30-45kt LLJ overnight will promote poleward moisture transport into C OK tomorrow where DPs currently sit in the low-mid 50's. Might get a bit of a surprise event tomorrow--with tornadoes and very large hail-- in OK, possibly including a small part of N TX, if morning convection/ possible MCS does not linger too much into the afternoon.

[bubba hotep]

MESOSCALE DISCUSSION 0488
NWS STORM PREDICTION CENTER NORMAN OK
0752 PM CDT THU APR 28 2016

AREAS AFFECTED...PARTS OF CENTRAL TEXAS

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 290052Z - 290215Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED TO WIDELY SCATTERED VIGOROUS STORM DEVELOPMENT...
ACCOMPANIED BY AT LEAST SOME RISK FOR SEVERE HAIL AND WIND...IS
POSSIBLE THIS EVENING NEAR THE TEMPLE/WACO AREAS OF CENTRAL TEXAS.
A WATCH IS NOT CURRENTLY ANTICIPATED...BUT TRENDS WILL BE MONITORED.

DISCUSSION...THUNDERSTORMS HAVE RECENTLY INITIATED NORTH OF THE
AUSTIN TX AREA. LARGE-SCALE FORCING FOR ASCENT APPEARS
NEGLIGIBLE...OR IS AT LEAST UNCLEAR...BUT THIS APPEARS TO BE
OCCURRING ALONG THE LEADING EDGE OF BETTER LOW-LEVEL MOISTURE
RETURN...JUST TO THE NORTH OF WARMER AND MORE STRONGLY CAPPING
ELEVATED MIXED LAYER AIR WHICH IS ADVECTING NORTHEAST OF THE RIO
GRANDE VALLEY. IN THE PRESENCE OF MIXED LAYER CAPE PERHAPS IN
EXCESS OF 2000 J/KG...AND MODEST DEEP LAYER SHEAR...FURTHER
INTENSIFICATION OF ISOLATED TO WIDELY SCATTERED STORMS APPEARS
POSSIBLE ACROSS THE TEMPLE THROUGH WACO VICINITIES DURING THE NEXT
HOUR OR TWO. HOWEVER...EVEN IF THIS OCCURS...IT CURRENTLY SEEMS
LIKELY TO BE SHORT-LIVED...AS INHIBITION BEGINS TO INCREASE WITH THE
ONSET OF DIURNAL BOUNDARY LAYER COOLING THROUGH THE 03-05Z TIME
FRAME.

..KERR/HART.. 04/29/2016

[WishingForWarmWeather]

Currently in Killeen, waiting for this nice little storm to pass over. Has a significant weather advisory attached to it for 1/2 inch hail and damaging winds. 

[bubba hotep]

Current run of the HRRR kills those cells off before they reach DFW. It has been pretty consistent today with keeping the best storm chances north of DFW tonight. The HRRRx did have cells growing in coverage as they moved towards DFW this evening but it looks like it hasn't run since 12z. 

[NTXYankee]

Well round one never happened here, guess we'll see if round two does today. If models have their way, south and east of us will be the norm.

[bubba hotep]

DFW upgraded to Enh 

 

[radarman]

12z FWD sounding reveals a warm layer that will probably take a little while to overcome.  Fairly strong low level winds out there. 

[bubba hotep]

12z FWD sounding reveals a warm layer that will probably take a little while to overcome. Fairly strong low level winds out there.

And it appears to be pretty widespread based on other soundings. The longer that can hold on the more likely that the dryline will be the focal point. Or at least keep junk from going off too quickly to our east and south.

[NTXYankee]

And it appears to be pretty widespread based on other soundings. The longer that can hold on the more likely that the dryline will be the focal point. Or at least keep junk from going off too quickly to our east and south.

I second that.

[tornadoguy11]

We are getting breaks in the clouds with the sun popping through here in north denton

[bubba hotep]

Looks like a sw expansion of the 10% Tor in latest SPC update captures DFW.

[Calderon]

May be able to get some breaks, maybe some substantial amounts of sun, once this low stratus is scoured out some. This is some very heavy, tropical air in Dallas this morning.

[bubba hotep]

Looking at Sat and surface obs, the warm front appears to still be south of the Red River and there looks to be a decent outflow boundary there as well. Whatever capping there was to the east appears to be lifting pretty quickly westward from Louisiana towards Texas south of I20. Capping appears to still be holding farther west along the I35 corridor.

[NTXYankee]

Looking at Sat and surface obs, the warm front appears to still be south of the Red River and there looks to be a decent outflow boundary there as well. Whatever capping there was to the east appears to be lifting pretty quickly westward from Louisiana towards Texas south of I20. Capping appears to still be holding farther west along the I35 corridor.

There appears to be a few boundaries laying around, one looks like it is moving up from the south east as well

[Calderon]

There appears to be a few boundaries laying around, one looks like it is moving up from the south east as well

Looks like a thermal or moisture convergence zone, and it lines up fairly well with what the HRRR is trying to depict later, heavy rainfall in that general vicinity.

 

Also, you can see the ripple-like appearance in the visible, showing we're still capped down here in the Metroplex and southwestward. The warm front has stalled, for now, just south of the Red River and it could surge northward as the low clouds are mixed out. 

[bubba hotep]

Latest from FWD:

 

[jhamps10]

Were still socked in up here on the 33rd floor in downtown ft worth, however when I look down on 7th Street you can see the sun trying to poke through with reflections on cars as they drive by from time to time

[1900hurricane]

HRRR doing HRRR things in southeast Texas.

 

[bubba hotep]

https://

[radarman]

18z sounding (as an aside I like that these have been fairly regular ) has the cap mostly gone.  Lapse rates are not quite as stellar as what we've seen recently, but the windfields are certainly notable.

 

[bubba hotep]

18z sounding (as an aside I like that these have been fairly regular ) has the cap mostly gone. Lapse rates are not quite as stellar as what we've seen recently, but the windfields are certainly notable.

That combined with how far south the warm front has stayed certainly raises an eyebrow. Then add in all the roaming boundaries....

[bubba hotep]

Well that was quick, MD was still warm from printing when Tor Watch went up

[jhamps10]

Cells developing rapidly on the sw burbs of Ft worth..