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

[bubba hotep]

The 00z FWD sounding was pretty unimpressive... surface instability will be on the wane while there isn't much elevated instability at all.  Lapse rates are pretty mediocre.  Winds aloft are OK, but weak at the surface with little in the way of helicity.   There will be some frontogenetic lift, but I suspect this will weaken substantially as it moves east.

 

Yea, the 00z was a little less impressive than I was thinking but the low level flow should continue to increase a bit as the evening goes on in a basically uncapped environment. This should advect some better low level moisture towards the line as it moves into DFW. CAPE and helicity could see an increase across the area but not drastically and it is already lower than areas in the vicinity of the stronger cells. The threat could persist well into the evening but timing will be key for the DFW area. I wouldn't be surprised to see some svr wind reports when I wake in the morning but I agree that we are probably seeing the peak intensity of the storms. 

[Quixotic1]

Yeah, that would get stuff into DFW by 3:00ish? They might have to extend the watch eastward, if they keep up that kind of motion.

some cells firing up out ahead of the line in the sw half of the watch area around Abilene.

[bubba hotep]

some cells firing up out ahead of the line in the sw half of the watch area around Abilene.

 

All the way back to New Mexico now

 

[bubba hotep]

This warning is right up to the LBJ Grasslands, I consider that the last outpost of the DFW area. That cell is nasty looking with increasing lightning and what appears to be a nasty hail core. Unfortunately, it just outside the reach of the Denton CASA radar. 

 

 

[bubba hotep]

Bowie, esp the south side of town, is about to get hammered. If this cell continues to persist, then the watch may need to be expanded here shortly. 

 

[bubba hotep]

Still going early this morning

 

[radarman]

SPC going with a rare day 7 risk contour this morning.

[weatherextreme]

Some strong wording from the SPC following a day 7 outlook

 

 

 

THE MODELS SUGGEST A DRYLINE ORGANIZES ACROSS THE SRN PLAINS DURING THE DAY ON
TUESDAY WITH THUNDERSTORMS DEVELOPING ALONG AND EAST OF THE DRYLINE
LATE TUESDAY AFTERNOON. THE ECMWF SOLUTION ALSO SHOWS THE EXIT
REGION OF A MID-LEVEL JET OVERSPREADING THE SRN PLAINS ON TUESDAY.
THE MODELS ARE IN GENERAL AGREEMENT AND HAVE SHOWN ENOUGH RUN TO RUN
CONSISTENCY TO ADD A 15 PERCENT CONTOUR FOR PARTS OF CNTRL AND NORTH
TX...OK...SRN KS...NW AR AND FAR SW MO FOR TUESDAY AND TUESDAY
NIGHT. A SEVERE WEATHER EVENT WITH TORNADOES.

[bubba hotep]

White Rock Creek in Dallas spiked pretty good last night with the storm

 

 

We ended up doing pretty well up my way, avoided another round of hail and not too much wind but plenty of rain. Now to watch things today and see if we can do it again tonight. 

 

[bubba hotep]

SPC going with a rare day 7 risk contour this morning.

 

[bubba hotep]

A blend of the 12z HRRRx and 4k NAM would be pretty similar to last night around the DFW area.

[radarman]

Yea, the 00z was a little less impressive than I was thinking but the low level flow should continue to increase a bit as the evening goes on in a basically uncapped environment. This should advect some better low level moisture towards the line as it moves into DFW. CAPE and helicity could see an increase across the area but not drastically and it is already lower than areas in the vicinity of the stronger cells. The threat could persist well into the evening but timing will be key for the DFW area. I wouldn't be surprised to see some svr wind reports when I wake in the morning but I agree that we are probably seeing the peak intensity of the storms. 

 

Turned out to be good analysis by you.  The line did stay relatively strong, and there probably was some enhanced helicity as the LLJ picked up.    At one point, SE of Mansfield it threatened to produce a QLCS spin up, although I didn't see a definitive signature in the velocity.

 

[bubba hotep]

SPC has kind of been bouncing around with things today but the latest D1 shifts back towards the DFW area:

 

 

[Chinook]

The NAM and NAM-4km have some cells in the northern Panhandle developing into a squall line or cluster, heading southeastward later into the evening. I'm a little surprised at the fact that there is only about 1100-1200 J/kg of CAPE, at maximum, while this begins to develop. The HRRR has even less CAPE in the TX Panhandle. Perhaps if anything develops, it will be driven more by dynamics than the big CAPE values.

[Roy]

Next Tuesday looks interesting....and of course it's the night I chose for my students to have our yearbook/newspaper banquet. May be a repeat of last year when they had to take cover with a tornado warning.

[bubba hotep]

The San Antonio hail storm damage is now estimated at $1.36 billion.

 

[bubba hotep]

Blend of the 18z 4k NAM and 18z HRRRx would be another nice soaking for DFW. Looks the 4k NAM might be overdoing instability, esp. given how stubborn the clouds have been today. However, the 4k NAM seems to be doing a decent job this week with all these little impulses.

18z 4k NAM

ETA: Clouds have really thinned out this afternoon, SPC Meso has an axis of instability nosing to DFW from the SW and FWD seems to think there will be ample elevated instability for storms overnight. It will be interesting to see the 00z sounding.

[bubba hotep]

MESOSCALE DISCUSSION 0425
NWS STORM PREDICTION CENTER NORMAN OK
0454 PM CDT WED APR 20 2016

AREAS AFFECTED...PANHANDLE...NORTHWEST TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 202154Z - 210000Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...ISOLATED STORMS SHOULD DEVELOP ALONG THE I-27 CORRIDOR ON
A WEAKLY CONVERGENT DRYLINE. SCATTERED STORMS NEAR THE RATON MESA
SHOULD EVENTUALLY CONSOLIDATE INTO A CLUSTER AS THEY SPREAD ACROSS
THE TX PANHANDLE. ISOLATED TO WIDELY SCATTERED SEVERE HAIL/WIND
SHOULD BE THE PRIMARY HAZARDS.

DISCUSSION...21Z SURFACE ANALYSIS PLACED A DRYLINE OVER THE TX SOUTH
PLAINS INTO THE PERMIAN BASIN. INCIPIENT STORM DEVELOPMENT IS
OCCURRING NEAR LUBBOCK ALONG THE PERIPHERY OF WEAK SURFACE-BASED
BUOYANCY. WITH A PLUME OF MID TO UPPER 50S SURFACE DEW POINTS JUST
TO THE SOUTH-SOUTHEAST THAT WILL BE ADVECTED NORTHWARD THIS
EVENING...THIS INITIAL ACTIVITY SHOULD POSE A RISK FOR ISOLATED
SEVERE HAIL GIVEN A VEERING WIND PROFILE WITH HEIGHT. FARTHER
NORTH...CONVECTION NEAR THE RATON MESA IS BEING AIDED BY A MID-LEVEL
VORTICITY LOBE ROTATING ACROSS THE CENTRAL HIGH PLAINS. RECENT
ESRL-HRRR RUNS ARE CONSISTENT WITH 12Z CAMS IN DEPICTING A
CONSOLIDATING CLUSTER SPREADING SOUTHEASTWARD ACROSS THE PANHANDLE.
WHILE BUOYANCY WILL BE LIMITED...PRESENCE OF STEEP LAPSE RATES AND
STRONG DEEP SHEAR SHOULD FOSTER A RISK FOR SEVERE HAIL/WIND.

..GRAMS/GOSS.. 04/20/2016

[bubba hotep]

Nice view of that Panhandle cell

 

[weatherextreme]

Mike Morgan ‏@MikeMorganKFOR  3h3 hours ago

Here is my latest 10 Day SVR and TOR Outlook for the K4 viewing area. Higher #'s mean higher chance of SVR and TOR.

 

 

[bubba hotep]

 

Mike Morgan ‏@MikeMorganKFOR  3h3 hours ago

Here is my latest 10 Day SVR and TOR Outlook for the K4 viewing area. Higher #'s mean higher chance of SVR and TOR.

 

 

 

A 7 for D7? I mean, yes, it's April and, yes, the models are showing western throughing with ridging in the east. However, beyond that there is so much to be resolved before pinning any one day as  the "big" one. It will be interesting to watch things play out over the weekend.

[bubba hotep]

[radarman]

Was somewhat surprised to see the cap on the sounding tonight... more elevated stuff perhaps?

[Chinook]

I just discovered something cool. The NWS MRMS (Multi-Radar/Multi-Sensor) data is available- and easy to use. You can check composite radar, maximum expected hail size, hail swaths, and rotation swaths, and warnings.  This is MESH (hail size) right now near Lubbock. Looks like the hail sizes are a bit less than GRLevel3 (Nexrad-level 3 hail estimation) and that's good. Unfortunately some of the products appear to be 5-9 minutes later than real-time.

 

http://wdssii.nssl.noaa.gov/maps/

http://www.wdssii.org/

 

[NTXYankee]

However never works out for us, I am pretty sure we'll be saying bye to the Tuesday threat as quick as it showed up.

NEXT WEEK IS SHAPING UP TO BE AN ACTIVE WEEK OF WEATHER WITH

OPPORTUNITIES FOR STORMS NEARLY EVERY DAY. ANOTHER DEEP CUTOFF LOW

IS EXPECTED TO ENTER THE FOUR CORNERS REGION BY TUESDAY WHICH

WILL LEAD TO RAPID SURFACE LEE CYCLOGENESIS ON TUESDAY AFTERNOON.

INCREASED SOUTHERLY FLOW NOTED BY A LOW-LEVEL JET OF AROUND 40 KTS

WILL OVERSPREAD MUCH OF THE SOUTHERN PLAINS. SURFACE DEWPOINTS

SHOULD CLIMB INTO THE UPPER 60S AND 70S BENEATH A CAPPING ELEVATED

MIXED LAYER ADVECTED EASTWARD OFF THE HIGH PLAINS. STEEP LAPSE

RATES ALOFT COMBINED WITH VERY WARM/MOIST SURFACE CONDITIONS WILL

COMBINE FOR SUBSTANTIAL SURFACE BASED INSTABILITY WITH MODELS

ADVERTISING 4000-5000 J/KG OF SBCAPE TUESDAY AFTERNOON WITH A

SURFACE DRYLINE DRAPED ACROSS WESTERN TEXAS. IF ANY STORMS ARE

ABLE TO DEVELOP TUESDAY AFTERNOON...THEY WOULD QUICKLY BECOME

SEVERE IN THIS ENVIRONMENT. HOWEVER...LATEST GUIDANCE HAS BEEN

MAINTAINING A NORTHWARD SOLUTION TO THE UPPER-LEVEL FORCING WHICH

WHICH KEEP THE STRONGEST SYNOPTIC SCALE ASCENT WELL NORTH OF THE

CWA. THIS ASCENT WILL BE CRUCIAL FOR ELIMINATING AN INCREDIBLY

STRONG CAPPING INVERSION IN PLACE. IF MODELS CONTINUE WITH THIS

NORTHWARD TREND...LITTLE TO NO CONVECTION MAY IMPACT OUR CWA ON

TUESDAY SINCE THE CAP WOULD HOLD IN PLACE AND STORMS WOULD BE

UNLIKELY TO DEVELOP.

[Quixotic1]

I just discovered something cool. The NWS MRMS (Multi-Radar/Multi-Sensor) data is available- and easy to use. You can check composite radar, maximum expected hail size, hail swaths, and rotation swaths, and warnings. This is MESH (hail size) right now near Lubbock. Looks like the hail sizes are a bit less than GRLevel3 (Nexrad-level 3 hail estimation) and that's good. Unfortunately some of the products appear to be 5-9 minutes later than real-time.

http://wdssii.nssl.noaa.gov/maps/

http://www.wdssii.org/

Thanks for this!

[bubba hotep]

However never works out for us, I am pretty sure we'll be saying bye to the Tuesday threat as quick as it showed up.

NEXT WEEK IS SHAPING UP TO BE AN ACTIVE WEEK OF WEATHER WITH

OPPORTUNITIES FOR STORMS NEARLY EVERY DAY. ANOTHER DEEP CUTOFF LOW

IS EXPECTED TO ENTER THE FOUR CORNERS REGION BY TUESDAY WHICH

WILL LEAD TO RAPID SURFACE LEE CYCLOGENESIS ON TUESDAY AFTERNOON.

INCREASED SOUTHERLY FLOW NOTED BY A LOW-LEVEL JET OF AROUND 40 KTS

WILL OVERSPREAD MUCH OF THE SOUTHERN PLAINS. SURFACE DEWPOINTS

SHOULD CLIMB INTO THE UPPER 60S AND 70S BENEATH A CAPPING ELEVATED

MIXED LAYER ADVECTED EASTWARD OFF THE HIGH PLAINS. STEEP LAPSE

RATES ALOFT COMBINED WITH VERY WARM/MOIST SURFACE CONDITIONS WILL

COMBINE FOR SUBSTANTIAL SURFACE BASED INSTABILITY WITH MODELS

ADVERTISING 4000-5000 J/KG OF SBCAPE TUESDAY AFTERNOON WITH A

SURFACE DRYLINE DRAPED ACROSS WESTERN TEXAS. IF ANY STORMS ARE

ABLE TO DEVELOP TUESDAY AFTERNOON...THEY WOULD QUICKLY BECOME

SEVERE IN THIS ENVIRONMENT. HOWEVER...LATEST GUIDANCE HAS BEEN

MAINTAINING A NORTHWARD SOLUTION TO THE UPPER-LEVEL FORCING WHICH

WHICH KEEP THE STRONGEST SYNOPTIC SCALE ASCENT WELL NORTH OF THE

CWA. THIS ASCENT WILL BE CRUCIAL FOR ELIMINATING AN INCREDIBLY

STRONG CAPPING INVERSION IN PLACE. IF MODELS CONTINUE WITH THIS

NORTHWARD TREND...LITTLE TO NO CONVECTION MAY IMPACT OUR CWA ON

TUESDAY SINCE THE CAP WOULD HOLD IN PLACE AND STORMS WOULD BE

UNLIKELY TO DEVELOP.

Still too far off to work out the details. The high amp GWO moving through 8-1-2 certainly peaks my interest in the next two weeks. One concern would be that over the past week or so the GEFS has been too quick to get the GWO moving in to those phases. Also, everyone is focusing on Tuesday but the worst of it may be later in the week.

[NTXYankee]

Still too far off to work out the details. The high amp GWO moving through 8-1-2 certainly peaks my interest in the next two weeks. One concern would be that over the past week or so the GEFS has been too quick to get the GWO moving in to those phases. Also, everyone is focusing on Tuesday but the worst of it may be later in the week.

I'll eventually get over the frustrations of severe weather season in the southern plains.  Very different compared to Ohio Valley and how storms form.

[bubba hotep]

FWD is pointing towards a big hail (that again!?) threat for mostly the western areas on Tuesday. I still think that later in the week is when DFW might be more under the gun. After Tuesday, there looks to be a string of days of unsettled weather with each day being influenced by mesoscale features leftover from the prior evening. Those tricky setup days seem to always give us trouble.

 

The latest from FWD:

 

 

MODELS ARE STILL GENERATING IMPRESSIVE AMOUNTS OF INSTABILITY
ALONG THE DRYLINE...WITH SB CAPE EXCEEDING 3000 J/KG TUESDAY
AFTERNOON. A CAPPING INVERSION SHOULD INHIBIT CONVECTIVE
DEVELOPMENT MOST OF THE DAY...BUT THE CURRENT THINKING IS THAT
THIS CAP WILL ERODE TO THE POINT OF ALLOWING CONVECTIVE INITIATION
IN THE 4 TO 7 PM TIME FRAME ACROSS THE WEST OR NORTHWEST
COUNTIES. LOW LEVEL HELICITY LOOKS UNIMPRESSIVE BUT BULK SHEAR
VALUES WILL APPROACH 40 KT DURING THE LATE AFTERNOON AND EARLY
EVENING AS THE SHORTWAVE CROSSES INTO THE CENTRAL AND SOUTHERN
PLAINS. WHEN COMBINED WITH THE UNSTABLE AIRMASS...A SCENARIO
INCLUDING ROTATING CELLS CAPABLE OF PRODUCING LARGE HAIL AND
DAMAGING WINDS...ALONG WITH THE OUTSIDE CHANCE OF A
TORNADO...SEEMS VIABLE. THIS THREAT WILL BE MOST LIKELY ACROSS THE
WESTERN COUNTIES INITIALLY...BEFORE STORMS BECOME BETTER ORGANIZED
AND SHIFT EAST ACROSS THE REST OF THE REGION LATE IN THE EVENING
AND OVERNIGHT. THE SHIFT TO A MORE LINEAR MODE OF CONVECTION
OVERNIGHT SHOULD LOWER THE THREAT OF LARGE HAIL AND
TORNADOES...WITH DAMAGING WINDS BECOMING THE MOST LIKELY SEVERE
THREAT. THAT SAID...IT IS STILL TOO EARLY TO POUNCE ON ANY
CERTAINTY OF THE DETAILS OF THIS PART OF THE FORECAST...BUT GIVEN
THE TIME OF YEAR AND THE LATEST MODEL PROJECTIONS ITS DIFFICULT TO
IGNORE THE POSSIBILITY OF SEVERE WEATHER ON DAY 5.

[bubba hotep]

Monday could be a sneaky day for the DFW area, there doesn't appear to be any mechanism to provide extra lift and there is probably enough ridging behind the weekend s/w to keep anything from happening. However, if a rouge cell could get off the dryline then it would have some potential. It's the kind of afternoon that Cavanaugh would write up several paragraphs on and then say something like, "however, we don't anticipate any storms initiating this afternoon." Below is form just west of Ft. Worth: