Severe weather Potential Nov 30-Dec 1

[janetjanet998]

Models have trended more unstable the last couple of days...dew points already to 60 at  the Red river and moisture will continue to improve with time....cold temps aloft moving in 

models now have SBCAPE to 2000 later this evening

 

here are the latest 12z outlook form SPC....

 

DAY 1 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
0654 AM CST FRI NOV 30 2018  
  
VALID 301300Z - 011200Z  
  
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS CENTERED OVER  
THE ARKLATEX REGION...  
  
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE  
ENHANCED RISK AND SEPARATELY OVER THE LOWER MISSISSIPPI DELTA  
REGION...  
   
..SUMMARY  
  
SEVERE THUNDERSTORMS ARE FORECAST FROM PARTS OF THE SOUTHERN PLAINS  
TO THE LOWER MISSISSIPPI VALLEY THIS AFTERNOON INTO TONIGHT, WITH A  
RISK FOR TORNADOES, DAMAGING GUSTS AND OCCASIONAL HAIL.  
   
..SYNOPSIS  
  
THE MID/UPPER-LEVEL PATTERN THIS PERIOD WILL BE DOMINATED BY A  
SOUTHERN-STREAM WAVE TRAIN, FEATURING A STRONG SHORTWAVE TROUGH NOW  
LOCATED OVER PORTIONS OF AZ AND SONORA.  THIS TROUGH IS EXPECTED TO  
MOVE EASTWARD ACROSS NM AND CHIHUAHUA TODAY, REACHING THE EASTERN  
BORDER OF NM AND THE TX BIG BEND BY 00Z.  A 500-MB LOW SHOULD  
DEVELOP IN THE NORTHERN PARTS OF THE TROUGH AROUND 00Z, NEAR THE  
OK/NM BORDER, THEN FOLLOW A CURVING PATH ACROSS SOUTHWESTERN/CENTRAL  
KS THROUGH 12Z.  BY THEN, THE ACCOMPANYING TROUGH SHOULD ASSUME MORE  
NEGATIVE TILT ACROSS PORTIONS OF EASTERN OK AND NORTH-CENTRAL/  
NORTHEAST TX, WITH CYCLONIC FLOW COVERING A VAST AREA FROM NORTHERN  
MX TO THE MID/LOWER MISSISSIPPI VALLEY.  A 110-140-KT 250-MB JET  
WILL FLOW THROUGH THE TROUGH, EXTENDING/EXPANDING FROM FAR WEST TX  
TO EAST-CENTRAL TX AND THE LA/AR BORDER BY THE END OF THE PERIOD.  
  
IN RESPONSE TO THOSE DEVELOPMENTS, SURFACE LEE TROUGHING NOW LOCATED  
OVER THE CENTRAL/SOUTHERN HIGH PLAINS WILL INTENSIFY.  A CYCLONE  
SHOULD DEVELOP THROUGH AFTERNOON OVER THE SOUTHEASTERN CO/EXTREME  
NORTHEASTERN NM AREA, OCCLUDING AS IT DEEPENS, WITH WARM FRONT  
ACROSS NORTHERN OK AND THE OZARKS.  A "PACIFIC" COLD FRONT WILL MOVE  
OUT OF THE SOUTHERN ROCKIES TODAY AND OVERTAKE THE DRYLINE FROM  
NORTH TO SOUTH, SOUTHEAST OF THE SURFACE LOW.  BY 00Z THE COMBINED  
BOUNDARY SHOULD ARC FROM WEST-CENTRAL/SOUTHWESTERN OK ACROSS  
NORTHWEST/WEST-CENTRAL TX.  BY 12Z, THE BOUNDARY SHOULD REACH  
SOUTHEASTERN KS, EXTREME EASTERN OK, EXTREME NORTHEAST TX, TO THE  
PSX/CRP AREAS.   
  
THREE DISTINCT CONVECTIVE PROCESSES CONTRIBUTE TO THIS OUTLOOK, THE  
FIRST TWO OVERLAPPING SPATIALLY.    
   
..WARM-ADVECTION CONVEYOR, EAST TX TO SOUTHEAST OK AND AR  
  
THUNDERSTORMS ARE EXPECTED TO DEVELOP GRADUALLY TODAY INTO THIS  
EVENING WITHIN A BROAD AREA OF CLOUDS AND PRECIP FROM EAST TX ACROSS  
NORTHERN LA AND AR INTO THE MID-SOUTH REGION.  THE SEVERE THREAT  
SHOULD RAMP UP FROM MID/LATE AFTERNOON INTO TONIGHT AND SPREAD  
NORTHWARD ACROSS THE ARKLATEX, EASTERN OK AND AR, WITH SOME STORMS  
BECOMING SUPERCELLS CAPABLE OF TORNADOES, DAMAGING GUSTS AND LARGE  
HAIL.  A FEW STRONG/EF2+ TORNADOES MAY OCCUR GIVEN THE FAVORABLE  
PARAMETER SPACE FORECAST.   
  
AS SUPPORTIVE LOW-LEVEL WARM ADVECTION AND MOISTURE TRANSPORT  
PERSIST, LOW-LEVEL MOIST-LAYER QUALITY, DEPTH AND THETA-E EACH WILL  
INCREASE, WHILE MLCINH WEAKENS AND TEMPERATURES ALOFT COOL WITH THE  
APPROACHING INTENSE SHORTWAVE TROUGH.  THIS WILL STEEPEN LOW/MIDDLE-  
LEVEL LAPSE RATES, LEADING TO THE DEVELOPMENT OF MLCAPE OF 500-1500  
J/KG AND VERY LOW LCLS.  WITH THIS REGIME BEING IN THE EASTERN RIM  
OF THE WARM SECTOR, LAPSE RATES WILL NOT BE AS LARGE AS IN THE  
FRONTAL PROCESS; HOWEVER, VERY FAVORABLE LOW-LEVEL SHEAR AND  
HODOGRAPHS SHOULD DEVELOP BENEATH THE STRENGTHENING EVENING LLJ,  
WITH MORE SUSTAINED POTENTIAL FOR AT LEAST SEMI-DISCRETE SUPERCELLS.  
 EFFECTIVE SRH 250-400 J/KG SHOULD BECOME COMMON, WITH LOCALLY  
HIGHER VALUES.  THE FRONTAL ARC WILL IMPINGE ON THE WESTERN PART OF  
THIS REGIME LATE TONIGHT.  
   
..COLD FRONT/DRYLINE, SOUTHERN PLAINS EASTWARD  
  
AS THE FRONT OVERTAKES THE DRYLINE AND THE COMBINED BOUNDARY THRUSTS  
EASTWARD INTO FAVORABLE LOW-LEVEL MOISTURE LATE AFTERNOON AND  
ESPECIALLY THIS EVENING, AT LEAST A BROKEN ARC OF CONVECTION IS  
EXPECTED TO FORM OVER PARTS OF CENTRAL/EASTERN OK AND NORTH TO  
CENTRAL TX.  STRENGTHENING OF BOTH CONVECTIVE-SCALE/LOW-LEVEL LIFT  
AND LARGE-SCALE FORCING ALOFT WILL SUPPORT THIS DEVELOPMENT, WHILE  
DEEP-LAYER WINDS AND SHEAR STRENGTHEN.  EARLY-STAGE CONVECTION MAY  
BE SUPERCELLULAR, WITH LARGE HAIL AND A FEW TORNADOES POSSIBLE.   
GEOMETRY OF AMBIENT FLOW, INCLUDING BACKING WITH HEIGHT IN LOW/  
MIDDLE LEVELS, SUGGESTS MODE COULD GET MESSY WHERE STORMS DO FORM,  
WITH LIMITED TIME WINDOW FOR DISCRETE CELLS.  REGARDLESS, THIS  
ACTIVITY WILL MOVE INTO A SETTING OF STRENGTHENING LOW-LEVEL SHEAR,  
MOISTURE AND LAPSE RATES ABOVE THE BOUNDARY LAYER, SUPPORTING A  
CONTINUED TORNADO RISK INTO TONIGHT, PERHAPS FROM EMBEDDED  
SUPERCELLS OR QLCS/LEADING-EDGE CIRCULATIONS.   
   
..GULF COAST, LATE IN PERIOD  
  
WIDELY SCATTERED TO SCATTERED THUNDERSTORMS SHOULD MOVE ONSHORE FROM  
THE GULF OVERNIGHT, POSING AN INCREASING RISK FOR DAMAGING GUSTS AND  
A FEW TORNADOES AS THE SUPPORTING INFLOW LAYER BECOMES PROGRESSIVELY  
MORE SURFACE-BASED AND UNSTABLE.  A WEDGE OF MARINE AIR WILL SPREAD  
INLAND ACROSS PORTIONS OF THE CENTRAL GULF COAST FROM LA TO AL AND  
PERHAPS THE WESTERN FL PANHANDLE OVERNIGHT, WITH DEW POINTS RISING  
THROUGH THE 60S F, AND A DEEPENING MOIST LAYER WITH TIME.  ALTHOUGH  
WEAK MIDLEVEL LAPSE RATES ARE EXPECTED TO PERSIST, BOUNDARY-LAYER  
THETA-E IN THE MARINE LAYER SHOULD OFFSET THAT FACTOR ENOUGH TO  
YIELD MLCAPE RISING INTO THE 500-800 J/KG RANGE, WITH ENLARGED AND  
STRONGLY CURVED LOW-LEVEL HODOGRAPHS.  STRENGTHENING CYCLONIC FLOW  
ALOFT AND DEEP SHEAR FURTHER WILL SUPPORT SUPERCELL MODES WITH THIS  
CONVECTION, WHICH MAY REPRESENT THE NORTHERN PART OF A BROAD AREA OF  
SUPERCELL POTENTIAL EXTENDING WELL SOUTHWARD OVER THE OPEN GULF BY  
12Z.  

 

Day 2

 

DAY 2 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
1151 PM CST THU NOV 29 2018  
  
VALID 011200Z - 021200Z  
  
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF  
THE SOUTHEAST...  
   
..SUMMARY  
  
A FEW SEVERE STORMS WILL BE POSSIBLE ON SATURDAY ACROSS PARTS OF THE  
SOUTHEAST. MARGINALLY SEVERE STORMS COULD OCCUR NORTHWARD ACROSS THE  
TENNESSEE AND LOWER OHIO VALLEYS INTO THE MID MISSISSIPPI VALLEY.  
   
..SOUTHEAST  
  
AN UPPER-LEVEL LOW AND AN ASSOCIATED NEGATIVELY TILTED UPPER-LEVEL  
TROUGH WILL MOVE NORTHEASTWARD INTO THE MID MISSISSIPPI VALLEY ON  
SATURDAY. A STRONG SURFACE LOW WILL MOVE NORTHEASTWARD INTO THE  
LOWER MISSOURI VALLEY AS A COLD FRONT ADVANCES EASTWARD ACROSS THE  
SOUTHERN PLAINS. A PRE-FRONTAL TROUGH WILL MOVE ACROSS THE LOWER  
MISSISSIPPI VALLEY AS LOW-LEVEL MOISTURE ADVECTS NORTHWARD INTO THE  
CENTRAL GULF COAST STATES. IN THE CENTRAL GULF COAST STATES, A 50 TO  
60 KT LOW-LEVEL JET WILL MOVE NORTHEASTWARD. TO THE WEST OF THIS  
FEATURE, MORNING SHOWERS AND THUNDERSTORMS ARE FORECAST DEVELOP FROM  
SOUTH-CENTRAL MISSISSIPPI INTO SOUTH-CENTRAL ALABAMA. THIS COMBINED  
WITH ABUNDANT CLOUD COVER, INTRODUCES UNCERTAINTY INTO THE FORECAST  
CONCERNING INSTABILITY. IN SPITE OF THIS, FORECAST SOUNDINGS AROUND  
MIDDAY INTO SOUTHERN MISSISSIPPI AND SOUTHERN ALABAMA SHOW SURFACE  
DEWPOINTS IN THE MID 60S F WITH MLCAPE VALUES REACHING THE 800 TO  
1200 J/KG RANGE. THIS COMBINED WITH STRONG DEEP-LAYER SHEAR OF 50 TO  
60 KT SHOULD BE SUFFICIENT FOR A SEVERE THREAT. THE TYPE OF SEVERE  
SHOULD DEPEND UPON WHICH MODE IS FAVORED. WIND DAMAGE AND QLCS-TYPE  
TORNADOES WOULD BE POSSIBLE WITH LINE SEGMENTS. IF A CLUSTER  
ORGANIZES WITH DISCRETE MODES, THEN SUPERCELLS ALONG WITH A TORNADO  
THREAT WOULD ALSO BE POSSIBLE.  
NEGATIVE FACTORS FOR THIS EVENT INCLUDE  
  
1) THE UPPER-LEVEL SYSTEM AND THE ASSOCIATED LARGE-SCALE ASCENT IS  
TOO FAR NORTH  
2) WIDESPREAD MORNING CONVECTION SHOULD HAMPER DESTABILIZATION  
  
FOR THESE REASONS, AN UPGRADE WILL NOT BE ISSUED FOR THIS OUTLOOK  
AND A SLIGHT RISK WILL BE MAINTAINED IN THE SAME GENERAL AREA.  
   
..TENNESSEE AND LOWER OHIO VALLEYS/MID MISSISSIPPI VALLEY  
  
AN UPPER-LEVEL LOW AND AN ASSOCIATED NEGATIVELY-TILTED UPPER-LEVEL  
TROUGH WILL MOVE NORTHEASTWARD INTO THE MID MISSISSIPPI VALLEY ON  
SATURDAY. THE EXIT REGION OF A 75 TO 90 MID-LEVEL JET WILL  
OVERSPREAD THE OHIO VALLEY AS A SURFACE LOW MOVES INTO THE LOWER  
MISSOURI VALLEY. SOUTH TO SOUTHEASTERLY WINDS ARE FORECAST ACROSS  
THE OHIO AND TENNESSEE VALLEYS WHICH WILL HELP MAINTAIN A CORRIDOR  
OF LOW-LEVEL MOISTURE. ALTHOUGH INSTABILITY WILL REMAIN WEAK ALONG  
THIS CORRIDOR, LARGE-SCALE ASCENT WILL BE STRONG ENOUGH FOR  
THUNDERSTORM DEVELOPMENT DURING THE LATE MORNING AND AFTERNOON. DEEP  
LAYER-SHEAR OF 70 TO 80 KT ALONG WITH THE LARGE-SCALE ASCENT AND  
COLD AIR ALOFT, MAY BE ENOUGH FOR A MARGINAL HAIL THREAT DURING THE  
AFTERNOON. A FEW STRONG WIND GUSTS WILL ALSO BE POSSIBLE.  
   
..MAXIMUM RISK BY HAZARD  
  
TORNADO:   5%     - SLIGHT  
WIND:     15%     - SLIGHT  
HAIL:      5%     - MARGINAL  
  
..BROYLES.. 11/30/2018  
  
 

[CheeselandSkies]

Morning visible shows some breaks in the clouds across eastern OK and west-central AR. Not sure how much it matters, but widespread morning clouds/precip was mentioned as one possible limiting factor for this setup by SPC in the Day 2 and 3 outlooks issued yesterday and Wednesday.

Instability might not be as much of a problem as first thought, but as I alluded to in the other thread, NAM forecast soundings (this sample valid for 03Z tonight near Quinton, OK) show somewhat unidirectional wind profiles above 850mb. Even so, there's a sharp turn from SE to SW and very strong winds in the lowest 1KM (reflected by the SRH number).

To me the lack of turning and even slight backing above that is a red flag for storm mode/maintenance, but CAMs so far depict a pretty discrete mode, and with 1KM shear like that any organized supercell should be able to produce.

[CheeselandSkies]

15Z HRRR has a lot more updraft helicity with cells across the Arklatex/SE OK and even into eastern Kansas overnight compared to the 12Z/13Z runs and the 12Z 3KM NAM.

[janetjanet998]

Back in the day this would have likely been a moderate risk day..with a 990mb low, cold temps aloft and 64-67 dewpoints...and other parameters

in addition to AR area...need to watch the triple point in central OK too

latest out of Tulsa hinting at a northward expansion of the threat also 1630z SPC outlook which IMO is on the tame side

 

  
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TULSA OK  
1028 AM CST FRI NOV 30 2018  
   
DISCUSSION  
  
WARM FRONT CONTINUES TO LIFT NORTH ACROSS SOUTHEAST OKLAHOMA THIS  
MORNING, WITH DEW POINTS IN THE 60S TO THE SOUTH OF THE BOUNDARY.  
LATEST HIGH-RES MODEL DATA SUPPORTS A BIT FARTHER NORTH   
ADVANCEMENT OF THIS BOUNDARY AHEAD OF THE STRONG NEGATIVE TILT   
UPPER TROUGH NOW MOVING ACROSS NEW MEXICO. THESE TRENDS SUPPORT A  
NORTHWARD EXPANSION OF HIGHER SEVERE WEATHER PROBABILITIES WITH   
MODELS NOW BRINGING 60-ISH DEW POINTS TO NEAR KS/OK BORDER THIS   
EVENING AROUND 03-06Z. STILL LOOKS LIKE TWO AREAS OF SEVERE   
DEVELOPMENT, FIRST WITHIN THE WARM CONVEYOR BELT SETTING UP ACROSS  
SOUTHEAST OK INTO WESTERN AR PERHAPS A BIT BEFORE 00Z, AND   
ADDITIONAL STORMS FORCED BY THE UPPER LOW ITSELF OVER CENTRAL OK   
WHICH WILL MOVE INTO PARTS OF EASTERN OK DURING THE EVENING. THE   
OVERALL FORECAST WILL NOT CHANGE A GREAT DEAL ASIDE FROM THE   
AFOREMENTIONED INCREASE IN SEVERE WEATHER PROBABILITY.  

--------------------

DAY 1 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
1027 AM CST FRI NOV 30 2018  
  
VALID 301630Z - 011200Z  
  
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER PARTS OF  
WESTERN AND CENTRAL ARKANSAS...SOUTHEAST OKLAHOMA...NORTHEAST  
TEXAS...AND NORTHWEST LOUISIANA...  
  
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE  
SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY...  
   
..SUMMARY  
  
SEVERE THUNDERSTORMS ARE FORECAST FROM PARTS OF THE SOUTHERN PLAINS  
TO THE LOWER MISSISSIPPI VALLEY THIS AFTERNOON INTO TONIGHT, WITH A  
RISK FOR TORNADOES, DAMAGING WINDS, AND LARGE HAIL.  
   
..OK/KS  
  
A POWERFUL, NEGATIVELY TILTED SHORTWAVE TROUGH OVER THE FOUR CORNERS  
REGION WILL TRACK RAPIDLY EASTWARD TODAY INTO THE SOUTHERN PLAINS.   
THIS WILL LEAD TO RAPID CYCLOGENESIS AND STRENGTHENING OF SOUTHERLY  
LOW-LEVEL WIND FIELDS.  TRENDS IN THE MOST RECENT MODEL SOLUTIONS  
INDICATE THAT AN UNSTABLE AIR MASS WILL DEVELOP FARTHER WEST THAN  
EARLIER DATA SUGGESTED, AND THAT CONVECTIVE INITIATION IN THIS ZONE  
OF WESTERN OK IS ALSO MORE LIKELY BY LATE AFTERNOON.  THEREFORE,  
HAVE EXPANDED THE SLGT RISK AREA BACK TO INCLUDE THIS POTENTIAL.   
FORECAST SOUNDINGS AND CAM SOLUTIONS SUGGEST DISCRETE SUPERCELLS ARE  
POSSIBLE, WITH LOW-LEVEL SHEAR PROFILES SUPPORTIVE OF SOME TORNADO  
THREAT.  HOWEVER, LIMITED LOW-LEVEL MOISTURE SUGGEST THAT LARGE HAIL  
MAY BE THE MAIN THREAT WITH THESE STORMS.  THE ACTIVITY WILL SPREAD  
NORTHEASTWARD INTO PARTS OF SOUTHERN KS EARLY THIS EVENING WITH A  
CONTINUED THREAT OF LARGE HAIL AND PERHAPS DAMAGING WINDS.  
   
..ARKLATEX REGION  
  
MULTIPLE ROUNDS OF STRONG/SEVERE CONVECTION APPEAR POSSIBLE OVER  
PARTS OF AR/LA AND NORTHEAST TX DURING THIS FORECAST PERIOD.  THE  
FIRST ACTIVITY WILL LIKELY FORM LATE THIS AFTERNOON IN A ZONE OF  
INCREASING LOW-LEVEL WARM/MOIST ADVECTION OVER AR.  SHEAR PROFILES  
WILL ONLY BE MARGINALLY FAVORABLE FOR SUPERCELL STRUCTURES AT THIS  
TIME, BUT WILL STRENGTHEN RAPIDLY THROUGH THE EARLY EVENING AS  
STRONGER FORCING AND GREATER CONVECTIVE COVERAGE OCCURS.  BY  
MID-LATE EVENING, SHEAR PROFILES BECOME MUCH MORE FAVORABLE FOR  
TORNADIC SUPERCELLS.  HAVE ADJUSTED THE AREA OF HIGHEST SEVERE  
PROBABILITIES TO CONFORM TO THE PLACEMENT OF THE LOW-LEVEL JET AXIS  
AND WHERE CAM SOLUTIONS ARE MOST CONFIDENT IN SUPERCELL STORM  
STRUCTURES.  A FEW STRONG TORNADOES ARE POSSIBLE IN THE ENH REGION  
THIS EVENING AND TONIGHT.  
   
..CENTRAL/EAST TX TONIGHT  
  
RECENT HRRR RUNS ARE SUGGESTING THAT CONVECTIVE DEVELOPMENT MAY  
OCCUR ALONG THE TRAILING COLD FRONT OVER CENTRAL AND EAST TX LATE  
TONIGHT.  IF THIS OCCURS, FORECAST SOUNDINGS WOULD SUPPORT A RISK OF  
A FEW SEVERE STORMS CAPABLE OF GUSTY WINDS AND HAIL.  HAVE MADE  
ADJUSTMENTS TO ACCOUNT FOR THIS UNCERTAIN BUT GROWING POTENTIAL.  
   
..SOUTHERN LA/MS LATE TONIGHT  
  
LATE TONIGHT, MODELS CONTINUE TO SHOW THE POTENTIAL FOR SCATTERED  
THUNDERSTORMS SPREADING INTO SOUTHERN LA/MS.  LOW-LEVEL SHEAR  
PROFILES WILL BE SUFFICIENTLY STRONG AFTER 06Z TO MERIT SOME CONCERN  
FOR ROTATING STORMS AND THE RISK OF A TORNADO OR TWO.  
  

[yoda]

Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0155 PM CST Fri Nov 30 2018

   Valid 302000Z - 011200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   WESTERN AND CENTRAL ARKANSAS...SOUTHEASTERN OKLAHOMA...NORTHEASTERN
   TEXAS...AND NORTHWESTERN LOUISIANA...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   SOUTHERN LOUISIANA AND MISSISSIPPI...

   ...SUMMARY...
   Severe thunderstorms are forecast from parts of the southern Plains
   to the lower Mississippi Valley this afternoon into tonight, with a
   risk for tornadoes, damaging winds, and large hail.

   ...20Z Update...
   Primary change with this update was to include a significant hail
   area for the potential of 2 inch or greater hail for portions of
   central OK. Steep mid-level lapse rates of 7.5 to 8 C/km noted on
   12Z/18Z area soundings and continued low-level moistening will
   likely result in MUCAPE of 1500-1750 J/kg in the presence of 45-50
   kt of effective bulk shear across this region, which will easily
   support supercells. Have nudged the Marginal/Slight risk areas a
   little bit farther southwestward to include more of southern OK and
   western north TX based on recent short-term model guidance.

   Have also expanded the Marginal/Slight risks northeastward to
   include more of northeastern AR and southern MO to account for
   near-surface based thunderstorms late tonight spreading eastward in
   tandem with a strong low-level jet. No changes have been made to the
   Enhanced Risk area across portions of the ArkLaTex and vicinity.
   Tornadoes, some of which could be strong, still appear possible for
   this region beginning later this afternoon/evening and continuing
   into the overnight hours.

   ..Gleason.. 11/30/2018

[janetjanet998]

ESOSCALE DISCUSSION 1668  
NWS STORM PREDICTION CENTER NORMAN OK  
0351 PM CST FRI NOV 30 2018  
  
AREAS AFFECTED...PORTIONS OF NORTH-CENTRAL TX INTO CENTRAL OK  
  
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY   
  
VALID 302151Z - 302315Z  
  
PROBABILITY OF WATCH ISSUANCE...80 PERCENT  
  
SUMMARY...SEVERE THREAT WILL INCREASE AFTER 23Z FROM PORTIONS OF  
NORTH-CENTRAL TX INTO CENTRAL OK. LARGE HAIL IS LIKELY WITH THIS  
ACTIVITY ALONG WITH SOME TORNADO THREAT. WW WILL LIKELY BE ISSUED BY  
00Z.  
  
DISCUSSION...LEADING EDGE OF LARGE-SCALE ASCENT IS SPREADING EAST  
ACROSS THE SOUTHERN HIGH PLAINS AT ROUGHLY 30KT. LATEST VISIBLE  
SATELLITE IMAGERY SUPPORTS THIS WITH BLOWING DUST AND STRONG  
WESTERLY SURFACE FLOW APPROACHING SOUTHWEST OK. STRENGTHENING  
MID-LEVEL HEIGHT FALLS, ON THE ORDER OF 150-210M, DURING THE LATTER  
HALF OF THE PERIOD ARE INDUCING A FOCUSED LOW-LEVEL RESPONSE ACROSS  
THE RED RIVER VALLEY INTO CENTRAL OK. MODIFIED GULF AIR MASS HAS NOW  
SPREAD INTO ALL BUT EXTREME SOUTHWEST OK WITH MID 50S SURFACE DEW  
POINTS NOW INTO JACKSON COUNTY. OVER THE NEXT FEW HOURS, NEAR 60 DEW  
POINTS ARE EXPECTED TO ADVANCE INTO CENTRAL OK. GIVEN THE  
AFOREMENTIONED SPEED OF APPROACHING LARGE-SCALE FORCING, LATEST  
THINKING IS DEEP CONVECTION SHOULD DEVELOP BY 23Z OVER SOUTHWEST OK,  
PERHAPS EXTENDING SOUTH OF THE RED RIVER INTO NORTHWEST TX. VERY  
STRONG SHEAR AND STEEP MID-LEVEL LAPSE RATES WILL SUPPORT SUPERCELL  
DEVELOPMENT BY EARLY EVENING. LARGE HAIL IS EXPECTED WITH THIS  
INITIAL ACTIVITY. AS CONVECTION SPREADS TOWARD THE I-35 CORRIDOR A  
BIT MORE MOIST PROFILES WILL BECOME MORE SUPPORTIVE OF POTENTIAL  
TORNADIC DEVELOPMENT, ESPECIALLY WHERE LOWER-MID 60S DEW POINTS ARE  
ENCOUNTERED. BACK EDGE OF SEVERE CONVECTION SHOULD SHIFT EAST OF  
I-35 BY 03Z.  

[Sydney Claridge]

Though DFW has been dropped to a Marginal risk, a few of the models are bringing DFW back in on storm action, especially the last couple runs of the HRRR.

[It's Always Sunny]

Yeah I've been following that too.  21Z sounding doesn't show much difference than from 18Z but radar already shows cells popping near SPS.

[Sydney Claridge]

New Tornado Watch issued, including most of the DFW area (Tarrant & Dallas counties northwards).  SPC seems to not be ruling out the possibility of storms in DFW.

[Weatherdemon]

Fairly large tornado watch issued.

[CheeselandSkies]

This is just a guess, but I suspect more of OK is under a tornado watch on the last day of November 2018 than ever was at any point in May 2018.

[cheese007]

Kinda shocked that DFW and areas west got includes tbh

[It's Always Sunny]

CAMS did a bad job on this event. HRRR catching onto it 2 hours out doesn't count as a "hit" in my book.

[janetjanet998]

 What is SPC waiting for pulling the trigger on the AR watch?? A touchdown?

 

Storm east of FT Smith looking good

 

[Weatherdemon]

Tornado warning Franklin Ark

[janetjanet998]

Oh for Christ sakes just issue a watch NOW

 

MESOSCALE DISCUSSION 1669  
NWS STORM PREDICTION CENTER NORMAN OK  
0617 PM CST FRI NOV 30 2018  
  
AREAS AFFECTED...NORTHEAST TX...FAR SOUTHEAST OK...MOST OF  
AR...NORTHWEST/NORTH-CENTRAL LA  
  
CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY   
  
VALID 010017Z - 010115Z  
  
PROBABILITY OF WATCH ISSUANCE...95 PERCENT  
  
SUMMARY...THREAT FOR SEVERE STORMS CAPABLE OF TORNADOES CONTINUES TO  
GRADUALLY INCREASE. A TORNADO WATCH WILL BE NEEDED SOON.  
  
DISCUSSION...WARM ADVECTION CONTINUES TO BE THE PRIMARY FORCING FOR  
ASCENT, EVIDENCED BY LINEAR/ARCHING REFLECTIVITY STRUCTURE AND  
FAIRLY TRANSIENT UPDRAFTS. HOWEVER, STRONGER FORCING FOR ASCENT IS  
QUICKLY APPROACHING AS A POTENT SHORTWAVE TROUGH MOVES INTO THE  
SOUTHERN PLAINS. STORM IN FRANKLIN COUNTY AR HAS RECENTLY SHOWN  
BETTER ORGANIZATION, SHEDDING A WELL-DEVELOPED LEFT-SPLIT AND  
DEVELOPING A STRONG UPDRAFT DURING THE PAST HALF HOUR. WITH THE  
INCREASED FORCING FOR ASCENT, STORM COVERAGE IS EXPECTED TO  
INCREASE. THE THERMODYNAMIC ENVIRONMENT IS FAIRLY MARGINAL AS SHOWN  
BY THE DEEP BUT ONLY WEAKLY UNSTABLE LAYER FROM THE SURFACE UP TO  
700 MB ON THE 00Z SHV SOUNDING. EVEN SO, INSTABILITY IS EXPECTED TO  
GRADUALLY INCREASE AS MID-LEVEL TEMPERATURES COOL WITHIN THE  
APPROACHING SHORTWAVE. IN CONTRAST TO THE THERMODYNAMICS, THE  
KINEMATICS ARE ALREADY FAVORABLE FOR ROTATING STORMS WITH AN  
INCREASING LOW-LEVEL JET EXPECTED TO RESULT IN EVEN STRONGER  
LOW-LEVEL SHEAR PROFILES. PRIMARY THREAT WILL BE TORNADOES, ONE OR  
TWO OF WHICH COULD BE STRONG. DAMAGING WIND GUSTS ARE ALSO POSSIBLE.  
SMALL HAIL CANNOT BE COMPLETELY RULED OUT.  
  
..MOSIER/GOSS.. 12/01/2018  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT  
  
ATTN...WFO...MEG...JAN...LZK...SHV...TSA...  

[janetjanet998]

TX/OK update

 

MESOSCALE DISCUSSION 1670  
NWS STORM PREDICTION CENTER NORMAN OK  
0635 PM CST FRI NOV 30 2018  
  
AREAS AFFECTED...CENTRAL/EASTERN OK...NORTH TX  
  
CONCERNING...TORNADO WATCH 429...  
  
VALID 010035Z - 010200Z  
  
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 429 CONTINUES.  
  
SUMMARY...THE THREAT FOR LARGE HAIL, DAMAGING WINDS, AND A FEW  
TORNADOES WILL INCREASE THIS EVENING ALONG AND EAST OF THE I-35  
CORRIDOR.  
  
DISCUSSION...AT 0030Z, SCATTERED THUNDERSTORMS HAVE DEVELOPED ALONG  
TWO BANDS FROM NORTH TX INTO SOUTHWEST OK; ONE BAND IS ALONG A  
PREFRONTAL CONFLUENCE AXIS APPROACHING THE I-35 CORRIDOR, WITH THE  
SECOND BAND FURTHER WEST ALONG THE PRIMARY PACIFIC COLD FRONT.  
STORMS HAVE LARGELY REMAINED SUBSEVERE THUS FAR, BUT AN INCREASE IN  
COVERAGE AND INTENSITY IS EXPECTED THIS EVENING IN ADVANCE OF A  
POWERFUL NEGATIVELY TILTED TROUGH MOVING INTO THE SOUTHERN PLAINS.  
REGIONAL 00Z SOUNDINGS FROM OUN AND FWD EXHIBIT VERY STEEP MIDLEVEL  
LAPSE RATES AND MODERATE BUOYANCY (MLCAPE OF 1000-1500 J/KG).  
DEEP-LAYER SHEAR IS QUITE STRONG AND LOW-LEVEL SHEAR WILL CONTINUE  
TO INCREASE THIS EVENING IN ADVANCE OF THE UPPER TROUGH. GIVEN THE  
FAVORABLE ENVIRONMENT, IT IS POSSIBLE THAT STORMS WILL BECOME SEVERE  
AS THEY APPROACH THE I-35 CORRIDOR BETWEEN NOW AND 7 PM CDT, WITH  
MAINTENANCE OR CONTINUED GRADUAL INCREASE IN THE SEVERE THREAT  
FURTHER EAST AS STORMS ENCOUNTER MORE FAVORABLE LOW-LEVEL MOISTURE.  
THE PRIMARY INITIAL THREAT WILL BE LARGE HAIL, WHILE ANY SUSTAINED  
DISCRETE SUPERCELL WILL ALSO EVENTUALLY POSE A TORNADO THREAT. LATER  
THIS EVENING AS THE PRIMARY PACIFIC COLD FRONT CATCHES UP TO THE  
STORMS FURTHER EAST, AN EVOLUTION INTO MORE OF A LINEAR MODE IS  
EXPECTED, WITH A CORRESPONDING DAMAGING WIND THREAT.    
  
FURTHER EAST, STORMS HAVE BEEN INCREASING WITHIN A LOW-LEVEL WARM  
ADVECTION REGIME ACROSS EASTERN OK. WHILE MUCH OF THIS ACTIVITY IS  
LIKELY SLIGHTLY ELEVATED, THUNDERSTORM CLUSTERS MAY EVENTUALLY  
BECOME ROOTED NEAR THE SURFACE, POSING A NEAR-TERM THREAT FOR  
DAMAGING WINDS AND PERHAPS ISOLATED LARGE HAIL. VERY FAVORABLE  
LOW-LEVEL WIND PROFILES WILL ALSO RESULT IN A TORNADO THREAT ACROSS  
THIS REGION IF SUPERCELL STRUCTURES CAN BECOME ESTABLISHED.  
  
SOME SEVERE THREAT WILL LIKELY EXTEND SOUTH OF TORNADO WATCH 429  
THIS EVENING. WHILE COVERAGE FURTHER SOUTH REMAINS UNCERTAIN, SOME  
AREAL EXTENSION OF THE WATCH MAY BE REQUIRED IF STORMS BECOME  
ESTABLISHED SOUTH OF THE METROPLEX.  
  
..DEAN.. 12/01/2018  

[janetjanet998]

At Last

 

URGENT - IMMEDIATE BROADCAST REQUESTED  
TORNADO WATCH NUMBER 430  
NWS STORM PREDICTION CENTER NORMAN OK  
640 PM CST FRI NOV 30 2018  
  
THE NWS STORM PREDICTION CENTER HAS ISSUED A  
  
* TORNADO WATCH FOR PORTIONS OF   
  MUCH OF ARKANSAS  
  FAR SOUTHEASTERN OKLAHOMA  
  PARTS OF NORTHEASTERN TEXAS  
  
* EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 640 PM  
  UNTIL 200 AM CST.  
  
* PRIMARY THREATS INCLUDE...  
  A FEW TORNADOES LIKELY WITH A COUPLE INTENSE TORNADOES POSSIBLE  
  SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE  
  SCATTERED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE  
  
SUMMARY...THUNDERSTORMS ONGOING OVER THE WATCH AREA AT THIS TIME  
WILL CONTINUE TO INTENSIFY OVER THE NEXT FEW HOURS, WHILE ADDITIONAL  
STRONG/SEVERE STORMS WILL MOVE INTO THE WATCH AREA FROM THE WEST  
LATER THIS EVENING.  ALONG WITH RISK FOR HAIL AND DAMAGING WINDS, A  
FEW TORNADOES ARE ALSO EXPECTED.  

[Indystorm]

Interesting that we have multiple lines of storms with this system as well as pre frontal WAA convection.

[Indystorm]

Nice couplet in tor warned storm ne of McAlester OK at present with strong low level rotation.

[Santa Clause]

Very impressive storm in E Ok, one to watch.

[Indystorm]

Confirmed dangerous tornado presently on the ground in eastern OK.

[Stebo]

14 minutes ago, Indystorm said:

Confirmed dangerous tornado presently on the ground in eastern OK.

Debris up to 15,000 feet with that one, big time tornado for sure.

[yoda]

TORNADO EMERGENCY FOR COOKSON OKLAHOMA

[yoda]

Yikes

 

[Stebo]

Went right through Tenkiller which has a population of around 650.

[yoda]

 

[Indystorm]

Large tornado at Cherokee Landing state park moving ne.

[weatherextreme]

Joshusa Myers is streaming from there. Looks like something happened on the stream

 

https://livestormchasing.com/map

[Indystorm]

SPC expected tornado activity might ramp up during the overnight hours as the strong jet max roars into the area.  Seems to be the case.