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Chicago Storm

April 24-30th Severe Potential

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Not sure if it means anything, but weak convection in SW OK is laying down an outflow boundary near a line from Quanah to Synder. Possible focal point?

There is another old outflow boundary that is laying right through Frederick.

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AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE FORT WORTH TX  
1222 PM CDT FRI APR 29 2016  
 
...LATEST REGARDING THE SEVERE WEATHER THREAT THIS FRIDAY  
AFTERNOON INTO THE EVENING HOURS...  
   
UPDATE
 
 
CURRENT FORECASTS WITH SEVERE POTENTIAL STILL LOOK GOOD...ALONG  
WITH BEST RAIN CHANCES OCCURRING ALONG AND EAST OF I-35/35W. A  
STRONG NEGATIVE TILTED TROUGH CONTINUES ROTATING NORTHEAST OVER  
THE CENTRAL/SOUTHERN HIGH PLAINS AT MIDDAY. A BROAD SURFACE LOW  
AND TRIPLE-POINT WAS NOTED FROM SNYDER TO SEYMOUR...WITH A WARM  
FRONT TAILING BACK ESE ALONG A BRIDGEPORT/BOWIE...TO MCKINNEY...  
TO COOPER/SULPHUR SPRINGS LINE. A DRYLINE TAILING SOUTH-SOUTHWEST  
FROM THE SURFACE LOW WAS ALREADY BULGING EAST TOWARD ABILENE IN  
RESPONSE TO ENHANCED MID LEVEL HEIGHT FALLS ACROSS THE SOUTH  
PLAINS. TEMPERATURES ARE WARMING RAPIDLY THROUGH THE 70S TO  
AROUND 80 IN THE WARM AND HUMID SECTOR EAST OF THE DRYLINE AND  
SOUTH OF THE WARM FRONT.  
 
A VERY MOIST AND UNSTABLE ENVIRONMENT WILL COINCIDE WITH STRONGAFTERNOON  
HEATING TO PRODUCE A VERY UNSTABLE ENVIRONMENT ACROSS THE WARM  
SECTOR THIS MORNING. IN ADDITION...LARGE SCALE ASCENT WILL  
INCREASE BY 2 PM CDT AND AFTER FOR THE RAPID DEVELOPMENT OF SEVERE  
STORMS ALONG OR JUST WEST OF I-35 IN AN AREA OF ENHANCED  
ISENTROPIC ASCENT. INITIALLY...DISCRETE SUPERCELL THUNDERSTORMS  
WITH LOW LCL/S WILL BE POSSIBLE...AS SURFACE DEW PT TEMPERATURES  
ARE HIGH AND IN THE LOWER-MID 70S WITHIN THE WARM SECTOR. ALL  
MODES OF SEVERE WEATHER WILL BE POSSIBLE. THE BIG WILD CARD LATER  
IN THE AFTERNOON AND EVENING WILL BE HOW LONG DISCRETE STORMS WILL  
OCCUR...AS LARGE-SCALE ASCENT OCCURS QUICKLY AT CONVECTIVE  
TEMPERATURE AND MAY RESULT IN INFLOW INTERRUPTION WITH IF STORMS  
BECOME MORE WIDESPREAD SOONER.  
 
IF ACTIVITY BECOMES TOO WIDESPREAD TOO FAST...THEN DISCRETE  
SUPERCELLS WILL BE LESS LIKELY. HOWEVER...BOWING LINE SEGMENTS OR  
LEWPS WITH TORNADOES WILL BE POSSIBLE INTO THE EVENING HOURS DUE  
TO VERY STRONG LOW LEVEL WINDS AND DEEP LAYER SHEAR ACROSS THE  
AREA WITH CURVED LOW LEVEL HODOGRAPHS NOTED ON FORCAST SOUNDSING.  
VERY LARGE HAIL WILL ALSO BE POSSIBLE...ESPECIALLY WITH DISCRETE  
CELLS AS INSTABILITY WILL BE PUSHING BETWEEN 3000-4000 J/KG WITH  
PLENTY OF LOW LEVEL CAPE BELOW CLOUD BASE FOR POTENTIAL  
TORNADOGENESIS. SEVERAL OFFICES INCLUDING OURS ARE SENDING UP  
SPECIAL MIDDAY SOUNDINGS TO ASSESS OUR ENVIRONMENT AND POTENTIAL  
AND THE FEELING IS THIS COULD BE A BIG SEVERE WEATHER DAY.  
 
AFTER COLLABORATION...THE ENHANCED RISK WAS EXTENDED SOUTH ALL  
THE WAY INTO EASTERN CENTRAL TEXAS AND SOUTHEAST TEXAS DUE TO THE  
STRONG HODOGRAPHS AND INSTABILITY. ALL PARTIES SHOULD BE ON HIGH  
ALERT BEGINNING AFTER 2 PM AND CONTINUING THROUGH THIS EVENING FOR  
ALL MODES OF SEVERE WEATHER. A SQUALL LINE WILL EVOLVE BY THIS  
EVENING ACROSS OUR E/SE COUNTIES WITH THE A DAMAGING WIND THREAT  
BECOMING MORE DOMINANT. 

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MESOSCALE DISCUSSION 0498  
NWS STORM PREDICTION CENTER NORMAN OK  
1252 PM CDT FRI APR 29 2016  
 
AREAS AFFECTED...NORTHERN AND CENTRAL TX  
 
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY  

 
VALID 291752Z - 291945Z  

 
PROBABILITY OF WATCH ISSUANCE...80 PERCENT  
 
SUMMARY...NEW THUNDERSTORM DEVELOPMENT IS EXPECTED AS ONE OR MORE  
NORTH TO SOUTH ORIENTED BROKEN BANDS ACROSS CENTRAL INTO  
NORTH-CENTRAL TX...GENERALLY IN VICINITY AND WEST OF THE I-35  
CORRIDOR. ALL SEVERE HAZARDS WILL BE POSSIBLE WITH SEVERE WEATHER  
WATCHES LIKELY FOR THIS AFTERNOON INTO THE EVENING.  
 
DISCUSSION...SURFACE AND OBJECTIVE ANALYSES SHOWED RICH  
BOUNDARY-LAYER MOISTURE STREAMING TO THE NORTH/NORTHWEST THROUGH  
CENTRAL AND NORTHERN TX WITH SURFACE DEW POINTS IN THE LOWER 70S AS  
FAR NORTH AS THE DALLAS/FORT WORTH METROPLEX. GOES-14 1-MINUTE  
VISIBLE IMAGERY SHOWED CU FORMING AS N-S ORIENTED CLOUD STREETS  
ACROSS THE WARM SECTOR...AS SURFACE HEATING BENEATH STEEPENING LAPSE  
RATES IS RESULTING IN A VERY UNSTABLE AIR MASS /MLCAPE 2500-3000 J  
PER KG/.  
 
MOSAIC RADAR IMAGERY AND LIGHTNING DATA SHOWED ONE STORM HAD  
DEVELOPED IN HAYS COUNTY TX...WITH ADDITIONAL CONVECTION BECOMING  
DEEPER FARTHER WEST THROUGH NORTHWEST FROM KIMBLE TO ERATH COUNTIES  
TX. THIS LATTER CORRIDOR APPEARS TO BE OCCURRING ALONG THE LEADING  
EDGE OF STRONGER FORCING FOR ASCENT APPROACHING FROM THE SOUTHERN  
HIGH PLAINS SHORTWAVE TROUGH. STRENGTHENING SLY LOW-LEVEL AND SWLY  
MID-UPPER LEVEL WINDS WILL RESULT IN DEEP-LAYER SHEAR FAVORABLE FOR  
SUPERCELLS. AS THE ASCENT CONTINUES TO SPREAD EAST THIS  
AFTERNOON...ADDITIONAL DEEP MOIST CONVECTION IS EXPECTED WITH ALL  
SEVERE HAZARDS LIKELY GIVEN AFOREMENTIONED THERMODYNAMIC AND  
KINEMATIC FIELDS.  

 

ESOSCALE DISCUSSION 0497  
NWS STORM PREDICTION CENTER NORMAN OK  
1251 PM CDT FRI APR 29 2016  
 
AREAS AFFECTED...PORTIONS OF SRN AR/NRN LA/NERN TX/SERN OK  
 
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE  

 
VALID 291751Z - 291945Z  

 
PROBABILITY OF WATCH ISSUANCE...60 PERCENT  
 
SUMMARY...THE AREA IS BEING MONITORED FOR INCREASING SVR TSTM  
POTENTIAL THIS AFTERNOON...AND A TORNADO WATCH MAY BE REQUIRED  
DURING THE NEXT HOUR OR TWO.  
 
DISCUSSION...CONVECTION CONTINUES TO INCREASE IN COVERAGE/INTENSITY  
FROM NERN TX TO NWRN LA ALONG A ZONE OF MODEST ISENTROPIC  
ASCENT...WITH ADDITIONAL ACTIVITY BEING SUSTAINED NWD FROM FAR SERN  
OK TO SRN AR. THROUGH THE AFTERNOON...MODEST ASCENT WILL CONTINUE  
AHEAD OF AN UPPER TROUGH APPROACHING THE SRN HIGH PLAINS.  
MEANWHILE...A MOISTURE-RICH BOUNDARY LAYER WILL CONTINUE TO STREAM  
NWD...WITH UPPER 60S TO AROUND 70F DEWPOINTS SUPPORTING MODERATE TO  
STRONG INSTABILITY. THE SHV VWP IS SAMPLING AROUND 40 KT OF DEEP  
SHEAR THAT WILL SUPPORT ORGANIZED CONVECTIVE STRUCTURES...INCLUDING  
SUPERCELL CLUSTERS. SVR WIND/HAIL WILL BE POSSIBLE. LOW-LEVEL SHEAR  
WILL BE SUFFICIENT FOR SOME TORNADO RISK...THOUGH NUMEROUS  
INTERACTING CELLS MAY TEMPER THE OVERALL TORNADO POTENTIAL. WITH  
CONTINUED DIURNAL DESTABILIZATION OF STORM INFLOW...STORM INTENSITY  
WILL LIKELY INCREASE IN THE NEXT FEW HOURS...POTENTIALLY WARRANTING  
TORNADO WATCH ISSUANCE SOON.  

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RGENT - IMMEDIATE BROADCAST REQUESTED  
TORNADO WATCH NUMBER 124  
NWS STORM PREDICTION CENTER NORMAN OK  
105 PM CDT FRI APR 29 2016  
 
THE NWS STORM PREDICTION CENTER HAS ISSUED A  
 
* TORNADO WATCH FOR PORTIONS OF  
NORTH CENTRAL AND CENTRAL TEXAS  
 
* EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 105 PM UNTIL  
1000 PM CDT.  
 
* PRIMARY THREATS INCLUDE...  
A FEW TORNADOES LIKELY  
SCATTERED LARGE HAIL LIKELY WITH ISOLATED VERY LARGE HAIL EVENTS  
TO 2.5 INCHES IN DIAMETER POSSIBLE  
SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE  
 
SUMMARY...THUNDERSTORMS ARE BEGINNING TO DEVELOP IN MULTIPLE BANDS  
ACROSS CENTRAL AND N CENTRAL TX. THE STORM ENVIRONMENT WILL BE  
FAVORABLE FOR SUPERCELLS WITH LARGE HAIL AND POTENTIALLY A FEW  
TORNADOES THIS AFTERNOON...AS WELL AS A FEW DAMAGING GUSTS. STORM  
COVERAGE WILL INCREASE THROUGH THE AFTERNOON AND THE SEVERE WEATHER  
RISK SHOULD CONTINUE INTO THIS EVENING.  

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Looking at vis sat, KFDR, and the latest HRRR runs, I still feel like the storms responsible for these ominous UH tracks in OK will probably be undercut and slightly elevated. But it will be close, and the sfc map is very hard to diagnose - even NWS OUN seems to be unsure what to make of it in their latest mesoscale discussion! Plus, we've seen tornadoes from storms right along advancing cold fronts plenty of times in C OK over the years - usually not long-track sigtors, but a threat still exists. FWIW, the 17z HRRR already has the sfc low on the Red River SW of Ardmore by 22z (5pm CDT), which is not very encouraging.

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I haven't chased OK before, though I do wish to in a week and a half when I have vacation, this is a good tip in case I find myself in Frederick.

Another note is that there's like one road through the Wichita Mountains.

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Another note is that there's like one road through the Wichita Mountains.

 

Yeah, chasing down in the Lawton area is pretty rough.  The one road that you speak of has a 45 mph speed limit because of the buffalo and antelope.  Then you have Ft. Sill in which there aren't any roads that cut through there.  I usually try to stay north of there whenever I can.

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Looking at vis sat, KFDR, and the latest HRRR runs, I still feel like the storms responsible for these ominous UH tracks in OK will probably be undercut and slightly elevated. But it will be close, and the sfc map is very hard to diagnose - even NWS OUN seems to be unsure what to make of it in their latest mesoscale discussion! Plus, we've seen tornadoes from storms right along advancing cold fronts plenty of times in C OK over the years - usually not long-track sigtors, but a threat still exists. FWIW, the 17z HRRR already has the sfc low on the Red River SW of Ardmore by 22z (5pm CDT), which is not very encouraging.

The cell west of FDR looks like it is catching up to the outflow boundary, once it starts to ingest that warm/moist air it should go.

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ESOSCALE DISCUSSION 0499  
NWS STORM PREDICTION CENTER NORMAN OK  
0140 PM CDT FRI APR 29 2016  
 
AREAS AFFECTED...SW/S-CNTRL/CNTRL OK...FAR NW/FAR N-CNTRL TX  
 
CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY  

 
VALID 291840Z - 291945Z  

 
PROBABILITY OF WATCH ISSUANCE...80 PERCENT  
 
SUMMARY...SUPERCELLS CAPABLE OF ALL SEVERE HAZARDS ARE PROBABLE FROM  
SW OK EWD/NEWD TO CNTRL/S-CNTRL OK AND FAR N-CNTRL TX. A TORNADO  
WATCH WILL LIKELY BE NEEDED TO ADDRESS THIS SEVERE THREAT.  
 
DISCUSSION...RECENT GOES-14 1-MINUTE VISIBLE SATELLITE IMAGERY  
REVEALS SCATTERED CLEARING ACROSS MUCH OF THIS REGION WITH THIS  
FILTERED SUNSHINE CONTRIBUTION TO A JUMP IN SURFACE TEMPERATURES  
FROM THE MID 60S AT 15Z TO LOW/MID 70S AT 18Z ALONG THE RED RIVER.  
DEWPOINTS HAVE ALSO INCREASED OVER THE PAST FEW HOURS AS MOISTURE  
CONTINUES TO STREAM NWD. LATEST SURFACE ANALYSIS PLACED THE LOW  
ABOUT 50 MI SSE OF CDS WITH A WARM FROM EXTENDING NEWD TOWARDS CHK  
AND THEN EWD TO ADR AND SEWD TOWARDS DEQ IN SE OK /DEMARCATED FAIRLY  
WELL BY THE 65 DEG F ISODROSOTHERM/. SURFACE ANALYSIS ALSO REVEALS A  
CONVERGENT WIND FIELD AND A MORE BAROCLINIC BOUNDARY EXTENDING FROM  
JUST S OF AXS NEWD TO BVO.  
 
OVERALL SEVERE THREAT...AND LOCALIZED TORNADO THREAT...WILL DEPEND  
LARGELY ON HOW THE SURFACE PATTERN EVOLVES OVER THE NEXT FEW HOURS.  
CURRENT EXPECTATION IS THAT THE BAROCLINIC BOUNDARY WILL ACT AS THE  
NRN BOUND TO MOISTURE ADVECTION...EFFECTIVELY BECOMING THE WARM  
FRONT AS SECONDARY SURFACE CYCLOGENESIS OCCURS IN THE VICINITY OF  
LOGAN COUNTY.  
 
CONVECTIVE INITIATION HAS ALREADY OCCURRED OVER SW OK WITH  
ADDITIONAL DEVELOPMENT POSSIBLE AS THE SURFACE LOW NEAR CDS  
CONTINUES EWD. MESOANALYSIS ESTIMATES MLCAPE EWD ALONG THE RED RIVER  
FROM SW OK IS 2000 J PER KG WITH EFFECTIVE BULK SHEAR AROUND 40 KT.  
SOME BACKING IS NOTED AROUND 3 KM ON THE FDR AND TLX VAD PROFILES  
BUT BACKED SURFACE WINDS ARE CONTRIBUTING TO 0-1 KM SRH OVER 100  
M2/S2. THIS THERMODYNAMIC AND KINEMATIC ENVIRONMENT IS SUPPORTIVE OF  
SUPERCELLS CAPABLE OF ALL SVR HAZARDS. A WW WILL LIKELY BE NEEDED TO  
COVER THIS THREAT.  
 

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The cell west of FDR looks like it is catching up to the outflow boundary, once it starts to ingest that warm/moist air it should go.

shouldn't take too long... Interestingly that cell would be on a similar trek as a lot of those intense UH tracks. Also no obvious VBV on the OUN VWP, so the wind profile should only get better as it progresses eastward.

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That cell west of KFDR , that Stebo was talking about, is now sitting right on the OFB. Once it starts to ingest it that UH track shown by many high res models might verify.

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That cell west of KFDR , that Stebo was talking about, is now sitting right on the OFB. Once it starts to ingest it that UH track shown by many high res models might verify.

that supercell has a pretty nice radar presentation as of now.

EDIT: 60/20 on the new TOR watch... Includes OKC.

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Wall cloud with the Altus storm per Charles Peek's stream.

 

Very strong rotation aloft with that cell on tilts 2 and 3 from KFDR. Also showing up from KTLX.

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If it deviates a hair to the east it will produce in a big way, it is so close right now to getting to and ahead of the OFB.

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Cell out in front could be impeding the progression of the supercell. It is stuck right where inflow should be entering the storm. However the supercell looks to overtake it and conditions for a tornado should improve shortly.

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If it deviates a hair to the east it will produce in a big way, it is so close right now to getting to and ahead of the OFB.

Should deviate some with supercell dynamic effects beginning to take over

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Yeah, chasing down in the Lawton area is pretty rough.  The one road that you speak of has a 45 mph speed limit because of the buffalo and antelope.  Then you have Ft. Sill in which there aren't any roads that cut through there.  I usually try to stay north of there whenever I can.

 

 

Charles Peek lost control of his car on one of those roads driving 25 mph

 

 

 

 

http://www.stormviewlive.com/charles-peek.html

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Wonder why there isn't any data posted yet from the OUN special sounding. They were either doing it at 1830 or 1900Z I believe.

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