May: Isolated Showers To End The Month

[Andrew]

Watch out SW of the Dallas Fort Worth Area around Comanche. A nice rotating storm

[srainhoutx]

Update from Jeff:


Ongoing tornado outbreak which has already produced incredible damage over OK continues to unfold from N TX to KS.

Supercells capable of long tracked violent tornadoes continue to develop along the dryline from NC TX to SE KS. Current supercells near Comanche, TX continues to exhibit very strong rotation. These storms continue to develop in a very unstable air mass with CAPE of 3500-4000 J/kg and 40-50kts of low level wind shear. Supercells thus far have remained discrete and tornadic although it appears storms should begin to grow upscale into lines/clusters over the next few hours. Until that time violent tornadoes will be possible in any supercell along the dryline. Think current supercells SW of Fort Worth should weaken with time, but great interest over these cells over the next few hours as they near major urban centers.

This is a very dangerous tornado situation. Maximum tornado precautions must be taken to survive these tornadoes. If a tornado warning is issued for your area act immediately.

[Paul Robison]

Morning e-mail from Jeff:

Plume of smoke has returned into the area this morning from agricultural fires burning on the western coast of the Yucatan Peninsula.

Late evening visible images yesterday should a widespread and at times dense area of smoke over much of the Bay of Campeche and western Gulf of Mexico and with southerly winds advecting this plume northward it has arrived into TX overnight. Will continue to see periodic intrusions of dense smoke (visibilities 3-6 miles) as long as southerly winds remain in place which looks like most of this week.

Ridging has built over the area this weekend allowing hot afternoon high temperatures and continued moist onshore flow keeping dewpoints in the sticky 70’s making it feel like summer. Luckily south winds of 15-25mph have helped mix the afternoon air making it feel a touch cooler. Little chance in the overall pattern is expected today and Tuesday although a strong short wave trough will swing through the base of the large trough over the western US late Tuesday. West and central TX dry line will surge eastward in the afternoon hours on Tuesday with the air mass becoming very unstable across central TX. Significant capping is shown on the morning soundings with the placement of the upper level ridge nearby and it is going to be hard to erode this cap on Tuesday. However think storms will break the cap and rapidly go severe with CAPE values of 2500-3500 J/kg over central TX by late afternoon. Main threat will be extreme hail although 40-50kts of WSW shear could support a tornado. Initial isolated supercells will gradually grow upscale into a line of storms with the threats shifting to wind damage overnight. Current thinking is that these storms may approach or even move across the northern 1/3rd of SE TX Tuesday night into Wednesday morning, but the southern extent of this activity will be strongly tied to the intensity of the capping over the region. Currently looking hard pressed to break the cap south of HWY 105.

A low level boundary looks to sink southward from these storms on Wednesday and this may offer a window for storms to develop in the afternoon hours if the cap can be overcome.

Otherwise continued hot and humid with breezy onshore flow and periods of smoke/haze.

I live south of I-10, in the southwest suburbs, so what are my chances of me seeing a destructive thunderstorm?

[srainhoutx]

Update from Jeff:
Incredible tornado impact across Moore, OK.

 

37 fatal, 61 injured. Given the gravity of the widespread devastation these numbers are going to be horribly high.  

 

An estimated 4000-8000 structures has been damaged or destroyed over a 60 square mile area.

 


 

 

[Paul Robison]

[unome]

Southern Region Graphicasts at a glance http://innovation.srh.noaa.gov/ROC/gcastgis/

(edit to remove hotlinks)

stay safe everyone

[srainhoutx]

Morning e-mail from Jeff:

Severe/Tornado Outbreak possible this afternoon/evening over TX

Potential for long tracked violent tornadoes across N TX this afternoon and evening

SPC moderate risk for severe weather including tornadoes in effect for today for N TX

Multi-day severe/tornado outbreak continues to unfold this morning across the US plains which has already produced devastating results. Parent upper level storm system responsible for the daily outbreaks continues to spin over the northern plains with a slow moving cold front across OK at the current time. Air mass south of this front and east of the dry line is incredibly moist and unstable with frequent dewpoints in the 70’s and CAPES values of 1500-2500 J/kg. With surface heating, the air mass over N and C TX will become extremely unstable by midday with CAPE values approaching 4000-5000 J/kg ahead of the eastward moving dry line and south of the southward moving frontal boundary. Short wave moving out of New Mexico will help erode the capping overhead by early afternoon and expect explosive supercell development along both the dry line and cold front. Storms will go quickly severe with hail to greater than 2 inches likely. Initial mode will be very dangerous supercells capable of strong rotation and tornadoes given the degree of instability and shear in place. Current thinking is that the greatest tornado threat will be along I-20 including the Dallas/Fort Worth metro areas with a secondary threat along/west of I-35 all the way to west of Austin along the dry line. Best ingredients for potentially devastating tornadoes will be over N TX into AR and NW LA although the moderate risk outline does clip our northern set of counties.

Severe weather event will unfold NW of SE TX this afternoon and affect at least the north counties of our area this evening/overnight. Initial supercells will congeal into clusters and lines with the tornado threat weakening after dark and the threat for wind damage increasing as lines bow outward. Capping across our region looks to remain fairly potent, but very strong heating combined with lift from an approaching short wave will likely be enough to break the cap and allow central TX storms to move across the northern 1/3rd of our region or roughly from Columbus to Conroe to Livingston. Storms may attempt to build southward toward I-10 in the overnight hours, but it remains to be seen as to how strong the capping is over the southern portions of the area.

Think the main severe threat for SE TX will be wind damage and potentially very large hail. Tornado indices are fairly favorable from College Station to the Huntsville area this afternoon, but this is prior to the cap being breached. By early evening when the capping weakens likely allowing storms to develop, the tornado threat appears to be reduced. Should the cap weaken quicker than expected, the tornado threat across our northern counties will be increased

Low level boundary will remain in place on Wednesday and expect a continued threat for strong to severe storms across the central and southern counties with large hail and damaging winds being the main threat.

Residents across TX need to review their severe weather and tornado safety plans.

SPC Severe Weather Outlook:

05212013 Jeff image001.gif

[/i]

[srainhoutx]

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
454 AM CDT TUE MAY 21 2013

TXZ171>173-183>194-202>209-217>225-228-211700-
LLANO-BURNET-WILLIAMSON-VAL VERDE-EDWARDS-REAL-KERR-BANDERA-
GILLESPIE-KENDALL-BLANCO-HAYS-TRAVIS-BASTROP-LEE-KINNEY-UVALDE-
MEDINA-BEXAR-COMAL-GUADALUPE-CALDWELL-FAYETTE-MAVERICK-ZAVALA-
FRIO-ATASCOSA-WILSON-KARNES-GONZALES-DE WITT-LAVACA-DIMMIT-
INCLUDING THE CITIES OF...LLANO...BURNET...GEORGETOWN...DEL RIO...
ROCKSPRINGS...LEAKEY...KERRVILLE...BANDERA...FREDERICKSBURG...
BOERNE...BLANCO...SAN MARCOS...AUSTIN...BASTROP...GIDDINGS...
BRACKETTVILLE...UVALDE...HONDO...SAN ANTONIO...NEW BRAUNFELS...
SEGUIN...LOCKHART...LA GRANGE...EAGLE PASS...CRYSTAL CITY...
PEARSALL...PLEASANTON...FLORESVILLE...KARNES CITY...GONZALES...
CUERO...HALLETTSVILLE...CARRIZO SPRINGS
454 AM CDT TUE MAY 21 2013

...EXTREMELY UNSTABLE AIRMASS POISED TO ERUPT IN SEVERE THUNDERSTORMS
WITH LARGE HAIL AND DAMAGING WINDS BY LATE AFTERNOON THROUGH THIS
EVENING...

RICH LOW LEVEL GULF MOISTURE COUPLED WITH STEEP LAPSE RATES ALOFT
HAVE RESULTED IN AN EXTREMELY UNSTABLE AIR-MASS ACROSS SOUTH
CENTRAL TEXAS EARLY THIS MORNING. AN UPPER LEVEL TROUGH PUSHING
EAST OVER CENTRAL TEXAS WILL SLIDE A COLD FRONT INTO WESTERN
PORTIONS OF SOUTH CENTRAL TEXAS THIS AFTERNOON. SCATTERED
THUNDERSTORMS WILL DEVELOP RAPIDLY BY LATE AFTERNOON...QUICKLY
BECOMING SEVERE AS THE FRONT ENCOUNTERS THIS UNSTABLE AIR MASS.
THE MAIN THREATS WILL BE FROM LARGE HAIL AND DAMAGING THUNDERSTORM
WINDS...HOWEVER WITH THE EXTREME INSTABILITY PRESENT...ISOLATED
TORNADOES CANNOT BE RULED OUT. MUCH OF THE EASTERN HALF OF SOUTH
CENTRAL TEXAS WILL BE AFFECTED FROM LATE AFTERNOON UNTIL THE EARLY
MORNING HOURS WEDNESDAY. IN ADDITION...RAINFALL AMOUNTS MAY
AVERAGE 1 TO 3 INCHES WITHIN THE HEAVIEST STORMS PRODUCING SOME
LOCALIZED FLOODING.

HEIGHTENED CONCERN EXISTS ACROSS THE NORTHEAST CORRIDOR THIS
EVENING...INCLUDING THE CITIES OF BURNET...GEORGETOWN...AUSTIN AND
GIDDINGS. EROSION OF THE CAPPING INVERSION COUPLED WITH EXTREME
INSTABILITY ALONG THE FRONT AND AN INCREASING LOW LEVEL JET...MAY
LEAD TO VERY LARGE HAIL AND ISOLATED TORNADOES.

THE SYSTEM SHOULD EXIT THE REGION OVERNIGHT TONIGHT...EARLY
WEDNESDAY MORNING...WITH RAINS AND SEVERE WEATHER ENDING FROM THE
WEST.

LISTEN TO NOAA WEATHER RADIO OR YOUR LOCAL MEDIA FOR LATER UPDATES
ON THIS SEVERE WEATHER EVENT. ALSO...GO TO WEATHER.GOV/AUSTIN FOR
THE LATEST INFORMATION...FORECASTS AND WARNINGS.

[srainhoutx]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
355 AM CDT TUE MAY 21 2013

.DISCUSSION...
WARM AND HUMID EARLY MORNING ACROSS THE REGION THE CONTINUED
SOUTHERLY FLOW. UPPER TROUGH OVER THE GREAT PLAINS AND EXTENDING
DOWN TOWARD EL PASO THIS MORNING. VERY STRONG CAP IN PLACE THIS
MORNING WITH A FEW BITS OF LIGHT RAIN AND DRIZZLE SHOWING UP ON
RADAR AND OUT THE WINDOW...MAINLY OVER THE SOUTHERN AREAS. THE
UPPER TROUGH WILL SLOWLY SHIFT EAST WITH S/W OVER AZ/NM THIS
MORNING TRACKING EAST THROUGH THE AFTERNOON THEN ENE. THIS FEATURE
SHOULD COMBINE WITH THE STRONG MID/UPPER LEVEL FLOW TO
DRAMATICALLY INCREASE LIFT AFTER 3 PM AND AROUND THE CLL-DKR AREAS
PEAKING AFTER 7 PM. MODEL SOUNDINGS ARE FAVORABLE FOR STRONG TO
SEVERE THUNDERSTORMS. FRONTAL BOUNDARY PUSHES EAST WITH RAIN
COOLED AIR AND EXPECTING SHOWERS AND THUNDERSTORMS TO EXPAND
RAPIDLY IN COVERAGE BUILDING SOUTH INTO AUSTIN AREA THEN MOVING
EASTWARD. VERY UNSTABLE 3000-4000 J/KG ATMOSPHERE TO WEST OF THE
SETX WILL BE THE INITIATION ZONE BUT SHOULD BE REACHING THE CLL
AREA AROUND 6 PM WITH INSTABILITY DECREASING. EXPECT SEVERE THREAT
OF MAINLY HAIL AND DAMAGING WINDS BETWEEN AROUND 5 PM THROUGH
MIDNIGHT FOR THE NORTHERN AREAS WITH THE ARRIVAL OF S/W AND THE
ASSOCIATED COLD FRONT. TORNADO THREAT LOOKS LOW BUT CAN`T RULE OUT
SHORT LIVED SPIN UPS BUT WILL PROBABLY BE CONFINED TO AREAS NORTH
OF BRENHAM TO GROVETON LINE (GREATEST EHI 2.0+ FROM MADISONVILLE
TO CROCKETT BUT OUT AHEAD OF CAP ERODING). DO HAVE SOME CONCERNS
WITH THE STRONG COOLING ALOFT THAT THE SEVERE THREAT COULD NEED
EXTENDING BEYOND 06Z AND EXPANDING TO THE COASTAL AREAS. TEXAS
TECH WRF AND SOME OF THE HIGH RES ARW/NMM MODELS INDICATING
POSSIBLY SQUALL LINE/BOW DEVELOPING AND MOVING THROUGH HOUSTON AND
TO GALVESTON BETWEEN MIDNIGHT AND 2 AM. DIMINISHING INSTABILITY
AND RETURN OF CAP SHOULD LIMIT THAT OUTCOME. SO AS FOR THE
FORECAST HAVE RAISED RAIN CHANCES FOR AREAS GENERALLY NORTH OF
I-10 THIS AFTERNOON AND OVERNIGHT. BOUNDARY PUSHES TO NEAR THE
COAST AND SLOWS AND WILL RAISE THE RAIN CHANCES FOR WEDNESDAY IN
THE SOUTH WITH THE CAP ERODING IN THE AFTERNOON AND CAPE OF
1800-2500 RETURNING AND SLOW/ERRATIC STORM MOTIONS...MAY HAVE SOME
BRIEF HEAVY DOWNPOURS GIVEN THE LIGHT STEERING WINDS AND COUNTER
TO SEA BREEZE FLOW ALOFT.

UPPER RIDGE EXPANDS UP OUT OF MEXICO THURSDAY THROUGH SUNDAY WITH
THE 500 RIDGE CENTERED OVER SETX SATURDAY AN SUNDAY. THIS SHOULD
LEAD TO WARMER TEMPERATURES RETURNING AND HAVE GONE ABOVE GUIDANCE
FOR THE AFTERNOON FRI-SUN TIMEFRAME TEMPERATURES. RAIN CHANCES
FALL OFF AND MOIST SOUTHEAST FLOW RESUMES. ALSO OF INTEREST LOOKS
TO BE A TROPICAL WAVE MOVING OUT OF THE CARIBBEAN AND POSSIBLY
IMPACTING SETX AND WESTERN GULF MONDAY AND TUESDAY NEXT WEEK.

ON A TECHNICAL NOTE...SURFACE OBSERVATION AND LIGHTNING DATA
OUTAGE 04-07Z APPEARS TO BE CORRECTED.

[srainhoutx]

MESOSCALE DISCUSSION 0747
NWS STORM PREDICTION CENTER NORMAN OK
0812 AM CDT TUE MAY 21 2013

AREAS AFFECTED...PARTS OF SRN OK AND NRN TX

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 211312Z - 211445Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...POTENTIAL EXISTS FOR ONGOING STORMS EXTENDING FROM EAST
CENTRAL THROUGH SOUTH CENTRAL OK TO WRN NORTH TX TO BECOME SURFACE
BASED LATER THIS MORNING. ISOLATED DAMAGING WINDS AND HAIL WILL BE
THE PRIMARY THREATS WITH THE ONGOING ACTIVITY...WITH AN INCREASE IN
THE SEVERE WEATHER THREAT LATER THIS MORNING...AND THE POTENTIAL FOR
A NEW WW.

DISCUSSION...MOSAIC RADAR IMAGERY THE LAST FEW HOURS INDICATED TSTMS
CONTINUED TO DEVELOP AND MOVE ENEWD ACROSS CENTRAL...ERN OK INTO
WEST CENTRAL AR...WHILE ADDITIONAL STORMS HAVE DEVELOPED SWWD
THROUGH SWRN OK TO WRN N TX. THE ENTIRE EXTENT OF THE TSTM ACTIVITY
APPEARS TO BE ELEVATED INCLUDING THE LATTER SWRN OK/WRN N TX STORMS
THAT HAVE TENDED TO BECOME UNDERCUT BY A SWD ADVANCING COLD FRONT.

INCREASING FORCING FOR ASCENT WITH AN APPROACHING SHORTWAVE TROUGH
AND LOW LEVEL WAA OVER N TX AND SRN OK WILL SUPPORT CONTINUED TSTM
DEVELOPMENT THROUGH THIS MORNING. VISIBLE SATELLITE IMAGERY SHOWS
THE LIKELIHOOD FOR ABUNDANT SURFACE HEATING ALONG AND SOUTH OF THE
RED RIVER...WHICH WILL FURTHER BOOST AN ALREADY MODERATELY UNSTABLE
ENVIRONMENT...WITH THE POTENTIAL FOR STORMS TO BECOME SURFACE BASED.
FURTHER STRENGTHENING OF WSWLY MIDLEVEL WINDS/BULK SHEAR WITH THE
APPROACH OF THE SRN HIGH PLAINS TROUGH WILL SUPPORT STORM
ORGANIZATION. SWLY SHEAR VECTORS ORIENTED PARALLEL TO THE ONGOING
STORMS AND NEW DEVELOPMENT WILL FAVOR LINE SEGMENTS/BOWS WITH
DAMAGING WINDS THE PRIMARY THREAT. HOWEVER...THE PRESENCE OF STEEP
MIDLEVEL LAPSE RATES /NEAR 9 C PER KM ON THE 12Z FORT WORTH TX
SOUNDING/ SUGGESTS HAIL WILL BE A THREAT AS WELL. THE LAST SEVERAL
HRRR RUNS FORECAST UPSCALE GROWTH FOR ONE OR MORE QLCS STRUCTURES
ACROSS SRN OK AND N TX LATER THIS MORNING INTO THE AFTERNOON.

..PETERS/KERR.. 05/21/2013


ATTN...WFO...LZK...SHV...TSA...FWD...OUN...

[srainhoutx]

Carefully watching the Hill Country area this morning. Developing CU field and a rather potent upper level jet streak dropping SE over New Mexico may well enhance severe storm development a bit further S this afternoon.

05212013 1325Z TX VIS latest.jpg

[srainhoutx]

HGX has requested a special sounding from CLL if they have any students left since the semester is over. We will see.

[unome]

HGX weather briefing (may be updated this afternoon)

http://www.srh.noaa.gov/hgx/?n=briefing

[srainhoutx]

Andrew informs me that a special 12Z launch was done from CLL.

[unome]

NWS Ft Worth weather briefing

http://youtu.be/R4SdjFy50f0

[srainhoutx]

The 12Z HRRR suggests some storms may try to pop ahead of the linear squall line from Temple up to Waco this afternoon. That meso model is also rather impressive that a strong squall line will march SE later today into the overnight hours.

[srainhoutx]

MESOSCALE DISCUSSION 0749
NWS STORM PREDICTION CENTER NORMAN OK
1009 AM CDT TUE MAY 21 2013

AREAS AFFECTED...MUCH OF NRN TX

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 211509Z - 211645Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...STORMS WILL INCREASE IN COVERAGE AND INTENSITY OVER THE
NEXT 1-2 HRS...AND PARTICULARLY DAMAGING WINDS ARE EXPECTED TO
AFFECT MUCH OF NRN TX. IN ADDITION...A FEW TORNADOES AND VERY LARGE
HAIL WILL ALL BE POSSIBLE. A WATCH WILL BE ISSUED SHORTLY.

DISCUSSION...AN OUTFLOW BOUNDARY CURRENTLY EXTENDS FROM WRN AR WWD
ALONG THE RED RIVER TO JUST W OF ABILENE TX...JOINING WITH A
DEVELOPING COLD FRONT WHICH WILL CONTINUE SWD ACROSS W TX. TO THE
E...AN EXTREMELY MOIST AND UNSTABLE ATMOSPHERE WAS IN PLACE...WITH
MIDLEVEL LAPSE RATES OF 8.0-9.0 C/KM.

STORMS WILL RAPIDLY DEVELOP ALONG THE ADVANCING COLD FRONT WHICH
ALSO INTERSECTS THE OUTFLOW BOUNDARY IN THE NEXT FEW HOURS...AND ARE
EXPECTED TO QUICKLY GROW UPSCALE INTO A DAMAGING MCS. WIND GUSTS
OVER HURRICANE FORCE...WIND DRIVEN HAIL...AND A FEW TORNADOES WILL
BE POSSIBLE AS THE SYSTEM MATURES AND FORWARD PROPAGATES ACROSS A
LARGE PART OF NRN TX AND INTO THE ARKLATEX THIS EVENING.

ALTHOUGH MAINLY A LINEAR STORM MODE IS EVENTUALLY EXPECTED...INITIAL
DEVELOPMENT MAY BE SUPERCELLS WITH AN ENHANCED TORNADO THREAT. WHEN
STORMS DO MERGE...THERE WILL LIKELY BE AREAS OF ROTATION EMBEDDED
WITHIN THE ADVANCING LINE...PERHAPS PRODUCING SWATHS OF PARTICULARLY
DAMAGING WINDS.

..JEWELL/KERR.. 05/21/2013


ATTN...WFO...SHV...TSA...HGX...FWD...OUN...SJT...

[tireman4]

Everyone from DFW to Austin to East Texas to Houston needs to be weather aware. As was seen on Sunday and Monday in Oklahoma, things ramped up quickly. Just stay tuned to all outlets for the latest in what is happening. Stay safe.

[srainhoutx]

Tornado Watch coming for portions of Central/N/NE Texas until 7:00 PM CDT

Code: Select all

BULLETIN - IMMEDIATE BROADCAST REQUESTED
     TORNADO WATCH OUTLINE UPDATE FOR WT 201
     NWS STORM PREDICTION CENTER NORMAN OK
     1025 AM CDT TUE MAY 21 2013
     
     TORNADO WATCH 201 IS IN EFFECT UNTIL 700 PM CDT FOR THE
      FOLLOWING LOCATIONS
     
     OKC013-023-085-095-220000-
     /O.NEW.KWNS.TO.A.0201.130521T1525Z-130522T0000Z/
     
     OK 
     .    OKLAHOMA COUNTIES INCLUDED ARE
     
     BRYAN                CHOCTAW             LOVE                
     MARSHALL             
     
     
     TXC001-009-023-027-035-049-059-077-083-085-093-095-097-099-113-
     119-121-133-139-143-145-147-161-181-193-207-213-217-221-223-231-
     237-251-253-257-267-277-281-289-293-307-309-319-327-331-333-337-
     349-363-367-379-395-397-399-411-417-425-429-439-441-447-467-497-
     503-220000-
     /O.NEW.KWNS.TO.A.0201.130521T1525Z-130522T0000Z/
     
     TX 
     .    TEXAS COUNTIES INCLUDED ARE
     
     ANDERSON             ARCHER              BAYLOR              
     BELL                 BOSQUE              BROWN               
     CALLAHAN             CLAY                COLEMAN             
     COLLIN               COMANCHE            CONCHO              
     COOKE                CORYELL             DALLAS              
     DELTA                DENTON              EASTLAND            
     ELLIS                ERATH               FALLS               
     FANNIN               FREESTONE           GRAYSON             
     HAMILTON             HASKELL             HENDERSON           
     HILL                 HOOD                HOPKINS             
     HUNT                 JACK                JOHNSON             
     JONES                KAUFMAN             KIMBLE              
     LAMAR                LAMPASAS            LEON                
     LIMESTONE            MASON               MCCULLOCH           
     MCLENNAN             MENARD              MILAM               
     MILLS                MONTAGUE            NAVARRO             
     PALO PINTO           PARKER              RAINS               
     ROBERTSON            ROCKWALL            RUNNELS             
     SAN SABA             SHACKELFORD         SOMERVELL           
     STEPHENS             TARRANT             TAYLOR              
     THROCKMORTON         VAN ZANDT           WISE                
     YOUNG                
     
     
     ATTN...WFO...OUN...FWD...SJT...TSA...
     
     
     

[unome]

Watches, Warnings or Advisories for Texas http://alerts.weather.gov/cap/tx.php?x=1

This page shows alerts currently in effect for Texas and is normally updated every two-three minutes. Please see here for other state and listing by county. http://alerts.weather.gov/