DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 022002
SWODY1
SPC AC 022000

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0300 PM CDT TUE APR 02 2013

VALID 022000Z - 031200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM SWRN THROUGH CNTRL AND
SERN TX...

...SWRN THROUGH CNTRL AND SERN TX...

WARM SECTOR HAS BECOME MODERATELY UNSTABLE SOUTH OF A COLD FRONT
THAT EXTENDS FROM NERN TX SWWD THROUGH SWRN TX NEAR FORT STOCKTON
WHERE IT INTERSECTS A DRYLINE. STORMS ARE DEVELOPING ALONG THE SWD
ADVANCING FRONT ACROSS CNTRL AND SWRN TX AS WELL AS OVER THE
MOUNTAINS OF SWRN TX. VERTICAL SHEAR FROM 30-35 KT CHARACTERIZES
MOST OF THE WARM SECTOR WITH ELY NEAR SFC WINDS VEERING TO WLY WITH
HEIGHT. WV IMAGERY INDICATES WHAT APPEARS TO BE AN UPPER IMPULSE
MOVING INTO SWRN TX AHEAD OF THE MAIN UPPER LOW...AND SOME INCREASE
IN DEEP LAYER VERTICAL SHEAR MAY OCCUR DURING THE EVENING AS THIS
FEATURE CONTINUES EWD. THE ENVIRONMENT SHOULD BECOME INCREASINGLY
FAVORABLE FOR ORGANIZED STORMS INCLUDING POTENTIAL FOR ROTATING
UPDRAFTS AND LATER POSSIBLE BOWING SEGMENTS AS STORMS CONGEAL WHILE
DEVELOPING EWD. PRIMARY THREATS APPEAR TO BE LARGE HAIL AND DAMAGING
WIND WITH VERY LARGE HAIL POSSIBLE OVER PORTIONS OF SWRN INTO CNTRL
TX WHERE STEEPER LAPSE RATES AND STRONGER INSTABILITY EXIST. THOUGH
HODOGRAPHS ARE NOT PARTICULARLY LARGE...A COUPLE TORNADOES CANNOT BE
RULED OUT FROM SWRN TX INTO SCNTRL TX GIVEN SUFFICIENT
INSTABILITY...A MOIST BOUNDARY LAYER AND VEERING LOW LEVEL WINDS
WITH HEIGHT.

OTHER ELEVATED STORMS MAY DEVELOP LATER TONIGHT OVER WRN TX NORTH OF
THE FRONT AND POSE SOME RISK FOR HAIL.

..DIAL.. 04/02/2013

.PREV DISCUSSION... /ISSUED 1147 AM CDT TUE APR 02 2013/

...SYNOPSIS...
THE LARGE SCALE PATTERN LIKELY WILL CONTINUE TO SHOW MINIMAL CHANGE
THIS PERIOD AS SLOWLY-PROGRESSIVE SPLIT FLOW PATTERN PERSISTS OVER
THE WRN AND CNTRL STATES...IN WAKE OF DEEP VORTEX OVER NEW
ENGLAND/SRN QUE. LOW-LVL WARM ADVECTION/UPR LVL DIVERGENCE WILL
CONTINUE OVER MUCH TX AND THE WRN GULF CST REGION...DOWNSTREAM FROM
FOUR CORNERS UPR LOW. AT THE SAME TIME...DIVERGENCE/ASCENT WILL
INCREASE OVER S TX LATER TODAY...AND OVER THE NWRN GULF THROUGH
TNGT...AS SRN STREAM IMPULSE NOW OVER NW MEXICO/NRN SONORA TRACKS E
TO THE BIG BEND REGION BY EVE...AND INTO LA EARLY WED.

AT THE SFC...SHALLOW POLAR FRONT EXPECTED TO CONTINUE ADVANCING S
ACROSS W TX TODAY. THE S TO SE ADVANCE OF THE BOUNDARY SHOULD BE
MORE GRADUAL WITH EWD EXTENT ACROSS THE LWR PLNS AND HILL COUNTRY.
BY EVE THE FRONT SHOULD ARC NEWD FROM N OF THE BIG BEND REGION INTO
A WEAK WAVE NEAR DFW. A SERIES OF WEAKER BOUNDARIES NOW EXTENDING
ROUGHLY WNW/ESE ACROSS E TX INTO THE WRN GULF SHOULD FURTHER WEAKEN
AS LOW-LVL ESE FLOW PERSISTS ACROSS REGION.

COMBINATION OF MOIST...LOW-LVL UPSLOPE FLOW...SFC HEATING...
APPROACHING SRN STREAM DISTURBANCE...AND UPLIFT ALONG POLAR FRONT
TOGETHER SHOULD SUPPORT FAIRLY WIDESPREAD TSTM DEVELOPMENT ACROSS
PARTS OF CNTRL AND SRN TX LATER TODAY THROUGH EARLY WED. SOME OF
THESE STORMS COULD BECOME SVR.

...CNTRL/SRN TX LATER TODAY THROUGH EARLY WED...
MOIST UPSLOPE FLOW HAS CONTRIBUTED TO EXTENSIVE LOW-LVL CLOUD COVER
AHEAD OF COLD FRONT OVER MUCH OF SRN AND CNTRL TX.
NEVERTHELESS...MODERATE SFC HEATING WILL OCCUR IN PRE-FRONTAL AIR.
COUPLED WITH RELATIVELY COOL MID-LVL TEMPS AND FAVORABLY-TIMED
ASCENT ASSOCIATED WITH SONORAN UPR IMPULSE...EXPECT TSTMS TO FORM
OVER S CNTRL TX BY MID TO LATE AFTN...LIKELY PREFERENTIALLY ALONG
WRN FRINGE OF LOW CLOUD DECK/NEAR LEE TROUGH NOW EXTENDING NWD FROM
THE BIG BEND.

WHILE NOT PARTICULARLY STRONG /AROUND 35 KTS/...DEEP WLY SHEAR
SHOULD BE AMPLE FOR SUSTAINED STORMS/SUPERCELLS GIVEN RICHLY-MOIST
ENVIRONMENT /PW AOA 1.25 INCHES AND 850 MB DEWPOINTS ABOVE 12 C/ AND
ELY COMPONENT TO NEAR-SFC FLOW. OTHER STORMS MAY FORM ALONG AND
BEHIND SHALLOW POLAR FRONT OVER CNTRL AND N CNTRL TX. WHILE EXPECTED
FAIRLY EXTENSIVE STORM COVERAGE MAY RESULT IN SOME DEGREE OF
DESTRUCTIVE INTERFERENCE...AT LEAST SOME STORMS WILL HAVE THE
POTENTIAL TO PRODUCE LARGE HAIL AND LOCALLY DMGG WIND BEFORE
CONSOLIDATING INTO LARGER-SCALE CLUSTERS. THE STORM CLUSTERS SHOULD
MOVE/DEVELOP GENERALLY ESE TNGT THROUGH EARLY WED...THEREBY EXPOSING
MUCH OF THE TX GULF CSTL PLN /ESPECIALLY MIDDLE PORTIONS/ TO A RISK
FOR LOCALLY DMG WIND AND SVR HAIL. A RISK ALSO WILL EXIST FOR A
TORNADO OR TWO...CONDITIONAL ON FAVORABLE STORM-SCALE INTERACTIONS.


...NW TX/OK THROUGH EARLY WED...
FARTHER N...EPISODES OF ELEVATED TSTMS EXPECTED TO CONTINUE THROUGH
THE PERIOD N OF THE POLAR FRONT ACROSS NW TX AND MUCH OF OK.
DEEPENING OF POST-FRONTAL COLD AIR MASS AND DEVELOPMENT OF STRONGER
SFC-BASED STORMS FARTHER S SUGGEST THAT ELEVATED CAPE WILL REMAIN
TOO LIMITED TO POSE AN APPRECIABLE RISK FOR SVR HAIL.

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