DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 261954
SWODY1
SPC AC 261952

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT SAT OCT 26 2013

VALID 262000Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON THROUGH EARLY
TONIGHT ACROSS NW TX...

NO ADDITIONAL CHANGES WERE MADE TO THE OUTLOOK EXCEPT FOR MINOR
ADJUSTMENTS TO LOW SEVERE PROBABILITY DELINEATIONS AND THE REMOVAL
OF THE 10 PERCENT OR GREATER PROBABILITY OF TSTMS FROM THE ERN TX
PANHANDLE AREA.

..SMITH/JEWELL.. 10/26/2013

.PREV DISCUSSION... /ISSUED 1115 AM CDT SAT OCT 26 2013/

...SYNOPSIS...
THE AMPLIFIED PATTERN OF A WRN RIDGE AND ERN TROUGH IS BEGINNING TO
TRANSITION AS A STRONG SHORTWAVE TROUGH BEGINS TO DIG SSEWD FROM THE
NE GULF OF AK TOWARD BC...RESULTING IN HEIGHT FALLS ACROSS THE PAC
NW AND NRN ROCKIES. DOWNSTREAM...THE FLOW REGIME WILL BECOME MORE
ZONAL AS A STRONG EMBEDDED SHORTWAVE TROUGH PROGRESSES QUICKLY EWD
FROM THE GREAT LAKES TO NEW ENGLAND. ISOLATED LIGHTNING STRIKES
WILL BE POSSIBLE EARLY TONIGHT WITH SHALLOW CONVECTIVE BANDS OVER
LAKE ONTARIO...AS FLOW VEERS TO WLY WITH FRONTAL PASSAGE AND THE
MIDLEVEL THERMAL TROUGH MOVES OVER THE LOWER LAKES. FARTHER S...A
SEPARATE SRN STREAM WILL REMAIN INTACT THROUGH TONIGHT FROM THE SRN
ROCKIES TO THE LOWER MS VALLEY. THE PRIMARY THUNDERSTORM RISK
AREA...WITH A FEW POTENTIALLY SEVERE STORMS...WILL ACCOMPANY A SRN
STREAM WAVE MOVING OVER NW TX TODAY AND TONIGHT.

...NW TX AREA THIS AFTERNOON INTO EARLY TONIGHT...
A MIDLEVEL SHORTWAVE TROUGH OVER THE TX PANHANDLE WILL MOVE ESEWD
THROUGH TONIGHT...ALONG WITH A REMNANT LEE CYCLONE AND WEAK COLD
FRONTAL SURGE. IN ADVANCE OF THIS SYSTEM...A NARROW CORRIDOR OF
MOISTURE RETURN /LOW-MID 60S BOUNDARY LAYER DEWPOINTS/ IS UNDERWAY
FROM THE RIO GRANDE VALLEY INTO NW TX. SURFACE HEATING WITHIN CLOUD
BREAKS AND CONTINUED LOW-LEVEL MOISTENING WILL CONTRIBUTE TO THE
DEVELOPMENT OF MODERATE BUOYANCY THIS AFTERNOON ACROSS NW TX /MLCAPE
OF 1000-1500 J PER KG/.

SURFACE-BASED THUNDERSTORM DEVELOPMENT IS EXPECTED NEAR OR AFTER 21Z
ACROSS NW TX NEAR THE N/NE EDGE OF THE STRONGER INSTABILITY ...ALONG
THE WEAK SURFACE FRONT AND NEAR THE AXIS OF THE MIDLEVEL
TROUGH...WITH STORMS SUBSEQUENTLY SPREADING SEWD INTO CENTRAL TX
OVERNIGHT. THE MODERATE BUOYANCY AND EFFECTIVE BULK SHEAR IN EXCESS
OF 40 KT WILL FAVOR SUPERCELLS WITH THE INITIAL STORM
DEVELOPMENT...AND THESE STORMS WILL BE CAPABLE OF PRODUCING LARGE
HAIL GIVEN RELATIVELY COOL MIDLEVEL TEMPERATURES /ROUGHLY -15 C AT
500 MB/. A FEW DAMAGING GUSTS WILL ALSO BE POSSIBLE...ESPECIALLY
LATE THIS EVENING AND EARLY TONIGHT AS CONVECTION LIKELY GROWS
UPSCALE INTO A SMALL MCS OR TWO.

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