DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 261958
SWODY1
SPC AC 261956

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0256 PM CDT TUE JUN 26 2012

VALID 262000Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NRN HIGH PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SOUTH TX...

...THERE IS A SLGT RISK OF SVR TSTMS OVER THE FL PENINSULA...

EARLIER THOUGHTS REGARDING NRN HIGH PLAINS CONVECTION LARGELY
REMAIN. ONGOING NW-SE BROKEN LINE OF TSTMS IS PROGRESSING NEWD AT
ROUGHLY 40KT. THIS ACTIVITY WILL STRUGGLE TO DEVELOP SWD BUT RATHER
BE SHUNTED INTO SK WHERE LARGE SCALE ASCENT IS EXPECTED TO FOCUS.
DOWNSTREAM...THERE IS INCREASING CONCERN THAT INTENSE HEAT ACROSS
THE PLAINS OF SERN MT WILL YIELD HIGH-BASED CONVECTION OVER THE NEXT
SEVERAL HOURS. LATEST VIS IMAGERY DEPICTS AN EXPANDING CU FIELD
EAST OF BIL TOWARD THE NRN BLACK HILLS REGION WHERE A DEVELOPING
SHOWER IS NOTED OVER BUTTE COUNTY SD. WITH SFC TEMPERATURES NOW IN
EXCESS OF 100F FROM MLS TO RAP IT WOULD SEEM THAT DEEP CONVECTION
MAY SOON DEVELOP/MATURE. AN AXIS OF MOISTURE HOLDS JUST DOWNSTREAM
ACROSS NERN MT/WRN DAKOTAS AND FOR THIS REASON WILL INCREASE SEVERE
PROBS ACROSS THE NRN HIGH PLAINS AND A SLIGHT RISK WILL BE ADDED TO
ACCOUNT FOR THIS EVOLUTION.

FARTHER SOUTH ACROSS TX...CU FIELD IS EXPANDING IN AREAL COVERAGE
AND DEPTH AS SFC TEMPERATURES SOAR ABOVE 100F. OVER THE LAST HOUR
OR SO TOWERING CU HAS DEVELOPED NORTH OF HOU. IN ALL LIKELIHOOD A
FEW THUNDERSTORMS WILL EVOLVE ACROSS THIS REGION WITH WSWWD
MOVEMENT/PROPAGATION EXPECTED TOWARD SCNTRL TX. ISOLATED DAMAGING
DOWNBURSTS ARE THE GREATEST CONCERN.

..DARROW.. 06/26/2012

.PREV DISCUSSION... /ISSUED 1125 AM CDT TUE JUN 26 2012/

...NRN MT...
WATER VAPOR IMAGERY SHOWS AN UPPER SHORT WAVE TROUGH ROTATING NEWD
ACROSS THE NRN INTERMOUNTAIN REGION...AND MODEL GUIDANCE INDICATES
THE SYSTEM WILL CONTINUE NEWD INTO SRN ALBERTA BY TONIGHT. LARGE
SCALE ASCENT IS SPREADING NEWD ACROSS THE REGION AND WILL AFFECT
PARTS OF NRN MT INTO THE AFTERNOON AND POSSIBLY EVENING HOURS.
EARLIER STRONG/SEVERE STORMS HAVE MOVED NWD ACROSS THE BORDER...BUT
THE ENVIRONMENT OVER PARTS OF NRN MT REMAINS UNSTABLE AS INDICATED
BY THE 12Z TFX RAOB WHERE STEEP MID LEVEL LAPSE RATES ARE LOCATED
ABOVE A RATHER MOIST LOW LEVEL AIR MASS. POTENTIAL EXISTS FOR
REDEVELOPMENT OF A FEW STRONG/SEVERE STORMS THIS AFTERNOON AS THE
PRIMARY ZONE OF ASCENT SPREADS NEWD...WITH STRONGER CELLS CAPABLE OF
PRODUCING PRIMARILY LARGE HAIL AND STRONG WIND GUSTS. THE THREAT
SHOULD DIMINISH BY THIS EVENING.

...FL PENINSULA...
TS DEBBY IS FORECAST TO BEGIN MOVING ENEWD TOWARD THE NRN FL
PENINSULA ACCORDING TO THE LATEST NHC FORECASTS. LOW LEVEL WINDS
BASED ON 12Z RAOBS AND LOCAL VAD PROFILES MAINTAIN A MODERATELY
STRONG SSWLY FLOW WITH LARGEST CYCLONICALLY CURVING LOW LEVEL
HODOGRAPHS OVER EAST CENTRAL FL. RADAR HAS SHOWN SOME WEAK
ROTATIONAL COUPLETS WITH A FEW CONVECTIVE ELEMENTS NORTH OF LAKE
OKEECHOBEE AND NEAR THE TPA BAY AREA...BUT NO ACTIVE CG LIGHTNING
HAS BEEN DETECTED BY NLDN IN THE LAST SEVERAL HOURS. SATELLITE
IMAGERY SHOWS A NUMBER OF SW/NE ORIENTED CONVECTIVE BANDS MOVING
FROM THE ERN GULF ACROSS THE PENINSULA. OCCASIONAL BREAKS/THINNING
OF CLOUDS BETWEEN THE BANDS MAY PROMOTE ADDITIONAL
HEATING/DESTABILIZATION THIS AFTERNOON WITH CONTINUED LOW RISK FOR
ISOLATED TORNADOES/STRONG WIND GUSTS TO OCCUR.

...SERN/SOUTH CENTRAL TX...
STRONG HEATING IS OCCURRING OVER THIS REGION WITH SURFACE
TEMPERATURES ALREADY IN THE 95-100 RANGE OVER A NUMBER OF LOCATIONS.
THE STRONG HEATING IS ESTABLISHING A RELATIVELY DEEP MIXED
LAYER...AND AS THE CAP GRADUALLY WEAKENS...MODEL GUIDANCE CONSENSUS
INDICATES DEEP CONVECTION WILL DEVELOP OVER THE REGION THIS
AFTERNOON. MODERATELY STRONG NELY MID LEVEL WINDS /30-40 KT AT
500MB/ WILL RESULT IN SUFFICIENT SHEAR FOR ORGANIZED MULTICELL
CLUSTERS THAT WILL MOVE SWWD AND BE CAPABLE OF PRODUCING DAMAGING
WIND GUSTS AND POSSIBLE HAIL. THE SEVERE THREAT SHOULD DIMINISH
THIS EVENING.

...NRN/CENTRAL HIGH PLAINS FROM ERN MT/WRN DAKOTAS INTO NERN CO...
SOUNDINGS THIS AFTERNOON ARE EXPECTED TO AGAIN REFLECT A STEEP LAPSE
RATE ENVIRONMENT WITH A DEEP MIXED LAYER...RESULTING IN STRONGLY
UNSTABLE CONDITIONS WITH MLCAPE OF 2000-3000 J/KG. LARGE SCALE
FORCING FOR ASCENT IS EXPECTED TO BE LIMITED...AND CONVECTIVE STORM
COVERAGE IS EXPECTED TO BE LOW BASED ON A VARIETY OF MODEL GUIDANCE.
HOWEVER...THERE WILL BE A RELATIVELY HIGH CONDITIONAL PROBABILITY
OF SEVERE STORMS GIVEN THE OCCURRENCE OF SUSTAINED UPDRAFTS...AND
AREA WILL BE MONITORED CLOSELY FOR SIGNS OF CONVECTIVE INITIATION
LATER THIS AFTERNOON AND EVENING.

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