Forecast Discussion
SPC AC 061959
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0259 PM CDT FRI APR 06 2012
VALID 062000Z - 071200Z
...NO SVR TSTM AREAS FORECAST...
...SOUTH FL...
TSTMS/ANY ASSOCIATED SEVERE THREAT IS EXPECTED TO QUICKLY WANE/SHIFT
OFFSHORE INTO THIS EVENING OWING TO INCREASING SUBSIDENCE AND
EVENTUAL FRONTAL PASSAGE.
...NORTHERN HIGH PLAINS...
NO CHANGES. SEE 1630Z-BASED DISCUSSION BELOW AND EARLIER MESOSCALE
DISCUSSION 470.
...TX PANHANDLE/WEST TX...
VARIOUS NUMERICAL GUIDANCE CONTINUE TO IMPLY A POTENTIAL FOR
ISOLATED STRONG/SEVERE TSTM DEVELOPMENT LATE THIS AFTERNOON/EARLY
EVENING IN VICINITY OF THE DRYLINE. THIS INCLUDES 12Z DETERMINISTIC
ECMWF/GFS AND CONVECTION ALLOWING RUNS SUCH AS THE 00Z
WRF-NSSL/RECENT HRRR. PROVIDED THIS OCCURS...SOME SUPERCELLS CAPABLE
OF SEVERE HAIL/LOCALLY DAMAGING WINDS WOULD BE POSSIBLE IN THE
PRESENCE OF 35-40 KT EFFECTIVE BULK SHEAR.
...KS/NORTHERN OK LATE TONIGHT...
NO CHANGES TO FORECAST REASONING...ALTHOUGH SPATIAL ADJUSTMENTS
WERE MADE ACROSS KS REGARDING INCIPIENT DEVELOPMENT/LOW SEVERE
POTENTIAL BASED ON LATEST GUIDANCE.
..GUYER.. 04/06/2012
.PREV DISCUSSION... /ISSUED 1107 AM CDT FRI APR 06 2012/
A HIGH-AMPLITUDE UPPER RIDGE IS IN PLACE OVER THE CENTRAL UNITED
STATES...WHILE UPPER TROUGHS AFFECT THE EASTERN AND WESTERN STATES.
THE AREAS MOST LIKELY TO SEE ORGANIZED STRONG TO SEVERE
THUNDERSTORMS TODAY ARE OVER SOUTH FL...AND ACROSS PORTIONS OF THE
PLAINS STATES.
...SOUTH FL...
SCATTERED THUNDERSTORMS CONTINUE TO AFFECT PARTS OF SOUTH FL...ALONG
AND SOUTH OF WEAK SURFACE BOUNDARY LYING JUST SOUTH OF LAKE
OKEECHOBEE. A WEAK UPPER TROUGH IS APPROACHING FROM THE
WEST...WHICH MAY RESULT IN SUFFICIENT LARGE SCALE LIFT TO PROMOTE
FURTHER INTENSIFICATION OF STORMS WITH ISOLATED SEVERE WEATHER
POSSIBLE. LARGE HAIL AND GUSTY WINDS WILL BE THE PRIMARY
THREATS...SINCE LOW LEVEL VERTICAL SHEAR IS QUITE LIMITED. ENHANCED
LOW LEVEL CONVERGENCE AND SHEAR NEAR THE EAST-COAST SEA-BREEZE MAY
HELP FOCUS THE SEVERE THREAT.
...NORTHERN HIGH PLAINS...
A RATHER STRONG UPPER SHORTWAVE TROUGH OVER PARTS OF WY/UT WILL
TRACK NORTHEASTWARD AND AFFECT THE WESTERN DAKOTAS AND EASTERN MT/WY
LATER TODAY. LOW LEVEL MOISTURE IS VERY LIMITED IN THIS REGION WITH
DEWPOINTS EXPECTED TO BE ONLY IN THE 40S. HOWEVER...STEEP LOW/MID
LEVEL LAPSE RATES WILL HELP TO YIELD AFTERNOON MLCAPE VALUES AROUND
500 J/KG. THUNDERSTORMS ARE EXPECTED TO INTENSIFY ALONG THE LOW
LEVEL THERMAL AXIS NEAR THE WESTERN DAKOTA BORDER AND SPREAD
EASTWARD THROUGH THE EVENING. HIGH-BASED STORMS CAPABLE OF GUSTY
WINDS AND HAIL ARE POSSIBLE. THE LACK OF GREATER LOW LEVEL MOISTURE
PRECLUDES HIGHER SEVERE WEATHER PROBABILITIES.
...WEST TX THIS EVENING...
MORNING LOW CLOUDS ARE ERODING ACROSS WEST TX THIS MORNING...WHICH
SHOULD ALLOW FULL SUNSHINE THIS AFTERNOON. THE DRYLINE IS FORECAST
TO BECOME ESTABLISHED ACROSS THE REGION...WITH A RELATIVELY WEAK CAP
AND MODERATE INSTABILITY TO ITS EAST. WHILE LARGER SCALE FORCING
MECHANISMS ARE HARD TO IDENTIFY...IT SEEMS LIKELY THAT AT LEAST AN
ISOLATED STORM OR TWO WILL FORM AND PERSIST ALONG THE DRYLINE LATER
THIS EVENING. SUFFICIENT EFFECTIVE SHEAR WILL PROMOTE SUPERCELL
STRUCTURES CAPABLE OF HAIL AND LOCALLY DAMAGING WINDS.
...KS/NRN OK LATE TONIGHT...
MODEL SOLUTIONS CONTINUE TO SUGGEST THAT A CLUSTER OF THUNDERSTORMS
WILL DEVELOP LATE TONIGHT OVER CENTRAL KS AND SPREAD SOUTHEASTWARD
INTO NORTHERN OK BEFORE 12Z. IF THIS SCENARIO OCCURS...PARAMETERS
WOULD FAVOR A RISK OF HAIL IN THE STRONGER STORMS. THEREFORE...WILL
INCLUDE THIS REGION IN LOW SEVERE HAIL PROBABILITIES.
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
CURRENT UTC TIME: 2106Z (4:06PM), RELOAD THIS PAGE TO UPDATE THE TIME
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| CATEGORICAL OUTLOOK |
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| SEVERE POTENTIAL OUTLOOK |
SPC AC 061716
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1216 PM CDT FRI APR 06 2012
VALID 071200Z - 081200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SOUTHERN OK AND
WEST/NORTHWEST TX...
...SYNOPSIS...
AN UPPER TROUGH CURRENTLY OVER THE NORTHERN INTERMOUNTAIN REGION
WILL CONTINUE TO SPREAD EAST-NORTHEASTWARD TOWARD THE CANADIAN
PRAIRIES AND NORTHERN PLAINS/UPPER MIDWEST THROUGH SATURDAY NIGHT.
AN ASSOCIATED COLD FRONT WILL SPREAD EASTWARD ON SATURDAY ACROSS THE
UPPER MS RIVER VALLEY/UPPER GREAT LAKES REGION...WHERE TSTM
POTENTIAL SHOULD REMAIN VERY LIMITED DUE TO WEAK BUOYANCY/MARGINAL
PROSPECTS FOR CHARGE SEPARATION...WHILE THE FRONT ADVANCES
SOUTH-SOUTHEASTWARD ACROSS THE SOUTH-CENTRAL PLAINS/OZARKS.
...OK AND WEST/NORTHWEST TX...
SOME EARLY PERIOD HAIL MAY BE POSSIBLE FOR AREAS SUCH AS
NORTHERN/EASTERN OK AND PERHAPS EVEN THE ADJACENT ARKLATEX.
HOWEVER...ANY SUCH SEVERE HAIL THREAT IS LIKELY TO REMAIN VERY
MARGINAL/ISOLATED GIVEN THE WEAK OVERALL BUOYANCY AND UNDERCUTTING
NATURE OF THE FRONT.
INTO THE AFTERNOON...DEEP/SEVERE CAPABLE CONVECTION WILL BE MORE
PROBABLE AS THE FRONT DECELERATES AND OTHERWISE MAKES A SLOW
SOUTH-SOUTHEASTWARD PROGRESSION ACROSS SOUTHERN OK AND MUCH OF
WEST/NORTHWEST TX. WHILE LARGE SCALE FORCING FOR ASCENT WILL REMAIN
RELATIVELY NEBULOUS NEAR THE CREST OF THE UPPER RIDGE
ALOFT...SUFFICIENT NEAR-FRONTAL CONVERGENCE/AMPLE HEATING WITHIN THE
ADJACENT WARM SECTOR...ALONG WITH LOW-LEVEL UPSLOPE INFLUENCES
ACROSS SOUTHWEST TX/FAR SOUTHEAST NM...WILL BE CONDUCIVE FOR SUCH
TSTM DEVELOPMENT BY MID/LATE AFTERNOON. WITH THE POTENTIAL FOR
MLCAPE TO 1000-2000 J/KG BY AFTERNOON...THE INITIATING INFLUENCE OF
THE FRONT...ALONG WITH THE STRONGEST SHEAR LAGGING THE
FRONT...IMPLIES THAT A MULTICELLULAR CONVECTIVE MODE WILL BE
DOMINANT ASIDE FROM THE POSSIBILITY FOR A FEW BRIEF SUPERCELLS.
BOUTS OF SEVERE HAIL WILL LIKELY BE THE PRIMARY HAZARD...WITH
DAMAGING WIND GUSTS ALSO POSSIBLE GIVEN A WELL-MIXED BOUNDARY LAYER.
MUCH OF THE SEVERE POTENTIAL IS LIKELY TO WANE BY MID/LATE EVENING
AS THE BOUNDARY LAYER COOLS.
..GUYER.. 04/06/2012
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z
CURRENT UTC TIME: 2107Z (4:07PM), RELOAD THIS PAGE TO UPDATE THE TIME
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