Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
SPC AC 101956
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0256 PM CDT TUE JUN 10 2014
VALID 102000Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM A PORTION OF THE OH AND TN
VALLEYS INTO THE SERN U.S....
...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE NRN HIGH
PLAINS...
...SUMMARY...
SCATTERED SEVERE THUNDERSTORMS CAPABLE OF STRONG WINDS AND PERHAPS A
COUPLE OF TORNADOES ARE LIKELY FROM SOUTHERN PARTS OF THE OHIO
VALLEY TO CENTRAL GULF COAST. ELSEWHERE...ISOLATED SEVERE STORMS
CAPABLE OF SEVERE HAIL AND DAMAGING WINDS ARE POSSIBLE OVER PARTS OF
NORTHERN HIGH PLAINS.
...OH VALLEY THROUGH CNTRL GULF COAST STATES...
ONGOING FORECAST APPEARS TO BE ON TRACK WITH SQUALL LINE POSING A
THREAT FOR ISOLATED DAMAGING WIND GUSTS AS IT CONTINUES THROUGH ERN
KY...ERN TN...ERN AL...WRN AND NRN GA AND EVENTUALLY INTO THE WRN
CAROLINAS. HAVE SHIFTED THE 5% TORNADO PROBABILITIES INTO ERN KY
WHERE A FEW DISCRETE CELLS ARE DEVELOPING AHEAD OF THE LINE AND
WHERE DEEP SHEAR AROUND 40 KT IS SUPPORTIVE OF UPDRAFT ROTATION AND
MAYBE A TORNADO OR TWO...THOUGH LOW-LEVEL HODOGRAPHS ARE NOT
PARTICULARLY LARGE WHICH SHOULD SERVE AS A LIMITING FACTOR. ACTIVITY
SHOULD BEGIN A GENERAL DECREASE THIS EVENING WITH ONSET OF NOCTURNAL
COOLING.
...NRN HIGH PLAINS...
NO CHANGES TO FORECAST IN THIS REGION. STORMS INITIATION OVER THE
HIGHER TERRAIN WILL CONTINUE EWD WITHIN DEVELOPING POST-FRONTAL
UPSLOPE FLOW REGIME WHERE 40-45 KT EFFECTIVE SHEAR AND 500-1000
MLCAPE WILL SUPPORT A THREAT FOR SUPERCELLS. ACTIVITY MAY EVENTUALLY
CONGEAL INTO A COUPLE OF CLUSTERS. DAMAGING WIND AND LARGE HAIL WILL
BE THE MAIN THREATS THROUGH MID EVENING.
..DIAL.. 06/10/2014
.PREV DISCUSSION... /ISSUED 1121 AM CDT TUE JUN 10 2014/
...SYNOPSIS...
A SPLIT-FLOW PATTERN WILL PERSIST THROUGH THE DAY ONE PERIOD WITH
THE PRIMARY FEATURE OF INTEREST BEING A MID TO UPPER-LEVEL LOW WHICH
WILL EDGE EWD THROUGH THE MIDDLE AND LOWER MS VALLEYS. ELSEWHERE...A
POLAR-BRANCH SHORT-WAVE TROUGH AND ASSOCIATED 50 KT JET STREAK AT
500 MB WILL PROGRESS EWD INTO THE NRN HIGH PLAINS.
AT THE SURFACE...AN AREA OF LOW PRESSURE OVER CNTRL MO AS OF MID
MORNING WILL DEVELOP NEWD TO THE VICINITY OF CHICAGO BY 11/12Z. AN
ASSOCIATED WARM FRONT WILL SHIFT NWD THROUGH THE OH VALLEY WHILE A
TRAILING COLD FRONT ADVANCES EWD INTO THE LOWER MS VALLEY. FARTHER
TO THE N...A COLD FRONT FROM N-CNTRL ND TO NRN WY WILL STALL IN
RESPONSE TO THE DEVELOPMENT OF A CYCLONE OVER ERN WY LATER TODAY.
THIS LOW PRESSURE WILL SUBSEQUENTLY DEVELOP EWD INTO CNTRL SD
OVERNIGHT.
...OH/TN VALLEYS INTO CNTRL GULF STATES AND SRN APPALACHIANS THIS
AFTERNOON/EVENING...
A LEADING-LINE TRAILING-STRATIFORM MCS IS IN PROGRESS FROM PORTIONS
OF MIDDLE TN TO SRN LA ALONG THE WARM-CONVEYOR AIR STREAM ATTENDANT
TO THE OZARKS CYCLONE. 12Z REGIONAL SOUNDINGS SAMPLED A VERY MOIST
INFLOW AIR MASS WITH LOWEST 100-MB MEAN-MIXING RATIOS OF 16-17
G/KG...WHICH WHEN COUPLED WITH THE DIURNAL HEATING OF THE BOUNDARY
LAYER...WILL YIELD AFTERNOON MLCAPE OF 1500-3000 J/KG.
LATEST CONVECTION-ALLOWING MODEL GUIDANCE REMAINS IN GOOD AGREEMENT
IN SUGGESTING THAT THIS MCS WILL INTENSIFY BY AFTERNOON OWING TO THE
INTERACTION OF THE ESTABLISHED COLD POOL WITH THE DESTABILIZING AIR
MASS AND 30-40 KT OF SSWLY DEEP-LAYER SHEAR. THESE DATA INDICATE THE
EVOLUTION OF A LARGE-SCALE BOWING CONFIGURATION SURGING NEWD/EWD
THROUGH MIDDLE/ERN TN...CNTRL/ERN KY...NRN/CNTRL AL INTO NRN GA AND
PERHAPS INTO THE WRN CAROLINAS THIS AFTERNOON INTO EVENING. SIMILAR
TO MONDAY...DAMAGING WINDS WILL BE THE PRIMARY HAZARD...THOUGH SOME
HAIL AND PERHAPS A TORNADO OR TWO ARE POSSIBLE.
FOR ADDITIONAL NEAR-TERM GUIDANCE...SEE SEVERE THUNDERSTORM WATCHES
273...274 AND MESOSCALE DISCUSSIONS 935...936.
...NRN HIGH PLAINS THIS AFTERNOON/EVENING...
LOW-LEVEL FLOW WILL ASSUME AN INCREASING ELY COMPONENT TODAY ALONG
THE STALLING FRONT IN RESPONSE TO THE DEVELOPING LEE CYCLONE OVER
ERN WY. THIS WILL PROMOTE THE WWD FLUX OF A MORE MOIST BOUNDARY
LAYER INTO THE HIGH TERRAIN WHILE AT THE SAME TIME ENHANCING
DEEP-LAYER SHEAR. ISOLATED TO WIDELY SCATTERED TSTMS ARE EXPECTED TO
DEVELOP BY MID/LATE AFTERNOON WITHIN THE ELY UPSLOPE REGIME AND
IMMEDIATE COOL SIDE OF THE FRONT ALONG THE MT-WY BORDER AS
DEEP-LAYER ASCENT IS AUGMENTED BY THE POLAR-BRANCH SHORT-WAVE
TROUGH.
THE COMBINATION OF STEEP LAPSE RATES AND INCREASING LOW-LEVEL
MOISTURE WITH EWD EXTENT SHOULD YIELD SUFFICIENT BUOYANCY AMIDST
50-60 KT OF DEEP-LAYER SHEAR TO SUPPORT SUPERCELLS AND BOWING
STRUCTURES CAPABLE OF LARGE HAIL AND DAMAGING WINDS. A BRIEF TORNADO
IS ALSO POSSIBLE. STORMS MAY CONGEAL INTO AN MCS LATER THIS EVENING
WITH A DAMAGING WIND AND HAIL THREAT SPREADING EWD INTO WRN SD.
...FL THIS AFTERNOON...
12Z SOUNDING DATA INDICATE THE PRESENCE OF A VERY MOIST AND ALREADY
MODERATELY UNSTABLE AIR MASS IN PLACE. TSTMS HAVE DEVELOPED THIS
MORNING FROM THE BAHAMAS WWD INTO THE FAR SRN PENINSULA IN
ASSOCIATION WITH A VORTICITY MAXIMUM THAT WILL PROGRESS NNWWD ALONG
OR JUST OFFSHORE OF THE ERN PENINSULAR COAST. FORCING FOR ASCENT
ASSOCIATED WITH THIS FEATURE WILL AUGMENT LOW-LEVEL CONVERGENCE
ALONG THE DEVELOPING SEA-BREEZE FRONTS TO FOSTER NUMEROUS STORMS BY
AFTERNOON THAT WILL HAVE A TENDENCY TO AMALGAMATE INTO WWD-MOVING
CLUSTERS. LOCALLY DAMAGING WIND GUSTS WILL BE THE PRIMARY HAZARD
WITH THESE STORMS.
...OZARKS/MID MS VALLEY THIS AFTERNOON...
SIMILAR TO THE SETUP OVER S-CNTRL KS ON MONDAY...DAYTIME HEATING AND
BOUNDARY-LAYER DEWPOINTS IN THE 60S WILL ALIGN WITH COOL MIDLEVEL
TEMPERATURES TO YIELD WEAK TO MODERATE INSTABILITY FROM THE VICINITY
OF THE SURFACE LOW EWD/NEWD ALONG THE OCCLUDED FRONT. VERTICAL SHEAR
WILL REMAIN WEAK OWING TO THE CLOSE PROXIMITY TO THE DEEP-LAYER
CYCLONE. HOWEVER...GIVEN A VORTICITY-RICH ENVIRONMENT AND THE
PRESENCE OF RELATIVELY COOL MIDLEVEL TEMPERATURE PROFILES...A BRIEF
TORNADO OR TWO AND/OR MARGINALLY SEVERE HAIL WILL BE POSSIBLE.
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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