SPC AC 161629

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1129 AM CDT TUE JUN 16 2015

   VALID 161630Z - 171200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL AND NRN
   HIGH PLNS...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE OH VLY TO THE
   MID-ATLANTIC CST...

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF E TX AND WRN
   LA...

   ...THERE IS A MRGL RISK OF SVR TSTMS FROM THE NRN RCKYS TO THE NRN
   PLNS...

   ...THERE IS A MRGL RISK OF SVR TSTMS FROM PARTS OF THE SRN PLNS TO
   THE MID-ATLANTIC CST...

   ...SUMMARY...
   SCATTERED STORMS WITH LARGE HAIL...STRONG WINDS...AND A COUPLE
   TORNADOES ARE EXPECTED THIS AFTERNOON AND EVENING OVER PARTS OF THE
   CENTRAL AND NORTHERN HIGH PLAINS. AFTERNOON STORMS CAPABLE OF
   LOCALLY DAMAGING WIND ALSO WILL AFFECT PARTS OF THE OHIO VALLEY AND
   MID-ATLANTIC STATES. A FEW TORNADOES MAY OCCUR LATER TODAY THROUGH
   TONIGHT NEAR AND EAST OF TROPICAL STORM BILL AS IT TRACKS FARTHER
   INLAND FROM THE MIDDLE TEXAS GULF COAST.

   ...SYNOPTIC SETUP...
   MODERATE ZONAL FLOW WILL PREVAIL ACROSS THE NRN U.S...WITH ELONGATED
   RIDGES REMAINING QSTNRY OVER THE SOUTHEAST AND OFF THE SRN CA/NRN
   BAJA CST. ELSEWHERE...REMNANT SRN STREAM JET WILL PERSIST DOWNSTREAM
   FROM WEAK TROUGH OVER THE SRN/CNTRL PLNS. PER NHC...T.S. BILL IS
   EXPECTED TO CONTINUE GENERALLY NNW...AND LATER N ...ACROSS TX IN ERN
   PORTION OF THE TROUGH.

   A WEAK COLD FRONT ASSOCIATED WITH THE NRN STREAM JET WILL CONTINUE
   TO SETTLE SLOWLY SE ACROSS THE NRN MID-ATLANTIC STATES AND OH VLY.
   AT THE SAME TIME...ZONAL FLOW WILL MAINTAIN LEE TROUGH OVER THE
   CNTRL HIGH PLNS. WAA WILL PERSIST NEAR AND DOWNSTREAM FROM THE
   TROUGH IN RESPONSE TO SEVERAL IMPULSES CROSSING THE NRN RCKYS/GRT
   BASIN.

   ...NRN/CNTRL HIGH PLNS INTO NRN RCKYS/NRN PLNS THIS AFTN/EVE...
   MCS NOW OVER S CNTRL SD/N CNTRL NEB...ASSOCIATED WITH LEAD UPR
   IMPULSE OVER THE NRN HIGH PLNS...SHOULD FURTHER WEAKEN AS IT
   CONTINUES EWD. NEW STORMS SHOULD FORM THIS AFTN/EVE OVER
   NRN-CNTRL-ERN WY AND SW MT AS HEATING IN WAKE OF LEAD SYSTEM...AND
   MID-LVL COOLING/ASCENT WITH WEAKER IMPULSE NOW OVER CNTRL
   MT...FURTHER DESTABILIZE REGION. DEVELOPMENT SHOULD FOCUS OVER
   HIGHER TERRAIN AND ALONG WEAK FRONT EDGING S INTO WY IN WAKE OF LEAD
   IMPULSE. OTHER STORMS LIKELY WILL FORM IN AREA OF ENHANCED LOW-LVL
   CONVERGENCE ALONG LEE TROUGH/OUTFLOW BOUNDARY SEGMENTS IN WRN NEB
   AND SW SD.

   STEEP MID-LVL LAPSE RATES AND 40+ KT WLY 500 MB FLOW WILL SUPPORT
   SUSTAINED STORMS/SUPERCELLS WITH VERY LARGE HAIL AND LOCALLY DMGG
   WIND...ESPECIALLY FROM ERN WY INTO WRN NEB/SRN SD. TORNADOES ALSO
   WILL BE POSSIBLE IN THE LATTER AREA...WITH THE DEGREE OF THAT THREAT
   DEPENDENT UPON LOW-LVL WINDS REMAINING BACKED NEAR SFC
   BOUNDARIES...AND THE STORMS REMAINING SOMEWHAT DISCRETE. THE
   CONVECTION LIKELY WILL MERGE INTO AN ESE-MOVING MCS WITH A
   DIMINISHING RISK FOR HAIL/LOCALLY DMGG WIND OVER WRN/NRN NEB AND SRN
   SD LATER TNGT.

   ...OH VLY TO MID-ATLANTIC ST THIS AFTN/EVE...
   PASSING NRN STREAM DISTURBANCE NEAR LK ONT WILL MAINTAIN
   EXISTING...UNIDIRECTIONAL WNW FLOW FROM THE CNTRL APPALACHIANS TO
   THE MID-ATLANTIC CST TODAY...WITH 700-500 MB SPEEDS REMAINING AROUND
   40 KTS. SATELLITE INDICATES THAT STRONG HEATING WILL OCCUR IN
   WEAKLY-CAPPED...VERY MOIST /PW AOA 2 INCHES/ ENVIRONMENT OVER MUCH
   OF SRN OH/ERN KY/WRN WV/MD/DE/VA...SE OF WEAK COLD FRONT...AND OVER
   SRN NJ...SW OF BACK-DOOR BOUNDARY NEAR NYC. MID-LVL LAPSE RATES WILL
   BE WEAK AND COULD SOMEWHAT DELAY DEEP CONVECTIVE DEVELOPMENT. BUT
   ONCE STORMS FORM...SETUP COULD YIELD SHORT LINES/CLUSTERS OF
   MULTICELLS CAPABLE OF LOCALLY DMGG WIND/VERY HEAVY RAIN. THE
   ACTIVITY SHOULD INITIATE OVER THE HIGHER TERRAIN ALONG/AHEAD OF THE
   COLD FRONT...AND COULD LINGER THROUGH LATE EVE.

   ...SE/E TX AND WRN LA TODAY THROUGH TNGT...
   SATELLITE SUGGESTS THAT SUBSTANTIAL HEATING WILL OCCUR TODAY ALONG
   NRN AND ERN FRINGES OF T.S. BILL AS THE SYSTEM CONTINUES GENERALLY
   NNW THROUGH THE PERIOD. THIS SHOULD FOSTER INTENSIFICATION/INCREASED
   COVERAGE OF SCTD SHOWERS/TSTMS WITHIN ASSOCIATED LOW-LVL CONFLUENCE
   BANDS LATER TODAY.

   MODERATE FORWARD MOTION OF BILL...AND EXISTING...SEASONABLY STRONG
   PRESSURE GRADIENT BETWEEN THE T.S. AND THE RIDGE TO ITS EAST...WILL
   RESULT IN A FAIRLY BROAD...INLAND-ADVANCING
   ZONE OF MODERATE TO STRONG LOW-LVL DIRECTIONAL SHEAR ACROSS E TX/WRN
   LA. COUPLED WITH VERY HIGH PW /AROUND 2.25 INCHES/ AND 700 MB WINDS
   INCREASING TO AOA 40 KTS...SETUP COULD PROMOTE THE DEVELOPMENT OF
   LOW-LVL MESOCYCLONES AND TORNADOES. THIS POTENTIAL MAY BE GREATEST
   AWAY FROM THE CENTER OF CIRCULATION TODAY. BUT THE RISK FOR
   TORNADOES MAY INCREASE CLOSER TO THE CENTER TNGT THROUGH EARLY WED
   NWD ACROSS E CNTRL/NE TX GIVEN VERY MOIST/WARM ENVIRONMENT AND THE
   POTENTIAL FOR NOCTURNAL INTENSIFICATION OF REMNANT CIRCULATION.

   ..CORFIDI/PICCA.. 06/16/2015

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