Jul 4, 2008 1300 UTC Day 1 Convective Outlook
Updated: Fri Jul 4 12:57:12 UTC 2008
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20080704 1300 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20080704 1300 UTC Day 1 Tornado Probabilities Graphic
Tornado Legend Image
Probabilistic Damaging Wind Graphic
20080704 1300 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20080704 1300 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 041253
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0753 AM CDT FRI JUL 04 2008
   
   VALID 041300Z - 051200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER THE NRN RCKYS...
   
   ...SYNOPSIS...
   UPR RIDGE WILL REMAIN MORE OR LESS STNRY OVER THE FOUR CORNERS THIS
   PERIOD AS NWRN FLANK IS TEMPORARILY FLATTENED BY POSITIVE TILT
   TROUGH NOW OVER WRN WA/ORE AND NW CA.  THE TROUGH SHOULD CONTINUE NE
   INTO THE NRN GRT BASIN/NRN RCKYS BY 12Z SATURDAY.  DOWNSTREAM FROM
   THE RIDGE...ALTHOUGH MAIN BELT OF THE WLYS WILL REMAIN IN CANADA...
   A BAND OF MODEST CYCLONIC FLOW WILL PREVAIL FROM THE LWR MO VLY INTO
   THE MID/LWR OH VLY. 
   
   AT THE SFC...A FAIRLY WELL-DEFINED COLD FRONT WILL MOVE E ACROSS MT
   AND THE NRN GRT BASIN...AHEAD OF WA/ORE UPR TROUGH.  A WEAKER
   BOUNDARY NOW EXTENDING FROM THE DELMARVA PENINSULA WSW INTO THE
   OZARKS WILL SETTLE SLOWLY S INTO THE LWR OH/TN VLYS...BUT REMAIN
   NEARLY STNRY ALONG THE E CST.  
   
   ...NRN RCKYS...
   NRN PART OF AFOREMENTIONED TROUGH WILL EDGE E INTO NRN ID/NW MT
   LATER TODAY.  SECONDARY IMPULSE NOW ENTERING NW CA SHOULD REACH NW
   NV BY EVENING BEFORE CONTINUING NE INTO ERN ID/WRN MT TONIGHT/EARLY
   SATURDAY.  AHEAD OF THESE FEATURES...LOW/MID-LVL MOISTURE WILL
   INCREASE OVER THE NRN RCKYS AS A RESULT OF BOTH ADVECTION AND
   RECYCLING OF MOISTURE FROM PREVIOUS CONVECTION. 
   
   STRONG HEATING AND STEEP MID LEVEL LAPSE RATES COMBINED WITH
   THE INCREASING MOISTURE WILL YIELD SBCAPE AOA 1500 J/KG BY MID/LATE
   AFTN FROM CNTRL ID NE INTO NW MT.  TSTMS SHOULD FORM THIS AFTN FIRST
   OVER THE HIGHER TERRAIN OF NRN ID/WRN MT...AND THEN ALONG COLD FRONT
   PERHAPS AS FAR SW AS SW ID.  SUPERCELLS WITH HAIL...HIGH WINDS AND
   MARGINALLY SVR HAIL WILL BE POSSIBLE AHEAD OF THE FRONT...ESPECIALLY
   JUST E OF THE MOUNTAINS IN MT WHERE 40+ KT DEEP SW SHEAR WILL
   PREVAIL.  WITH TIME...GOOD COLD POOL POTENTIAL AND FORCING
   ASSOCIATED WITH SRN PART OF APPROACHING UPR TROUGH SHOULD SUPPORT
   EVOLUTION INTO A BAND OR TWO OF STORMS.  THE ACTIVITY SHOULD MOVE
   RAPIDLY NE TOWARD THE CANADIAN BORDER THIS EVENING WITH THE
   POTENTIAL FOR HIGH WIND/HAIL.
   
   ...AZ...
   AFTER A FAIRLY ACTIVE CONVECTIVE DAY OVER THE LWR DESERTS OF S CNTRL
   AND SE AZ YESTERDAY...ANOTHER ACTIVE DAY APPEARS TO BE ON THE WAY. 
   MODEST ELY FLOW...SLIGHTLY VEERED AND WEAKER COMPARED WITH
   YESTERDAY...SHOULD EXIST OVER THE SRN HALF OF THE STATE.  THROUGH A
   DEEP LAYER...SATELLITE AND GPS PW DATA SHOW AMPLE MOISTURE PRESENT
   FOR ROBUST STORMS.  IN ADDITION...LOW LEVEL MOISTURE HAS INCREASED
   FROM THE S OVER THE LOWER DESERTS.  OVERALL SETUP APPEARS FAVORABLE
   FOR A ROUND OR TWO OF FAIRLY WIDESPREAD STORMS.  THESE COULD YIELD
   ISOLD DMGG WIND GUSTS/SVR HAIL...IN ADDITION TO AN INCREASED RISK
   FOR HEAVY RAIN...AND COULD PERSIST INTO LATE TONIGHT. 
   
   ...MID-ATLC/SERN STATES WWD INTO AR/ERN OK...
   WEAK FRONT...PRE-FRONTAL OUTFLOW BOUNDARIES...AND/OR DIFFERENTIAL
   HEATING BOUNDARIES WILL SERVE AS FOCI FOR DIURNALLY-ENHANCED STORMS
   FROM THE MID MS/LWR OH VLY REGION TO THE MID ATLANTIC CST TODAY. 
   DEEP SHEAR WILL REMAIN MODEST /AOB 30 KTS/ BENEATH BELT OF MODEST
   CYCLONIC FLOW ALOFT.  SATELLITE AND VWP DATA ATTM DO NOT SHOW ANY
   IDENTIFIABLE IMPULSES TO ENHANCE UVV...ALTHOUGH SUCH FEATURES MIGHT
   BE MASKED BY CONVECTIVE DEBRIS.  THE STRONGEST STORMS SHOULD OCCUR
   IN AREAS RECEIVING GREATEST HEATING/ CONVERGENCE ON SRN EDGE OF
   STRONGER MID LEVEL FLOW....I.E. FROM MIDDLE/ERN TN INTO SRN KY...AND
   FROM CNTRL/ERN VA INTO SRN MD/DE AND PERHAPS NC.  WEAK LAPSE RATES
   AND MODEST WIND FIELDS SHOULD LIMIT OVERALL SVR RISK.  HOWEVER...ONE
   OR TWO CORRIDORS OF LOCALLY-ENHANCED SVR RISK /IN THE FORM OF DMGG
   WIND GUSTS/ MAY BECOME MORE CLEARLY DEFINED A BIT LATER TODAY.
   
   ..CORFIDI/JEWELL.. 07/04/2008
   
   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z