Jul 4, 2008 1630 UTC Day 1 Convective Outlook
Updated: Fri Jul 4 16:24:12 UTC 2008
Probabilistic to Categorical Outlook Conversion Table (Effective Feb 14, 2006).
Categorical Graphic
20080704 1630 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20080704 1630 UTC Day 1 Tornado Probabilities Graphic
Tornado Legend Image
Probabilistic Damaging Wind Graphic
20080704 1630 UTC Day 1 Damaging Wind Probabilities Graphic
Wind Legend Image
Probabilistic Large Hail Graphic
20080704 1630 UTC Day 1 Large Hail Probabilities Graphic
Hail Legend Image
   SPC AC 041620
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1120 AM CDT FRI JUL 04 2008
   
   VALID 041630Z - 051200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS NRN ROCKIES INTO A LARGE PART
   OF MT...
   
   ...NRN RCKYS...
   PROGRESSIVE SHORTWAVE TROUGH NOW PUSHING INLAND ACROSS THE PAC NW
   WILL CONTINUE EWD INTO THE NRN ROCKIES WITH SOMEWHAT OF A POSITIVE
   TILT TODAY.  AHEAD OF THIS...MORE SUBTLE WAVE EJECTING NNEWD ACROSS
   NRN NV ATTM WILL LIFT INTO SWRN/CENTRAL MT.  IN RESPONSE TO
   APPROACHING SYSTEMS...ELONGATED SURFACE LOW/TROUGH WILL DEVELOP JUST
   EAST OF THE CONTINENTAL DIVIDE DURING THE AFTERNOON...WHICH WILL
   BECOME MORE DEFINED LATE TODAY AS N-S ORIENTED COLD FRONT SHIFTS EWD
   INTO THE NRN HIGH PLAINS.  SLIGHT INCREASE IN ESELY LOW LEVEL FLOW
   EAST OF THE SURFACE TROUGH SHOULD ALLOW RICHER MOISTURE IN PLACE
   OVER ERN MT THIS MORNING TO ADVECT WNWWD THROUGH THE DAY.
   
   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 LARGE HAIL AND DAMAGING
   WINDS 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...STRENGTHENING COLD POOL POTENTIAL AND FORCING ASSOCIATED WITH
   SRN PART OF APPROACHING UPPER TROUGH SHOULD SUPPORT EVOLUTION INTO A
   LINEAR 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. 
   12Z SOUNDINGS INDICATE ELY FLOW HAS STRENGTHENED OVER THE PAST 24
   HOURS AT BOTH PHX AND TUS...WITH GREATER MOISTURE ALSO IN PLACE
   THROUGHOUT DEEP BOUNDARY LAYER.  MID/UPPER LEVEL RIDGE IS FORECAST
   TO SHIFT A BIT EWD THROUGH THE DAY AS TROUGH AMPLIFIES OVER THE PAC
   NW...WHICH MAY WEAKEN WINDS A BIT AND SUSTAIN A MORE ELY COMPONENT
   TO STEERING FLOW AS COMPARED TO THE PAST FEW DAYS.
   EXPECT HEATING WILL GENERATE INCREASING MOIST CONVECTION OVER HIGHER
   TERRAIN LATE TODAY...YIELDING THREATS OF ISOLATED DAMAGING WINDS AND
   HAIL AS ACTIVITY DEVELOPS WWD THROUGH THE LATE EVENING.
   
   ...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 MID LEVEL
   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/ CAN BE EXPECTED ACROSS THIS BROAD REGION.
   
   ..EVANS/SMITH/CORFIDI.. 07/04/2008
   
   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z