Jul 29, 2016 1730 UTC Day 2 Convective Outlook
Updated: Fri Jul 29 17:30:55 UTC 2016 (20160729 1730Z Day 2 shapefile | 20160729 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20160729 1730 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 110,807 10,531,198 Washington, DC...Richmond, VA...Arlington, VA...Alexandria, VA...Columbia, MD...
Probabilistic Graphic
20160729 1730 UTC Day Probabilitic Graphic
Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe within 25 miles of a point.
Day 2 Prob. Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 111,488 10,531,328 Washington, DC...Richmond, VA...Arlington, VA...Alexandria, VA...Columbia, MD...
   SPC AC 291730

   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1230 PM CDT FRI JUL 29 2016

   VALID 301200Z - 311200Z

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS A PORTION OF THE CENTRAL
   AND NORTHERN HIGH PLAINS...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF VA...CENTRAL
   AND WESTERN MD...EASTERN WV PANHANDLE AND FAR SOUTHERN PA...

   ...SUMMARY...
   ISOLATED STRONG STORMS ARE POSSIBLE ACROSS PARTS OF THE CENTRAL HIGH
   PLAINS AND MID-ATLANTIC REGION SATURDAY AFTERNOON AND EVENING.

   ...HIGH PLAINS...
   A BAND OF MID-LEVEL NORTHWESTERLY WINDS OF 25-30 KT IS EXPECTED TO
   EXTEND FROM THE NORTHERN ROCKIES/HIGH PLAINS THROUGH THE CENTRAL
   PLAINS...WHILE SOUTHERLY LOW-LEVEL WINDS GRADUALLY STRENGTHEN
   THROUGH THIS FORECAST PERIOD.  THE LATTER FLOW WILL SUPPORT POLEWARD
   MOISTURE RETURN ACROSS THE FULL EXTENT OF THE GREAT PLAINS.  DESPITE
   SOME BOUNDARY-LAYER MIXING ACROSS THE HIGH PLAINS...SURFACE DEW
   POINTS IN THE UPPER 50S TO LOWER 60S ARE EXPECTED IN THE MARGINAL
   SEVERE-WEATHER THREAT AREA SATURDAY AFTERNOON.  THIS COMBINED WITH
   DIABATIC HEATING BENEATH STEEP MIDLEVEL LAPSE RATES WILL RESULT IN
   MUCAPE OF 1000-2000 J/KG.  THIS DESTABILIZATION WITHIN AN
   ENVIRONMENT WITH VERTICALLY VEERING WINDS SUGGESTS ANY STORMS THAT
   DEVELOP AND MOVE OFF THE HIGHER TERRAIN SHOULD BE ORGANIZED.  A
   MARGINAL SEVERE RISK WILL BE MAINTAINED...SINCE THIS REGION WILL
   HAVE A LACK OF STRONGER FORCING ALOFT...RESULTING IN A LOW COVERAGE
   FOR SEVERE STORMS.  GREATER STORM COVERAGE MAY OCCUR LATER SATURDAY
   NIGHT AS TWO BRANCHES OF THE SOUTHERLY LOW-LEVEL JET FOCUS
   MOISTURE/WARM AIR ADVECTION ACROSS THE DAKOTAS AND KS.  MODERATE
   ELEVATED INSTABILITY COULD RESULT IN A COUPLE OF STRONGER TO SEVERE
   STORMS...THOUGH COVERAGE OF THAT POTENTIAL IS EXPECTED TO BE
   SUFFICIENT TO EXPAND THE MARGINAL RISK AT THIS TIME.

   ...MID-ATLANTIC REGION...
   A MIDLEVEL SHORTWAVE TROUGH IS EXPECTED TO MOVE FROM THE MID
   MS/LOWER OH VALLEYS TOWARD SOUTHERN ONTARIO/LOWER GREAT LAKES
   REGION...WITHIN A REGIME OF BROAD CYCLONIC MID- TO UPPER-LEVEL FLOW
   AND WEAK TO NEUTRAL HEIGHT RISES ACROSS THE NORTHEAST QUARTER OF THE
   UNITED STATES.  MODELS MAINTAIN A CORRIDOR OF STRONGEST CYCLONIC
   FLOW TO AROUND 30 KT EXTENDING FROM THE CENTRAL PLAINS THROUGH THE
   OH VALLEY TO THE MID-ATLANTIC STATES.  RESIDUAL RICH BOUNDARY-LAYER
   MOISTURE IS EXPECTED IN THIS MARGINAL RISK AREA...BOUNDED BY THE
   HIGHER TERRAIN AND LEE TROUGH TO THE WEST AND A BOUNDARY DRAPED FROM
   THE UPPER OH VALLEY THROUGH NORTHERN TO SOUTHEAST VA. DESPITE THE
   PRESENCE OF WEAK MIDLEVEL LAPSE RATES EAST OF THE PLAINS STATES...
   THE AVAILABLE MOISTURE AND SOME SURFACE HEATING WILL RESULT IN
   MODERATE INSTABILITY.  THIS COMBINED WITH ENHANCED DEEP-LAYER SHEAR
   PER MODERATELY STRONG WESTERLY FLOW REGIME ALOFT WILL PROVIDE A
   FAVORABLE CAPE/SHEAR PARAMETER SPACE FOR ORGANIZED STORMS.  THIS
   OUTLOOK HAS EXPANDED THE MARGINAL SEVERE-WEATHER RISK AREA EAST AS
   THE BREADTH OF DESTABILIZATION SHOULD EXTEND INTO CENTRAL MD AS
   WELL.  A SOUTHWARD EXTENSION IS TO ACCOUNT FOR DEVELOPMENT NEAR THE
   LEE TROUGH.  THE LACK OF STRONGER MIDLEVEL FORCING FOR ASCENT AND
   THE PRESENCE OF NEUTRAL TO WEAK HEIGHT RISES SUGGEST OVERALL
   COVERAGE OF SEVERE STORMS SHOULD BE LOW.  THUS...THIS OUTLOOK WILL
   MAINTAIN A LOW SEVERE PROBABILITY...WITH ISOLATED DAMAGING WINDS THE
   GREATEST THREAT.

   ...AZ TO SOUTHERN AND NORTHERN CA...
   STORMS WILL BE POSSIBLE ALONG THE FULL EXTENT OF THE SIERRAS AND
   ALSO THE MOUNTAINS OF SOUTHERN CA.  MEANWHILE...FARTHER EAST INTO
   AZ...MODELS CONTINUE TO SUGGEST WEAKER EASTERLY 500-MB WINDS THAN
   EXPECTED DURING DAY 1.  THUS...WILL NOT INTRODUCE SEVERE
   PROBABILITIES AT THIS TIME.

   ..PETERS.. 07/29/2016

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z