Apr 6, 2017 1630 UTC Day 1 Convective Outlook
Updated: Thu Apr 6 16:12:42 UTC 2017 (20170406 1630Z Day 1 shapefile | 20170406 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170406 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 22,231 4,721,222 Baltimore, MD...Virginia Beach, VA...Norfolk, VA...Chesapeake, VA...Newport News, VA...
MARGINAL 53,841 33,657,996 Philadelphia, PA...Washington, DC...Richmond, VA...Arlington, VA...Providence, RI...
Probabilistic Tornado Graphic
20170406 1630 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 20,893 5,768,391 Baltimore, MD...Virginia Beach, VA...Norfolk, VA...Chesapeake, VA...Newport News, VA...
2 % 29,408 10,469,575 Washington, DC...Richmond, VA...Arlington, VA...Alexandria, VA...Suffolk, VA...
Probabilistic Damaging Wind Graphic
20170406 1630 UTC Day 1 Damaging Wind Probabilities Graphic
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.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 22,484 5,259,065 Baltimore, MD...Virginia Beach, VA...Norfolk, VA...Chesapeake, VA...Newport News, VA...
5 % 41,042 18,409,087 Philadelphia, PA...Washington, DC...Richmond, VA...Arlington, VA...Alexandria, VA...
Probabilistic Large Hail Graphic
20170406 1630 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 18,396 3,301,753 Virginia Beach, VA...Norfolk, VA...Chesapeake, VA...Newport News, VA...Hampton, VA...
5 % 49,189 31,252,030 Philadelphia, PA...Baltimore, MD...Boston, MA...Washington, DC...Richmond, VA...
   SPC AC 061612

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1112 AM CDT Thu Apr 06 2017

   Valid 061630Z - 071200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
   EASTERN NC/VA/MD INTO DE/NJ...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
   THE MID-ATLANTIC REGION AND SOUTHERN NEW ENGLAND...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
   THE SOUTH FL...

   ...SUMMARY...
   Isolated severe storms with damaging winds, hail, and perhaps a
   tornado will be possible through early afternoon across the
   Mid-Atlantic into southern New England.  A marginal wind risk will
   diminish slowly this morning across central Florida.

   ...Mid Atlantic Region...
   An intense negatively-tilted shortwave trough over the Carolinas
   will lift rapidly northward today, resulting in strong upper forcing
   for vertical motion to overspread the Mid-Atlantic region into New
   England.  Thunderstorms have been ongoing this morning along/ahead
   of the primary cold front moving across NC/VA, but overall storm
   intensities have been modest.  Dense clouds ahead of the convection
   and limited time for further moisture advection will likely limit
   the severe threat.  Nevertheless, the approach of the upper trough
   and intense wind fields aloft suggest a continued risk of locally
   damaging winds or perhaps a tornado until the storms move across the
   Chesapeake Bay and into increasingly stable surface conditions.

   ...Southern New England...
   As the convection spreads northeastward into southern New England,
   model forecast soundings suggest a substantial low-level inversion
   will be maintained over parts of MA/RI/CT.  However, strong ascent
   and cool temperatures aloft will result in a pocket of elevated CAPE
   sufficient to warrant a marginal risk of hail in the strongest
   cells.

   ...FL...
   Thunderstorms continue to track slowly southeastward across the
   southern FL Peninsula.  Most model guidance suggests the storms will
   slowly weaken through the day.  However, ample low level moisture
   and moderate CAPE values indicate some conditional risk of gusty
   winds in the strongest cells.

   ..Hart/Cohen.. 04/06/2017

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