Jul 16, 2017 1730 UTC Day 2 Convective Outlook
Updated: Sun Jul 16 17:23:12 UTC 2017 (20170716 1730Z Day 2 shapefile | 20170716 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170716 1730 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 111,371 6,029,516 Syracuse, NY...Albany, NY...Fargo, ND...Scranton, PA...Schenectady, NY...
MARGINAL 350,774 31,827,476 Phoenix, AZ...Baltimore, MD...Washington, DC...Tucson, AZ...Mesa, AZ...
Probabilistic Graphic
20170716 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
15 % 110,173 5,983,195 Syracuse, NY...Albany, NY...Fargo, ND...Scranton, PA...Schenectady, NY...
5 % 353,694 32,639,809 Phoenix, AZ...Baltimore, MD...Washington, DC...Tucson, AZ...Mesa, AZ...
   SPC AC 161723

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1223 PM CDT Sun Jul 16 2017

   Valid 171200Z - 181200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL SOUTH
   DAKOTA INTO NORTHERN MINNESOTA...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
   PENNSYLVANIA ACROSS MUCH OF NEW YORK AND VERMONT...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
   THE NORTHERN PLAINS AND VICINITY...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS NEW YORK
   AND WESTERN NEW ENGLAND SOUTHWARD ACROSS THE APPALACHIANS...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN
   ARIZONA...

   ...SUMMARY...
   A few severe thunderstorms are expected Monday afternoon and evening
   from South Dakota into northern Minnesota, and during the day from
   Pennsylvania into New York and Vermont. Isolated severe storms are
   expected from Wyoming into Nebraska, across the Appalachians, and
   across southern Arizona.

   ...Synopsis...
   A broad upper trough will move eastward across south central Canada,
   with strong westerly flow aloft affecting the northern Plains. To
   the east, a weak upper trough will stretch from New England
   southward across the Appalachians, with cool temperatures aloft and
   weak flow. At the surface, a moist air mass will exist from the
   Plains eastward to the Atlantic coast, the exception being over the
   upper Great Lakes where high pressure will exist. A deepening
   surface trough over the northern Plains will provide the main focus
   for severe storms producing large hail or locally damaging wind
   gusts. Elsewhere, isolated gusty winds are possible over AZ late in
   the day.

   ...Northern Plains and vicinity...
   A deepening surface trough and strong heating will provide a focus
   for severe storm development, most probable from the Dakotas into MN
   during the late afternoon and evening. Hot temperatures across SD
   suggest gusty winds likely. The strongest winds aloft will be over
   ND and MN, where large, perhaps very large hail is possible along
   with damaging winds. Other localized clusters of severe storms are
   possible into central NE, and extending westward across the Black
   Hills and into WY.

   ...NY/VT/PA...
   Cool air aloft with the upper trough will result in steep lapse
   rates for this time of year, and this will in turn maximize updraft
   potential. Daytime heating and sufficient convergence within a
   surface trough will result in scattered storms. Although wind
   profiles will be weak, they will veer with height, supporting
   perhaps a few supercells. Substantial instability will further
   support a severe risk, most likely in the form of large hail. Storms
   should form relatively early given lack of any capping.

   Farther south across the Appalachians, heating combined with cool
   temperatures aloft will result in scattered afternoon storms capable
   of marginal hail.

   ..Jewell.. 07/16/2017

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