Jul 16, 2019 1730 UTC Day 2 Convective Outlook
Updated: Tue Jul 16 17:32:13 UTC 2019 (20190716 1730Z Day 2 shapefile | 20190716 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20190716 1730 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 65,101 6,263,096 Minneapolis, MN...St. Paul, MN...Madison, WI...Sioux Falls, SD...Rochester, MN...
MARGINAL 351,940 60,332,368 New York, NY...Philadelphia, PA...Baltimore, MD...Milwaukee, WI...Boston, MA...
Probabilistic Graphic
20190716 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 % 65,253 6,288,577 Minneapolis, MN...St. Paul, MN...Madison, WI...Rochester, MN...Bloomington, MN...
5 % 350,474 60,638,317 New York, NY...Philadelphia, PA...Baltimore, MD...Milwaukee, WI...Boston, MA...
   SPC AC 161732

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1232 PM CDT Tue Jul 16 2019

   Valid 171200Z - 181200Z


   Strong/severe thunderstorms are possible across portions of the
   upper Mississippi Valley. Isolated strong storms may also be noted
   across parts of the Plains and over portions of the northeastern US.


   Upper pattern will change little through Wednesday with belt of
   stronger westerlies confined to the northern third of the country. A
   low amplitude shortwave trough currently moving through the
   northwestern U.S. will undergo further deamplification as it moves
   through the mean ridge position across the northern Plains and into
   the upper MS valley. Farther east, remnants of Barry will become
   absorbed within slightly stronger westerlies and weaken further as
   it continues through the central Appalachians and Middle Atlantic
   region. By 12Z Wednesday a quasi-stationary front should extend from
   the upper Great Lakes to a weak surface low over SD. A cold front
   will trail southwest from the low through western NE with a
   pre-frontal trough from the eastern CO into southwestern NE. Farther
   east a cold front will advance southeast into the Northeast States
   during the day.

   ...Upper MS Valley region...

   A very moist boundary layer will with 70 F dewpoints will reside
   along and south of the quasi-stationary front from eastern SD into
   southern MN and WI. It is likely that an MCS will be ongoing north
   of this boundary on nose of a modest southerly low-level jet posing
   some risk for strong to damaging wind gusts. Future evolution of
   this MCS is somewhat uncertain, and model solutions including the
   CAMS differ significantly. It is possible that MCS could reorganize
   and intensify while continuing east as the boundary layer in
   vicinity of the front destabilizes and especially since at least a
   modest low-level jet is forecast to persist within the exit region
   of a mid-level jet. Another possibility is that the MCS could weaken
   or dissipate, and additional storms develop upstream later in the
   afternoon or early evening along/north of the front as the low-level
   jet strengthens. If this occurs, strong vertical shear and
   instability in vicinity of the convectively enhanced but modifying
   stationary front would support supercells capable of large hail and
   possibly a few tornadoes. This activity would subsequently grow
   upscale and move east through southern MN and WI during the evening
   and overnight with a continuing threat for mainly damaging wind.
   Given these uncertainties regarding the mesoscale and convective
   scale evolution, will maintain SLGT risk this outlook, but an
   enhanced might be required for a portion of this region in future
   day 1 updates. 

   ...Central and northern Plains region...

   Within a modest post-frontal upslope regime, dewpoints at least in
   the 50s F will persist beneath steep lapse rates contributing to
   moderate instability over the central High Plains. This region will
   reside beneath belt of stronger winds aloft and vertical shear will
   support supercells as storms develop and move off the higher
   terrain. Will maintain the MRGL risk category this update given
   uncertainty regarding storm coverage, but an upgrade to SLGT risk
   may be needed in later updates. Other storms with multicell
   characteristics are expected to develop within the more deeply mixed
   regime along the pre-frontal trough from western KS into south
   central NE with downburst winds the main threat.

   ...Northeast States...

   A moist, weakly capped warm sector will reside across the
   pre-frontal warm sector over the northeast U.S. and the atmosphere
   may become moderately unstable as the boundary layer destabilizes
   during the afternoon, south of any ongoing convection/clouds.
   Mid-level lapse rates will be very weak along with weak vertical
   shear. Nevertheless, storms are expected to intensify south of the
   cold front in association with remnant boundaries as well as over
   the higher terrain and spread east into the destabilizing boundary
   layer. A few locally strong wind gusts will be possible as storms
   merge into line segments and clusters, but modest winds aloft and
   the overall marginal thermodynamic environment may serve as limiting
   factors for a more robust threat.

   Tornado:   5%     - Slight
   Wind:     15%     - Slight
   Hail:     15%     - Slight

   ..Dial.. 07/16/2019