Jul 22, 2017 1630 UTC Day 1 Convective Outlook
Updated: Sat Jul 22 16:08:32 UTC 2017 (20170722 1630Z Day 1 shapefile | 20170722 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170722 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 179,292 35,582,387 Philadelphia, PA...Indianapolis, IN...Columbus, OH...Baltimore, MD...Washington, DC...
MARGINAL 342,712 56,869,446 New York, NY...Milwaukee, WI...Kansas City, MO...Virginia Beach, VA...Minneapolis, MN...
Probabilistic Tornado Graphic
20170722 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
2 % 22,113 2,114,842 Charleston, WV...Huntington, WV...Parkersburg, WV...Wheeling, WV...Morgantown, WV...
Probabilistic Damaging Wind Graphic
20170722 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 % 120,833 33,360,521 Philadelphia, PA...Indianapolis, IN...Columbus, OH...Baltimore, MD...Washington, DC...
5 % 383,145 56,678,072 New York, NY...Milwaukee, WI...Kansas City, MO...Virginia Beach, VA...Minneapolis, MN...
Probabilistic Large Hail Graphic
20170722 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 % 58,421 2,213,123 Green Bay, WI...Duluth, MN...Appleton, WI...Oshkosh, WI...Eau Claire, WI...
5 % 330,320 40,368,170 Indianapolis, IN...Columbus, OH...Milwaukee, WI...Kansas City, MO...Minneapolis, MN...
   SPC AC 221608

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1108 AM CDT Sat Jul 22 2017

   Valid 221630Z - 231200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OH VALLEY TO
   MID-ATLANTIC...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS UPPER MIDWEST...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
   SLIGHT RISKS TO THE CENTRAL GREAT PLAINS...

   ...SUMMARY...
   Scattered wind damage is possible from parts of the Ohio Valley
   eastward into the Mid-Atlantic through this evening, with scattered
   severe hail possible across parts of the Upper Midwest late this
   afternoon and evening.

   ...Mid-Atlantic States...
   A lead MCV is progressing east across northwest PA with a short
   convective line segment farther south across the MD/eastern WV
   Panhandles. Surface wind gusts with this leading-line convection
   have remained modest amid a minimal cold pool. Robust diabatic
   heating downstream across the Piedmont and Coastal Plain should
   result in convection expanding in coverage and intensifying during
   mid/late afternoon. With area RAOBs sampling 700-500 mb lapse rates
   of 5.5-6.0 degree C/km, setup should favor damaging winds as the
   main hazard. On the periphery of 700-mb winds at or above 30 kt
   along with an ill-defined surface pattern, wind damage should
   primarily be produced by scattered strong wind gusts.

   ...OH Valley/Midwest...
   Primary change this outlook is to expand Slight Risk west.
   Destabilization is well underway with south to southwest surface
   winds in the wake of leading-line convection over the central
   Appalachians. More pronounced outflow has been established from
   decaying convection over east-central IL and this should mark the
   western edge of organized severe potential. Weak confluence
   boundaries and low-level WAA atop the remnant outflow across parts
   of southern IL/IN/OH should aid in multiple rounds of scattered
   storms through this evening. Large buoyancy to the south amid a
   swath of 30-40 kt 700-mb flow will offer a primary risk of damaging
   winds and secondary risk of severe hail. 

   ...Upper Midwest...
   A compact shortwave trough over southern MB should reach Lake
   Superior tonight. Widely scattered storms are expected downstream
   and south of this trough first across northern MN and later into WI.
   A nearly unidirectional mid/upper-level profile with robust speed
   shear will favor elongated hodographs supportive of splitting
   supercells. Overall intensity should be stymied by ongoing light
   northerly surface winds and swaths of stratus evident from the MN
   Arrowhead into southern WI. But on the northeastern periphery of an 
   air mass that should become moderately unstable, the setup should
   yield risks of severe hail and locally damaging winds.

   ..Grams/Bunting.. 07/22/2017

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