Jul 14, 2017 1630 UTC Day 1 Convective Outlook
Updated: Fri Jul 14 16:24:02 UTC 2017 (20170714 1630Z Day 1 shapefile | 20170714 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170714 1630 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 74,827 23,617,461 Philadelphia, PA...Baltimore, MD...Washington, DC...Tucson, AZ...Virginia Beach, VA...
MARGINAL 372,451 46,424,973 New York, NY...Phoenix, AZ...Nashville, TN...Mesa, AZ...Raleigh, NC...
Probabilistic Tornado Graphic
20170714 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 % 8,527 7,283,561 Philadelphia, PA...Camden, NJ...Reading, PA...Wilmington, DE...Cherry Hill, NJ...
Probabilistic Damaging Wind Graphic
20170714 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 % 74,704 23,523,416 Philadelphia, PA...Baltimore, MD...Washington, DC...Tucson, AZ...Virginia Beach, VA...
5 % 372,606 46,602,179 New York, NY...Phoenix, AZ...Nashville, TN...Mesa, AZ...Raleigh, NC...
Probabilistic Large Hail Graphic
20170714 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
5 % 132,818 22,839,701 Philadelphia, PA...Baltimore, MD...Washington, DC...Virginia Beach, VA...Norfolk, VA...
   SPC AC 141624

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1124 AM CDT Fri Jul 14 2017

   Valid 141630Z - 151200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
   MID-ATLANTIC REGION...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   EASTERN ARIZONA...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER WESTERN
   MT...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MID MS
   VALLEY INTO THE MID ATLANTIC STATES...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
   AZ...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER THE
   NORTHERN PLAINS...

   ...SUMMARY...
   Widely scattered damaging winds will be possible today across parts
   of the central Appalachians and Mid-Atlantic vicinity, and over
   parts of eastern Arizona. Isolated severe storms will be possible
   elsewhere across portions of the eastern states to the Mid-South,
   across the north-central states, as well as central and southern
   Arizona.

   ...Mid Atlantic Region...
   Water vapor imagery shows a strong shortwave trough over the Great
   Lakes area tracking southeastward into the northeastern US. Ahead of
   the trough, considerable cloud cover is present over much of
   central/eastern NY/PA into New England.  This will limit afternoon
   instability and mitigate the risk of organized severe storms. 
   However, full heating is occurring from southeast PA into VA/DE/MD
   where more robust thunderstorms are likely to develop later today. 
   Westerly mid-level winds of 30-40 knots will help to organize
   convective elements and track them eastward across the SLGT risk
   area through the afternoon.  Forecast soundings suggest sufficient
   CAPE and effective shear for a few bowing structures capable of
   damaging wind gusts.  An isolated tornado cannot be ruled out along
   the warm front over southeast PA and NJ.  Southward extent of the
   greater severe threat will diminish across southern VA where mid
   level winds are weaker.

   ...AZ...
   The MCS that affected parts of southeast AZ last night has
   dissipated, with full sunshine occurring over the mountains of
   eastern AZ today.  Considerable low and mid level moisture remain in
   this area, suggesting that the development of afternoon
   thunderstorms is likely.  12z model solutions suggest a corridor of
   25-35 kt northeasterly mid-level steering flow that will help
   convection that forms over east-central AZ to move/develop
   southwestward toward the TUS area.  Given the consistent signals in
   several recent CAM solutions, have opted to add a SLGT risk for
   damaging wind potential across parts of the area.  The primary
   severe risk should be in the 22-05z time frame.

   ...Western MT...
   The northern fringe of a plume of mid level moisture is moving
   across parts of ID into western MT this morning.  Most model
   solutions suggest this moisture will aid in the development of
   high-based showers and thunderstorms over the mountains of southwest
   MT later this afternoon.  The mid-level ridge is building into this
   area, resulting in weak flow aloft and hot surface temperatures. 
   The result will likely include a few more intense thunderstorms
   capable of locally gusty/damaging winds.

   ..Hart/Smith.. 07/14/2017

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z