Sep 9, 2017 0600 UTC Day 2 Convective Outlook
Updated: Sat Sep 9 05:47:56 UTC 2017 (20170909 0600Z Day 2 shapefile | 20170909 0600Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20170909 0600 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 25,803 11,126,705 Jacksonville, FL...Miami, FL...Hialeah, FL...Orlando, FL...Fort Lauderdale, FL...
MARGINAL 43,533 8,251,612 Tampa, FL...St. Petersburg, FL...Cape Coral, FL...Savannah, GA...Gainesville, FL...
Probabilistic Graphic
20170909 0600 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
5 % 69,454 19,381,623 Jacksonville, FL...Miami, FL...Tampa, FL...St. Petersburg, FL...Hialeah, FL...
   SPC AC 090547

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1247 AM CDT Sat Sep 09 2017

   Valid 101200Z - 111200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE EASTERN
   FL PENINSULA  AND FAR SOUTHEAST GA...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE FL
   PENINSULA AND GA/SC COAST...

   ...SUMMARY...
   Brief tornadoes are possible across portions of the Florida
   Peninsula and coastal Georgia and South Carolina Sunday as Hurricane
   Irma impacts the region.

   ...Synopsis...
   Latest forecast track from the 03Z/Saturday advisory from the
   National Hurricane Center takes the center of Hurricane Irma across
   the western Florida Keys around 12Z Sunday and into the southwestern
   FL Peninsula (in the Naples/Fort Myers FL vicinity) 00Z Monday. A
   general north-northwestward motion is forecast to continue after
   that, placing the center of system about 90 miles north-northwest of
   Tampa Bay at 12Z Monday. Given that track, an environment supportive
   of tropical cyclone tornadoes is anticipated along the eastern coast
   of the FL Peninsula and into far southeast GA (discussed in more
   detail below).

   Elsewhere, upper ridging will remain centered near the Four Corners
   while an upper low off the southern CA coast drifts slightly
   north-northwestward and deepens.

   ...Hurricane Irma: FL Peninsula and Coastal GA/SC...
   The more westerly storm track will place a relatively higher threat
   for tornadoes across eastern portions of the FL Peninsula than
   anticipated by the previous outlook. Rainbands will likely be
   impacting the entire peninsula at the start of the period, resulting
   in a low threat for a few tornadoes along the length of the eastern
   peninsula. Threat across the area will increase throughout the day
   as the strong low/mid-level winds associated with Irma move over the
   region. As expected, low-level shear will be more than sufficient
   for tornadoes with instability and updraft strength/persistence
   acting as the main limiting factors.

   A comparatively higher tornado threat may develop in the vicinity of
   the FL Space Coast during the afternoon. In this area, modest
   heating between rainbands could align with very strong low/mid-level
   flow, dewpoints in the mid 70s, and climatologically favorable
   tropical cyclone orientation to support a locally higher tornado
   potential. That being said, the threat for tropical cyclone-spawned
   tornadoes is very track dependent and updates/changes to this
   forecast may be needed in subsequent outlooks as the track changes.

   ...Southern CA...
   Moisture will continue advecting northward into the region as
   southerly/southeasterly flow around the eastern periphery of
   previously mentioned the upper low persists. PW values will likely
   be near 1.50" by 00Z Monday. This moisture coupled with orographic
   effects and large-scale forcing for ascent provided by the upper low
   will result in widely scattered thunderstorm development Sunday
   afternoon/evening. Bulk shear supports a few strong storms but
   overall severe coverage is currently expected to remain below 5%.

   ..Mosier.. 09/09/2017

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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z