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SPC Activity Chart
Hazard Mon (09/26) Tue (09/27) Wed (09/28) Thu (09/29) Fri (09/30) Sat (10/01) Sun (10/02) Mon (10/03)
Severe Marginal Slight Slight No Area No Area No Area No Area No Area
Fire No Critical Elevated No Area No Area No Area No Area No Area No Area

Forecast Discussion - Convective Outlook

   SPC AC 260528

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1228 AM CDT Mon Sep 26 2022

   Valid 261200Z - 271200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
   FLORIDA KEYS...

   ...SUMMARY...
   Risk for damaging winds and brief tornadoes will increase late
   Monday night across the Florida Keys.

   ...FL Keys...

   Tropical Storm Ian has progressed to near 17N/81W as of late this
   evening and is forecast to strengthen into a major hurricane by the
   end of the day1 period as it tracks across the western tip of Cuba.
   This evolution is expected to result in strengthening wind fields
   across the southeastern Gulf Basin, including the FL Keys late.
   Forecast soundings for EYW exhibit ample buoyancy for robust
   updrafts within a sheared environment that will support organized
   rotating updrafts, as tropical air mass already resides across this
   region. Supercell structures are expected to materialize within the
   outer bands which should encroach on the Keys primarily after
   midnight.

   ...Northeastern US...

   Strong 500mb speed max is forecast to track into southern OH by the
   start of the day1 period, then progress to the southern New England
   Coast by 27/00z. Cooling mid-level temperatures (500mb temperatures
   <-20C) and steep lapse rates will encourage scattered convection
   across upstate NY into VT/NH. Forecast soundings suggest hail will
   likely be generated in the most robust updrafts; however, magnitude
   of instability suggests hail should remain below severe levels (1
   inch).

   ..Darrow/Wendt.. 09/26/2022

    

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z

        
   SPC AC 260555

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1255 AM CDT Mon Sep 26 2022

   Valid 271200Z - 281200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE FLORIDA
   KEYS AND SOUTHWEST FLORIDA PENINSULA...

   ...SUMMARY...
   A few tornadoes will be possible across parts of Florida Tuesday
   into Tuesday night, in association with Tropical Cyclone Ian.

   ...Synopsis...
   The deep mid/upper-level trough over the eastern CONUS is forecast
   to gradually weaken and shift eastward on Tuesday. Farther west, a
   vigorous mid/upper-level trough will approach the Pacific Northwest,
   while a weak upper ridge persists over portions of the Southwest and
   southern Plains. With dry and stable conditions covering most of the
   CONUS, the primary concern will be the potential impact of Tropical
   Cyclone Ian across Florida. 

   ...Florida...
   Tropical Storm Ian is forecast to intensify into a hurricane on
   D1/Monday as it moves toward western Cuba, and then move into the
   southeast Gulf of Mexico on D2/Tuesday. See NHC advisories and
   forecasts for more information regarding Ian. Rich tropical moisture
   will remain in place through the period across the Keys and most of
   the peninsula, south of a cold front that will become nearly
   stationary across north FL. Strengthening low-level flow/shear will
   support a gradually increasing threat of rotating cells within any
   rain bands associated with Ian. Some tornado threat may be ongoing
   at the start of the period across the lower FL Keys, with this
   threat spreading northward with time, and potentially peaking late
   in the period as favorable low-level shear/SRH overspreads a larger
   portion of the peninsula. 

   Uncertainties remain regarding Ian's track and intensity, and the
   magnitude of destabilization, but at this time the greatest threat
   for a few tornadoes appears to be over the FL Keys and southwest FL
   Peninsula, in closer proximity to the forecast track of Ian through
   12Z Wednesday. A 5% tornado area has been included for these areas,
   though some adjustments will likely be needed in subsequent outlooks
   as Ian's forecast track and intensity are refined, and important
   mesoscale details come into better focus.

   ..Dean.. 09/26/2022

   WUUS02 PTSDY2 

   

        
   SPC AC 260729

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0229 AM CDT Mon Sep 26 2022

   Valid 281200Z - 291200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR MUCH OF THE
   FLORIDA PENINSULA...

   ...SUMMARY...
   A few tornadoes will be possible across the Florida Peninsula on
   Wednesday, in association with Tropical Cyclone Ian.

   ...Florida...
   Tropical Cyclone Ian is forecast to move north-northeastward as a
   hurricane across the eastern Gulf of Mexico on Wednesday (see NHC
   advisories and forecasts for more information regarding Ian). The
   track and intensity of Ian remain uncertain, but it appears likely
   that favorable low-level shear/SRH will overspread rich tropical
   moisture across the FL Peninsula, with some potential for modest
   diurnal heating/destabilization. These factors will support the
   threat for rotating cells within any of Ian's outer rain bands, with
   an attendant risk for a few tornadoes. 

   A southwest-to-northeast oriented stationary front is expected to
   limit the northern extent of the tornado threat, as the baroclinic
   zone is reinforced by substantial rainfall on the cool side of the
   boundary. Ian may begin entraining dry air into its circulation on
   Wednesday, which may aid in destabilization potential across
   portions of the peninsula during the day, but also tend to gradually
   decrease the threat from southwest to northeast by Wednesday night.
   Some tornado threat could persist into early Thursday morning in
   closer proximity to the stationary front, and also near the center
   of Ian, depending on how close it approaches the FL west coast. A
   Slight Risk has been introduced where the greatest tornado threat on
   Wednesday is currently expected, with some adjustments likely in
   subsequent outlooks based on shorter-term observational and guidance
   trends.

   ..Dean.. 09/26/2022

   WUUS03 PTSDY3 

   NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z