Sep 12, 2022 1730 UTC Day 2 Convective Outlook
Updated: Mon Sep 12 17:12:44 UTC 2022 (20220912 1730Z Day 2 shapefile | 20220912 1730Z Day 2 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20220912 1730 UTC Day 2 Outlook Graphic
Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MARGINAL 68,906 18,443,714 Boston, MA...Providence, RI...Worcester, MA...Springfield, MA...Bridgeport, CT...
Probabilistic Tornado Graphic
20220912 1730 UTC Day 2 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 2 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
2 % 19,810 11,255,149 Boston, MA...Providence, RI...Worcester, MA...Springfield, MA...Bridgeport, CT...
Probabilistic Damaging Wind Graphic
20220912 1730 UTC Day 2 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 2 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 68,918 18,418,748 Boston, MA...Providence, RI...Worcester, MA...Springfield, MA...Bridgeport, CT...
Probabilistic Large Hail Graphic
20220912 1730 UTC Day 2 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 2 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
No Risk Areas Forecast
   SPC AC 121712

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1212 PM CDT Mon Sep 12 2022

   Valid 131200Z - 141200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
   OF NEW ENGLAND AND THE NORTHEAST...

   ...SUMMARY...
   Isolated severe thunderstorms capable of damaging wind gusts and a
   brief weak tornado are possible across New England on Tuesday.

   ...Northeastern CONUS and New England...
   A compact upper low over the northern OH Valley and Great Lakes will
   transition to an open wave early Tuesday, as it is re-absorbed into
   stronger westerly flow over the northeastern CONUS. A moderate H5
   jet along the southern periphery of the wave will spread dynamic
   lift eastward through much of Tuesday morning. At the surface, an
   occluded cyclone over the northern Great Lakes will slowly fill as a
   secondary surface low over southern ON/QC deepens and draws 60s and
   70s F surface dewpoints northward. A cold front associated with the
   new surface low will strengthen as it shifts eastward, providing the
   main impetus for strong to severe storms Tuesday afternoon. 

   With persistent lift from the upper low and jet streak overspreading
   the region early, widespread cloud cover and precipitation are
   expected Tuesday morning. Regional model soundings show deep
   saturated surface layers with dewpoints in the upper 60s to low 70s
   F. Buoyancy is expected to be weak owing to widespread cloud cover
   and poor mid-level lapse rates, but modest destabilization (MLCAPE
   ~500 J/kg) is still possible given the degree of low-level
   moistening. Deep-layer vertical shear of 40-50 kt will be favorable
   for organized storms with the upper jet overhead. While the strong
   frontal forcing will favor a more linear band of convection with
   northern extent, a pre-frontal supercell or two is possible across
   southern New England. 

   Confidence in severe storm development is relatively low given the
   potential for early morning storms delaying destabilization.
   High-res guidance shows the most coverage of potential strong/severe
   storms along the cold front closer to the surface low across upstate
   NY, VT and NH. Here, the primary risk will be isolated damaging wind
   gusts given the moderate low and mid-level wind fields. Damaging
   gusts and a brief/weak tornado will be also be possible farther
   south across CT/RI/MA where greater backed surface flow may locally
   enhance low-level shear. However, this is conditional upon any
   supercells able to evolve ahead of the main cold front.

   ...Southwest/Great Basin/Intermountain West...
   The remains of Tropical Cyclone Kay will progress eastward across
   the Great Basin towards the northern/central Rockies as a remnant
   trough Tuesday. Lift and moisture attendant to this system will
   result in widespread thunderstorms, with the highest storm coverage
   anticipated over northern AZ and northwest NM. Weak buoyancy and
   vertical shear within the modified tropical airmass should serve to
   limit the overall severe potential.

   ..Lyons/Gleason.. 09/12/2022

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