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.
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.)
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...
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.
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