SPC AC 210518
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1118 PM CST Wed Nov 20 2024
Valid 211200Z - 221200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
A few thunderstorms are possible across southern New England
Thursday morning.
...Southern New England...
Strong upper low will shift southeast from the Great Lakes into the
upper Ohio Valley by late afternoon. This evolution will encourage
low-level warm advection across southern New England as a surface
low repositions itself off the middle Atlantic coast, south of Long
Island. Forecast soundings suggest weak elevated buoyancy will
develop north of this boundary as mid-level lapse rates will steepen
as 500mb temperatures cool in advance of the approaching trough.
Strongest elevated updrafts may exceed levels necessary for
lightning discharge, but this should mainly be prior to 18z.
Thereafter, deepest convection will focus offshore.
..Darrow/Wendt.. 11/21/2024
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
SPC AC 210612
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1212 AM CST Thu Nov 21 2024
Valid 221200Z - 231200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
A few thunderstorms are possible along the Pacific Northwest Coast
on Friday.
...Synopsis...
A large, deep upper low will exist over the northeast Friday
morning, and will gradually weaken as it drifts east through the
period. Meanwhile, an upper ridge will slowly shift east from the
Rockies into the Plains, while yet another trough pushes across the
Pacific Northwest region late.
Substantial northwest surface winds will maintain relatively stable
conditions from the Plains to the East Coast, with no instability
forecast over much of the CONUS.
The exception will be again along the coastal counties of WA and OR,
as strong cooling aloft occurs. Scattered low-topped convection will
be most likely over the ocean overnight. A few thunderstorms may
move onshore, but at this time the stronger shear farther north does
not appear to overlap with the minimal instability required for a
severe threat.
..Jewell.. 11/21/2024
WUUS02 PTSDY2
SPC AC 210748
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0148 AM CST Thu Nov 21 2024
Valid 231200Z - 241200Z
...NO THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Thunderstorms appear unlikely across the USA on Saturday.
...Synopsis...
A temporary/weakening upper ridge will exist over the Plains, with a
departing trough over the Northeast and a broad region of
west/southwest flow aloft over the West. By 12Z Sunday, this ridge
will all but disappear due in part to an upper wave from MT into ND,
and continued height falls across the West.
The beginnings of moisture return will develop over TX in response
to lower pressure over the Plains, with 50s F dewpoints primarily
away from coast. Little if any instability is forecast across the
entire CONUS through the period, and as such thunderstorms are not
expected.
..Jewell.. 11/21/2024
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 1930Z
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