SPC AC 280729

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0229 AM CDT Fri Jun 28 2024

   Valid 301200Z - 011200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN MT
   INTO WESTERN ND...AND ALSO FROM THE MID ATLANTIC INTO
   SOUTHERN/EASTERN NEW ENGLAND...

   ...SUMMARY...
   Scattered damaging winds are possible across parts of the Mid
   Atlantic and Northeast on Sunday. Hail and severe gusts will also be
   possible from eastern Montana into western North Dakota.

   ...Carolinas into the Northeast...
   A seasonably deep and positively tilted trough is forecast to move
   southeastward across the Northeast and Mid Atlantic on Sunday. A
   surface low will move from eastern Quebec into the Canadian
   Maritimes, as a trailing cold front moves across parts of the
   eastern CONUS. Weak midlevel lapse rates could limit prefrontal
   destabilization to some extent across parts of the Northeast/New
   England, but potentially strong diurnal heating and sufficient
   deep-layer shear could result in scattered strong storms capable of
   scattered damaging wind and possibly some hail during the
   afternoon/evening. 

   Guidance continues to vary somewhat regarding timing of the front. A
   Slight Risk has been included from parts of the Mid Atlantic into
   New England, where organized damaging-wind potential appears most
   possible at this time. Some adjustments will likely be needed,
   depending on trends regarding timing of the front and prefrontal
   destabilization.  

   Farther south, somewhat stronger destabilization will be possible
   into the Carolinas, within a very moist environment. Mid/upper-level
   flow will be weaker, but modest west-northwesterlies aloft could
   support some stronger cells/clusters capable of at least isolated
   damaging wind. 

   ...Montana into the western Dakotas...
   A mid/upper-level trough is forecast to move from the Northwest
   across northern Rockies during the day on Sunday, with some
   influence of the trough expected to spread into the northern High
   Plains by Sunday evening. A surface low is expected to deepen across
   northern WY, with low-level moisture return expected east and north
   of the low into parts of Montana and the western Dakotas. 

   At least modest diurnal destabilization will be possible from
   southwest into central MT, with moderate buoyancy potentially
   developing farther east into parts of eastern MT and the western
   Dakotas. Guidance still varies somewhat regarding timing of stronger
   ascent across the region, but storm development will be possible
   across western into central MT during the afternoon. These storms
   may move eastward with time, with other isolated development
   possible by early evening into eastern MT. 

   Increasing deep-layer shear will support organized convection, and a
   few stronger clusters and/or supercells will be possible, with a
   threat of hail and severe gusts. An MCS may develop Sunday night and
   move into western/central ND, as a low-level jet nocturnally
   strengthens. The severity of any MCS will be more uncertain with
   eastward extent, due to increasing low-level stability. However,
   some threat for severe gusts could spread across western and
   possibly central ND.

   Storm development/coverage is more uncertain farther south, but with
   the environment expected to become conditionally favorable by late
   afternoon into the evening, a strong/severe storm or two will also
   be possible into western SD. 

   ...CO Front Range into the central High Plains...
   In the wake of a cold frontal passage, low-level moisture will
   stream westward into the CO Front Range vicinity and adjacent
   central High Plains, with the western extension of the boundary
   expected to lift northward as a warm front through the day. Moderate
   destabilization will be possible during the afternoon, with
   potential for at least isolated storm development. Midlevel flow
   will likely remain weak to modest, but sufficient veering with
   height could support organized multicell clusters and perhaps a
   supercell or two, with a threat of hail and severe gusts. 

   ...South-central Great Plains into the Southeast and TN Valley...
   A cold front is forecast to move into parts of the south-central
   Great Plains and Ozark vicinity Sunday morning, potentially
   accompanied by ongoing convection. Moderate to locally strong
   buoyancy may develop along/south the front during the afternoon, in
   areas that are not as influenced by early-day convection. Midlevel
   flow will likely remain weak, but may take on a more northerly
   component later in the day, which could provide sufficient
   deep-layer shear for briefly organized storms. Given the rather
   weakly sheared environment and uncertainty regarding the favored
   frontal corridor, no probabilities have been included for this
   regime at this time.

   ..Dean.. 06/28/2024

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