spc ac 070733
day 3 convective outlook
nws storm prediction center norman ok
0233 am cdt tue jul 07 2026
valid 091200z - 101200z
...there is a marginal risk of severe thunderstorms thursday into
thursday night across parts of the central great plains through
middle mississippi valley...parts of the northern great plains and
parts of the mid atlantic...
...summary...
scattered strong thunderstorm development, potentially including a
few evolving clusters, may impact portions of the central great
plains through middle mississippi valley and parts of the mid
atlantic thursday through thursday night. much more isolated strong
storms may impact parts of central north dakota late thursday
afternoon into evening.
...discussion...
modest mid-latitude westerlies are forecast to remain centered near
the canadian/u.s border through this period. in the wake of one
short wave trough slowly continuing to pivot northward into the
northwest territories, and ahead of another digging near the british
columbia coast, broad mid-level ridging is forecast to build along
the central canadian/u.s. border thursday through thursday night.
downstream, to the south of a perturbation digging southeast of the
hudson/james bays, broad mid-level troughing is forecast to
overspread the lower great lakes through northern atlantic seaboard.
in lower latitudes, models suggest that a number of more subtle
perturbations, a couple of which may generated or strengthened by
convection, will progress through otherwise weak, zonal flow around
the northern periphery of mid-level ridging centered in the
subtropics. it appears that the most substantive thunderstorm
development through this period will focus along this corridor,
roughly east of the front range and sangre de cristo mountains into
portions of the middle mississippi valley, and across portions of
the mid atlantic.
...front range through middle mississippi valley...
the 07/00z nam is most prominent in generating a notable mcv by 12z
thursday, associated with thunderstorm development across the
central great plains wednesday night. and it substantively
intensifies this feature as it migrates across the lower
missouri/middle mississippi valleys thursday through thursday night.
this includes a strengthening jet to 50-70 kt around 700 mb,
suggesting the existence of intensifying organized convective system
with the potential to produce swaths of damaging surface gusts.
this is much stronger than what is generated by the ecmwf, with the
gfs indicating a perturbation between these extremes.
given the potential for a moist boundary layer with seasonably high
moisture content, including lower/mid 70s f, it does appear that
there may be sufficient cape to support the evolution of a
significant severe convective system. however, the predictability
of this type of feature in this type of regime at this extended
range is relatively low, and reflected in the guidance. at this
point severe probabilities will be introduced at 5 percent, but this
will change if the consensus of guidance trends in the current
direction of the nam.
otherwise, destabilization to the lee of the front range and sangre
de cristo mountains will probably depend on the extent of
stabilizing outflow left across the central great plains at the
outset of the period. however, at least the eastern slopes into
adjacent high plans may become a focus for scattered strong
thunderstorm development posing a risk for severe hail and wind by
late afternoon. a remnant baroclinic zone associated with the
convective outflow across missouri into kansas may provide another
focus for strong to severe thunderstorm development late thursday
evening into thursday night, near the nose of a nocturnally
strengthening low-level jet.
...mid atlantic...
destabilization to the lee of the blue ridge mountains (centered
across virginia thursday) may again become sufficient to support
convection with potential to produce strong wind gusts and grow
upscale, aided by forcing for ascent associated with a remnant short
wave impulse emerging from the tennessee valley.
..kerr.. 07/07/2026
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note: the next day 3 outlook is scheduled by 1930z