SPC AC 290532
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1232 AM CDT Fri Mar 29 2024
Valid 291200Z - 301200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE MIDWEST...
...SUMMARY...
Marginally severe hail is possible with storms over portions of the
Midwest Friday night.
...Midwest...
Upper ridge is forecast to shift east across the MS Valley today as
a short-wave trough currently located over the lower CO River valley
advances into the central Plains by 30/00z. This feature will then
shift east, inducing weak height falls over the upper Midwest,
before progressing to near 87W longitude by the end of the period.
Latest model guidance suggests a LLJ will strengthen across the
central Plains early, then shift downstream into IL by 06z, in
response to the approaching short wave. While moisture is initially
quite scant across this region, there is reason to believe PW values
may increase to near one inch later this evening, with mean mixing
ratios expected near 8 g/kg.
Moisture is beginning to advance north across TX early this morning,
as evidenced by 50F surface dew points now approaching the DFW
Metroplex. While absolute moisture content will remain seasonally
low with this return event, 500mb temperatures will remain cold
(-20C) north of the midlevel jet. Forecast soundings suggest
elevated parcels will become weakly inhibited by mid evening, and
scattered convection should develop ahead of the short wave within
the warm advection zone. While the magnitude of instability will
remain a bit weak, steep midlevel lapse rates are expected to
support robust updrafts, the strongest of which could generate
marginally severe hail. Convection should initiate over eastern IA
then spread into northern IL/southern WI during the late
evening/overnight hours.
..Darrow/Bentley.. 03/29/2024
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
SPC AC 290559
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1259 AM CDT Fri Mar 29 2024
Valid 301200Z - 311200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
A severe threat is not expected to develop across the continental
U.S. on Saturday and Saturday night.
...DISCUSSION...
Anticyclonic mid-level flow is forecast across much of the central
and eastern U.S. on Saturday. Thunderstorms will be possible during
the day into the evening from the Mid Mississippi Valley into the
upper Ohio Valley, as a subtle shortwave trough moves eastward.
Thunderstorms will also be possible across parts of California and
Nevada, along the eastern edge of an upper-level system moving
south-southeastward, offshore and parallel to the California coast.
A severe threat is not expected to develop in any of these areas on
Saturday and Saturday night.
..Broyles.. 03/29/2024
WUUS02 PTSDY2
SPC AC 280726
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0226 AM CDT Thu Mar 28 2024
Valid 301200Z - 311200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Organized severe thunderstorms are not forecast on Saturday.
...Synopsis and Discussion...
A deep, closed upper low initially off the coast of central CA
should move slowly southward along/near the southern CA Coast on
Saturday. Cold mid-level temperatures and strong forcing for ascent
associated with an enhanced mid/upper-level jet should support weak
instability, and the potential for isolated lighting flashes with
any low-topped convection that can develop from parts of central
into southern CA. Organized severe thunderstorms appear unlikely
across this region given the meager MUCAPE forecast.
Isolated thunderstorms may occur Saturday over parts of the southern
Great Lakes/OH Valley, as a low-amplitude shortwave trough moves
east-southeastward across these areas. A weak surface low is also
forecast to develop eastward over this region in tandem with the
shortwave trough. Limited low-level moisture, with surface dewpoints
generally in the low 50s, should temper how much instability can
develop through Saturday afternoon given the presence of modest to
poor mid-level lapse rates. This will likely hinder the overall
severe threat across the OH Valley, even though deep-layer shear
conditionally supports the potential for organized convection.
Finally, occasional lightning flashes may occur with elevated
convection that develops late Saturday night into early Sunday
morning across parts of NE into southwestern IA and northern MO.
Low-level moisture is expected to gradually return northward across
the southern/central Plains through the day, and this area will be
on northern fringe of this process. Strong forcing associated with a
southerly low-level jet may provide sufficient lift for parcels to
reach their LFC. Still, forecast MUCAPE appears too weak to support
a meaningful hail threat through the end of the period (early Sunday
morning).
..Gleason.. 03/28/2024
WUUS03 PTSDY3
NOTE: THE NEXT DAY 3 OUTLOOK IS SCHEDULED BY 0730Z
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