705
ACUS02 KWNS 051711
SWODY2
SPC AC 051709

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1209 PM CDT Fri Jul 05 2024

Valid 061200Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE CENTRAL PLAINS...

...SUMMARY...
Severe thunderstorms are possible from southern South Dakota into
the southern High Plains on Saturday, with the highest coverage
expected in parts of Nebraska and Kansas. Large hail (some greater
than 2 inches) and severe winds are the expected hazards.

...Central Plains into eastern NM...

Modest height falls are forecast across the region as a broad upper
trough persists across much of the central U.S. Several shortwave
impulses are forecast to rotate through northwesterly flow aloft and
will support areas of convection through the period. At the surface,
a weak surface low may develop over western NE/KS, while generally
surface troughing extending into southeast CO/northeast NM.
Boundary-layer moisture will be modest across much of the region
given prior cold frontal passages in the past few days. However,
south/southeasterly low-level flow will allow for upper 50s to low
60s F dewpoints expanding northward across the southern High Plains
into portions of KS/NE. Cool temperatures aloft and a plume of steep
midlevel lapse rates spreading into KS/NE will support a corridor of
moderate instability from the Raton Mesa vicinity north/northeast
into western KS/central NE by mid-afternoon.

Some forecast guidance suggests convection may be ongoing across
parts of SD/NE. This introduces uncertainty in convective
evolution/timing, as this activity may slowly increase in intensity
through the day. Or, convection may dissipate and leave an outflow
boundary across central NE. Confidence is higher that convection
will develop further south into western KS and the southern High
Plains in the vicinity of the surface through during the afternoon.
Vertical shear will support initial high-based supercells. Steep
low-level lapse rates and high temperature-dewpoint spreads amid
mostly weak low-level flow will support strong/severe outflow winds.
This may allow for storm consolidation into an east/southeast
propagating MCS during the evening. If this occurs, damaging wind
potential will increase. In the absence of a strong low-level jet
during the evening, eastward extent of the severe risk should
diminish into central KS with time. Initial supercell storms also
will pose a risk for large hail, with some hail up to baseball size
possible.

With southward extent, vertical shear and large-scale ascent will
weaken, and organized thunderstorm coverage should be somewhat lower
into eastern NM and the TX Panhandle.

...Northeast and Mid-Atlantic...

Showers may be ongoing Saturday morning across parts of NY and New
England in a warm advection regime ahead of a cold front. This may
limit heating and low-level destabilization into the afternoon. As a
result, severe potential may be limited despite 35+ kt effective
shear magnitudes and a very moist low-level airmass. A few strong
gusts are possible, but confidence is too low to add unconditional
severe probabilities at this time.

Thunderstorms are expected with southward extent into eastern VA and
the Carolinas ahead of the surface cold front. While stronger
destabilization is expected with southward extent, vertical shear
will be very weak. However, steep low-level lapse rates and high PW
values may support a couple of strong wet microbursts in otherwise
disorganized storm clusters.

..Leitman.. 07/05/2024

$$