MD 1589 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF THE MID-ATLANTIC
Mesoscale Discussion 1589
NWS Storm Prediction Center Norman OK
0156 PM CDT Sat Jul 11 2026
Areas affected...portions of the Mid-Atlantic
Concerning...Severe potential...Watch unlikely
Valid 111856Z - 112100Z
Probability of Watch Issuance...5 percent
SUMMARY...Widely scattered thunderstorms may bring a risk for
isolated damaging wind gusts and perhaps an instance of marginally
severe hail to portions of the Mid-Atlantic through this evening.
DISCUSSION...Widely scattered thunderstorms developing along a
west-east oriented cold front are expected to progress southward
across portions of the Mid-Atlantic this afternoon amid a warm,
moist low-level air mass. While poor mid-level lapse rates (5.5 C/km
or less sampled by the IAD 12z observed sounding) are largely
limiting the magnitude of available buoyancy to around 1000 J/kg,
latest objective analysis suggests that localized pockets of up to
1500 J/kg may exist across this region. Concurrently, modestly
stronger mid-to-upper level flow is overspreading the region ahead
of an approaching mid-level shortwave trough, which is contributing
to 25-35 kts of effective shear. This may support some organization
of thunderstorms, including the potential for transient supercell
structures. While the overall thermodynamic environment remains
rather limited, the aforementioned combination of buoyancy and shear
coupled with modestly steep low-level lapse rates may support
isolated damaging winds and perhaps an instance of marginally severe
hail through this evening. Given the expectation for severe
magnitude/coverage to remain limited, watch issuance is not
anticipated at this time.
..Chalmers/Smith.. 07/11/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PHI...BGM...AKQ...CTP...LWX...
LAT...LON 38937467 38627491 38457503 38437536 38547575 38787618
39277669 39717693 40147700 40617689 40877662 40977632
40927596 40607543 40167495 40057479 39797458 39537436
39347437 39217443 38937467
MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
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