LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1243 AM CDT Sat Jul 08 2023
Valid 081200Z - 091200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY INTO TONIGHT
ACROSS PARTS OF EASTERN COLORADO...NORTHEASTERN NEW
MEXICO...SOUTHWESTERN KANSAS...WESTERN AND SOUTHERN
OKLAHOMA...NORTHWESTERN AND NORTHERN TEXAS...MUCH OF ARKANSAS...THE
MISSOURI BOOTHEEL...SOUTHWESTERN KENTUCKY...WESTERN
TENNESSEE...NORTHERN AND CENTRAL MISSISSIPPI AND ADJACENT PORTIONS
OF WESTERN ALABAMA...
...SUMMARY...
Scattered strong to severe thunderstorms, and one or two organized
thunderstorm clusters, are possible east of the Front Range and
Sangre de Cristo Mountains through the Texas and Oklahoma Panhandles
and Red River Valley vicinity. Additional strong to severe
thunderstorm development is possible across parts of the lower
Mississippi into Ohio Valleys.
...Synopsis...
Perhaps most prominently in mid/upper levels, models indicate that
blocking mid-level ridging will become increasingly prominent to the
south of Greenland, with a pair of flanking, broad and anamalously
deep closed lows. The center of the western one is forecast to
redevelop west/southwest of Hudson Bay into northeastern Manitoba,
with cyclonic flow strengthening on its western periphery, across
the eastern Canadian Prairies.
At the same time, relatively amplified, but weak, split flow is
forecast to persist across the eastern Pacific into western North
America. Mid-level ridging in one branch appears likely to build
across the eastern Great Basin, in advance of mid-level troughing
approaching the Pacific coast. Downstream, broadly cyclonic and
northwesterly flow will prevail from the lee of the Front Range and
Sangre de Cristo Mountains into larger-scale troughing digging
across the lower Mississippi Valley, more or less in phase with
troughing digging across the Upper Midwest, to the south of the
Canadian cyclone.
Steep lapse rates, associated with warm-elevated mixed-layer air
emanating from the Mexican Plateau/Intermountain West, have already
become confined to a plume across the southern Great Plains into
portions of the lower Mississippi Valley. This may become
suppressed a bit further southward/southwestward in response to
pattern developments today, with associated contribution to
instability providing the primary focus for strong to severe storm
development.
...Front Range/Sangre de Cristo Mountains into Red River...
Seasonably moist southeasterly near-surface flow appears likely to
persist into the Raton Mesa and Palmer Divide vicinities, with
models also indicating the development of a weak surface low across
southeastern Colorado by late afternoon. Upslope flow, along the
southern slopes into crest of the Palmer Divide to the north of the
low, may contribute to intensifying thunderstorm development off the
Front Range by late this afternoon, as mixed-layer CAPE becomes
moderately large and inhibition weakens.
A few supercells are possible initially, which appear likely to
propagate south-southeastward across southeastern Colorado into late
evening, accompanied by a risk for large hail and potential for a
tornado or two. Thereafter, in the presence of strengthening
lower/mid-tropospheric warm advection, another upscale growing and
organizing cluster of storms is possible by late this evening, which
may be accompanied by strong to severe surface gusts across the
Texas/Oklahoma Panhandles into Red River vicinity by daybreak
Sunday.
...Lower Mississippi into Lower Ohio Valleys vicinity...
Convective evolution and potential is more unclear across this area.
However, a corridor of stronger daytime heating, ahead of a remnant
MCV, may contribute to sizable mixed-layer CAPE in excess of 2000
J/kg by early this afternoon. This regime may support the
development of one or two upscale growing clusters of storms capable
of producing potentially damaging wind gusts, while tending to
propagate eastward and southeastward through this evening.
..Kerr/Thornton.. 07/08/2023
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