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ACUS01 KWNS 031254

SWODY1

SPC AC 031252



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0752 AM CDT Fri May 03 2024



Valid 031300Z - 041200Z



...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NEAR THE

WEST TEXAS CAPROCK ONTO ADJOINING LOW ROLLING PLAINS...



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE

ENHANCED AREA...AND OVER PORTIONS OF THE CENTRAL PLAINS...



...SUMMARY...

Large hail and damaging gusts are possible over parts of the

central/southern Great Plains from southern Nebraska to west Texas,

along with some tornado potential over parts of west Texas.



...Synopsis...

Today's transitional mid/upper-level synoptic pattern is a tale of

two cyclones -- one astride the Upper Midwest/Canadian border, and

another digging southeastward out of the Gulf of Alaska.  The broad,

complex leading cyclone will eject northeastward over MB and

northwestern ON through the period.  A trailing shortwave trough --

apparent in moisture-channel imagery over parts of southern ID and

northern NV -- will move east-northeastward to eastern SD and

central NE by 12Z tomorrow.  The strong, well-developed Pacific

cyclone will proceed southeastward to just off the coast of OR by

the end of the period.  Southwest flow aloft will be maintained with

weak synoptic-scale height rises over most of the central/southern

Plains.  Still, sufficient moisture, buoyancy, lift and shear are

apparent for a couple relative maxima in severe potential as

discussed below.



At the surface, 11Z analysis showed a low attached to a cold front

over south-central WY.  The front should proceed southeastward

through the day, extending from southeastern SD to western NE an

central CO by 00Z, with the low over northeastern CO.  By 12Z

tomorrow, the front should extend from a low over IA to south-

central KS, the northern TX Panhandle, and north-central NM.  This

front will overtake a developing dryline over the central High

Plains from north-south, with the dryline position at 00Z over

eastern CO, the western TX Panhandle, and Permian Basin.  A weak/

residual, nearly stationary front extended from a low near FST

northeastward across northwest TX, eastern OK and the Ozarks, and

should continue to lose definition amidst considerable convective

outflow.  The southern rim of that outflow was evident from

southeast TX (between GLS-BPT) across the HOU metro then west-

northwestward to near SJT.  The western part will shift northward

slowly through the day toward the front, which itself should drift

northward up the Caprock.



...West/southwest TX...

Widely scattered to scattered thunderstorms are expected to form

this afternoon near the dryline and the residual outflow boundary

over the South Plains to Low Rolling Plains/Concho Valley regions. 

Isolated to widely scattered convection possible farther south off

the dryline past the Rio Grande, and into strongly heated/CINH-

minimized higher terrain of the Serranias del Burro range in

northern Coahuila.  This activity should move eastward across areas

below the Caprock and around the Big Country to Edwards Plateau,

with potential for some of the Mexican convection to cross the Rio

Grande this evening as well.  Supercells -- with large to very large

hail and at least isolated potential for tornadoes -- will be more

probable in and near the 30%/"enhanced" hail area.  Dryline and

orographic activity to the south will be an early hail/wind threat. 

Some of this activity may aggregate into clusters offering mainly

strong-severe gusts, with one or two small MCSs possible this

evening into the early overnight hours.



Despite multiple days of MCS and smaller-scale convective activity

to the east and southeast, a reservoir of rich low-level moisture

remains not far upstream across south-central TX and into the

southern Edwards Plateau, where upper 60s to low 70s F surface

dewpoints and PW commonly 1-1.5 inches.  When advected northwestward

amid diurnal heating and beneath steep midlevel lapse rates,

3000-4000 J/kg MLCAPE should become common.  Though low-level flow

should not be particularly strong, it will be backed, contributing

to elongated hodographs ad around 30-40 kt effective-shear

magnitudes.  Splitting storms may be common early, offering the

greatest hail potential (size and coverage).  The damaging-wind

threat will be maximized on the mesoscale where organized cold pools

can develop, and should extend farther east at greater density than

the hail potential this evening into tonight.  In the absence of

substantial large-scale support, tornado potential will be locally

maximized with any supercells that can interact favorably with

outflow boundaries or each other.



...Central Plains...

Large hail and severe gusts are possible from mid/late afternoon

into tonight, from thunderstorms shifting eastward across portions

of the central Plains.  Though nowhere nearly as moist as the TX

outlook area, a diurnally destabilized plume of moist advection

should support a secondary relative max in severe potential

along/ahead of the cold front and dryline from parts of eastern CO

to western/northern KS and southern NE.  Convection should develop

by mid/late afternoon in a regional convergence maximum near and

northeast of the surface low, with MLCINH weakened by favorable

diurnal heating.  Surface dewpoints in the 40s to low 50s F should

be common, with steep surface-500-mb lapse rates, 500-1000 J/kg

MLCAPE and well-mixed subcloud layers.  Effective-shear magnitudes

around 40-50 kt indicate potential for organized convection -- both

in quasi-linear form near the front and initially discrete (but

later merging upscale) off the dryline.  Though activity will

encounter a more-stable boundary layer with time and eastward extent

across KS/NE, at least marginal severe-gust potential may last

overnight as far eastward as parts of the Missouri Valley region.



..Edwards/Broyles.. 05/03/2024



$$