594
ACUS03 KWNS 200728
SWODY3
SPC AC 200727
DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0227 AM CDT MON APR 20 2026
VALID 221200Z - 231200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE HIGH PLAINS OF NEBRASKA SOUTH INTO THE TEXAS PANHANDLE...
..SUMMARY
SEVERE THUNDERSTORMS CAPABLE OF HAIL AND GUSTY WINDS MAY DEVELOP
DURING THE LATE AFTERNOON AND EVENING ACROSS PORTIONS OF THE HIGH
PLAINS. ELSEWHERE, THUNDERSTORMS WILL BE POSSIBLE ACROSS THE
NORTHERN GULF COAST AND PORTIONS OF THE OHIO VALLEY.
.. SYNOPSIS
A SHORTWAVE TROUGH WILL EJECT NORTHEAST OUT OF THE BASAL REGION OF
THE WESTERN CONUS TROUGH AND INTO THE NORTHERN PLAINS ON WEDNESDAY.
AS THIS HAPPENS, STRENGTHENING SOUTHERLY/SOUTHWESTERLY MIDLEVEL FLOW
WILL OVERSPREAD MUCH OF THE HIGH PLAINS. A SURFACE CYCLONE OVER
EASTERN MONTANA WILL GRADUALLY DEEPEN AS IT SLOWLY MOVES EAST.
.. CENTRAL HIGH PLAINS SOUTH INTO THE SOUTHERN HIGH PLAINS
AS THE MONTANA SURFACE CYCLONE GRADUALLY DEEPENS ON WEDNESDAY, GULF
MOISTURE WILL BE DRAWN NORTHWARD INTO THE CENTRAL AND NORTHERN
PLAINS. AS THE UPPER TROUGH APPROACHES THE REGION DURING THE LATE
AFTERNOON/EVENING, MODEST HEIGHT FALLS ARE EXPECTED TO OVERSPREAD A
SHARPENING DRYLINE ACROSS FAR EASTERN COLORADO OR WESTERN NEBRASKA
SOUTH INTO THE TEXAS PANHANDLE. KINEMATIC PROFILES UP AND DOWN THE
DRYLINE SHOW AMPLE VERTICAL SHEAR FOR SUPERCELLS CAPABLE OF
PRODUCING HAIL AND GUSTY WINDS. HOWEVER, CONSIDERABLE UNCERTAINTY
REMAINS REGARDING THUNDERSTORM COVERAGE OWING TO THE SIGNIFICANT
DIFFERENCES IN THE DEPTH AND QUALITY OF THE BOUNDARY LAYER MOISTURE
RETURN NOTED IN THE 20260420/00Z GUIDANCE SUITE. FOR EXAMPLE, THE
NAM IS NEARLY 5F MORE MOIST ALONG THE DRYLINE ACROSS PORTIONS OF
NEBRASKA THAN GLOBAL MODELS.
THAT SAID, PATTERN RECOGNITION AND 00Z RRFS SUGGEST THAT AT LEAST A
COUPLE OF STORMS SHOULD DEVELOP ALONG THE DRYLINE FROM NEBRASKA
SOUTH INTO THE EASTERN TEXAS PANHANDLE. DEEP-LAYER FLOW WILL LARGELY
PARALLEL THE DRYLINE DURING THE AFTERNOON WHICH SHOULD PRECLUDE MUCH
EASTWARD ADVANCEMENT. A 5% UNCONDITIONAL RISK AREA HAS BEEN ADDED TO
ACCOUNT FOR THIS POTENTIAL.
.. ELSEWHERE ACROSS THE CONUS
THUNDERSTORMS MAY BE ONGOING AT THE START OF THE FORECAST PERIOD AND
PERSIST INTO THE EARLY AFTERNOON ACROSS PORTIONS OF THE NORTHERN
GULF COAST. THE THUNDERSTORM POTENTIAL SHOULD WANE WITH TIME AS
INCREASING MIDLEVEL HEIGHTS SUPPRESS LARGE-SCALE ASCENT.
ADDITIONALLY, MODEST LOW-LEVEL MOISTURE AND WEAK INSTABILITY MAY
SUPPORT A FEW LIGHTNING STRIKES WITHIN A WEAK SURFACE BOUNDARY
ACROSS THE OHIO VALLEY.
..MARSH.. 04/20/2026
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