294
ACUS01 KWNS 260527
SWODY1
SPC AC 260525
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1225 AM CDT FRI APR 26 2024
VALID 261200Z - 271200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE LOWER TO MID MISSOURI VALLEY...AND CENTRAL PLAINS...
..SUMMARY
SEVERE THUNDERSTORMS WILL BE LIKELY TODAY FROM PARTS OF EASTERN
NEBRASKA INTO WESTERN AND CENTRAL IOWA, SOUTHWARD INTO EASTERN
KANSAS AND NORTHWEST MISSOURI. ALL HAZARDS WILL BE POSSIBLE,
INCLUDING TORNADOES WITH SOME POTENTIALLY STRONG, VERY LARGE HAIL
OVER TWO INCHES IN DIAMETER, AND WIND DAMAGE. A MORE ISOLATED SEVERE
THREAT WILL EXTEND SOUTH-SOUTHWESTWARD INTO PARTS OF THE SOUTHERN
PLAINS, OZARKS AND ARK-LA-TEX FROM LATE AFTERNOON INTO THE EVENING.
...SIGNIFICANT SEVERE WEATHER EVENT EXPECTED TODAY ACROSS PARTS OF
THE LOWER TO MID MISSOURI VALLEY AND CENTRAL PLAINS...
..LOWER TO MID MISSOURI VALLEY/CENTRAL PLAINS
A NEGATIVELY TILTED UPPER-LEVEL TROUGH WILL MOVE NORTHEASTWARD
ACROSS THE MID MISSOURI VALLEY TODAY, AS AN ASSOCIATED 50 TO 60 KNOT
MID-LEVEL JET TRANSLATES NORTHEASTWARD THROUGH THE BASE OF THE
SYSTEM. AT THE SURFACE, A LOW WILL DEEPEN AND MOVE NORTHEASTWARD
ACROSS NEBRASKA. A NORTH-TO-SOUTH CORRIDOR OF MAXIMIZED LOW-LEVEL
MOISTURE, WITH SURFACE DEWPOINTS IN THE MID 60S F, WILL BE IN PLACE
BY MIDDAY ACROSS EASTERN KANSAS AND SOUTHEAST NEBRASKA. MODERATE
INSTABILITY WILL DEVELOP ACROSS MOST OF THE MOIST SECTOR BY
AFTERNOON, WITH THUNDERSTORMS FIRST DEVELOPING IN EAST-CENTRAL
NEBRASKA AROUND MIDDAY. THESE STORMS ARE EXPECTED TO MOVE EASTWARD
ACROSS EASTERN NEBRASKA DURING THE AFTERNOON, AS CONVECTIVE COVERAGE
GRADUALLY EXPANDS SOUTH-SOUTHEASTWARD INTO EASTERN KANSAS. THE
ENVIRONMENT WILL BE FAVORABLE FOR SEVERE STORMS, WITH SEVERAL
CLUSTERS MOVING EASTWARD FROM NEBRASKA INTO IOWA, AND FROM KANSAS
INTO MISSOURI DURING THE LATE AFTERNOON AND EARLY EVENING.
SEVERAL FACTORS APPEAR TO BE SUPPORTIVE OF A SIGNIFICANT TORNADO
EVENT TODAY ACROSS EASTERN PART OF THE CENTRAL PLAINS INTO THE LOWER
TO MID MISSOURI VALLEY. THE FIRST IS THAT A 60 TO 70 KNOT MID-LEVEL
JET, ASSOCIATED WITH A NEGATIVELY TILTED TROUGH, WILL BECOME COUPLED
WITH A 50 TO 60 KNOT LOW-LEVEL JET OVER A MOIST AND UNSTABLE WARM
SECTOR. A SECOND FACTOR IS THAT A BAND OF LARGE-SCALE ASCENT WILL
MOVE OVER THE WARM SECTOR THIS AFTERNOON, AS THE CAPPING INVERSION
DIMINISHES. STEEP LOW TO MID-LEVEL LAPSE RATES ARE FORECAST TO
SPREAD OVER THE WARM SECTOR, WHICH COMBINED WITH MODERATE DEEP-LAYER
SHEAR, WILL BE FAVORABLE SUPERCELLS WITH STRONG UPDRAFTS AT
RELATIVELY LOW-LEVELS WITHIN THE STORMS. IN ADDITION, 0-3 KM
STORM-RELATIVE HELICITY IS FORECAST TO INCREASE INTO THE 300 TO 400
M2/S2 RANGE ALONG THE WESTERN EDGE OF THE LOW-LEVEL JET, WHICH WILL
BE FAVORABLE FOR STRONG TORNADOES. A FEW TORNADIC SUPERCELLS ARE
EXPECTED, WITH THE GREATEST POTENTIAL FROM NEAR OMAHA EASTWARD TO
NEAR DES MOINES AND SOUTHWARD TO SOUTH OF THE KANSAS CITY METRO.
ALONG THIS CORRIDOR, THE MORE DOMINANT SUPERCELL STORMS WILL ALSO
HAVE A POTENTIAL TO PRODUCE HAILSTONES GREATER THAN 2 INCHES IN
DIAMETER AND WIND DAMAGE. THE SEVERE THREAT IS EXPECTED TO SHIFT
EASTWARD ACROSS IOWA AND MISSOURI DURING THE MID TO LATE EVENING,
WITH AN ISOLATED SEVERE THREAT CONTINUING AFTER MIDNIGHT.
..SOUTHERN PLAINS/OZARKS/ARK-LA-TEX
SOUTHWESTERLY MID-LEVEL FLOW WILL BE IN PLACE TODAY ACROSS THE
SOUTH-CENTRAL U.S., WITH A BROAD MOIST WARM SECTOR LOCATED FROM THE
SOUTHERN PLAINS EASTWARD INTO THE ARK-LA-TEX AND OZARKS. AN MCS IS
EXPECTED TO MOVE ACROSS CENTRAL AND EASTERN OKLAHOMA DURING THE
MORNING, WHICH WILL STABILIZE THE AIRMASS. HOWEVER, INSTABILITY IS
FORECAST TO REDEVELOP ACROSS OKLAHOMA BY AFTERNOON. FURTHER SOUTH,
STRONG INSTABILITY IS EXPECTED TO DEVELOP ACROSS MUCH OF CENTRAL AND
EAST TEXAS BY AFTERNOON, WHERE MLCAPE SHOULD PEAK IN THE 2500 TO
3500 J/KG RANGE. ALTHOUGH LARGE-SCALE ASCENT WILL BE WEAK ACROSS
MOST OF THE SOUTHERN PLAINS, THE CAP IS EXPECTED TO DIMINISH AND
ISOLATED THUNDERSTORMS APPEAR LIKELY TO DEVELOP BY LATE AFTERNOON. A
SEVERE THREAT IS EXPECTED TO PERSIST ALONG AND NEAR THE INSTABILITY
AXIS DURING THE EARLY TO MID EVENING.
RAP FORECAST SOUNDINGS AT 00Z/SATURDAY ALONG AND NEAR THE
INSTABILITY AXIS FROM SOUTHEAST/SOUTH-CENTRAL OKLAHOMA INTO
NORTH-CENTRAL TEXAS HAVE 0-6 KM SHEAR BETWEEN 40 AND 50 KNOTS. LOW
TO MID-LEVEL LAPSE RATES WILL BECOME STEEPEST IN AREAS THAT HEAT UP
THE MOST. THE ENVIRONMENT WILL LIKELY BE FAVORABLE FOR ISOLATED
SUPERCELLS WITH LARGE HAIL. BY LATE AFTERNOON, FORECAST SOUNDINGS
ALSO HAVE 0-3 KM STORM-RELATIVE HELICITY REACHING 200 M2/S2
SUGGESTING THAT AN ISOLATED TORNADO THREAT WILL BE POSSIBLE. THE
TORNADO THREAT IS EXPECTED TO BE THE GREATEST ACROSS EASTERN
OKLAHOMA, NORTHEAST TEXAS AND WESTERN ARKANSAS, AS THE LOW-LEVEL JET
RAMPS UP IN THE EARLY EVENING. WIND DAMAGE WILL ALSO BE POSSIBLE
WITH STORMS THAT DEVELOP.
..BROYLES/THORNTON.. 04/26/2024
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