Severe Storm Outlook Narrative (AC)
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
000
ACUS02 KWNS 300454
SWODY2
SPC AC 300453

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1153 PM CDT MON SEP 29 2014

VALID 011200Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE MID MO VALLEY AND
CNTRL PLAINS...

...SUMMARY...
SCATTERED SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS PARTS OF THE
CENTRAL PLAINS AND MID MISSOURI VALLEY WEDNESDAY.  LARGE
HAIL...STRONG WINDS...AND PERHAPS A TORNADO OR TWO CAN BE EXPECTED.

...CENTRAL PLAINS/MID MO VALLEY...

WHILE NEUTRAL-WEAK HEIGHT RISES ARE EXPECTED ACROSS THE MIDDLE OF
THE CONUS WEDNESDAY...LATEST MODEL GUIDANCE CONTINUES TO SUGGEST
THUNDERSTORMS WILL DEVELOP ACROSS THE CNTRL PLAINS/MID MO VALLEY.
LEE SFC CYCLONE SHOULD DEVELOP OVER SWRN KS AND MOVE LITTLE THROUGH
THE PERIOD...PERHAPS SHIFTING EAST AFTER MIDNIGHT AS SHORT-WAVE
TROUGH EJECTS INTO THE HIGH PLAINS.  SLOWLY STRENGTHENING LEE TROUGH
SHOULD ALLOW HIGHER BOUNDARY LAYER MOISTURE TO ADVANCE NWD BENEATH
LLJ THAT WILL FOCUS OVER ERN KS INTO EARLY THURSDAY MORNING.  GIVEN
THE LACK OF HEIGHT FALLS IT APPEARS MOST CONVECTION WILL BE DRIVEN
BY LOW LEVEL WARM ADVECTION AND TSTMS SHOULD BE ONGOING AT THE START
OF THE PERIOD ACROSS THE MID MO VALLEY WHERE ACTIVITY SHOULD BE
ROOTED AOA 850MB.  CLOUD LAYER SHEAR SHOULD SUPPORT MULTI-CELL
UPDRAFTS AND ELEVATED PARCELS MAY BE BUOYANT ENOUGH FOR MARGINAL
SEVERE HAIL.  THIS EARLY MORNING CONVECTION SHOULD REINFORCE A
PSEUDO-WARM FRONT WITH RAIN-COOLED OUTFLOW EXPECTED TO ENHANCE ELY
LOW LEVEL FLOW ACROSS NEBRASKA AND PERHAPS EXTREME NRN KS.

IT/S NOT CLEAR HOW MUCH CONVECTION WILL EVOLVE DURING THE DAY ACROSS
ERN KS/NEB AS PRE-DAWN TSTMS SHIFT EAST INTO IA/NRN MO.  IN THE
ABSENCE OF STRONG UVV IT APPEARS BOUNDARY LAYER HEATING WILL PROVE
INSTRUMENTAL IN SFC-BASED CONVECTION DURING THE AFTERNOON HOURS.
LATEST SHORT-RANGE MODEL GUIDANCE SUGGEST STRONG BOUNDARY LAYER
HEATING WILL BE NOTED ALONG DRY LINE FROM NWRN TX INTO WRN KS WHERE
SFC-3KM LAPSE RATES COULD APPROACH DRY ADIABATIC BY 21Z.  THIS WILL
WEAKEN THE CAP SUFFICIENTLY FOR A THREAT OF TSTM INITIATION AHEAD OF
SFC LOW.  FORECAST SOUNDINGS ACROSS NCNTRL KS NEAR THE
AFOREMENTIONED OUTFLOW/PSEUDO-WARM FRONT EXHIBIT SUBSTANTIAL VEERING
WITH HEIGHT AND SFC-6KM BULK SHEAR AOA 40KT.  IF DEW POINTS RISE
INTO THE MID-UPPER 60S AS DEPICTED BY LATEST NAM THEN SUBSTANTIAL
SBCAPE WILL EXIST ACROSS THIS REGION BY 21Z.  ISOLATED SUPERCELLS
SHOULD EVOLVE THEN SPREAD/DEVELOP EAST AND NORTH INTO SERN NEB.
EARLY IN THE CONVECTIVE MODE DISCRETE SUPERCELLS ARE POSSIBLE WITH
THUNDERSTORM CLUSTERS LIKELY EVOLVING DURING THE OVERNIGHT HOURS
ALONG NOSE OF LLJ OVER THE MID MO VALLEY.  LARGE HAIL...A FEW
DAMAGING WIND GUSTS AND PERHAPS A FEW TORNADOES CAN BE EXPECTED.

...SOUTHERN PLAINS...

FARTHER SOUTH ALONG THE DRY LINE ACROSS OK/TX...STRONG HEATING
SHOULD CONTRIBUTE TO ISOLATED...INITIALLY HIGH-BASED...TSTMS AFTER
22Z.  THIS ACTIVITY SHOULD LINGER UNTIL 04-05Z TIME FRAME BEFORE
DISSIPATING OVER CNTRL OK.  VERY LATE IN THE PERIOD A PRONOUNCED
SHORT-WAVE TROUGH SHOULD APPROACH THE SRN HIGH PLAINS.  THERE IS
SOME RISK CONVECTION COULD EVOLVE ALONG THE DRY LINE TOWARD 12Z BUT
CAPPING IS CURRENTLY EXPECTED TO BE A BIT STRONG AND STORMS ARE MORE
LIKELY TO EVOLVE DOWNSTREAM LATER IN THE DAY3 PERIOD.

..DARROW.. 09/30/2014



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.