Severe Storm Outlook Narrative (AC)
Issued by NWS

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389
ACUS02 KWNS 270603
SWODY2
SPC AC 270601

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0101 AM CDT FRI MAY 27 2016

VALID 281200Z - 291200Z

...THERE IS A MRGL RISK OF SVR TSTMS EXTENDING FROM SOUTH...CENTRAL
AND EAST TX THROUGH EASTERN OK AND WESTERN AR TO THE MID MS VALLEY
AND CENTRAL IL...

...SUMMARY...
ISOLATED SEVERE THUNDERSTORMS WITH HAIL AND STRONG WIND GUSTS WILL
BE POSSIBLE ACROSS THE SOUTH AND CENTRAL TEXAS THROUGH THE OZARKS TO
THE MIDDLE MISSISSIPPI VALLEY TO CENTRAL ILLINOIS.

...SYNOPSIS...
THE SOUTHWEST STATES TROUGH IS EXPECTED TO CONTINUE TRACKING
NORTHEAST ACROSS THE CENTRAL U.S. ON SATURDAY AND SATURDAY NIGHT AS
IT MOVES ACROSS THE LOWER AND MID MO VALLEY TO THE UPPER MS VALLEY
THIS FORECAST PERIOD.  STRONGEST SOUTHWESTERLY 500-MB FLOW ATTENDANT
TO THIS PROGRESSIVE TROUGH WILL SPREAD FROM THE SOUTHERN PLAINS AND
MID MS VALLEY TO THE UPPER GREAT LAKES.  AT THE SURFACE...AN AREA OF
LOW PRESSURE WILL MOVE FROM EASTERN NEB AT 12Z SATURDAY THROUGH
SOUTHERN MN BY LATE AFTERNOON AND SHOULD REACH NORTHWEST ONTARIO
/NORTH OF MN/ BY 12Z SUNDAY.  THE TRAILING COLD FRONT IS EXPECTED
MOVE THROUGH THE UPPER MS VALLEY AND TOWARD THE LOWER MO
VALLEY...WHILE SOUTHERN EXTENT OF THIS BOUNDARY BECOMES
QUASI-STATIONARY THROUGH CENTRAL OK...NORTH-CENTRAL TX TO THE TX BIG
BED REGION.

...SOUTH AND CENTRAL TX TO ARKLATEX AND EASTERN OK...
THE AIR MASS SOUTH AND EAST OF THE QUASI-STATIONARY BOUNDARY IS
EXPECTED TO REMAIN QUITE MOIST AND VERY UNSTABLE WITH MUCAPE OF
3000-4500 J/KG LIKELY SATURDAY AFTERNOON.  GRADUAL HEIGHT RISES AND
UNCERTAINTY IN TIMING OF WEAK IMPULSES WITHIN WEST/SOUTHWEST 500-MB
FLOW ARE THE PRIMARY LIMITING FACTORS FOR GREATER COVERAGE OF SEVERE
STORMS AND THE INTRODUCTION OF GREATER SEVERE PROBABILITIES AT THIS
TIME.  STORMS THAT DO FORM ACROSS THESE AREAS SATURDAY AFTERNOON
INTO THE EVENING WILL HAVE THE POTENTIAL TO BE SUPERCELLS...GIVEN
VERTICALLY VEERING WIND PROFILES AND EFFECTIVE BULK SHEAR OF 35-40
KT.  HOWEVER...UNCERTAINTY IN PLACEMENT FOR HIGHER SEVERE
PROBABILITIES IS FURTHER INHIBITED BY WEAK CONVERGENCE IN THE
LOW-LEVELS.

...OZARKS AND MID MS VALLEY TO CENTRAL IL...
A MOIST AIR MASS /SURFACE DEW POINTS IN THE MID-UPPER 60S/ WILL BE
PRESENT ACROSS THE WARM SECTOR SATURDAY AS A PLUME OF STEEP MIDLEVEL
LAPSE RATES SPREADS ACROSS THE OZARKS THROUGH MO TO IL.  THIS WILL
RESULT IN MUCAPE OF 2000-3000 J/KG AND UP TO 3500 J/KG IN THE
WESTERN AR.  WEAK MIDLEVEL IMPULSES EMBEDDED WITHIN A CYCLONIC FLOW
REGIME SHOULD PROVIDE SOME FORCING FOR ASCENT TO SUPPORT TSTM
DEVELOPMENT SATURDAY AFTERNOON INTO THE EVENING...DESPITE FORECAST
HEIGHT RISES.  WEAK FORCING AND EFFECTIVE BULK SHEAR OF 20-30 KT
SUGGEST MULTICELLS WILL BE THE PRIMARY STORM MODE.  THESE FACTORS
SHOULD ALSO LIMIT WIDESPREAD COVERAGE OF SEVERE WEATHER...
MAINTAINING THE MARGINAL SEVERE-WEATHER RISK.

...COASTAL AREAS OF GA/SC/NC...
NHC IS MONITORING THE POTENTIAL DEVELOPMENT OF A TROPICAL OR
SUB-TROPICAL SYSTEM BETWEEN THE BAHAMAS AND BERMUDA.  THE COASTAL
AREAS OF GA/SC/NC WILL NEED TO BE MONITORED IN LATER OUTLOOKS FOR AN
INCLUSION OF POTENTIAL SEVERE HAZARDS ATTENDANT TO A TROPICAL/
SUB-TROPICAL SYSTEM APPROACHING THE SOUTHEAST U.S. COAST.  REFER TO
NHC FOR UPDATES ON THIS SYSTEM.

..PETERS.. 05/27/2016

$$



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