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 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
ACUS01 KWNS 040601
SWODY1
SPC AC 040600

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT MON MAY 04 2015

VALID 041200Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS WESTERN AND NORTHERN
KS...SOUTHEAST NEBRASKA...NORTHERN MO...SOUTHERN IA AND FAR
WEST-CENTRAL IL...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SOUTHEAST NM AND
PORTIONS OF WEST AND SOUTHWEST TX...

...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE SLGT RISK AREAS
FROM THE SOUTHERN HIGH PLAINS THROUGH THE CENTRAL PLAINS...MIDWEST
TO THE SOUTHERN GREAT LAKES REGION...

...SUMMARY...
ISOLATED TO SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON AND EVENING FROM WESTERN AND NORTHERN KANSAS INTO IOWA AND
NORTHERN MISSOURI TO WEST-CENTRAL ILLINOIS.  ISOLATED TO SCATTERED
SEVERE STORMS WILL ALSO BE POSSIBLE ACROSS SOUTHEAST NEW MEXICO INTO
WEST AND SOUTHWEST TEXAS.

...SYNOPSIS...
A PROGRESSIVE SHORTWAVE TROUGH WILL SHIFT EWD FROM NRN ONTARIO/UPPER
GREAT LAKES REGION THROUGH SRN QUEBEC...WHILE THE ATTENDANT COLD
FRONT ADVANCES FROM LOWER MI TO THE NORTHEAST STATES.  THE TRAILING
PORTION OF THE COLD FRONT IS EXPECTED TO BECOME QUASI-STATIONARY
FROM NRN IND/IL THROUGH NRN MO TO NRN OR CENTRAL KS BENEATH WEAKER
WLY FLOW ALOFT.  MEANWHILE...A MID-UPPER LEVEL TROUGH WILL MOVE EWD
ACROSS THE SWRN STATES AND NRN MEXICO TODAY.  A DIFFLUENT FLOW
REGIME IS EXPECTED DOWNSTREAM ACROSS ERN NM AND WEST/SOUTHWEST TX ON
THE NORTH SIDE OF A STRONG WLY SUB-TROPICAL JET EXTENDING FROM NRN
MEXICO INTO SOUTH TX TO THE WRN GULF OF MEXICO.

...CENTRAL KS...SERN NEB TO SOUTHERN IA/NRN MO...
A MIDLEVEL IMPULSE...CURRENTLY MOVING NEWD ACROSS NERN NM PER
MOISTURE-CHANNEL IMAGERY...MAY TEND TO SHEAR ENEWD WITHIN AN UPPER
RIDGE AS IT TRACKS FROM WRN KS TO NRN MO/SRN IA BY EARLY EVENING.
PERSISTENT SLY LOW-LEVEL FLOW ACROSS THE SRN/CENTRAL PLAINS AND
LOWER MO VALLEY WILL MAINTAIN MOISTURE RETURN ON THE WRN PERIPHERY
OF A SURFACE RIDGE EXTENDING FROM THE SERN STATES TO ERN TX/OK.
DESPITE SURFACE DEW POINTS IN THE UPPER 50S TO AROUND 60 F BENEATH
OF PLUME OF 700-500-MB LAPSE RATES OF 7-8 C/KM...SOME UNCERTAINTY
EXISTS WITH THE DEGREE OF DESTABILIZATION TODAY.  CLOUDINESS LEFT
OVER FROM EARLY MORNING STORMS ACROSS THIS SLIGHT RISK AREA MAY
LIMIT SURFACE HEATING.  MODELS SUGGEST MODERATE INSTABILITY WILL BE
POSSIBLE WITH MLCAPE UP TO 2000 J/KG IN AREAS WITH STRONGEST SURFACE
HEATING.  ALTHOUGH MID-UPPER LEVEL WINDS WILL TEND TO BE WEAK
BETWEEN STRONGER NRN STREAM AND SUB-TROPICAL JETS...MIDLEVEL WINDS
MAY BE ENHANCED SOME FROM NRN KS TO SRN IA GIVEN THE PRESENCE OF THE
WRN KS MIDLEVEL IMPULSE.  EFFECTIVE BULK SHEAR...WHILE WEAK /20-30
KT/ SOUTH OF THE CENTRAL PLAINS TO MIDWEST FRONT AND STRONGER NEAR
AND NORTH OF THE FRONT...SUGGESTS MULTICELLS WILL BE THE PRIMARY
STORM MODE WITH HAIL AND STRONG WIND GUSTS BEING THE PRIMARY
THREATS.  A TORNADO THREAT CANNOT BE RULED OUT ACROSS NORTH-CENTRAL
KS LATE THIS AFTERNOON AND EARLY EVENING...GIVEN SOME ENHANCED
LOW-LEVEL SHEAR NEAR A WEAK SURFACE LOW /IN VICINITY OF HYS AND
RSL/.  TSTM CLUSTERS MAY PERSIST THROUGH MONDAY EVENING AND EARLY
OVERNIGHT WITHIN A WAA REGIME...BUT WEAKENING INSTABILITY SHOULD
LIMIT THE SEVERE WEATHER THREAT AFTER SUNSET.

...SERN NM AND WRN TX...
STRENGTHENING SELY LOW-LEVEL WINDS WILL SUPPORT MOISTURE RETURN INTO
THE PECOS VALLEY AND SOUTHWEST TX/SOUTHEAST NM...WITH AROUND 1 INCH
OF PRECIPITABLE WATER EXPECTED EAST OF THE HIGHER TERRAIN IN SRN NM
AND SOUTHWEST TX.  STRONG SURFACE HEATING AND UPSLOPE FLOW SHOULD
SUPPORT TSTM DEVELOPMENT THIS AFTERNOON WITH SUPERCELLS
LIKELY...GIVEN EXPECTED MODERATE INSTABILITY AND EFFECTIVE BULK
SHEAR OF 35-50 KT.  LARGE HAIL...SOME VERY LARGE...AND DAMAGING
WINDS WILL BE THE PRIMARY THREATS.

...NRN IL/NRN IND/NRN OH/SERN LOWER MI...
TSTM DEVELOPMENT WILL BE POSSIBLE WITH EWD EXTENT ALONG THE COLD
FRONT...BUT WEAK INSTABILITY/SHEAR WILL TEND TO RESULT IN ISOLATED
COVERAGE OF ANY STRONGER TO POTENTIALLY SEVERE STORMS.  ISOLATED
HAIL AND LOCALLY STRONG WIND GUSTS SHOULD BE THE PRIMARY THREATS.

..PETERS/MOSIER.. 05/04/2015




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