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 041954
SWODY1
SPC AC 041953

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0253 PM CDT TUE AUG 04 2015

VALID 042000Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON FROM SE NEW
ENGLAND TO ERN MAINE...

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON/EVENING FOR
PARTS OF THE MID ATLANTIC...

...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON/EVENING FOR SW
NEB AND WRN KS...

...THERE IS A MRGL RISK OF SVR TSTMS FROM PARTS OF VA TO ERN NY...

...THERE IS A MRGL RISK OF SVR TSTMS FOR PARTS OF THE CENTRAL PLAINS
AND NRN HIGH PLAINS...

...SUMMARY...
A FEW SEVERE THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS WILL
CONTINUE THIS AFTERNOON ACROSS SOUTHEAST NEW ENGLAND AND EASTERN
MAINE...AS WELL AS INTO LATE EVENING ACROSS WESTERN KANSAS.  A MORE
ISOLATED AND MARGINAL SEVERE STORM RISK CONTINUES FOR SURROUNDING
AREAS IN THE NORTHEAST STATES AND ACROSS THE PLAINS.

...NEW ENGLAND THIS AFTERNOON...
ISOLATED SUPERCELLS ARE ONGOING ACROSS SE NH AND CENTRAL/ERN
MA...AND THESE STORMS HAVE A HISTORY OF PRODUCING LARGE HAIL AND
TREE DAMAGE.  THE STORM ENVIRONMENT REMAINS FAVORABLE FOR SUPERCELLS
WITH SUBSTANTIAL DEEP-LAYER VERTICAL SHEAR /EFFECTIVE SHEAR AOA 50
KT/ AND MODERATE BUOYANCY /MLCAPE 1500-2000 J PER KG/.  LOW-LEVEL
SHEAR IS RELATIVELY WEAK...THOUGH AN ISOLATED TORNADO CANNOT BE
RULED OUT WITH THE CENTRAL MA STORM CLUSTER MOVING ALONG THE OUTFLOW
BOUNDARY FROM A LEAD STORM N OF BOSTON.  OTHERWISE...THE HAIL/WIND
RISK WILL CONTINUE FOR THE NEXT FEW HOURS ACROSS SE NEW ENGLAND AND
ERN MAINE BEFORE CONVECTIVE OVERTURNING AND THE LOSS OF DAYTIME
HEATING REDUCE BUOYANCY.

...MID ATLANTIC THIS AFTERNOON/EVENING...
DEEPER CUMULUS CONVECTION HAS BEEN RELEGATED TO THE BLUE RIDGE THUS
FAR...BUT STRONG SURFACE HEATING/MIXING SHOULD STILL ALLOW A FEW
STORMS TO SPREAD E OF THE MOUNTAINS THIS AFTERNOON ACROSS VA.
MODERATE CAPE AND EFFECTIVE BULK SHEAR OF 35-40 KT WILL BE
SUFFICIENT FOR ORGANIZED MULTICELLS/SUPERCELLS CAPABLE OF PRODUCING
AT LEAST ISOLATED LARGE HAIL AND DAMAGING WINDS.

...CENTRAL PLAINS THIS AFTERNOON/EVENING...
CONVECTION HAS INCREASED IN COVERAGE/INTENSITY OVER SW NEB/NW KS
THIS PAST COUPLE OF HOURS.  THE CONVECTION IS FOCUSED ALONG A
STALLED SURFACE FRONT AND IMMEDIATELY IN ADVANCE OF A MIDLEVEL
TROUGH OVER THE CENTRAL HIGH PLAINS...AND WILL LIKELY SPREAD SEWD AS
A SMALL MCS.  AN ISOLATED TORNADO COULD OCCUR WITH THE INITIAL
SUPERCELLS ON THE BOUNDARY IN NW KS WHERE LOW-LEVEL SHEAR IS
STRONGER...THOUGH RATHER MODEST LOW-LEVEL MOISTURE ACROSS NW KS AND
EXPECTED UPSCALE GROWTH OF THE STORMS SUPPORT THE PRIMARY RISKS OF
LARGE HAIL AND DAMAGING WINDS THROUGH LATE EVENING.

..THOMPSON.. 08/04/2015

.PREV DISCUSSION... /ISSUED 1127 AM CDT TUE AUG 04 2015/

...NEW ENGLAND...
VISIBLE SATELLITE IMAGERY SHOWS AN INCREASING CU FIELD OVER MUCH OF
NY AND NEW ENGLAND...WITH SCATTERED THUNDERSTORMS BEGINNING TO
DEVELOP.  STRONG HEATING AND DEWPOINTS IN THE 60S WILL YIELD
AFTERNOON MLCAPE VALUES OF 1000-1500 J/KG.  RATHER STRONG WESTERLY
FLOW ALOFT AND FAVORABLE VERTICAL SHEAR PROFILES WILL PROMOTE
DAMAGING WINDS AND HAIL IN THE STRONGER STORMS.  REFERENCE MCD 1605
AND WW 469 FOR FURTHER DETAILS.

...MID ATLANTIC REGION...
STRONG HEATING IS OCCURRING ACROSS THE MID ATLANTIC REGION...WHERE
DEWPOINTS IN THE 60S TO NEAR 70F AND AFTERNOON HIGHS IN THE 90S WILL
RESULT IN MODERATE CAPE VALUES.  AN INCREASING CU FIELD OVER THE
MOUNTAINS OF WV/WESTERN VA MAY BE INDICATIVE OF DEEPER MIXING AND
WILL LIKELY RESULT IN SCATTERED AFTERNOON THUNDERSTORMS.  THESE
STORMS WILL SPREAD EASTWARD ACROSS THE DELMARVA REGION.  AFTERNOON
FORECAST SOUNDINGS SHOW SUFFICIENT VERTICAL SHEAR AND STEEP LOW
LEVEL LAPSE RATES TO POSE A RISK OF MULTICELL OR EVEN TRANSIENT
SUPERCELL STORMS CAPABLE OF DAMAGING WINDS AND HAIL.

...CENTRAL/NORTHERN PLAINS...
NO CHANGES HAVE BEEN MADE TO THE OUTLOOK FOR THIS REGION.  SCATTERED
THUNDERSTORMS WILL BE POSSIBLE ALONG THE CORRIDOR FROM EASTERN MT
INTO KS/MO TODAY...WITH POCKETS OF AFTERNOON HEATING RESULTING IN A
FEW STRONG/SEVERE STORMS.  THE AREA SHOWING THE GREATEST POTENTIAL
FOR ORGANIZED SEVERE LATER TODAY APPEARS TO BE PARTS OF NEB/KS.




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