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 280102
SWODY1
SPC AC 280100

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0800 PM CDT SUN JUL 27 2014

VALID 280100Z - 281200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS ERN PARTS OF THE OH
VALLEY...TN VALLEY...SRN TO CNTRL APPALACHIAN MTNS...THE
MID-ATLANTIC AND SRN NEW ENGLAND...

...THERE IS A SLGT RISK OF SVR TSTMS FOR PORTIONS OF CNTRL AND SERN
AZ...

...SUMMARY...
SEVERE THUNDERSTORMS ARE EXPECTED THIS EVENING AND TONIGHT ACROSS
THE EASTERN PORTIONS OF THE OHIO VALLEY...SOUTHERN
APPALACHIANS...AND MID ATLANTIC COAST REGION.  ISOLATED LARGE
HAIL...DAMAGING STRAIGHT-LINE WINDS...AND THE THREAT FOR A FEW
TORNADOES WILL REMAIN POSSIBLE.  SCATTERED THUNDERSTORMS ARE
FORECAST TO POSE AN ISOLATED DAMAGING WIND GUST THREAT OVER CENTRAL
AND SOUTHEASTERN ARIZONA THIS EVENING.

...ERN TN INTO NC/VA...
A POTENT MID-LEVEL TROUGH/SPEED MAX WILL MOVE FROM THE SRN GREAT
LAKES EWD TO THE CNTRL APPALACHIANS BY MONDAY MORNING AND MID LEVEL
HEIGHT FALLS WILL OVERSPREAD THIS AREA THIS EVENING AND INTO THE
OVERNIGHT HOURS.  EVENING SURFACE OBSERVATIONS CONFIRM MOISTURE RICH
LOW-LEVELS ARE IN PLACE...AND CHARACTERIZED BY DEWPOINTS IN THE
70-72 DEG F RANGE.  DESPITE THE LOSS OF HEATING...MODERATE BUOYANCY
/1000-2000 J PER KG MLCAPE/ WILL CONTRIBUTE TO MAINTAINING SOME
SEVERE THREAT INTO THE LATE NIGHT HOURS.  ALTHOUGH MODELS VARY
CONSIDERABLY REGARDING CONVECTIVE COVERAGE...ISOLATED TO SCATTERED
STORMS ARE FORECAST TO POSE AN ISOLATED LARGE HAIL/DMGG WIND THREAT.
 PERHAPS THE HIGHEST POTENTIAL TORNADO RISK WILL OCCUR THIS
EVENING/TONIGHT E OF THE APPALACHIANS AS EFFECTIVE SRH INCREASES
CONCURRENT WITH STRENGTHENING LOW- TO MID-LEVEL WIND FIELDS.

...LOWER TN VALLEY AND OH VALLEY EWD TO PA AND SRN NY/NJ...
SIGNIFICANT FORCING FOR ASCENT PROVIDED BY DCVA ASSOCIATED WITH THE
MID LEVEL TROUGH WILL PROVIDE AN IMPETUS FOR SCTD CLUSTERS OF STRONG
TO SEVERE STORMS THIS EVENING.  ISOLD OCCURRENCES OF LARGE HAIL/DMGG
WINDS AND PERHAPS A TORNADO OR TWO ARE POSSIBLE WITH THIS ACTIVITY.

...CNTRL AND SERN AZ...
SCTD THUNDERSTORMS HAVE DEVELOPED THIS EVENING AND ARE MOVING FROM
THE HIGHER TERRAIN IN ERN AND CNTRL AZ WESTWARD INTO THE LOWER
DESERTS OF SERN AND CNTRL AZ.  STEEP LAPSE RATES SAMPLED BY THE
EVENING RAOBS AHEAD OF THIS ACTIVITY WILL LIKELY FOSTER POTENTIAL
FOR ISOLATED DMGG WINDS WITH THE MORE INTENSE EVAPORATIVELY-COOLED
DOWNDRAFTS.  THE UPSCALE GROWTH OF COLD POOLS THIS EVENING MAY SERVE
TO ENHANCE OVERALL STORM LONGEVITY AND AUGMENT COVERAGE OF STRONG TO
SEVERE WIND GUSTS--LENDING AN UPGRADE TO CATEGORICAL SLIGHT RISK.

...AR/OK AND THE SRN HIGH PLAINS THIS EVENING...
THE SWRN EXTENSION OF THE ERN U.S. COLD FRONT WILL SLOWLY MOVE SWD
ACROSS THIS REGION TONIGHT.  A FEW AREAS OF ISOLATED THUNDERSTORMS
HAVE DEVELOPED INVOF THIS BOUNDARY WHERE LOW-LEVEL CONVERGENCE AND
THETA-E ARE MAXIMIZED.  A FEW STRONGER UPDRAFT PULSES MAY RESULT IN
THE CHANCE FOR A LOCALIZED STRONG WIND GUST FOR THE NEXT FEW
HRS...BUT NOCTURNAL COOLING THIS EVENING WILL LIKELY SERVE TO WEAKEN
STORMS.

..SMITH.. 07/28/2014



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