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
000
ACUS03 KWNS 110738
SWODY3
SPC AC 110737

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0237 AM CDT FRI JUL 11 2014

VALID 131200Z - 141200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MIDWEST AND OH VALLEY
TO WESTERN PA/NY...

...SUMMARY...
SEVERE STORMS WILL BE POSSIBLE OVER PARTS OF THE OHIO VALLEY AND
NORTHEAST ON SUNDAY. MORE ISOLATED STRONG TO SEVERE STORMS WILL ALSO
BE POSSIBLE ACROSS THE CENTRAL PLAINS...THE SOUTHWEST...AS WELL AS
OREGON.

...SYNOPSIS...
A POSITIVE-TILT MID/UPPER TROUGH AND ASSOCIATED DEEP-LAYER CYCLONE
WILL CONTINUE TO UNDERGO AMPLIFICATION/DEEPENING ACROSS THE NORTHERN
PLAINS AND GREAT LAKES THROUGH SUNDAY. AS A LEADING SHORTWAVE TROUGH
ON THE EASTERN FLANK OF THE UPPER LOW TRACKS FROM NEAR LAKE HURON TO
SOUTHERN QUEBEC...NORTH OF THE ST. LAWRENCE VALLEY...A STRONGER
IMPULSE IS FORECAST TO PIVOT AROUND THE WESTERN FLANK OF THE UPPER
LOW AND DIG SOUTH ACROSS THE NORTHERN PLAINS AND UPPER MS VALLEY.
BETWEEN THESE TWO SHORTWAVE TROUGHS...A BELT OF FASTER MID-LEVEL
CYCLONIC FLOW WILL EXTEND FROM THE DAKOTAS ACROSS THE GREAT LAKES TO
NORTHERN NEW ENGLAND...COINCIDENT WITH A SURFACE COLD FRONT. A
WEAKER/LEADING TROUGH AND ASSOCIATED WARM/MOIST CONVEYOR BELT WILL
EXTEND FROM THE MIDWEST/OH VALLEY NORTHEAST TO NY/NEW ENGLAND.

ELSEWHERE...MID-LEVEL ANTICYCLONE WILL REMAIN CENTERED ACROSS THE
GREAT BASIN WHILE A PACIFIC SHORTWAVE TROUGH PRODUCES WEAK HEIGHT
FALLS OVER THE NORTHWEST.

...MIDWEST/OH VALLEY...
THIS SHOULD BE THE MOST LIKELY REGION TO EXPERIENCE SCATTERED SEVERE
STORMS DURING THE DAY ON SUNDAY. WHILE REGION WILL LIE AMIDST A
RELATIVE MIN IN TERMS OF STRONGER HEIGHT FALLS ASSOCIATED WITH THE
DEVELOPING UPPER TROUGH...ONGOING CONVECTION AND/OR CONVECTIVE
DEBRIS SHOULD AID IN THE DEVELOPMENT OF STRONGER LOW LEVEL
BOUNDARIES TO RE-FOCUS STORMS DURING THE DIURNAL HEATING CYCLE.
AREAS OF STRONG INSTABILITY ARE LIKELY GIVEN 1) PROXIMITY TO STEEPER
MID-LEVEL LAPSE RATES EMANATING FROM THE CENTRAL PLAINS...AND 2)
CORRIDOR RICH LOW LEVEL MOISTURE WITH ORIGINS ACROSS THE SOUTH/LOWER
MS VALLEY. STRENGTHENING AND DIFFLUENT MID-LEVEL FLOW WILL FURTHER
AID STORM DEVELOPMENT/ORGANIZATION WITH THE POSSIBILITY OF CLUSTERS
AND/OR LINES OF STORMS CAPABLE OF PRODUCING WIND DAMAGE.

...ERN NY/NEW ENGLAND...
MORE UNCERTAINTY EXISTS WITH RESPECT TO STORM TIMING AND EVOLUTION
ACROSS THESE AREAS. REGION WILL LIKELY LIE NEAR THE NOSE OF STRONGER
LOW LEVEL JET ACCOMPANYING THE LEADING/DEAMPLIFYING SHORTWAVE
CROSSING QUEBEC. MODEST INSTABILITY AND ADEQUATE SHEAR COULD SUPPORT
AT LEAST ISOLATED SEVERE STORMS WITH HAIL/WIND...POSSIBLY RELATIVELY
EARLY IN THE DAY FROM EASTERN NEW YORK ACROSS VT/NH. IF GREATER
CONFIDENCE IS REALIZED IN LATER FORECASTS...SEVERE PROBABILITY OVER
SOME OF THESE AREAS MAY NEED TO BE INCREASED IN LATER OUTLOOKS.

...SOUTHWEST...
EASTERLY FLOW ON THE SOUTHERN FLANK OF GREAT BASIN ANTICYCLONE...IN
COMBINATION WITH MONSOON MOISTURE AND STRONG HEATING...SHOULD RESULT
IN ISOLATED TO SCATTERED STORMS SPREADING WEST OFF THE HIGHER
TERRAIN WITH BOTH DAMAGING WINDS AND MARGINAL HAIL POTENTIAL.

...NORTHWEST...
STRONG HEATING OF THE NORTHERN PERIPHERY OF MONSOON MOISTURE PLUME
AND ASCENT ASSOCIATED WITH A PACIFIC SHORTWAVE TROUGH MOVING INLAND
COULD RESULT IN SCATTERED STRONG TO A FEW SEVERE STORMS ACROSS PARTS
OF OREGON DURING THE DAY/EVENING.

..CARBIN.. 07/11/2014



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