Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS02 KWNS 131731
SWODY2
SPC AC 131730

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT SUN JUL 13 2014

VALID 141200Z - 151200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE OZARKS/LOWER OH/TN
VALLEY TO THE MID-ATLANTIC STATES/SRN NEW ENGLAND...

...SUMMARY...
SEVERE THUNDERSTORMS WILL BE POSSIBLE PRIMARILY ACROSS PARTS OF THE
OZARKS...LOWER OHIO VALLEY...TENNESSEE VALLEY...MID-ATLANTIC STATES
AND SOUTHERN NEW ENGLAND ON MONDAY. MORE ISOLATED STRONG TO SEVERE
STORMS WILL BE POSSIBLE FROM THE SOUTHERN PLAINS NORTHWEST INTO THE
NORTHERN ROCKIES AND ACROSS CENTRAL AND SOUTHERN ARIZONA.

...SYNOPSIS...
AMPLIFICATION OF THE LARGE-SCALE UPPER AIR PATTERN WILL OCCUR MONDAY
AS A SEASONABLY STRONG UPPER LEVEL TROUGH BECOMES ESTABLISHED FROM
ONTARIO/QUEBEC SWD ACROSS THE GREAT LAKES AND OHIO VALLEY. A SERIES
OF IMPULSES OVER THE PAC NW/NRN ROCKIES WILL MOVE E/SEWD AT THE
CREST OF A RIDGE OF HIGH PRESSURE CENTERED OVER THE GREAT BASIN. A
PRONOUNCED COLD FRONT WILL EXTEND FROM THE LOWER GREAT LAKES ACROSS
THE SRN PLAINS MONDAY AFTN...WHILE A PRE-EXISTING SURFACE FRONTAL
BOUNDARY...REINFORCED BY PRIOR CONVECTIVE OUTFLOWS...WILL BE IN
PLACE IN ADVANCE OF THE FRONT FROM SRN NEW ENGLAND SWWD INTO
PORTIONS OF THE OHIO VALLEY/OZARKS.

...OZARKS/LOWER OH VALLEY/TN VALLEY TO MID-ATLANTIC STATES/NEW
ENGLAND...
SHOWERS/TSTMS WILL LIKELY BE PRESENT ALONG THE PRE-EXISTING
COMPOSITE FRONT/OUTFLOW BOUNDARY EARLY MONDAY AND WILL LIKELY
INFLUENCE SUBSEQUENT TSTM DEVELOPMENT LATER IN THE DAY. HOWEVER...AN
INCREASE IN TSTM COVERAGE IS EXPECTED COINCIDENT WITH AFTN HEATING
ALONG BOTH THE SWD-SURGING COLD FRONT AND THE PRE-EXISTING BOUNDARY
AS 60-90 METER HEIGHT FALLS DEVELOPS ACROSS THE GREAT LAKES/OHIO
VALLEY. THE PRESENCE OF STRENGTHENING WIND FIELDS AND HEATING OF A
MOIST BOUNDARY LAYER WITH UPPER 60S/LOWER 70S DEW POINTS WILL
PROVIDE A FAVORABLE ENVIRONMENT FOR ORGANIZED MULTICELLS AND LINE
SEGMENTS CAPABLE OF DAMAGING WINDS...WITH A FEW REPORTS OF LARGE
HAIL MOST LIKELY OVER THE OH/TN VALLEY REGION WHERE GREATER
INSTABILITY/STRONGER UPDRAFTS WILL BE PRESENT. THE SLIGHT RISK AREA
WAS EXTENDED NWD ACROSS SRN NEW ENGLAND WHERE 35-40 KTS OF SHEAR
WILL BE PRESENT BY AFTN AND HEATING OF LOWER 70S DEW POINTS WILL
SUPPORT MLCAPE OF 1000-1500 J/KG. DAMAGING WINDS ARE ALSO LIKELY
WITH TSTMS ALONG THE FRONTAL BOUNDARY IN THIS AREA. BOTH NAM AND GFS
GUIDANCE DEPICT SOMEWHAT STRONGER LOW-LEVEL WINDS ASSOCIATED WITH A
WEAK SFC LOW THAT MAY RESULT IN AT LEAST SOME RISK FOR A TORNADO
WITH ANY SEMI-DISCRETE TSTM.

...SRN PLAINS NWWD TO NRN ROCKIES...
ISOLATED TO WIDELY SCTD TSTMS ARE EXPECTED DRIVEN MAINLY BY DIURNAL
HEATING AND/OR UPSLOPE FLOW FROM THE SRN PLAINS NWWD ACROSS THE NRN
ROCKIES. STRONGER EFFECTIVE SHEAR IN ASSOCIATION WITH A SEWD-MOVING
SHORTWAVE ACROSS THE NRN ROCKIES MAY RESULT IN A LOCALLY MORE
FAVORABLE ENVIRONMENT FOR ORGANIZED SVR TSTMS.

...SOUTHWEST...
ELY FLOW IN THE MID LEVELS AND STRONG DAYTIME HEATING WILL ALLOW
TSTMS MOVING WWD INTO THE LOWER ELEVATIONS TO POSE A RISK OF
DAMAGING WINDS IN THE PRESENCE OF STEEP LOW-LEVEL LAPSE RATES/DRY
SUB-CLOUD LAYER.

..BUNTING.. 07/13/2014



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