Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS02 KWNS 260607
SWODY2
SPC AC 260606

DAY 2 CONVECTIVE OUTLOOK AMEND 1
NWS STORM PREDICTION CENTER NORMAN OK
0106 AM CDT SAT JUL 26 2014

VALID 271200Z - 281200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF ERN KY...SRN
OH...AND WV...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE OH/TN VALLEYS EWD
ACROSS THE MID ATLANTIC AND NEW ENGLAND STATES...

AMENDED FOR SIG GRAPHIC

...SUMMARY...
TORNADOES...DAMAGING WINDS AND LARGE HAIL ARE EXPECTED ACROSS MUCH
OF EASTERN KENTUCKY...SOUTHERN OHIO AND WEST VIRGINIA DURING THE
AFTERNOON AND EVENING. SEVERE WEATHER IS ALSO EXPECTED ACROSS MUCH
OF THE MID-ATLANTIC AND NORTHEASTERN STATES WITH MAINLY DAMAGING
WINDS AND HAIL. ISOLATED HAIL AND WIND IS ALSO POSSIBLE ACROSS
SOUTHEASTERN ARIZONA.

...SYNOPSIS...
AN IMPRESSIVE UPPER TROUGH WILL DIVE SEWD FROM THE UPPER MS VALLEY
INTO THE OH VALLEY ON SUNDAY WITH MID TO UPPER LEVEL WINDS
INCREASING TO 60-90 KT RESPECTIVELY. AT THE SURFACE...THE PRIMARY
SURFACE LOW WILL TAKE SHAPE FROM LOWER MI INTO OH DURING THE
DAY...WITH SURFACE TROUGH/FRONT FROM OH SWWD ALONG THE OH RIVER.

PRECEDING THE COLD FRONT WILL BE CLUSTERS OF STORMS...PERHAPS A
SEVERE MCS...OVER SRN OH/WV/ERN KY IN THE MORNING...AND THIS MAY
AFFECT VA LATER IN THE DAY. OUTFLOW FROM THIS POTENTIAL MCS MAY AID
TORNADO POTENTIAL ACROSS THE MDT RISK AREA LATER IN THE DAY WHEN
WSWLY SURFACE WINDS AND COOLING ALOFT STRONGLY DESTABILIZE THE AREA.


TO THE E...A SURFACE TROUGH WILL ALSO DEEPEN E OF THE APPALACHIANS
WITH S WINDS BRINGING ATLANTIC MOISTURE NWD ACROSS THE DELMARVA AS
WELL AS INTO SRN NEW ENGLAND DURING THE DAY. AN UPPER-LEVEL
DISTURBANCE MAY AID IN RELATIVELY EARLY SEVERE STORM DEVELOPMENT
FROM ERN NY INTO SRN NEW ENGLAND WITH A SECOND ROUND OF STORMS
OCCURRING OVERNIGHT.

MOISTURE AND LIFT WITH A WWD-MOVING DISTURBANCE ACROSS NRN
MEXICO/SRN AZ MAY RESULT IN ISOLATED HAIL OR WIND.

...ERN INDIANA...CNTRL AND ERN KY...OH...WV...
A MORNING MCS IS LIKELY TO TRAVERSE THIS AREA AND MOST LIKELY AFFECT
THE SRN OH/ERN KY/WV AREA IN THE MORNING WITH AN ONGOING WIND
THREAT. BEHIND THIS SYSTEM...THE VEERED NATURE OF THE LOW-LEVEL FLOW
SHOULD ALLOW FOR RAPID DESTABILIZATION WITH UPPER 60S/LOWER 70S F
DEWPOINTS AS WELL AS EVENTUAL COOLING ALOFT WITH THE UPPER TROUGH.
AS FORCING FOR ASCENT INCREASES DURING THE AFTERNOON...STORMS SHOULD
FORM ALONG THE FRONT OVER ERN IND...WRN OH...AND INTO NRN
KY...MATURING AS THEY MOVE ESEWD INTO ERN KY...SRN OH...AND AGAIN
WV. STEEP LAPSE RATES ALOFT AND LONG HODOGRAPHS WILL SUPPORT ROBUST
SUPERCELLS WITH VERY LARGE HAIL LIKELY. RELATIVELY LOW LCLS AND
ENHANCED SRH MAY ALSO SUPPORT AN APPRECIABLE TORNADO THREAT. A
STRONG TORNADO OR TWO MAY OCCUR...ALTHOUGH THE PRECISE AREA WILL NOT
BE KNOWN UNTIL THE MORNING ACTIVITY DEPARTS AND MESOSCALE BOUNDARIES
SETUP.

...WV INTO PA AND NJ LATE...
A SEVERE MCS IS FORECAST TO EVOLVE OUT OF THE MDT RISK AREA...WITH
DAMAGING WINDS AND HAIL POSSIBLE ALONG THE LOW TRACK...AIDED BY A
STRONG VORT MAX AND ENHANCED CONVERGENCE WITH THE SURFACE LOW. A
TORNADO CANNOT BE RULED OUT WITH THIS ACTIVITY DUE TO BETTER
LOW-LEVEL SHEAR NEAR THE LOW.

...NRN VA...MD...DE...PA...NJ LATE AFTERNOON THROUGH EVENING...
AN MCS IS LIKELY TO BE ONGOING SOMEWHERE NEAR WV SUN MORNING...AND
IT IS UNCLEAR WHETHER IT WILL PERSIST INTO VA AND MD DURING THE DAY.
EVEN IF IT DOES NOT REMAIN INTACT...OUTFLOW BOUNDARIES...AS WELL AS
INCREASING CONVERGENCE WITH THE LEE SURFACE TROUGH SHOULD PROVIDE
ADDITIONAL FOCUS FOR SEVERE STORMS BY LATE AFTERNOON. SHEAR PROFILES
WILL BECOME QUITE FAVORABLE FOR SUPERCELLS WITH TIME...AND PLENTY OF
INSTABILITY WILL BE PRESENT TO SUPPORT THEM. LARGE HAIL WILL BE
LIKELY...AND A COUPLE TORNADOES WILL ALSO BE POSSIBLE GIVEN CELLULAR
STORM MODE AND MODESTLY-LOOPING HODOGRAPHS. THERE IS A STRONG
CONVECTIVE SIGNAL IN SEVERAL MODELS ACROSS MD...ERN VA AND DE NEAR
00Z.

...ERN NY INTO SRN NEW ENGLAND...
A LEADING UPPER DISTURBANCE IS FORECAST TO AFFECT ERN NY INTO SRN
NEW ENGLAND DURING THE LATE MORNING/EARLY AFTERNOON HOURS WITH
MOISTURE MOVING NWD OFF THE ATLANTIC. HEATING UPSTREAM ACROSS
NY...AS WELL AS LIFT ASSOCIATED WITH LOW-LEVEL WARM ADVECTION SHOULD
RESULT IN AT LEAST ISOLATED STORMS. SHEAR PROFILES WOULD FAVOR
SUPERCELLS CAPABLE OF LARGE HAIL AND GUSTY WINDS. LOW-LEVEL SHEAR
MAY BE WEAK THUS ANY TORNADO THREAT SHOULD BE BRIEF AND LIKELY WEAK.
OTHER STORMS WITH A DAMAGING WIND THREAT MAY APPROACH THE SRN NY
AREA LATE SUNDAY NIGHT AS ACTIVITY DEVELOPS ACROSS PA.

...SERN AZ...
A WEAK DISTURBANCE EMBEDDED IN THE EASTERLIES AROUND THE UPPER HIGH
WILL MOVE WWD ACROSS NRN MEXICO AND AFFECT SRN AZ BY AFTERNOON.
MEANWHILE...DAYTIME HEATING AND A MOIST AIR MASS WILL LEAD TO MUCAPE
UP TO 1500 J/KG WITH RELATIVELY STEEP LAPSE RATES ALOFT. ELY
MIDLEVEL FLOW AROUND 20 KT COMBINED WITH WLY SURFACE WINDS WILL HELP
MAXIMIZE HODOGRAPH LENGTH AND MAY FAVOR A FEW LONG-LIVED CELLS
CAPABLE OF HAIL AND WIND. PRESENCE OF EARLY CONVECTION AND CLOUDS
LENDS SOME UNCERTAINTY TO HOW MUCH SEVERE COVERAGE THERE MAY BE.

..JEWELL.. 07/26/2014




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