DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 011924
SWODY1
SPC AC 011922

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0222 PM CDT SUN JUL 01 2012

VALID 012000Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF THE MID
ATLANTIC...OH VALLEY AND UPPER MS VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF MT INTO THE WRN
DAKOTAS...

...CNTRL/ERN CAROLINAS INTO ERN GA...
EXPANDED THE SIGNIFICANT WIND PROBS ACROSS THE ENTIRE AREA. 18Z
SOUNDINGS SHOW EXCESSIVE INSTABILITY WITH LI VALUES OF -15 TO -18
AND HIGH PRECIPITABLE WATER APPROACHING 2.00 INCHES. STORMS SHOULD
CONTINUE TO GEL FROM CNTRL/ERN NC ALONG AND AHEAD OF THE
OUTFLOW...AS WELL AS INTO CNTRL SC AND ERN GA WITHIN THE SFC TROUGH.
DAMAGING WET MICROBURSTS ARE LIKELY...AND ONE OR MORE SMALL CLUSTERS
OF STORMS MAY EVENTUALLY FORM AND PROPAGATE SWD PRODUCING DAMAGING
WINDS. ALTHOUGH SHEAR IS WEAK...LARGE HAIL UP TO AROUND 2.00 INCHES
DIAMETER WILL BE POSSIBLE DUE TO EXTREME UPDRAFT VELOCITIES. A FEW
LARGER STONES COULD OCCUR WITH ISOLATED SUPERCELLS MOVING S OR SWWD
OFF THE HODOGRAPH

...IND/OH/WV...
A CLUSTER OF STORMS CONTINUES TO ORGANIZE ACROSS NRN IND...AND
SHOULD CONTINUE EWD...THEN SEWD ACROSS OH AND WV WHERE STRONG
INSTABILITY EXISTS. A CORRIDOR OF SEVERE WINDS MAY MATERIALIZE WITH
THIS CLUSTER...THUS HAVE EXTENDED THE 30% WIND PROBABILITIES SEWD.

...NERN KS/NWRN MO...
EXTENDED THUNDER AND 5% WIND PROBS SWD INTO THE REGION AS TOP
SOUNDING SHOWS A RELATIVELY MOIST/COOL PROFILE WITH LITTLE CAPPING.
GPS WATER VAPOR OBSERVATIONS SHOW A POCKET OF HIGHER VALUES AS
WELL...AND A STORM OR TWO COULD FORM OVER NERN KS WITH WEAK SPEED
CONVERGENCE AT THE SURFACE AND AN EXPANDING CU FIELD.

..JEWELL.. 07/01/2012

.PREV DISCUSSION... /ISSUED 1130 AM CDT SUN JUL 01 2012/

...MID ATLANTIC TO SRN NEW ENGLAND THIS AFTERNOON/EVENING...
STRONG SURFACE HEATING IS UNDERWAY FROM ERN VA TO SRN NEW
ENGLAND...WHERE BOUNDARY LAYER DEWPOINTS RANGE FROM 65-70 F. RECENT
VISIBLE IMAGERY SHOWS CUMULUS DEVELOPMENT IN SE NY ALONG A SURFACE
TROUGH...AND THUNDERSTORM DEVELOPMENT IS EXPECTED AROUND MIDDAY AS
THIS AREA IS BRUSHED BY A SUBTLE EMBEDDED SPEED MAX ROTATING EWD
FROM THE LOWER GREAT LAKES. STEEP LOW-LEVEL LAPSE RATES...MLCAPE
NEAR 1500 J/KG...AND EFFECTIVE BULK SHEAR NEAR 35 KT WILL SUPPORT
ORGANIZED MULTICELL CLUSTERS /AND PERHAPS SOME SUPERCELL STRUCTURES/
WITH AN ATTENDANT RISK FOR DAMAGING WINDS AND LARGE HAIL THIS
AFTERNOON.

FARTHER S INTO THE MID ATLANTIC...THE FOCUS FOR STORM DEVELOPMENT IS
NOT PARTICULARLY CLEAR. HOWEVER...THE MODIFIED 12Z IAD SOUNDING
SUPPORTS AFTERNOON MLCAPE OF AT LEAST 2500 J/KG WITH LITTLE
CONVECTIVE INHIBITION AS SURFACE TEMPERATURES WARM INTO THE LOW-MID
90S. THERE IS A WEAK UPSTREAM TROUGH/REMNANT MCV CROSSING THE
APPALACHIANS AS OF LATE MORNING...AND AT LEAST ISOLATED STORM
DEVELOPMENT APPEARS PROBABLE WITH CONTINUED DAYTIME HEATING. THE
MODERATE INSTABILITY AND MIDLEVEL FLOW NEAR 40 KT APPEARS SUPPORTIVE
OF BOTH ORGANIZED CLUSTERS AND MARGINAL SUPERCELLS...CAPABLE OF
PRODUCING DAMAGING WINDS AND LARGE HAIL.

...SRN VA/NC THIS AFTERNOON/EVENING...
A SMALL MCS OVER SW VA HAS PRODUCED DAMAGING WINDS AND ISOLATED
LARGE HAIL DURING THE PAST COUPLE OF HOURS. GIVEN THE STRONG
SURFACE HEATING DOWNSTREAM ACROSS VA/NC...MODIFIED 12Z SOUNDINGS
SUGGEST THAT SOME UPSCALE GROWTH AND MORE EXTENSIVE SURFACE-BASED
STORM DEVELOPMENT IS POSSIBLE THIS AFTERNOON. MIDLEVEL LAPSE RATES
ARE UNUSUALLY STEEP OVER THIS AREA...WHICH WILL SUPPORT
STRONG-EXTREME INSTABILITY THIS AFTERNOON AS SURFACE TEMPERATURES
WARM TO NEAR 100 F...ESPECIALLY ALONG AND E OF A WEAK SURFACE TROUGH
ACROSS THE CENTRAL CAROLINAS. GIVEN THE THERMODYNAMIC
ENVIRONMENT...AS WELL AS THE SRN FRINGE OF 30-40 KT MIDLEVEL WNWLY
FLOW...THERE WILL BE THE POTENTIAL FOR AN ORGANIZED DAMAGING WIND
CORRIDOR ACROSS SRN VA AND NC THIS AFTERNOON WITH THE ONGOING MCS.


...SC/GA/AL AREA THIS AFTERNOON/EVENING.
STORM DEVELOPMENT WILL LIKELY RELY ON INTENSE SURFACE HEATING AND
WEAK LOW-LEVEL CONVERGENCE ALONG THE SURFACE TROUGH FROM CENTRAL AL
ACROSS GA INTO SC...POTENTIALLY AIDED BY WEAK INLAND PENETRATION BY
THE ATLANTIC COAST SEA BREEZE IN SC/GA. VERTICAL SHEAR WILL BE
WEAK...BUT THE STRONG-EXTREME BUOYANCY AND STEEP LOW-MIDLEVEL LAPSE
RATES WILL STILL SUPPORT BOTH STRONG UPDRAFTS AND HAIL FORMATION
/PRIMARILY SC AND GA/...AS WELL AS DAMAGING WINDS WITH HYBRID
MICROBURSTS THIS AFTERNOON/EVENING.

...OH VALLEY THIS AFTERNOON/EVENING...
OUTFLOW/GRAVITY/FRONT MERGERS HAVE AIDED IN THE DEVELOPMENT OF A NEW
CLUSTER OF STORMS IMMEDIATELY S-SW OF CHICAGO. THIS AREA IS ON THE
SRN FRINGE OF THE STRONGER WLYS ALOFT...WHILE THE DOWNSTREAM AIR
MASS CONTINUES TO DESTABILIZE INTO INDIANA/OH. THERE WILL BE SOME
POTENTIAL FOR UPSCALE GROWTH/MCS FORMATION...WITH AN ATTENDANT RISK
FOR DAMAGING WINDS/LARGE HAIL TROUGH THE AFTERNOON.


...NRN HIGH PLAINS THIS AFTERNOON/TONIGHT...
NO SIGNIFICANT CHANGES...SEE PREVIOUS OUTLOOK DISCUSSION.

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