Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 011954
SWODY1
SPC AC 011953

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0253 PM CDT FRI JUL 01 2016

VALID 012000Z - 021200Z

...THERE IS AN ENH RISK OF SVR TSTMS ACROSS ERN NY...NERN PA AND NRN
NJ...WRN NEW ENGLAND...

...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN VA NWD INTO WRN NEW
ENGLAND...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS MUCH OF THE NERN
STATES...

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE CNTRL PLAINS...

...SUMMARY...
SEVERE THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND EVENING OVER
PARTS OF THE NORTHEAST AND MID-ATLANTIC. FARTHER WEST...ISOLATED
STRONG TO SEVERE STORMS ARE POSSIBLE MAINLY FROM EASTERN COLORADO
INTO CENTRAL KANSAS LATE THIS AFTERNOON AND TONIGHT.

...CNTRL PLAINS - REMOVED SLIGHT RISK...
EXTENSIVE CLOUDS REMAIN OVER THE AREA ALTHOUGH AREAS OF HEATING WERE
OCCURRING ESPECIALLY FROM SERN CO INTO THE OK/TX PANHANDLES. A
RELATIVELY MOIST BOUNDARY LAYER EXISTS AREA-WIDE AND A LOW-LEVEL JET
WILL INCREASE OUT OF THE S THIS EVENING. HOWEVER...TEMPERATURES
ALOFT REMAIN RELATIVELY WARM WITH LITTLE MID OR HIGH LEVEL FLOW. AN
ISOLATED SUPERCELL WITH HAIL OR BRIEF TORNADO APPEARS MOST LIKELY
OVER SERN CO...AND POSSIBLY EXTENDING INTO THE OK/TX PANHANDLE NEAR
OUTFLOW BOUNDARY LATE THIS AFTERNOON. BY THIS EVENING...STORMS WILL
BECOME MORE NUMEROUS DUE TO THE INCREASING WARM ADVECTION AND LIFT
NEAR THE WARM FRONT BUT SLOW-MOVING HEAVY RAIN STORMS APPEAR MOST
PROBABLE WITH ONLY ISOLATED SEVERE WIND GUSTS OR MARGINAL HAIL
EXPECTED.

...CAROLINAS - REMOVED MARGINAL RISK...
STRONGER MID TO UPPER LEVEL FLOW CURRENTLY EXISTS ROUGHLY N OF THE
VA/NC BORDER IN ASSOCIATION WITH THE UPPER TROUGH WITH MUCH WEAKER
WIND FIELDS SWD INTO SC. HERE...MIDLEVEL TEMPERATURES ARE ALSO
WARM...AND STORMS ACROSS THE ERN CAROLINAS HAVE BEEN WEAK AND ARE
ALSO FIGHTING DRY AIR ALOFT. AS A RESULT...HAVE REDUCED SEVERE
PROBABILITIES ACROSS THIS AREA.

...NERN STATES...
STORMS ARE EVOLVING AS DESCRIBED IN THE PREVIOUS OUTLOOK WITH
SUPERCELLS NOW OVER PARTS OF ERN NY. HAIL...WIND...AND ISOLATED
TORNADOES WILL CONTINUE TO BE POSSIBLE THROUGH EARLY EVENING AS WIND
FIELDS CONTINUE TO INCREASE...SUPPORTING SEVERE STORMS.

..JEWELL.. 07/01/2016

.PREV DISCUSSION... /ISSUED 1129 AM CDT FRI JUL 01 2016/

...SYNOPSIS...
PROGRESSIVE PATTERN WILL PERSIST ACROSS THE LWR 48...WITH THE MAIN
BELT OF THE WLYS CONTINUING OVER THE NRN TIER OF STATES. FAIRLY
POTENT SHORTWAVE TROUGH NOW APPROACHING THE LWR GRT LKS WILL PIVOT
E/SE INTO WRN QUE/NRN NY THIS EVE...AND CROSS THE LWR ST LAWRENCE
VLY EARLY SAT...WHILE ASSUMING A NEGATIVE TILT. ATTENDANT SFC LOW
WILL DEEPEN OVER SRN QUE TODAY/TNGT AS TRAILING COLD FRONT
ACCELERATES ESEWD...REACHING AN ERN NY/CNTRL MD AXIS BY EARLY EVE.
AT THE SAME TIME...LINGERING FRONT OVER THE LWR CHESAPEAKE BAY
REGION SHOULD FURTHER WEAKEN...ALLOWING RICHER LOW-LVL MOISTURE TO
SPREAD NE INTO SERN NY AND SRN/WRN NEW ENGLAND.

FARTHER W...MODEST MID-LVL WLY FLOW WILL CONTINUE FROM THE FOUR
CORNERS REGION INTO THE CNTRL PLNS BENEATH SRN STREAM JET. UPSLOPE
FLOW WILL PERSIST N OF DIFFUSE W-E FRONT NOW STALLING OVER OK/NW
TX...AND N OF LEE LOW EXPECTED TO EVOLVE LATER TODAY OVER NE NM AND
THE NWRN TX PANHANDLE.

...NORTHEAST/MID-ATLANTIC TODAY INTO TNGT...
SEASONABLY STRONG 700-500 MB FLOW ALREADY PRESENT OVER PARTS OF THE
NERN U.S. WILL FURTHER STRENGTHEN AND SPREAD E/NE INTO NEW ENGLAND
LATER TODAY/TNGT AS GRT LKS TROUGH CONTINUES GENERALLY EWD.
SFC/STREAMLINE ANALYSES SUGGEST THAT A CONFLUENCE AXIS IS BEGINNING
TO EVOLVE THIS MORNING FROM ERN WV NWD INTO CNTRL NY...WELL E OF
BOTH THE OHIO COLD FRONT AND WRN PA/NY CONVECTIVE BAND. AT THE SAME
TIME...SFC AND SATELLITE PW DATA SHOW APPRECIABLE MOISTURE
/DEWPOINTS IN THE UPR 60S F AND PW AROUND 1.5 INCHES/ SPREADING NWD
FROM THE DELMARVA REGION ACROSS ERN PA AND NJ.

CONTINUED SFC HEATING AND MOISTENING ALONG WITH MODERATE FORCING FOR
ASCENT WITH UPR TROUGH SHOULD RESULT IN FAIRLY WIDESPREAD AFTN STORM
DEVELOPMENT IN WEAKLY-CAPPED ENVIRONMENT FROM CNTRL/ERN NY SWD INTO
MD-VA. DEVELOPMENT MAY BE MOST CONCENTRATED ALONG THE CONFLUENCE
AXIS AND...POSSIBLY...ON ERN EDGE OF WRN PA/NY CONVECTIVE BAND.

AMPLE /40+ KT/ WSWLY DEEP SHEAR WILL BE PRESENT FOR SUSTAINED
STORMS/SUPERCELLS...BUT STORM MODE WILL BE COMPLEX GIVEN MULTIPLE
SOURCES OF LOW-LVL UPLIFT AND WEAK CINH. WITH TIME...OVERALL SET-UP
SUGGESTS LIKELY EVOLUTION INTO A FAIRLY EXTENSIVE NE/SW SQLN...WITH
THE MOST PROGRESSIVE/LONG-LIVED PART CONTINUING EWD INTO WRN/CNTRL
NEW ENGLAND BY EVE. STORMS THROUGHOUT THE SLIGHT RISK AREA WILL BE
CAPABLE OF SVR HAIL /ESPECIALLY THIS AFTN/...WITH INCREASING
LIKELIHOOD FOR DMGG WIND. DEPENDING UPON STORM MODE AND TERRAIN
INTERACTIONS...SOME RISK ALSO WILL EXIST FOR
TORNADOES...PARTICULARLY FROM ERN PA/NJ NEWD INTO ERN NY/WRN NEW
ENGLAND LATE THIS AFTN AND THIS EVE...WHERE IT APPEARS THAT MOST
FAVORABLE OVERLAP OF INCREASING MOISTURE/DIRECTIONAL SHEAR WILL
RESIDE ATOP POTENTIAL SUPERCELL STRUCTURES.

...CNTRL HIGH PLNS ESEWD LATE THIS AFTN/TNGT...
CONSIDERABLE CLOUD COVER IN WAKE OF OVNGT STORMS WILL LIMIT SFC
HEATING OVER THE CNTRL HIGH PLNS AND ADJACENT FOOTHILLS
TODAY...DOWNSTREAM FROM FOUR CORNERS/LWR CO VLY UPR IMPULSE AND N OF
STALLED FRONT. NEVERTHELESS...COMBINATION OF PERSISTENT MOIST/ESELY
UPSLOPE FLOW AND WEAK HEIGHT FALLS WITH APPROACHING UPR SYSTEM
LIKELY WILL SUPPORT FAIRLY WIDESPREAD AFTN/EVE STORMS OVER S
CNTRL/SE CO. OTHER STORMS MAY FORM ALONG RESIDUAL OUTFLOW BOUNDARY
SEGMENTS/DIFFERENTIAL HEATING ZONES ESEWD INTO KS. MARGINALLY SVR
HAIL AND LOCALLY DMGG GUSTS MAY ACCOMPANY SOME STORMS. A TORNADO OR
TWO ALSO CANNOT BE RULED OUT GIVEN DEGREE OF MOISTURE /PW AOA 1.5
INCHES/ AND SOME DEGREE OF LOW-LVL DIRECTIONAL SHEAR. BUT MODEST
MEAN FLOW...WEAK LOW- TO MID-LVL LAPSE RATES...AND COMPLEX STORM
MODES SHOULD LIMIT STRENGTH/PERSISTENCE OF INDIVIDUAL UPDRAFTS...AND
THE OVERALL SVR RISK. THE STORMS SHOULD MERGE INTO A SIZABLE ESE OR
SE-MOVING MCS OVER KS TNGT/EARLY SAT...WITH A CONTINUING RISK FOR
OCCASIONAL LOCALLY DMGG GUSTS.

...CAROLINAS THIS AFTN...
HAVE MAINTAINED EXISTING MRGL SVR RISK ACROSS S CNTRL VA AND CNTRL
PORTIONS OF THE CAROLINAS...WHERE MODERATE INSTABILITY WILL DEVELOP
IN WAKE OF OFFSHORE CONVECTIVE COMPLEX. MODEST DEEP SHEAR AND
FORCING FOR ASCENT SHOULD...HOWEVER...LIMIT STORM
STRENGTH/LONGEVITY.

$$



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