Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 290548
SWODY1
SPC AC 290547

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1247 AM CDT FRI JUL 29 2016

VALID 291200Z - 301200Z

...THERE IS A MRGL RISK OF SVR TSTMS FOR THE COASTAL MID-ATLANTIC
STATES AND SRN COASTAL NEW ENGLAND...

...THERE IS A MRGL RISK OF SVR TSTMS FROM THE N-CNTRL HIGH PLAINS
INTO THE SRN PLAINS AND NEWD INTO THE LOWER OH VALLEY...

...THERE IS A MRGL RISK OF SVR TSTMS FOR PORTIONS OF SRN AZ...

...SUMMARY...
ISOLATED STRONG THUNDERSTORMS ARE POSSIBLE ACROSS PARTS OF THE
MID-ATLANTIC REGION TO LONG ISLAND AND COASTAL AREAS OF SOUTHERN NEW
ENGLAND MAINLY THIS MORNING.  OTHER STRONG TO SEVERE THUNDERSTORMS
ARE POSSIBLE FROM PARTS OF THE OHIO VALLEY INTO THE SOUTHERN GREAT
PLAINS AND NORTHWESTWARD INTO THE CENTRAL HIGH PLAINS AND OVER THE
LOWER DESERTS OF SOUTHERN ARIZONA.

...SYNOPSIS...
A WEAK DISTURBANCE OVER THE CNTRL PLAINS WILL MOVE EWD INTO THE OH
VALLEY DURING THE PERIOD AS A BELT OF BROAD CYCLONIC UPPER-LEVEL
FLOW REMAINS FROM THE NRN HIGH PLAINS SEWD INTO THE MID MS VALLEY
AND NEWD TO THE CANADIAN MARITIMES.  A WEAK COLD FRONT WILL EXTEND
FROM THE OH VALLEY INTO ARKANSAS WITH THE WRN PORTION OF THE
BOUNDARY BECOMING MODULATED BY CONVECTIVE OUTFLOW AND EFFECTIVELY
DRAPED ACROSS OK TO WEAK LOW PRESSURE OVER NERN NM.  FARTHER E...A
SURFACE LOW WILL DEVELOP NEWD FROM THE DELMARVA REGION INTO THE WRN
ATLANTIC SE OF LONG ISLAND/SRN NEW ENGLAND THROUGH MIDDAY.

...DELMARVA INTO COASTAL SRN NEW ENGLAND THIS MORNING...
SURFACE LOW PRESSURE IS FORECAST TO DEVELOP NEWD FROM NEAR THE
DELMARVA COAST NEWD TO PROBABLY S OF LONG ISLAND.  MODELS VARY
SLIGHTLY ON THE TRACK OF THE LOW WITH SOME GUIDANCE SHOWING SOME
APPRECIABLE DESTABILIZATION OCCURRING NEAR THE IMMEDIATE COAST
DURING THE MORNING HOURS.  IF THE LOW TRACKS NEAR THE
COAST...LOW-LEVEL WIND PROFILES WILL CONDITIONALLY SUPPORT STORM
ORGANIZATION.  PROBABLY THE BIGGEST LIMITING FACTOR WILL BE THE VERY
MOIST/POOR LAPSE RATE ENVIRONMENT.  HOWEVER...IF A STRONG STORM
MANAGES TO DEVELOP...A RISK FOR LOCALIZED DAMAGING WIND MAY RESULT.

...TX/OK INTO THE OZARKS AND OH VALLEY...
A FRONTAL SEGMENT LOCATED OVE THE OH VALLEY WILL SERVE AS A FOCUS
FOR ISOLD STORM DEVELOPMENT DURING THE DAY.  MLCAPE RANGING FROM
1000-2500 J/KG IS FORECAST TO DEVELOP BY AFTERNOON WITHIN A CORRIDOR
OF EFFECTIVE SHEAR AROUND 30 KT FROM THE MID MS VALLEY INTO THE OH
VALLEY.  ORGANIZED MULTICELLS CAPABLE OF ISOLD DAMAGING WINDS WILL
BE THE MAIN THREAT.  FARTHER SW...THE EFFECTIVE FRONT/COMPOSITE
BOUNDARY WILL BECOME DRAPED ACROSS OK.  DEWPOINTS RANGING FROM THE
LOW-MID 70S OVER CNTRL-ERN OK TO THE 50S OVER PORTIONS OF THE TX
PANHANDLE WILL CONTRIBUTE TO MODERATE TO STRONG BUOYANCY AMIDST
MARGINAL WLY FLOW ALOFT.  ISOLD LARGE HAIL/SEVERE GUSTS WILL BE
POSSIBLE WITH THE STRONGER STORMS AND/OR CLUSTERS.

...BLACK HILLS INTO THE CNTRL HIGH PLAINS...
MODELS INDICATE THE TRAILING PORTION OF THE BELT OF STRONGER NWLY
MID-LEVEL FLOW WILL EXTEND NW FROM THE CNTRL PLAINS INTO THE N-CNTRL
HIGH PLAINS.  UPSLOPE COMPONENT TO THE LOW-LEVEL FLOW WILL MAINTAIN
A FETCH OF 50S TO LOWER 60S DEWPOINTS INTO THE HIGH PLAINS REGION
AND YIELD MODERATE CAPE BY MID-LATE AFTERNOON.  THE STRONGER STORMS
WILL PROBABLY BE CAPABLE OF LARGE HAIL/ISOLD SEVERE GUSTS.  THIS
ACTIVITY WILL LIKELY WEAKEN DURING THE EVENING AS CINH INCREASES AS
STORMS MOVE FARTHER E IN THE HIGH PLAINS AFTER SUNSET.

...SERN AND S-CNTRL AZ...
ISOLD STORMS ARE FORECAST TO DEVELOP BY LATE AFTERNOON OVER THE
HIGHER TERRAIN.  STRONG HEATING WILL LEAD TO VERY STEEP LAPSE RATES
AND 20 KT ELY H5 FLOW WILL CONTRIBUTE TO STORMS MOVING INTO THE
LOWER DESERTS POTENTIALLY POSING AN ISOLD RISK FOR SEVERE GUSTS.

..SMITH/GLEASON.. 07/29/2016

$$


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