Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 281248
SWODY1
SPC AC 281247

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0747 AM CDT THU JUL 28 2016

VALID 281300Z - 291200Z

...THERE IS AN ENH RISK OF SVR TSTMS NE CO...WRN KS...FAR SW
NEB...FAR NW OK...

...THERE IS A SLGT RISK OF SVR TSTMS CNTRL HIGH PLAINS TO S-CNTRL
PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS LOWER MID-ATLANTIC REGION...

...THERE IS A MRGL RISK OF SVR TSTMS CNTRL HIGH PLAINS TO S-CNTRL
PLAINS...

...THERE IS A MRGL RISK OF SVR TSTMS SRN APPALACHIANS TO LOWER
MID-ATLANTIC...

...THERE IS A MRGL RISK OF SVR TSTMS NRN NEW ENGLAND...

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

...SUMMARY...
SCATTERED SEVERE STORMS ARE MOST LIKELY ACROSS THE CENTRAL HIGH
PLAINS AND PARTS OF KANSAS TO NORTHERN OKLAHOMA. LARGE HAIL AND A
COUPLE TORNADIC STORMS ARE ANTICIPATED LATE AFTERNOON TO EARLY
EVENING...WITH STORMS EVOLVING INTO A SQUALL LINE PRODUCING SEVERE
WIND GUSTS TONIGHT.

...CENTRAL HIGH PLAINS TO THE SOUTH-CENTRAL GREAT PLAINS...
DECAYING OVERNIGHT CONVECTION WAS NOTED ACROSS PARTS OF WESTERN TO
SOUTH-CENTRAL KS...WITH PERSISTENT STORM CLUSTERS OVER THE NEB
PANHANDLE TO NORTHERN WY. PRESENCE OF THIS ACTIVITY AND THEIR
SUBSEQUENT EFFECT ON BOUNDARY-LAYER MOISTURE LENDS TO
LOWER-THAN-AVERAGE CONFIDENCE THIS FORECAST CYCLE. 00Z WRF/NMM-B
BASED CAMS...WHICH DID NOT HANDLE THE LONGEVITY OF THE KS CONVECTION
THAT WELL...SUGGEST THAT THE NEB PANHANDLE/NORTHERN WY CLUSTERS
EVOLVE INTO THE PRIMARY SHOW FOR SEVERE POTENTIAL...DEPICTING
UPSCALE GROWTH INTO A FORWARD-PROPAGATING MCS ACROSS PARTS OF
WESTERN/CENTRAL NEB/KS THIS AFTERNOON. MEANWHILE...THE 09Z HRRR-ESRL
FAVORS A VASTLY DIFFERENT SCENARIO WITH INITIALLY ISOLATED
SUPERCELLS DEVELOPING OFF THE FRONT RANGE LATE AFTERNOON...GROWING
INTO ONE OR MORE CLUSTERS ACROSS EASTERN CO/WESTERN KS TOWARDS THE
TX PANHANDLE/NORTHWEST OK.

DIABATIC HEATING AMID VERY STEEP MID-LEVEL LAPSE RATES /9.5 DEG C/KM
FROM 700-500 MB SAMPLED IN 12Z DNR RAOB/ IS MOST LIKELY ACROSS THE
CENTRAL HIGH PLAINS REGION WEST OF ONGOING CLOUD DEBRIS. WITH
SURFACE DEW POINTS FROM THE MIDDLE 50S TO LOWER 60S BEING MAINTAINED
WEST OF THE AFOREMENTIONED MORNING CONVECTION...MODERATE BUOYANCY
SHOULD DEVELOP. GIVEN SUBSTANTIAL VEERING OF THE WIND PROFILE WITH
HEIGHT...THE MOST PROBABLE CORRIDOR FOR A FEW SUPERCELLS SHOULD BE
IN THE LEE OF THE FRONT RANGE. WITH CONFINED INTENSIFICATION OF A
SOUTHERLY LLJ OVER THE SOUTH-CENTRAL HIGH PLAINS...IT SEEMS
PLAUSIBLE THAT UPSCALE GROWTH INTO A SOUTHEASTWARD-MOVING
FORWARD-PROPAGATING MCS MAY OCCUR.

FARTHER EAST...WHILE THE 12Z DDC RAOB SAMPLED THE DELETERIOUS
EFFECTS OF OVERNIGHT CONVECTION...A PLUME OF MIDDLE 60S SURFACE DEW
POINTS REMAINS PRESENT ALONG THE NEB/KS BORDER. STORMS WITHIN A
FAVORED CORRIDOR OF LARGE-SCALE ASCENT TIED TO THE SHORTWAVE TROUGH
SHIFTING SOUTHEAST ACROSS THE CENTRAL GREAT PLAINS MAY INTENSIFY AS
THEY IMPINGE ON THIS PLUME. THIS COULD BE TIMED FAVORABLY FOR PEAK
HEATING AND SUPPORT A SEVERE WIND RISK TO EASTERN KS THROUGH
EVENING.

...SOUTHERN APPALACHIANS TO LOWER MID-ATLANTIC REGION...
A BROAD SWATH OF CONVECTION IS ONGOING FROM THE OH VALLEY TO
MID-SOUTH. WHILE CLOUD DEBRIS IMMEDIATELY AHEAD OF THIS ACTIVITY
WILL SLOW DESTABILIZATION...AREAS FROM THE LEE OF THE SOUTHERN
APPALACHIANS INTO VA SHOULD HAVE PRONOUNCED DIABATIC HEATING AMID
RICH BOUNDARY-LAYER MOISTURE. THIS WILL CONTRIBUTE TO MODERATE
BUOYANCY WITH MLCAPE INCREASING TO AROUND 1500-2500 J/KG. SCATTERED
TO WIDESPREAD STORMS WILL DEVELOP DURING THE AFTERNOON WITHIN A BELT
OF 25-40 KT MID-LEVEL WEST-SOUTHWESTERLIES. THIS SHOULD FAVOR
ORGANIZED CLUSTERS AND A FEW TRANSIENT SUPERCELLS WITH DAMAGING
WINDS AS THE MAIN HAZARD.

...NORTHERN NEW ENGLAND...
ROBUST DEEP-LAYER SHEAR PROFILES WILL BE MAINTAINED SOUTH OF A
SHORTWAVE TROUGH SHIFTING EAST ACROSS QUEBEC. WIDELY SCATTERED
STORMS SHOULD FORM THIS AFTERNOON ALONG AND AHEAD OF A WEAK COLD
FRONT MOVING ACROSS THE REGION. WHILE BUOYANCY MAY REMAIN WEAK...THE
STRENGTH OF SHEAR COULD SUPPORT A FEW WEAKLY ROTATING STORMS
PRODUCING LOCALLY DAMAGING WINDS AND MARGINALLY SEVERE HAIL.

...SOUTHERN AZ...
15-30 KT 500-MB EAST-NORTHEASTERLIES ARE EXPECTED ACROSS THE REGION
LATE AFTERNOON TO EVENING. WHILE GUIDANCE LARGELY SUGGESTS STORM
COVERAGE WILL BE MORE ISOLATED OVER THE HIGHER TERRAIN COMPARED TO
WED...THE STRENGTH OF THE FLOW COULD FOSTER A COUPLE STORMS
PROPAGATING INTO THE LOWER ELEVATIONS WITH A RISK FOR SEVERE WIND
GUSTS.

..GRAMS/LEITMAN.. 07/28/2016

$$


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