Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 221258
SWODY1
SPC AC 221257

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0757 AM CDT FRI AUG 22 2014

VALID 221300Z - 231200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL HIGH
PLNS AND CNTRL PLNS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF NC...

...SUMMARY...
SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED FROM THE
CENTRAL HIGH PLAINS INTO PARTS OF THE CENTRAL PLAINS THIS AFTERNOON
THROUGH TONIGHT. LARGE HAIL...DAMAGING WIND...AND ISOLATED TORNADOES
MAY OCCUR. OTHER STORMS WITH LOCALLY DAMAGING WIND ARE EXPECTED OVER
PARTS OF NORTH CAROLINA.

...SYNOPTIC SETUP...
PATTERN WILL FURTHER AMPLIFY THIS PERIOD AS SEASONABLY STRONG PAC NW
TROUGH MOVES SEWD INTO THE NRN GRT BASIN AND RIDGE EDGES N ACROSS
THE UPR MS VLY/UPR GRT LKS. AS THIS OCCURS...AZ LOW/TROUGH SHOULD
SHEAR NNE ACROSS NM/CO TODAY AND ACROSS THE CNTRL HIGH PLNS
TNGT...WHILE A SERIES OF LESSER DISTURBANCES TRACK SEWD ACROSS THE
UPR OH VLY/MID ATLANTIC STATES ON ERN FLANK OF RIDGE.

AT THE SFC...EXISTING LEE TROUGH/LOW NOW CENTERED OVER SW KS SHOULD
ELONGATE NNW ACROSS THE CNTRL HIGH PLNS THOUGH THE PERIOD...BUT
REMAIN FAIRLY DIFFUSE/MULTI-CENTERED. IN THE EAST...WEAK NW-SE FRONT
WILL SETTLE SLOWLY S ACROSS THE MID-OH VLY/CNTRL APPALACHIANS/NC.

...CNTRL HIGH PLNS INTO CNTRL PLNS TODAY/TNGT...
MID/UPR LVL FLOW WILL STRENGTHEN AND BACK OVER THE CNTRL HIGH PLNS
TODAY...AHEAD OF EJECTING SW U.S. UPR TROUGH...WITH A CORRIDOR OF
30-40KT 500MB SSW FLOW EXPECTED OVER ERN CO/WRN KS BY EVE...AND INTO
WRN/CNTRL NEB EARLY SAT. STRENGTHENING FLOW AND ASCENT SHOULD
SUPPORT SUSTAINED...DIURNALLY-ENHANCED STORMS ACROSS THE REGION
BEGINNING THIS AFTN AND CONTINUING THROUGH THE OVERNIGHT.

WHILE MID-LVL LAPSE RATES WILL REMAIN MODEST...BUOYANCY WILL BE
ENHANCED BY COMPARATIVELY MOIST LOW-LVL ENVIRONMENT...ESPECIALLY IN
NE CO...NW KS AND WRN NEB AS MOISTURE SPREADS WWD N OF ELONGATING
SFC LOW. WITH SBCAPE OF 3000-4000 J/KG...INITIAL HIGH-BASED STORMS
JUST E OF THE FRONT RANGE AND/OR ALONG ERN CO N-S LEE TROUGH/WIND
SHIFT COULD MOVE DEVELOP NNEWD INTO INCREASINGLY MOIST/ BUOYANT AIR
OVER NE CO/SW NEB/NW KS BY BY LATE IN THE DAY. 30+ KT SSWLY DEEP
SHEAR COULD SUPPORT MID-LVL ROTATION/SUPERCELLS...AND THESE COULD
YIELD NOT ONLY SVR WIND/HAIL...BUT ALSO TORNADOES GIVEN SFC-3KM SRH
OF 200 M2/S2.

THE STORMS LIKELY WILL CONTINUE TO INCREASE INTO THE NIGHT NEWD
ACROSS WRN AND CNTRL NEB...AS LLJ INCREASES WITH THE CONTINUED NNE
ADVANCE OF UPR TROUGH. THE CONVECTION WILL CONTINUE TO POSE A MORE
LIMITED RISK FOR SVR WIND/HAIL AND ISOLD TORNADOES.

...NC/FAR SRN VA/FAR NRN SC THIS AFTN...
MORNING STLT DATA SUGGEST THAT AT LEAST MODERATE HEATING WILL OCCUR
OVER THE NC AREA TODAY...BENEATH 30 KT NWLY 700-500 MB FLOW. LARGE-
SCALE FORCING FOR ASCENT WILL BE WEAK...ALTHOUGH IT DOES APPEAR THAT
A DISTURBANCE NOW IN WV/ERN KY WILL MOVE ACROSS REGION LATER TODAY.
GIVEN HIGH PWS /AROUND 2 INCHES/...SETUP MAY YIELD A FEW S TO
SE-MOVING CLUSTERS OF AFTN/EVE STORMS ALONG DIFFUSE FRONT AND/OR LEE
TROUGH. THE STORMS COULD PRODUCE LOCALLY DMGG WIND.

...OH VLY THIS AFTN...
CLOUDS AND LOW-LVL OUTFLOW FROM OVERNIGHT MCSS WILL LIMIT
DESTABILIZATION AND SVR WEATHER CHANCES IN CORRIDOR OF ENHANCED NWLY
MID-LVL FLOW OVER THE MIDWEST AND MID/LWR OH VLY. IN ADDITION...WITH
AMPLIFICATION OF UPR RIDGE...MODEST HEIGHT RISES WILL PREVAIL OVER
THE REGION. NEVERTHELESS...SFC HEATING ON OUTFLOW BOUNDARIES ALONG
SRN FRINGE OF STRONGER FLOW ALOFT COULD YIELD A FEW INSTANCES OF
LOCALLY DMGG WIND GIVEN HIGH /AOA 2 IN/ PW.

...NRN GRT BASIN/NRN RCKYS THIS AFTN/EVE...
FALL-LIKE SHORTWAVE TROUGH WITH COOL MID-LVL TEMPS /AOB MINUS 12C AT
500 MB/ WILL MOVE SE INTO ID/NRN NV TODAY AND INTO WRN WY TNGT.
TSTMS SHOULD DIURNALLY STRENGTHEN IN CONFLUENT SW-SSWLY 700 FLOW
INVOF ASSOCIATED COLD FRONT BENEATH BACKING BUT DIFLUENT FLOW
ALOFT....ESPECIALLY FROM NRN UT THROUGH ERN ID INTO SW MT/WRN WY.
CLOUDS WILL LIMIT LOW-LVL DESTABILIZATION...BUT SUFFICIENT BUOYANCY
SHOULD DEVELOP FOR CLUSTERS/BANDS OF SUSTAINED STORMS AND POSSIBLY A
FEW SUPERCELLS GIVEN 30-40 KT SWLY CLOUD-LYR SHEAR. ISOLD SVR
WIND/HAIL MAY OCCUR...MAINLY WITH ANY ROTATING/MORE SUSTAINED
UPDRAFTS.

..CORFIDI/ROGERS.. 08/22/2014




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