Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS01 KWNS 251302
SWODY1
SPC AC 251300

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0800 AM CDT SAT APR 25 2015

VALID 251300Z - 261200Z

...THERE IS AN ENH RISK OF SVR TSTMS FROM ERN MO ESE INTO ERN KY/FAR
NRN TN...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE ENHD RISK AREA
FROM PARTS OF THE MID MS VLY SSE TO THE CNTRL/ERN GULF CST AND THE
CAROLINAS...

...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE ABOVE AREAS
FROM PARTS OF E TX TO THE SRN APPALACHIANS AND NC...

...SUMMARY...
SCATTERED SEVERE THUNDERSTORMS WILL OCCUR TODAY INTO TONIGHT FROM
SOUTHEAST TEXAS ACROSS THE LOWER MISSISSIPPI VALLEY AND CENTRAL GULF
COAST INTO NORTHERN FLORIDA AND THE CAROLINAS. OTHER SEVERE STORMS
MAY OCCUR FROM EASTERN MISSOURI EAST-SOUTHEAST INTO PARTS OF
KENTUCKY AND TENNESSEE. THE STORMS COULD INCLUDE A FEW TORNADOES IN
ADDITION TO LARGE HAIL AND LOCALLY DAMAGING WIND.

...SYNOPSIS...
KS-MO SHORTWAVE TROUGH EXPECTED TO SHEAR ESE INTO THE LWR OH VLY
THIS EVE...AND ACROSS THE CNTRL-SRN APPALACHIANS EARLY SUN...AS IT
BECOMES ABSORBED WITHIN CONFLUENT FLOW ON THE SW SIDE OF QSTNRY
LOW/TROUGH CENTERED OVER NS. IN THE MEAN TIME...FLOW ALOFT WILL BACK
OVER THE RCKYS...DOWNSTREAM FROM SLOWLY-PROGRESSIVE...AMPLIFYING
TROUGH ALONG THE W CST.

AT THE SFC...LOW ASSOCIATED WITH THE KS-MO SYSTEM SHOULD ELONGATE
ESE ACROSS ERN MO...SRN IL...AND WRN/SRN KY LATER TODAY...BEFORE
RE-FORMING EWD OFF THE NC CST EARLY SUN. STRENGTHENING WSWLY LOW-LVL
FLOW S OF THE LOW WILL SUPPORT AT LEAST A MODEST ENE ADVANCE OF
MARITIME TROPICAL AIR ACROSS PARTS OF AL...GA...AND SC THROUGH THIS
EVE. WEAK FRONT/WIND SHIFT TRAILING SW FROM THE LOW SHOULD FURTHER
WEAKEN OVER THE CNTRL GULF CST REGION...WHILE A NEW COOL AIR SURGE
SETTLES S ACROSS THE CNTRL PLNS AND OZARKS IN THE WAKE OF THE LOW.

...SE TX/LWR MS VLY/GULF CST TO CAROLINAS TODAY/TNGT...
SEVERAL ROUNDS OF SCTD STRONG TO SVR TSTMS ARE EXPECTED TODAY AS SFC
HEATING FURTHER DESTABILIZES CORRIDOR ALONG STALLED OUTFLOW
BOUNDARY/WEAK CONFLUENCE ZONE OVER PARTS OF THE SOUTH...ATTM
EXTENDING ENE FROM SE TX INTO SRN MS/AL. WHILE THE STRONGEST DEEP
WSWLY FLOW ROUNDING BASE OF MO UPR TROUGH WILL REMAIN N OF THE
REGION...AMPLE /40-50 KT/ 700-500 MB FLOW WILL EXIST TO SUPPORT
SUSTAINED/ORGANIZED STORMS. AND...ALTHOUGH LARGE-SCALE FORCING FOR
ASCENT WILL BE WEAK...TRAILING UPR IMPULSE NOW OVER E TX WILL
PROVIDE SOME DEGREE OF LIFT AT LEAST DURING THE FIRST HALF OF THE
PERIOD. OVERALL SETUP WITH RICH MOISTURE/STEEP MID-LVL LAPSE RATES
/PER 12Z AREA SOUNDINGS/ AND LOW-LVL UPLIFT ALONG OUTFLOW BOUNDARY
SHOULD BE SUFFICIENT FOR OCCASIONAL SUPERCELLS AND BOWING
STRUCTURES. THESE MAY YIELD DMGG GUSTS...SVR HAIL...AND PERHAPS A
COUPLE TORNADOES.  IN THE NEAR TERM...A FEW SVR STORMS WILL ALSO
TRACK GENERALLY E OR ENE ALONG RESIDUAL WARM FRONTAL SEGMENT OVER
NRN FL/S GA...POSSIBLY WITH AN INCREASING SVR RISK /REF MCD 451/.
LATER TODAY...MORE ISOLD SVR STORMS MAY FORM ALONG WEAKENING COLD
FRONT/WIND SHIFT CROSSING NRN PARTS OF MS...AL...AND ERN TN.

...MO ESE INTO KY/TN THIS AFTN/EVE...
A SEPARATE AREA OF STRONG TO SVR TSTMS SHOULD ARISE WITH AFTN
HEATING OF DRY SLOT ATTENDANT TO WEAKENING...ESE-SHEARING UPR LOW.
LOW-LVL MOISTURE WILL BE RELATIVELY LIMITED COMPARED TO POINTS
SOUTH...ESPECIALLY OVER ERN PORTIONS OF THIS RISK AREA. BUT COOL
MID-LVL TEMPERATURES AND STEEPENING LOW-LVL LAPSE RATES WILL YIELD
AMPLE CAPE /AROUND 1000 J PER KG/ FOR STRONG UPDRAFTS GIVEN
CYCLONIC/CONFLUENT LOW-LVL FLOW. 50 KT 700-500 MB WLY WINDS SUGGEST
THE LIKELIHOOD FOR SCTD SUPERCELLS WITH HAIL...LOCALLY DMGG
WIND...AND A FEW TORNADOES...ESPECIALLY ALONG STNRY FRONT EXTENDING
ESE FROM THE MO SFC LOW INTO SRN IL...SW IND...AND WRN/NRN KY. LOSS
OF SFC HEATING...STORM MERGERS...AND CONTINUED WEAKENING OF UPR LOW
SHOULD FOSTER FAIRLY RAPID WEAKENING OF STORMS AFTER SUNSET.

..CORFIDI/COHEN.. 04/25/2015



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