Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 031954
SWODY1
SPC AC 031952

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0152 PM CST TUE MAR 03 2015

VALID 032000Z - 041200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
ISOLATED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON OVER PARTS OF THE
SOUTHWEST STATES...AND ARE POSSIBLE TONIGHT FROM THE SOUTHERN GREAT
PLAINS TO THE LOWER OHIO/TENNESSEE VALLEYS.

...DISCUSSION...
NO MAJOR CHANGES NEEDED THIS OUTLOOK WITH PREVIOUS FORECAST
RATIONALE REMAINING VALID. ISOLATED TO WIDELY SCATTERED STORMS
APPEAR MOST PROBABLE OVER THE COLORADO VALLEY/FOUR CORNERS AREA THIS
AFTERNOON. THUNDER PROBABILITIES APPEAR ONLY AROUND 10 PERCENT FROM
THE WEST TEXAS TO OHIO VALLEY CORRIDOR TONIGHT WITH SPORADIC
LIGHTNING ACTIVITY POSSIBLE.

..GRAMS.. 03/03/2015

.PREV DISCUSSION... /ISSUED 1022 AM CST TUE MAR 03 2015/

...SYNOPTIC SETUP...
SLOWLY PROGRESSIVE SPLIT FLOW WILL CONTINUE OVER THE CONUS THROUGH
WED AS AMPLIFIED RIDGE PERSISTS OVER THE E PACIFIC...AND FLAT RIDGE
REMAINS STNRY OVER THE GULF OF MEXICO/WRN ATLANTIC. COLD FRONT
ATTENDANT TO NRN STREAM IMPULSE NOW OVER IA WILL CONTINUE SE INTO
THE SRN PLNS...THE OZARKS...AND THE LWR TN AND OH VLYS BY THE END OF
THE PERIOD. A WEAKER FRONT WILL ADVANCE SLOWLY E ACROSS NM INTO THE
SRN HI PLNS LATER TODAY/TNGT IN ASSOCIATION WITH SRN STREAM TROUGH
NOW APPROACHING NRN BAJA CA.

...LWR CO VLY TO FOUR CORNERS THIS AFTN...
LARGELY UNIMPEDED SFC HEATING...TERRAIN CIRCULATIONS...COOL AIR
ALOFT...AND POCKETS OF ASCENT ASSOCIATED WITH EWD-MOVING SRN STREAM
TROUGH SHOULD SUPPORT SCTD AFTN SHOWERS/TSTMS OVER PARTS OF
AZ...UT...CO...NM...AND SRN NV. A FEW OF THESE COULD YIELD SMALL
HAIL. MODEST CLOUD-LAYER SHEAR AND LIMIT BUOYANCY /SBCAPE GENERALLY
AOB 250 J PER KG/ SHOULD LIMIT UPDRAFT STRENGTH/LONGEVITY.

...W TX/SE NM LATER TODAY THROUGH EARLY WED...
WEAK BUOYANCY WILL DEVELOP NEWD ACROSS THE SRN HI PLNS LATER
TODAY/TNGT...ON WRN FRINGE OF LOW-LVL MOISTURE RETURN BENEATH WARM
CONVEYOR ASSOCIATED WITH APPROACHING SRN STREAM TROUGH. LOW- TO
MID-LVL LAPSE RATES WILL REMAIN WEAK GIVEN MULTI-LAYER CLOUDS AND
POSITIVE TILT OF TROUGH. BUT COMBINATION OF HEIGHT FALLS WITH
INCREASING MOISTURE MAY SUPPORT SUFFICIENT DEEPENING OF EMBEDDED...
NEAR SFC-BASED CONVECTION TO YIELD OCCASIONAL THUNDER...ESPECIALLY
LATER IN THE PERIOD.

...ARKLATEX/OZARKS TO OH VLY TNGT/EARLY WED...
850 MB WAA/MOISTURE TRANSPORT SHOULD STRENGTHEN AND BECOME
INCREASINGLY FOCUSED WITH TIME FROM THE ARKLATEX NEWD THROUGH THE
OZARKS INTO THE LWR OH AND TN VLYS AS NRN STREAM COLD FRONT
ENCOUNTERS EXISTING ELEVATED CONFLUENCE ZONE/MOIST AXIS MARKING THE
NW FRINGE OF GULF/WRN ATLANTIC RIDGE. LAPSE RATES WILL REMAIN WEAK
AND LARGE-SCALE FORCING FOR ASCENT NEUTRAL AT BEST /OUTSIDE WAA/.
BUT COMBINATION OF TIGHTENING FRONTAL CIRCULATION WITH PW
APPROACHING 1.50 IN MAY SUPPORT SUFFICIENT DEEPENING OF SCTD
ELEVATED CONVECTION TO YIELD SPORADIC THUNDER.



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