SWODY1
SPC AC 291952
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT SUN AUG 29 2010
VALID 292000Z - 301200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF AZ NWD THROUGH
ERN UT/WRN CO...
...SRN MT AREA...
SURFACE LOW WAS LOCATED IN CENTRAL SD...WITH TRAILING COLD FRONT
EXTENDING WWD ACROSS NRN WY. NORTH OF THE FRONT...THE SURFACE AIR
MASS IS RELATIVELY MOIST...DEWPOINTS IN THE 50S...RESULTING IN
MLCAPES BETWEEN 1000-2000 J/KG. SLY WINDS STREAMING NWD OVER THE
FRONT AND JET MAX SPREADING INTO THE AREA FROM THE SSW SHOULD
PROVIDE SUFFICIENT FORCING FOR STORMS IN NWRN WY TO SPREAD/DEVELOP
ENEWD THROUGH SRN MT...AND POSSIBLY WRN ND...THROUGH THE EVENING
HOURS. MODERATE INSTABILITY AND EFFECTIVE SHEAR AT 40-50 KT WOULD
SUPPORT SEVERE STORMS...INCLUDING SUPERCELLS. COVERAGE OF SEVERE
STORMS IS EXPECTED TO BE SPARSE...SO ONLY LOW SEVERE WEATHER
PROBABILITIES HAVE BEEN ADDED ATTM.
...AZ NEWD INTO ERN UT/WRN CO...
CU FIELD WAS EVIDENT ON VISIBLE SATELLITE ACROSS THE REGION...AND
SOME OF THE CU HAVE EVOLVED INTO THUNDERSTORMS. WITH ADDITIONAL
HEATING AND APPROACHING UPPER WAVE...SHEAR AND INSTABILITY ARE
FAVORABLE FOR SEVERE STORMS...REFERENCE MCD 1753 AND SEVERE
THUNDERSTORM WATCH #632.
...SOUTH CENTRAL GULF COAST...
WEAK SURFACE CIRCULATION...THAT WAS LOCATED SOUTH OF LFT ON SAT...
SHIFTED NWD DURING THE PAST 24 HOURS AND IN VISIBLE SATELLITE
APPEARED TO BE LOCATED NEAR SHV. THOUGH CONVECTION CONTINUES NEAR
LA/MS COAST...WIND PROFILES HAVE WEAKENED AND THE GREATEST SEVERE
THREAT WILL BE VERY HEAVY RAINFALL.
..IMY.. 08/29/2010
.PREV DISCUSSION... /ISSUED 1123 AM CDT SUN AUG 29 2010/
...SYNOPSIS...
LARGE SCALE PATTERN WILL REMAIN AMPLIFIED AS ADDITIONAL SPEED
MAXIMA DROP SE INTO WRN U.S. TROUGH...AND LARGE UPPER HIGH CONTINUES
TO BUILD OVER THE MID ATLANTIC STATES. VORT MAX NOW NEARING BASE OF
TROUGH IN CA SHOULD CONTINUE SLOWLY E/SE INTO SRN NV LATER
TODAY...AND INTO UT/NRN AZ EARLY MON...MAINTAINING BELT OF
SEASONABLY FAST SSWLY MID/UPR LVL FLOW FROM THE LWR CO VLY TO THE
ERN GRT BASIN/CNTRL RCKYS.
SFC FRONT ASSOCIATED WITH WRN TROUGH LIKELY WILL EDGE ONLY SLOWLY
E/SE THROUGH THE PERIOD WITH LOW LEVEL GULF OF CA MOISTURE
CONTINUING TO FEED NWD THRU AZ INTO ERN INTERMOUNTAIN REGIONS TO E
OF FRONTAL BOUNDARY.
...AZ...
LOW LEVEL MOISTURE CONTINUES TO STREAM NWD THRU THE ERN TWO THIRDS
OF AZ WITH A SHARP WRN GRADIENT...SIMILAR TO A DRY LINE... EXTENDING
FROM FAR WRN PIMA/MARICOPA/YAVAPAI COUNTIES NWD INTO SRN UT.
WITH 30-40 KT SWLY MID LVL FLOW...LIKELY DEVELOPMENT OF UPR LVL JET
ENTRANCE REGION AS CA VORT CONTINUES ESEWD...AND STEEP LOW LVL LAPSE
RATES TOGETHER SUGGEST THAT POTENTIAL WILL EXIST FOR SUSTAINED
STORMS/STORM CLUSTERS...AND POSSIBLY A FEW SUPERCELLS. CINH SHOULD
WEAKEN SUFFICIENTLY BY 21Z ...AS MLCAPES OVER LOWER ELEVATIONS CLIMB
ABOVE 1500 J/KG...FOR STORM DEVELOPMENT FROM THE DRY LINE
EWD...INITIALLY OVER THE HIGHER TERRAIN. WITH THE STRENGTH OF THE
WIND PROFILES...STORMS WILL THEN MOVE OVER THE ADJACENT DESERT
VALLEYS. IN ADDITION TO WIND DAMAGE WITH THE RISK OF
SUPERCELLS...LARGE HAIL WILL BE POSSIBLE ALONG WITH FUNNELS AND A
BRIEF TORNADO.
...ERN UT/WRN CO...
SUFFICIENT MOISTURE WILL PERSIST ACROSS ERN UT/WRN CO COUPLED WITH
STRONG HEATING FOR SCATTERED THUNDERSTORMS BY MID AFTERNOON WITH
MLCAPES TO 1000 J/KG. WITH 35-40 KT OF SHEAR...VERY STEEP LAPSE
RATES...DAMAGING WINDS AND HAIL WILL BE LIKELY WITH THE STRONGER
STORMS BY MID AFTERNOON.
HAVE EXTENDED THE SLIGHT RISK NWD THRU THIS AREA GIVEN THE CONTINUED
INFLOW OF MOISTURE FROM AZ.
...CNTRL GULF CST...
ENHANCED LOW LVL FLOW/DIRECTIONAL SHEAR ON N SIDE OF GULF CST
DISTURBANCE HAS SUPPORTED A FEW STORMS WITH WEAK/INTERMITTENT LOW
LVL ROTATION THIS MORNING. GIVEN VERY RICH MOISTURE PRESENT ACROSS
REGION...AND LIKELY NWD ADVANCE OF SHEAR ZONE/MOISTURE AXIS WITH
CONTINUED NWD MOTION OF UPR VORT...A CONDITIONAL THREAT WILL EXIST
FOR A TORNADO OR TWO AND/OR ISOLD LOCALLY DMGG WIND GUSTS OVER PARTS
OF LA...MS...AND AL. THE STRONGEST SHEAR/FLOW
SHOULD...HOWEVER...REMAIN REMOVED FROM THE AREA OF GREATEST
MOISTURE. IN ADDITION...THE UPR SYSTEM SHOULD WEAKEN TODAY AS IT IS
DRAWN NWD ON W SIDE OF MID ATLANTIC RIDGE. THUS...ANY SVR RISK
SHOULD REMAIN BRIEF/MINIMAL.
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