Severe Thunderstorm Warning 812, NWS Little Rock, AR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LITTLE ROCK AR
411 AM CDT WED AUG 10 2011

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

AN ACTIVE SHORT TERM PD IS SHAPING UP AS A STALLED FRONTAL BNDRY
REMAINS IN THE VICINITY OF AR THROUGH SATURDAY. A BELT OF H5 NWLYS
WILL CONTINUE OVER THE NRN PART OF THE STATE THROUGH SATURDAY.
RIPPLES IN THE BELT WILL PROVIDE IMPETUS FOR SEVERAL ROUNDS OF
CONVECTION. WITH AMPLE MOISTURE IN PLACE CHARACTERIZED BY PWATS IN
THE 1.8 TO 2.2 INCH RANGE...MUCAPE VALUES WILL GENERALLY BE IN THE
2000-3000 J/KG RANGE THROUGH THE PD. THE INCREASED SHEAR DUE TO THE
AFOREMENTIONED NWLYS WILL COMBINE WITH THE MODEST INSTABILITY TO
ALLOW SOME OF THE ROUNDS OF CONVECTION TO BE SEVERE. THE EXPECTED
MODE OF CONVECTION THROUGH SATURDAY WILL BE IN THE FORM OF PERIODIC
MESOSCALE CONVECTIVE SYSTEMS WITH DAMAGING WINDS LIKELY THE
PREDOMINATE SVR TYPE. HOWEVER...GIVEN STEEP MID LVL LAPSE RATES AND
MUCH LOWER WBZ HEIGHTS THAN OF LATE...ISOLATED SVR HAIL WILL ALSO BE
POSSIBLE. THIS ACTIVE PATTERN WILL COME TO AN END ON SAT NIGHT...AS
THE MODELS ALL CONT TO PUSH A SEASONABLY STRONG COLD FRONT ALL THE
WAY THROUGH THE STATE WITH THE HELP OF A FINAL...STRONGER NW FLOW
SHRTWV.

THIS MORNING...
THE FIRST ROUND OF CONVECTION IS KNOCKING AT THE DOOR. A SVR MCS IN
ERN OK HAS PROMPTED A SVR TSTORM WATCH FOR THE NWRN CORNER OF THE
LZK CWA. LATEST RADAR TRENDS SEEM TO INDICATE THE MCS IS IN ITS
MATURE STAGE WITH A BOOKEND VORTEX FULLY DEVELOPED. THIS TENDS TO
LEND ITSELF TOWARD A GRADUAL WEAKENING OF THE SYSTEM AS IT MOVES E
INTO AR. HOWEVER...THE AIRMASS AHEAD OF THE SYSTEM SUPPORTS
SUSTENANCE OF SVR CONVECTION...SO THE WEAKENING PROCESS MAY BE
SLOWED A BIT. BY THE TIME THE MCS REACHES THE NORTH CENTRAL PART OF
THE STATE...EXPECT IT TO BE BELOW SVR LIMITS. REGARDLESS...HAVE
INCREASED RAIN CHCS TO NEAR 100 PERCENT IN THE NW CWA AS IT WILL AT
LEAST RAIN AND THUNDER AT A MINIMUM.

LATER TODAY...EYES WILL NEED BE KEPT ON A POTENTIAL MCV THAT COULD
EMANATE FROM THE REMNANTS OF THE ONGOING MCS. A COMPLEX AND
MUDDLED BNDRY LAYER FCST FOR THIS AFTERNOON MAKES INSTABILITY A
QUESTION MARK FOR BOTH AFTERNOON HIGHS AND THE REDEVELOPMENT OF
AFTERNOON CONVECTION. TEMPS-WISE...HAVE LEANED TOWARD THE COOLER
SIDE OF GUIDANCE WITH EXPANSIVE HIGH CLOUD COVER EXPECTED AND
COOLING LOW LVL OUTFLOW BNDRYS LIKELY REINFORCING/SHOVING THE
STALLED FRONT BACK SOUTH TO THE CEN PART OF THE STATE. BELIEVE THE
BEST CHC FOR AFTERNOON REDEVELOPMENT WILL BE IN THE ERN AND SERN
PORTIONS OF THE CWA.

THURSDAY THROUGH SATURDAY NIGHT...
AS STATED EARLIER...CONVECTIVE CHCS WILL COME AND GO THROUGH THIS PD
UNTIL THE MAIN COLD FRONT COMES THROUGH ON SAT NIGHT. HAVE HEDGED
HIGHS TOWARD THE COOLER MET GUIDANCE GIVEN EXPECTED CLOUD
COVER/PRECIP/OUTFLOWS. LOWS SHOULD BE NEAR OR SLIGHTLY ABOVE
GUIDANCE DUE TO CLOUD COVER.

&&

.LONG TERM...SUNDAY THROUGH TUESDAY

NO SIG DIFFERENCES NOTED WITH THE MODEL SOLUTIONS THRU THE PD. HIGH
PRES ALOFT WL CONT BLDG TO THE W OF AR ACRS THE PLAINS STATES...WITH
AN UPR TROF OVR THE ERN STATES. THE END RESULT FOR THE MID SOUTH WL
BE A NWLY FLOW ALOFT. A CDFNT WL BE EXITING SERN AR EARLY ON SUN...
WITH JUST SOME LINGERING SLGT CHC/S OF SHRA/TSRA. HIGH PRESSURE WL
SETTLE INTO THE REGION BEHIND THE FNT WITH TEMPS RETURNING CLOSER TO
NORMAL FOR THIS TIME OF YEAR SUN AND MON. THE MODELS CONT TO INDC
THAT THE UPR RDG MAY BEGIN TO BLD BACK EWD LATE IN THE PD...ALLOWING
TEMPS TO BEGIN A GRADUAL REBOUND.

&&

.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR     84  69  85  71 /  80  50  30  30
CAMDEN AR        101  78 100  76 /  30  40  30  20
HARRISON AR       81  67  85  70 /  90  50  30  30
HOT SPRINGS AR    96  76  93  76 /  40  40  30  20
LITTLE ROCK   AR  92  74  90  75 /  50  50  30  20
MONTICELLO AR     99  76  98  77 /  40  40  30  20
MOUNT IDA AR      97  75  93  75 /  50  40  30  20
MOUNTAIN HOME AR  82  67  86  70 /  90  50  30  30
NEWPORT AR        84  69  86  71 /  70  50  30  30
PINE BLUFF AR     95  74  93  76 /  40  40  30  20
RUSSELLVILLE AR   91  71  90  73 /  90  50  30  30
SEARCY AR         88  70  87  72 /  70  50  30  30
STUTTGART AR      92  72  89  74 /  60  50  30  20
&&

.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&

SHORT TERM...63 / LONG TERM...44

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LITTLE ROCK AR
500 AM CDT WED AUG 10 2011

ARZ003>007-012>016-021>025-030>034-037>047-052>057-062>069-111000-
ARKANSAS-BAXTER-BOONE-BRADLEY-CALHOUN-CLARK-CLEBURNE-CLEVELAND-
CONWAY-DALLAS-DESHA-DREW-FAULKNER-FULTON-GARLAND-GRANT-HOT SPRING-
INDEPENDENCE-IZARD-JACKSON-JEFFERSON-JOHNSON-LINCOLN-LOGAN-LONOKE-
MARION-MONROE-MONTGOMERY-NEWTON-OUACHITA-PERRY-PIKE-POLK-POPE-
PRAIRIE-PULASKI-SALINE-SCOTT-SEARCY-SHARP-STONE-VAN BUREN-WHITE-
WOODRUFF-YELL-
500 AM CDT WED AUG 10 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR A LARGE PART OF ARKANSAS.

.DAY ONE...TODAY AND TONIGHT

SHOWERS AND THUNDERSTORMS WILL CONTINUE AFFECTING PARTS OF NORTHWEST
ARKANSAS THIS MORNING. STRONG AND SEVERE STORMS WILL BE POSSIBLE
DURING THE EARLY MORNING HOURS...WITH DAMAGING WINDS THE MAIN
THREAT. AS THE MORNING PROGRESSES...THE ACTIVITY IS EXPECTED TO
WEAKEN.

LATER TODAY...SCATTERED SHOWERS AND THUNDERSTORMS WILL REDEVELOP
OVER MUCH OF THE STATE. ANY STORM THAT DOES FORM COULD BECOME STRONG
TO SEVERE...WITH DAMAGING WINDS AND LARGE HAIL THE MAIN THREATS WITH
THE STRONGEST STORMS. LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NORTHWEST FLOW ALOFT WILL BRING A SERIES OF UPPER LEVEL IMPULSES
ACROSS THE AREA AS WE HEAD INTO THE WEEKEND. THIS WILL RESULT IN
CONTINUING CHANCES OF SHOWERS AND THUNDERSTORMS OVER MUCH OF
ARKANSAS. ANY STORMS HAVE THE POTENTIAL TO BECOME SEVERE...WITH
DAMAGING WINDS THE MAIN THREAT. LARGE HAIL AND LOCALLY HEAVY
RAINFALL WILL ALSO BE POSSIBLE.

BY SATURDAY AND SUNDAY...A COLD FRONT WILL PASS SOUTHWARD ACROSS THE
STATE...WITH SHOWERS AND THUNDERSTORMS ONCE AGAIN POSSIBLE. COOLER
AND DRIER CONDITIONS ARE EXPECTED BEHIND THIS FRONT...WITH BELOW
NORMAL TEMPERATURES POSSIBLE HEADING INTO EARLY NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME.

&&

VISIT NWS LITTLE ROCK ON THE WEB. GO TO HTTP://WEATHER.GOV AND
CLICK ON CENTRAL ARKANSAS.

44