Flash Flood Warning 40, NWS Little Rock, AR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LITTLE ROCK AR
200 PM CDT SUN AUG 20 2006

QUITE A BIT OF FLUX IN THE UPPER LEVEL PATTERNS OVER THE NEXT 7
DAYS...AND THE MODELS HAVE BEEN EXPERIENCING SOME DIFFICULTY
SETTLING ON A SOLUTION THE PAST FEW DAYS.

THE UPPER LEVEL RIDGE THAT HAS BEEN CENTERED OVER THE AREA FOR THE
PAST SEVERAL DAYS IS NOW OVER NERN TX...PUTTING ARKANSAS INTO A
NWLY FLOW PATTERN ALOFT. THE UPPER LEVEL RIDGE WILL NOT STAY
PUT...HOWEVER...AS THE MODELS RETROGRADE IT WESTWARD DURING THE
EARLY PART OF THE WEEK. MODELS THEN HAVE SOME DIFFICULTY DECIDING
WHAT TO DO WITH THE PATTERN...BUT IT APPEARS THAT THE RIDGE WILL
BROADEN AND FLATTEN OUT...PUTTING THE AREA UNDER A WESTERLY TO
SOUTHWESTERLY FLOW PATTERN ALOFT.

LOOKING MORE TOWARD THE IMMEDIATE FUTURE...THE WEAK SURFACE FRONT
THAT ENTERED ARKANSAS YESTERDAY IS NOW LOCATED ACROSS NORTHERN
ARKANSAS...AND IS SLOWLY PROGRESSING SOUTHWARD. THE FRONT SHOULD
MOVE GRADUALLY SOUTHWARD ACROSS THE STATE DURING THE NEXT 24
HOURS...BUT IT HAS NOT BEEN IN MUCH OF A HURRY TO MOVE.
TEMPERATURE GRADIENT ALONG THE FRONT HAS ACTUALLY BECOME MORE WELL
DEFINED DUE TO RAIN COOLED AIR AND CLOUDINESS TO THE NORTH...AND
THIS GRADIENT WILL BECOME LESS DEFINED AND DIFFUSE AS THE FRONT
TRANSITIONS TO THE SOUTH.

IN ANY EVENT...THE SURFACE HIGH BEHIND THE FRONT SHOULD BEGIN TO
BUILD MORE INTO THE STATE MONDAY NIGHT AND TUESDAY...BRINGING
SOMEWHAT COOLER AND DRIER AIR TO THE AREA...MAINLY FOR TUESDAY AND
WEDNESDAY. THE MODELS HAVE BEEN LESS AGRESSIVE ABOUT BUILDING THIS
HIGH SOUTHWARD DURING THE PAST FEW RUNS...AND IT APPEARS THAT THE
SLIGHTLY COOLER AND DRIER WEATHER WILL NOT STICK AROUND FOR
LONG...AND THERE IS SOME QUESTION IN MY MIND AS TO JUST HOW FAR
SOUTHWARD INTO THE CWA THE COOLER AND DRIER AIR WILL MAKE IT.

WHAT IS SOMEWHAT PROBLEMATIC AT THIS TIME IS THAT A SERIES OF
SHORTWAVES WILL LIKELY ZIP ACROSS THE NORTHERN HALF OF ARKANSAS
DURING THE MONDAY THRU WEDNESDAY TIME FRAME. I BELIEVE LOW POPS ARE
WARRANTED ON MONDAY BUT WITH THE DRIER AIR AT THE SURFACE ON
TUESDAY AND WEDNESDAY ITS TEMPTING TO GO WITH A DRY FORECAST. THE
PROBLEM IS TWOFOLD...HOW FAR WILL THE COOLER AND DRIER AIR
PENETRATE THE CWA...AND HOW DEEP IS THAT LAYER? FOR NOW I WILL
PUT SOME SLIGHT CHC POPS ACROSS THE SRN HALF OF THE CWA FOR
TUESDAY AND WILL STICK WITH A DRY FORECAST FOR WEDNESDAY.

LOOKING AHEAD TO THURSDAY AND BEYOND...I AM EXPECTING THE FLAT RIDGE
ALOFT TO PUT THE AREA UNDER A SWLY FLOW PATTERN WHILE LOW LEVEL
WINDS RETURN TO A SOUTHERLY DIRECTION. THIS SHOULD BRING THE CWA
BACK INTO WARMER AND MORE HUMID CONDITIONS ON FRIDAY AND SATURDAY.
I AM TEMPTED TO INTRODUCE SOME LOW CHANCE POPS TO THE NRN AND WRN
ZONES ON FRIDAY BUT THERE MAY NOT BE ENOUGH LOW LEVEL MOISTURE IN
PLACE TO GET ANY CONVECTION GOING. FOR NOW WILL STICK WITH THE DRY
FORECAST.

SATURDAY IS ANOTHER MATTER ALTOGETHER. ANOTHER SURFACE HIGH WILL
BE BUILDING ACROSS THE CENTRAL PLAINS LATE IN THE WEEK AND PUSHING
SOUTHWARD...AND THE MODELS ARE FORECASTING A FRONT TO PUSH INTO
NWRN ARKANSAS DURING THE DAY AND ACROSS THE REMAINDER OF THE STATE
BY LATE SATURDAY NIGHT INTO SUNDAY. I THINK THIS SCENARIO MAY BE A
LITTLE TOO FAST AND MY THOUGHTS ARE THAT THE FRONT WILL NOT ARRIVE
UNTIL LATE IN THE WEEKEND...SO FOR NOW I HAVE PLACED 20 POPS ACROSS
THE CWA ON SATURDAY AND DID NOT ACCOUNT FOR ANY FRONTAL PASSAGE.

53

&&

.PRELIMINARY POINT TEMPS/POPS...
LITTLE ROCK   AR  73  94  71  92 /  20  20  20  10
HARRISON AR       65  89  64  91 /  30  20  10  10
HOT SPRINGS AR    73  95  72  93 /  20  20  20  10
PINE BLUFF AR     74  95  72  93 /  20  20  30  10
MOUNTAIN HOME AR  65  88  64  90 /  30  20  10  10
MONTICELLO AR     74  96  74  94 /   0  20  30  10
SEARCY AR         71  92  70  91 /  20  30  20  10
MOUNT IDA AR      72  95  71  94 /  20  20  10  10
RUSSELLVILLE AR   71  93  70  92 /  20  20  10  10
&&

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

HAZARDOUS WEATHER OUTLOOK...CORRECTED DAY 1
NATIONAL WEATHER SERVICE LITTLE ROCK AR
715 AM CDT SUN AUG 20 2006

ARZ003>007-012>016-021>025-030>034-037>047-052>057-062>069-211000-
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-
715 AM CDT SUN AUG 20 2006

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

.DAY ONE...TODAY AND TONIGHT

A WEAKENING COLD FRONT WILL MOVE INTO ARKANSAS TODAY. SHOWERS AND
THUNDERSTORMS WILL INCREASE AROUND AND BEHIND THE FRONT THIS
AFTERNOON AND CONTINUE INTO TONIGHT WHEN THEY SHOULD WEAKEN.
AN ISOLATED STORM OR TWO THIS AFTERNOON COULD BECOME STRONG
ENOUGH TO PRODUCE DAMAGING WIND GUSTS. ALSO ISOLATED STORMS
THIS AFTERNOON AND TONIGHT COULD PRODUCE HEAVY RAINS THAT COULD
CAUSE BRIEF FLOODING OF LOW LYING AND POOR DRAINAGE AREAS.

TEMPERATURES WILL NOT BE AS HIGH TODAY AS THEY WERE THE PAST TWO
DAYS. HIGHS WILL BE IN THE UPPER 80S TO UPPER 90S AND THE
AFTERNOON HEAT INDEX WILL BE LESS THAN 105. HOWEVER...PEOPLE
IN CENTRAL AND SOUTHERN ARKANSAS SHOULD STILL TAKE PRECAUTIONS ABOUT
THE HEAT THIS AFTERNOON EVEN THOUGH IT WILL  NOT  BE UP TO HEAT
ADVISORY LEVELS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THERE WILL CONTINUE TO BE A CHANCE OF SHOWERS AND THUNDERSTORMS
THROUGH MONDAY NIGHT ASSOCIATED WITH THE FRONTAL SYSTEM OR
ASSOCIATED BOUNDARIES. ISOLATED STORMS WITH STRONG WIND GUSTS
OR LOCALLY HEAVY RAIN WILL REMAIN POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED.

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

38

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LITTLE ROCK AR
241 PM CDT SUN AUG 20 2006

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0230 PM     TSTM WND DMG     10 N MORRILTON          35.30N 92.74W
08/20/2006                   CONWAY             AR   LAW ENFORCEMENT

            TREES AND POWER LINES DOWN AND ROOF OFF OF TRAILER HOUSE.
            10 MILES NORTH OF MORRILTON AT THE JUNCTION OF HWY 95 AND
            FRYER BRIDGE ROAD.

&&

106