Tornadoes and Flood in Arkansas, May 24 to 26, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LITTLE ROCK AR
945 AM CDT TUE MAY 24 2011

.UPDATE...

JUST A QUICK MORNING UPDATE TO ADJUST A FEW THINGS SUCH AS SKY
COVER...TEMPS AND POP GRIDS. SKIES WERE MOSTLY CLEAR ACROSS THE
STATE THIS MORNING WITH SOME STRATUS DEVELOPING ALONG A BOUNDARY
FROM MEMPHIS TO MENA. EXPECT PARTLY CLOUDY SKIES ACROSS MUCH OF
ARKANSAS BY THIS AFTERNOON. GIVEN THE STATE OF THE CLOUD COVER
THIS MORNING...HAVE REMOVED ALL MENTION OF PRECIP UNTIL ROUGHLY
11AM. RAPID REFRESH RUC MODEL OUTPUT SHOWS THE POTENTIAL FOR SOME
ISOLATED SHOWER DEVELOPMENT BY MIDDAY ALONG AND NORTH OF THE
AFOREMENTIONED BOUNDARY...AND HAVE 20-30 PERCENT POPS IN THE NRN
HALF OF THE CWA TO ACCOUNT FOR THAT AFTER 16-17Z.

&&

PREV DISCUSSION... /ISSUED 336 AM CDT TUE MAY 24 2011/

SHORT TERM...TODAY THROUGH FRIDAY
STORM COMPLEX CONTINUES TO PROPAGATE SOUTHEASTWARD ALONG A MESOSCALE
BOUNDARY INTO THE EASTERN PORTION OF THE FORECAST AREA EARLY THIS
MORNING. THUNDERSTORM COVERAGE HAS DIMINISHED IN INTENSITY AS
OUTFLOW IS GETTING AHEAD OF THE MAIN SYSTEM. EXPECT THIS TREND TO
CONTINUE INTO THE EARLY MORNING HOURS...WITH THE SYSTEM DIMINISHING
TOWARD DAWN.

FOR MUCH OF THE DAY...THE AREA SHOULD SEE A BIT OF A LULL...WITH
ONLY ISOLATED OR WIDELY SCATTERED SHOWERS AND THUNDERSTORMS POSSIBLE
IN THE WARM SECTOR OF THE SYSTEM THAT CONTINUES TO BE STALLED TO THE
WEST OF ARKANSAS. ADDITIONAL SHOWERS AND THUNDERSTORMS WILL DEVELOP
LATE THIS AFTERNOON OVER OKLAHOMA...AND WILL SPREAD INTO ARKANSAS
TONIGHT. SEVERE STORMS ARE POSSIBLE YET AGAIN. THE MOST LIKELY AREA
TO SEE SEVERE STORMS WOULD TEND TO BE NORTH OF ARKADELPHIA TO
CLARENDON...AND BETWEEN 00Z AND 09Z.

ONCE THAT ROUND DIMINISHES...THERE SHOULD BE A BRIEF BREAK IN THE
MORNING WEDNESDAY. BY THE AFTERNOON...AN UPPER LOW IS EXPECTED TO
DROP DOWN TOWARD SOUTHERN MISSOURI...WHICH WILL GIVE THE STALLED
SYSTEM TO THE WEST SOME MOMENTUM. SHOWERS AND THUNDERSTORMS WILL
DEVELOP ALONG AND AHEAD OF THE FRONT DURING THE AFTERNOON AND MOVE
ACROSS THE FORECAST AREA WEDNESDAY NIGHT AND EARLY THURSDAY MORNING.

SEVERE STORMS WILL AGAIN BE POSSIBLE...WITH LARGE HAIL AND DAMAGING
WINDS THE PRIMARY CONCERN. TORNADOES ARE ALSO POSSIBLE...ESPECIALLY
IN AREAS EAST OF ARKADELPHIA TO MOUNTAIN HOME.

THE FRONT IS EXPECTED TO CLEAR THE REGION SOME TIME LATE WEDNESDAY
NIGHT OR EARLY THURSDAY MORNING. HOWEVER...THERE WILL BE SOME
LINGERING SHOWERS AND THUNDERSTORMS BEHIND IT AS THE UPPER LOW
PASSES ACROSS SOUTHERN MISSOURI. PRECIPITATION WILL DIMINISH ON
THURSDAY EVENING AS THE LOW PUSHES INTO THE OHIO VALLEY AND SURFACE
HIGH PRESSURE MOVES IN BEHIND IT.

THE UPPER LOW IS EXPECTED TO RAPIDLY HEAD NORTHEAST ON FRIDAY...THUS
NORTHWEST FLOW ALOFT WILL BE BRIEF...WHICH WILL PRECLUDE A
SIGNIFICANT COOLDOWN IN TEMPERATURES. THE FLOW WILL FLATTEN OUT...WITH
ANOTHER SYSTEM APPROACHING THE REGION FROM THE NORTHWEST. THIS WILL
BRING RAIN CHANCES BACK INTO THE FORECAST...MAINLY ACROSS THE WEST
AND NORTHWEST BY LATE IN THE DAY FRIDAY.

DUE TO THE AMOUNT OF MOISTURE PRESENT IN THE ATMOSPHERE...HEAVY
RAINFALL WILL REMAIN A CONCERN WITH ANY STRONGER STORM CELLS THAT
DEVELOP OVER THE NEXT FEW DAYS. THOUGH AVERAGE RAINFALL WILL BE
LESS...THERE COULD BE LOCALIZED AREAS OF ONE TO THREE INCHES OF
RAIN...PARTICULARLY ACROSS THE NORTHERN HALF OF THE AREA. WITH THE
AFOREMENTIONED AREA RECEIVING HEAVY RAINFALL IN THE LAST FEW DAYS
ALREADY...IT WILL NOT TAKE MUCH ADDITIONAL RAIN TO CAUSE ANY
FLOODING PROBLEMS. SO...WE WILL ALLOW THE WATCH TO CONTINUE THROUGH
WEDNESDAY MORNING.

PRESSURE GRADIENT WILL REMAIN ELEVATED OVER THE NEXT FEW DAYS...
PARTICULARLY DURING THE DAYTIME HOURS. SUSTAINED WINDS WILL BE BELOW
LAKE WIND ADVISORY CRITERIA TODAY...BUT WILL MENTION SOME GUSTS TO
25 MPH IN THE FORECAST. TOMORROW WILL LIKELY BE A DIFFERENT STORY AS
THE FRONT APPROACHES...WITH 15 TO 25 MPH WINDS COMMON...AND SOME
GUSTS APPROACHING 35 MPH.

AS HAS BEEN THE CASE THE LAST FEW DAYS...TEMPERATURES WILL BE DEPENDENT
ON CLOUD COVER AND RAINFALL...SO APPROACH THE NUMBERS WITH CAUTION.

LONG TERM...FRIDAY NIGHT THROUGH MONDAY
AN UPPER LOW PRESSURE SYSTEM WILL BE IN THE UPPER MIDWEST TO BEGIN
THE PERIOD WITH ZONAL FLOW OVER ARKANSAS. THIS UPPER LOW QUICKLY
MOVES TO THE EASTERN GREAT LAKES BY SUNDAY AND AN UPPER RIDGE BUILDS
OVER THE SOUTHEAST U.S. SOUTHWEST FLOW RETURNS TO ARKANSAS. THE
UPPER RIDGE EXPANDS OVER THE EASTERN U.S. MONDAY AND TUESDAY.

MODELS ARE IN GOOD AGREEMENT IN THE LONG TERM. A WEAK SHORT WAVE
MOVES THROUGH ARKANSAS SATURDAY WITH LITTLE MOISTURE TO WORK WITH.
WILL INCLUDE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS OVER THE
AREA FOR SATURDAY. HOWEVER...FROM SATURDAY NIGHT THROUGH THE END OF
THE PERIOD TUESDAY...HIGH PRESSURE BUILDS OVER THE AREA...INCREASING
SUBSIDENCE. THIS WILL RESULT IN A WARMING TREND. SUMMERLIKE
TEMPERATURES WILL BE COMMON WITH HIGHS IN THE 80S AND 90S.

&&

.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR     83  68  80  61 /  30  50  50  60
CAMDEN AR         92  72  88  64 /  10  40  50  60
HARRISON AR       81  66  80  57 /  30  60  40  50
HOT SPRINGS AR    87  72  85  65 /  10  40  50  50
LITTLE ROCK   AR  87  70  86  65 /  20  40  50  60
MONTICELLO AR     91  71  89  68 /  10  40  50  70
MOUNT IDA AR      85  72  82  61 /  10  40  40  40
MOUNTAIN HOME AR  82  67  79  57 /  30  60  50  50
NEWPORT AR        84  69  82  63 /  30  40  50  60
PINE BLUFF AR     89  71  89  67 /  10  40  50  60
RUSSELLVILLE AR   85  69  83  62 /  30  50  40  50
SEARCY AR         84  68  83  64 /  20  40  50  60
STUTTGART AR      88  70  88  66 /  20  40  50  60
&&

.LZK WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR BAXTER-BOONE-
CLEBURNE-CONWAY-FAULKNER-FULTON-INDEPENDENCE-IZARD-JACKSON-
JOHNSON-LOGAN-MARION-NEWTON-PERRY-POPE-SCOTT-SEARCY-SHARP-STONE-
VAN BUREN-WHITE-WOODRUFF-YELL.

&&

64

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LITTLE ROCK AR
500 AM CDT TUE MAY 24 2011

ARZ003>007-012>016-021>025-030>034-037>047-052>057-062>069-251000-
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 TUE MAY 24 2011

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

.DAY ONE...TODAY AND TONIGHT

THERE IS AGAIN A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY AND
TONIGHT ACROSS MOST OF ARKANSAS. A MODERATE RISK AREA INCLUDES A
PORTION OF WESTERN ARKANSAS.

AN UPPER LOW PRESSURE SYSTEM WILL MOVE INTO THE PLAINS TODAY AND
THIS WILL BRING ABOUT MORE WIDESPREAD THUNDERSTORMS. STRONG
THUNDERSTORMS WILL BE POSSIBLE ACROSS MAINLY CENTRAL AND NORTHERN
ARKANSAS THIS AFTERNOON AND TONIGHT. THESE STORMS WILL BE CAPABLE OF
PRODUCING VERY LARGE HAIL AND DAMAGING WINDS. A FEW STRONG TORNADOES
ARE ALSO EXPECTED.

IN ADDITION...ANY THUNDERSTORM THAT DEVELOPS COULD PRODUCE LOCALLY
HEAVY RAINFALL. A FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH
WEDNESDAY MORNING FOR THE NORTHERN HALF OF ARKANSAS.

RIVER FLOODING CONTINUES ACROSS EASTERN ARKANSAS. WHILE MOST RIVERS
HAVE CRESTED...SOME ARE RISING AGAIN...AND THE WATER WILL BE VERY
SLOW TO RECEDE. A FEW ROADS IN EASTERN SECTIONS OF THE STATE REMAIN
CLOSED.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SEVERE STORMS WILL BE POSSIBLE ONCE AGAIN ON WEDNESDAY ACROSS MUCH
OF ARKANSAS. THIS IS DUE TO A STALLED FRONT TO THE NORTH AND WEST OF
ARKANSAS. STORM SYSTEMS FROM THE SOUTHWEST WILL INTERACT WITH THE
FRONT. A MODERATE RISK OF SEVERE THUNDERSTORMS IS OVER THE EASTERN
HALF OF THE STATE...WITH A SLIGHT RISK OVER THE REST OF THE STATE.
WIDESPREAD SEVERE WEATHER IS EXPECTED WEDNESDAY AND WEDNESDAY NIGHT.

ONE TO THREE INCH RAINFALL AMOUNTS ARE POSSIBLE IN THE NORTHERN AND
CENTRAL COUNTIES NEAREST THE FRONT. THIS COULD LEAD TO RISES ON AREA
RIVERS...BUT NOT TO THE LEVELS REACHED EARLIER THIS MONTH. A FLASH
FLOOD WATCH REMAINS IN EFFECT FOR NORTHERN ARKANSAS THROUGH
WEDNESDAY MORNING.

IT APPEARS THE FRONT WILL FINALLY GAIN SOME MOMENTUM AND MOVE TO THE
SOUTHEAST WEDNESDAY NIGHT. ANOTHER ROUND OF SEVERE WEATHER AND HEAVY
RAIN IS POSSIBLE ALONG THE FRONT INTO EARLY THURSDAY MORNING. IT
APPEARS FRIDAY AND MOST OF THE UPCOMING HOLIDAY WEEKEND WILL BE DRY
AND WARM AS HIGH PRESSURE SETTLES OVER THE AREA.

RIVER FLOODING WILL REMAIN AN ISSUE ACROSS EASTERN ARKANSAS FOR THE
NEXT SEVERAL DAYS.

STAY TUNED TO LATER FORECASTS. INDIVIDUALS ARE ENCOURAGED TO MONITOR
NATIONAL WEATHER SERVICE FORECASTS FOR THE LATEST ON RIVER LEVELS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS EXPECTED LATE THIS AFTERNOON AND EVENING.

&&

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

51