Flash Flooding and Hail in Arkansas, May 19 to 20, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LITTLE ROCK AR
642 PM CDT WED MAY 19 2010

.AVIATION...
A WARM FRONT WAS LOCATED ACROSS OKLAHOMA AND THROUGH EXTREME
SOUTHWEST ARKANSAS ON THE LATEST WEATHER MAP. SURFACE WINDS WERE
SOUTH IN THE WARM SECTOR AND EAST IN THE COOL SECTOR. SCATTERED
THUNDERSTORMS HAVE DEVELOPED IN EASTERN OKLAHOMA AND MAINLY
SHOWERS WERE IN NORTH ARKANSAS. THUNDERSTORMS WILL BECOME MORE
WIDESPREAD IN WESTERN ARKANSAS TONIGHT AND WILL SPREAD EASTWARD.
VFR CEILINGS WILL LOWER TO MVFR AND IFR CONDITIONS THROUGH
TONIGHT. THUNDERSTORM CHANCES WILL CONTINUE THROUGH THE END OF THE
PERIOD AS THE WARM FRONT LIFTS NORTHWARD.

&&

.PREV DISCUSSION... /ISSUED 238 PM CDT WED MAY 19 2010/

SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
ALL SHORT TERM MODELS CONTINUE TO ADVERTISE A PERIOD OF ACTIVE
WEATHER THROUGH FRIDAY MORNING. LARGE UPPER LEVEL TROUGH CURRENTLY
OVER THE CENTRAL/NORTHERN ROCKIES SHOWS UP QUITE CLEARLY ON MOISTURE
CHANNEL IMAGERY THIS AFTERNOON. FEATURE WILL BE VERY SLOW TO MOVE
OUT OVER THE NEXT 24 TO 36 HOURS KEEPING THE POSSIBILITY OF SEVERE
WEATHER AND FLOODING IN THE FORECAST. FOR CONSISTENCY SAKE...WILL
CONTINUE TO FOLLOW A COMPROMISE BETWEEN THE ECMWF/GFS SOLUTIONS THIS
AFTERNOON.

MCS THAT ROLLED THROUGH OKLAHOMA LAST NIGHT WILL CONTINUE TO WEAKEN
BUT WILL ALSO KEEP PERIODS OF LIGHT RAIN OVER THE NORTH THIS
EVENING. A FEW OF THE STORMS COULD STILL PRODUCE SOME GUSTY WINDS
AND SMALL HAIL BUT WIDESPREAD SEVERE WEATHER NOT EXPECTED.

LATEST SURFACE ANALYSIS PLACES A WARM FRONTAL BOUNDARY APPROACHING
THE ARKLATEX AT THIS TIME. FRONT MAY PRODUCE A FEW SHOWERS AND
THUNDERSTORMS IN AN AREA OF STRONG WARM AIR ADVECTION THIS AFTERNOON
..AIDED BY ANY OUTFLOW BOUNDARIES FROM EARLIER CONVECTIVE COMPLEX
BUT MAIN SHOW WILL LIKELY OCCUR AFTER DARK AS THIS BOUNDARY LIFTS TO
THE NORTH.

MODELS CONTINUE TO SHOW FORMATION OF AN MCS TONIGHT INTO EARLY
THURSDAY OVER PARTS OF NORTHERN AND CENTRAL ARKANSAS. INCREASINGLY
FAVORABLE WARM AIR ADVECTION PATTERN WITH THE ADVANCING FRONT...DEEP
SOUTHERLY FLOW WITH PWATS CLOSE TO TWO INCHES AND STRONG SHORTWAVE
KICKING OUT OF AFOREMENTIONED UPPER TROUGH WILL PRODUCE LOCALIZED
RAINFALL AMOUNTS OF TWO INCHES OR MORE UNDER THE MCS. SOME OF THE
STRONGER STORMS COULD STILL PRODUCE HAIL AND DAMAGING WINDS.
PLACEMENT OF FLASH FLOOD WATCH LOOKS GOOD AND WILL NOT MAKE ANY
CHANGES TO IT AT THIS TIME.

RAINFALL ASSOCIATED WITH THE MCS WILL WEAKEN EARLY THURSDAY WITH
ONLY A BRIEF BREAK IN THE ACTION ANTICIPATED BEFORE NEXT ROUND OF
CONVECTION COMMENCES.

THE SLOW MOVING...NOW NEGATIVELY TILTED UPPER LEVEL TROUGH FORECAST
TO BE OVER THE CENTRAL PLAINS BY LATE THURSDAY. EXPECTING ADDITIONAL
CONVECTION TO DEVELOP THURSDAY AFTERNOON OVER EASTERN OKLAHOMA AND
SWEEPING OFF TO THE EAST. 0 TO 6KM SHEAR AND STRONG INSTABILITY WILL
LIKELY LEAD TO A SQUALL LINE/LINEAR MCS OF STRONG TO SEVERE
THUNDERSTORMS. MAIN SEVERE THREAT AT THIS POINT LOOKS TO BE DAMAGING
WINDS AND LARGE HAIL BUT THE TORNADO THREAT CAN NOT BE EXCLUDED...
ESPECIALLY IF ANY CELLS CAN DEVELOP IN ADVANCE OF THE MAIN
CONVECTION. TORNADIC STORMS COULD ALSO DEVELOP IN THE CONVECTIVE
LINE ITSELF. SQUALL LINE/LINEAR MCS WILL ALSO LIKELY BE ACCOMPANIED
BY LOCALLY HEAVY RAIN.

A COLD FRONT WILL SWEEP THROUGH THE STATE THURSDAY NIGHT WITH PRECIP
ENDING BY FRIDAY MORNING AS UPPER LEVEL TROF AXIS PASSES BY. DRY
CONDITIONS RETURN FRIDAY AND SATURDAY AS HIGH PRESSURE BUILDS IN.
MAV TEMPERATURES APPEARS TOO WARM THURSDAY WITH ONGOING CONVECTION
AND WILL GO BELOW GUIDANCE HERE. OTHERWISE MAV/MEX NUMBERS LOOK
REASONABLE WITH RETURN FLOW QUICKLY RETURNING BEHIND THE BOUNDARY
AND TEMPERATURES WARMING ACCORDINGLY.

LONG TERM...SUNDAY THROUGH WEDNESDAY
HIGH PRESSURE WILL CONTINUE OVER THE REGION THROUGH THE MIDDLE OF
NEXT WEEK. WARM AND MUGGY CONDITIONS WILL CONTINUE...AND AS THE
SURFACE HIGH MOVES EAST...SOUTH WINDS WILL RETURN. THERE IS THE
POTENTIAL FOR ISOLATED AFTERNOON CONVECTION TUESDAY AND
WEDNESDAY...BUT DID NOT INCLUDE AT THIS TIME.

&&

.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR     61  77  63  82 /  90  80  70  20
CAMDEN AR         68  86  67  88 /  60  60  60  20
HARRISON AR       61  75  60  80 / 100  90  60  10
HOT SPRINGS AR    66  82  65  85 /  80  70  60  10
LITTLE ROCK   AR  64  82  65  85 /  80  70  60  20
MONTICELLO AR     68  86  68  87 /  50  60  60  20
MOUNT IDA AR      66  82  64  85 /  80  70  60  10
MOUNTAIN HOME AR  60  75  61  80 / 100  90  60  20
NEWPORT AR        62  78  65  83 /  80  80  70  20
PINE BLUFF AR     66  84  67  86 /  60  60  60  20
RUSSELLVILLE AR   63  79  63  83 /  90  80  60  10
SEARCY AR         63  80  64  83 /  80  70  70  20
STUTTGART AR      65  83  66  85 /  70  70  70  20
&&

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

&&

AVIATION...51

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE LITTLE ROCK AR
1230 PM CDT WED MAY 19 2010

ARZ003>007-012>016-021>025-030>034-037>047-052>057-062>069-201000-
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-
1230 PM CDT WED MAY 19 2010

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

LOW PRESSURE...OVER THE EASTERN ROCKIES...IS FORECAST TO TRACK
SLOWLY EASTWARD INTO THE SOUTHERN PLAINS THROUGH TONIGHT. THE
CIRCULATION AROUND THE STORM WILL BRING A WARM FRONT NORTHWARD INTO
ARKANSAS.

SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ALONG THIS
FRONT THIS EVENING AND SOME OF THE STORMS COULD BE STRONG TO
POSSIBLY SEVERE WITH LARGE HAIL AND DAMAGING WINDS THE PRIMARY
CONCERN.

A LARGE COMPLEX OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO DEVELOP
OVERNIGHT ACROSS EASTERN OKLAHOMA AND SPREAD INTO NORTHERN AND
CENTRAL ARKANSAS BY MORNING. THIS COMPLEX OF STORMS WILL PRODUCE A
LARGE SWATH OF MODERATE TO HEAVY RAINFALL WITH OVER TWO INCHES OF
RAIN NOT OUT OF THE QUESTION. SOME OF THE STORMS MAY ALSO BE SEVERE
WITH DAMAGING WIND AND LARGE HAIL POSSIBLE AS WELL.

A FLASH FLOOD WATCH WILL BE IN EFFECT STARTING TONIGHT OVER MUCH OF
NORTHERN AND CENTRAL ARKANSAS AND REMAIN VALID THROUGH THURSDAY
NIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

SHOWERS AND THUNDERSTORMS WILL BE ONGOING ACROSS MUCH OF ARKANSAS
THURSDAY MORNING...AS THE AFOREMENTIONED WARM FRONT CONTINUES
LIFTING SLOWLY NORTHWARD. SOME STRONG OR SEVERE STORMS WILL BE
POSSIBLE DURING THE MORNING HOURS...ALONG WITH THE CONTINUED THREAT
OF LOCALLY HEAVY RAINFALL.

THE ASSOCIATED LOW PRESSURE SYSTEM IS EXPECTED TO TRACK NORTH OF
ARKANSAS THURSDAY NIGHT AND FRIDAY. AN ASSOCIATED COLD FRONT WILL
PASS THROUGH THE STATE DURING THAT TIME...BRINGING WITH IT ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS. THERE IS A SLIGHT CHANCE OF
SEVERE STORMS ALONG AND AHEAD OF THE FRONT...WITH LARGE HAIL AND
DAMAGING WINDS THE MAIN CONCERNS. LOCALLY HEAVY RAINFALL WILL REMAIN
POSSIBLE AS WELL.

THE STORM SYSTEM WILL BEGIN TO LIFT OUT OF THE MID SOUTH LATE FRIDAY
AND FRIDAY NIGHT. HIGH PRESSURE ALOFT WILL FOLLOW...BRINGING WITH IT
CONTINUED WARM AND HUMID CONDITIONS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TONIGHT AND AGAIN ON THURSDAY.

&&

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

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