Severe Thunderstorm Warning 344, NWS Little Rock, AR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LITTLE ROCK AR
1103 PM CDT SUN AUG 12 2012

.UPDATE...
UPDATED THE FORECAST FOR SEVERE THUNDERSTORM WATCH 575 IN
NORTHWEST AND WEST CENTRAL ARKANSAS. A FEW STRONG THUNDERSTORMS
ARE IN FAR NORTHWEST ARKNASAS PREPARING TO POSSIBLY MOVE INTO OUR
CWFA.

&&

.PREV DISCUSSION... /ISSUED 913 PM CDT SUN AUG 12 2012/

UPDATE...
A WARM FRONT HAS MOVED NORTH THROUGH CENTRAL ARKANSAS. THIS HAS
SIGNIFICANTLY SLOWED THE COOLING IN CENTRAL AND SOUTH ARKANSAS.
DEW POINTS HAVE ALSO BEEN RISING THE LAST FEW HOURS. A FEW SHOWERS
HAVE MOVED ACROSS ARKANSAS THIS EVENING AND AN AREA OF
THUNDERSTORMS MOVING THROUGH SOUTH OKLAHOMA WILL MOVE INTO
SOUTHWEST ARKANSAS SOON. THE WEST HAS A SLIGHT CHANCE OF SEVERE
THUNDERSTORMS TONIGHT. CENTRAL AND SOUTH SECTIONS HAVE BECOME MORE
UNSTABLE SO MORE THUNDERSTORMS SHOULD DEVELOP DURING THE OVERNIGHT
HOURS. ADJUSTED TEMPERATURES AND CLOUD COVER DUE TO THE GIVEN
CONDITIONS AND TRENDS.

PREV DISCUSSION... /ISSUED 730 PM CDT SUN AUG 12 2012/

AVIATION...

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL POP UP
OVERNIGHT AHEAD OF A COLD FRONT ARRIVING FROM THE PLAINS.

IN GENERAL...THERE WILL BE HIGH CLOUDS INITIALLY...WITH LOWER
CLOUDS FROM 4000 TO 6000 FEET AS STORMS DEVELOP. SURROUNDING
STORMS...MVFR CEILINGS/VISIBILITIES ARE EXPECTED.

CHANCES FOR PRECIPITATION WILL CONTINUE INTO MONDAY MORNING
BEFORE THE FRONT SWEEPS THROUGH THE REGION.

WINDS AHEAD OF THE FRONT WILL BE SOUTHEAST TO SOUTHWEST AT
4 TO 8 MPH OVERNIGHT. WINDS ON MONDAY WILL BE WEST/NORTHWEST
AT 8 TO 14 MPH BEHIND THE FRONT...WITH SOME GUSTS UP TO
20 MPH. (46)

DISCUSSION...

MAIN CONCERNS THIS FORECAST CYCLE ARE FIRST PERIOD TO SECOND
PERIOD CONVECTION CHANCES AND ANY CHANCE FOR SEVERE STORMS. COOLER
TEMPS TUESDAY. NEXT CHANCE OF RAIN WEDNESDAY WITH A LIFTING WARM
FRONT...THEN THE NEXT COLD APPROACHES THURSDAY TO FRIDAY WITH AN
UNSETTLED NW UPPER FLOW.

ONLY SAW LIGHT SHOWERS THIS MORNING BUT MOST DID NOT REACH THE
GROUND DUE TO QUITE DRY ATMOSPHERE. 12Z KLZK SOUNDING HAD A
PRECIP WATER VALUE OF 1 INCH AND QUITE DRY 2K TO 13K FT. SURFACE
ANALYSIS DOES HAVE THE SURFACE HIGH OFF TO THE NE NOW AND A LIGHT
SE FLOW HAS RETURNED TO AR. DEW POINT TEMPS THIS MORNING OVER
SOUTHERN AR WERE IN THE LOWER TO MID 60S AND NOW HAVE MADE IT TO
AROUND 70 IN SPOTS. CENTRAL AND NORTH WAS IN THE 50S THIS MORNING
ARE NOW HIT THE UPPER 50S TO LOWER 60S. MOISTURE SURGE OUT OF THE
SOUTH HAS HELPED WITH DEW POINT TEMPS OVER NE TX IN THE 70S.
WEAK SHORT WAVE ENERGY IN THE UPPER NW FLOW DID MOVE OVER AR AND
DEVELOP THE CLOUDS AND LIGHT SHOWERS THIS MORNING TO AFTERNOON. SPC
DAY 1 DOES HAVE A SLIGHT RISK OF SEVERE STORMS MAINLY OVER WESTERN
AREAS... WHICH WOULD BE LATER AS MORE JET DYNAMICS SET UP OVER THE
WEST...BETTER MOISTURE INFLUX...INSTABILITY...LIFT AND THE COLD
FRONT GRADUALLY SAGS SE. BETTER CHANCES OF CONVECTION WILL BE LATER
TODAY AND TONIGHT.

SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
WILL HAVE THE SLIGHT TO CHANCE POPS IN THE EVENING AND OVERNIGHT
HOURS OVER AR...ASSOCIATED WITH UPPER SUPPORT AND THE COLD FRONT.
MODEL TIMING IS CONSISTENT BUT GFS REMAINS MUCH MORE AGGRESSIVE
WITH CONVECTION AND QPF. WILL FAVOR MORE OF A NAM AND ECMWF BLEND
AND KEPT POPS BELOW 50 PERCENT AT THIS TIME. ADJUST MAY HAVE TO BE
MADE WITH LATER UPDATES BASED ON CONVECTION TRENDS WHEN IT
INITIATES. THE FRONT WILL GRADUALLY MOVE THROUGH AR ON MONDAY AND
SOME CONVECTION WILL BE POSSIBLE ALONG AND AHEAD OF THE BOUNDARY.
GRADUALLY END RAIN CHANCES MONDAY EVENING. HIGH PRESSURE DOMINATES
THE FORECAST ON TUESDAY WITH DRY AND TEMPS CLOSE TO NORMAL VALUES.
TUESDAY NIGHT TO WEDNESDAY ADDITIONAL SHORT WAVE ENERGY IS SEEN IN
THE UPPER NW FLOW...AND THE PREVIOUS BOUNDARY LIFTS BACK NORTH AS
WARM FRONT. A BIT OF A LULL WEDNESDAY NIGHT...THEN THURSDAY HAS
MORE CONVECTION POTENTIAL AS MORE SHORT WAVE ENERGY AND AN
APPROACHING FRONTAL SYSTEM EFFECT AR. THERE REMAINS SOME RISK OF
STRONG TO SEVERE STORMS...MAINLY ISOLATED...WITH EACH FRONT AND
SHORT WAVE...BUT PINNING DOWN THE EXACT TIMING AND LOCATION IS
DIFFICULT.

LONG TERM...THURSDAY THROUGH SUNDAY

THE SHORT OF IT...GOOD CHANCES FOR RAIN ON THU/FRI...WITH A NOTABLE
COOL DOWN HEADING INTO THE WEEKEND.

THE LONG STORY...THE LONG TERM PERIOD CONTINUES TO LOOK LIKE AN
ACTIVE ONE...WITH A PROGRESSIVE UPPER FLOW...A DECENT SHOT AT
WIDESPREAD RAIN WITH A FRONT ON THU/FRI...AND BELOW NORMAL TEMPS
FOLLOWING THE FRONT. MODELS STILL IN GOOD AGREEMENT ON THE
EVOLUTION OF THE UPPER FLOW LATE THIS WEEK. A STRONG NRN BRANCH
TROUGH WILL SLIP OUT OF CANADA AND MOVE ACROSS THE NRN PLAINS AND
UPPER MIDWEST THURSDAY INTO FRIDAY. THIS WILL PUSH A FRONT SOUTH
THROUGH THE PLAINS AND INTO ARKANSAS BY LATE THU EVENING. HELPING
DRIVE THE FRONT WILL BE A FORECAST SFC HIGH OF ABOUT
1020-1025MB..ORIGINATING FROM THE YUKON AND FAR NRN BRITISH
COLUMBIA PROVINCES. OBVIOUSLY THIS AIR MASS WILL UNDERGO
MODIFICATION AS IT TRAVELS SOUTH...BUT IT IS WORTH NOTING THAT IS
A COOL AIR MASS WITH DEWPOINTS IN THE 40S AND 50S ACROSS A LARGE
PORTION OF WRN CANADA. THIS GIVES SOME CREEDENCE TO THE MODELS
FORECASTING HIGHS AND LOWS SOME 5-10 DEGREES BELOW SEASONAL NORMS
FRIDAY ONWARD. IN FACT...IF YOU BUY THE GUIDANCE AT FACE
VALUE...SAT MAY BRING WIDESPREAD LOWS IN THE 50S IN NRN
ARKANSAS...AND AFTERNOON HIGHS THAT STRUGGLE TO MAKE 85 ACROSS
MUCH OF THE FORECAST AREA. WHILE I DID TREND THE FORECAST
DOWNWARDS...DID NOT COOL HIGHS/LOWS AS LOW AS CURRENT GUIDANCE
SUGGESTS. CONFIDENCE IS GROWING IN A NOTABLE PATTERN SHIFT AND
COOLDOWN...IT IS JUST NOT HIGH ENOUGH TO PULL THE TRIGGER ON THAT
TYPE OF FORECAST QUITE YET.

&&

.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR     69  91  66  88 /  40  30  10  10
CAMDEN AR         72  94  68  93 /  30  30  20  10
HARRISON AR       69  88  64  86 /  50  20  10  10
HOT SPRINGS AR    72  94  68  91 /  40  30  10  10
LITTLE ROCK   AR  72  92  68  89 /  40  30  10  10
MONTICELLO AR     71  94  70  91 /  20  40  20  10
MOUNT IDA AR      72  93  66  91 /  40  30  10  10
MOUNTAIN HOME AR  69  89  64  87 /  50  20  10  10
NEWPORT AR        68  91  67  88 /  40  30  10  10
PINE BLUFF AR     71  93  68  90 /  30  30  10  10
RUSSELLVILLE AR   71  91  68  90 /  40  20  10  10
SEARCY AR         70  90  67  88 /  40  30  10  10
STUTTGART AR      71  91  68  89 /  30  30  10  10
&&

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

51

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE LITTLE ROCK AR
950 PM CDT SUN AUG 12 2012

ARZ003>007-012>016-021>025-030>034-037>047-052>057-062>069-131000-
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-
950 PM CDT SUN AUG 12 2012

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

.DAY ONE...TONIGHT

SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE DEVELOPING IN
EASTERN OKLAHOMA AND WESTERN ARKANSAS LATE THIS EVENING. THE STORMS
WILL BE AHEAD OF A COLD FRONT APPROACHING FROM THE SOUTHERN
PLAINS.

DURING THE OVERNIGHT HOURS...HIT AND MISS STORMS WILL MOVE ACROSS
THE REGION WITH THE FRONT. A FEW OF THE STORMS COULD BE SEVERE...
MAINLY WEST OF LITTLE ROCK. QUARTER SIZE HAIL OR LARGER AND DAMAGING
WINDS WILL BE THE MAIN CONCERNS.

DUE TO ONGOING DROUGHT CONDITIONS AND DRY VEGETATION...THERE IS
ALSO A CONCERN FOR ISOLATED WILDFIRES DUE TO LIGHTNING STRIKES.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

RAIN CHANCES WILL CONTINUE IN SOUTHEAST ARKANSAS MONDAY MORNING
BEFORE THE COLD FRONT EXITS THE STATE. RAIN CHANCES WILL REENTER THE
FORECAST WEDNESDAY THROUGH FRIDAY AS A STRONGER FRONT ARRIVES FROM
THE WEST. THIS FRONT WILL ALSO BRING BELOW NORMAL TEMPERATURES TO
THE STATE AT THE END OF THE UPCOMING WEEK.

THE FIRE DANGER WILL REMAIN AN ISSUE UNTIL WIDESPREAD SUBSTANTIAL
RAIN IS RECEIVED. BURN BANS ARE IN PLACE IN MANY COUNTIES OF
ARKANSAS...AND ANY UNCONTROLLED OR ACCIDENTAL FIRE COULD QUICKLY
GROW OUT OF CONTROL.

.SPOTTER INFORMATION STATEMENT...

SEVERE STORMS ARE EXPECTED TO BE ISOLATED OVERNIGHT...SO SPOTTER
ACTIVATION IS NOT ANTICIPATED.

&&

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

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