FXUS64 KLZK 222343 AAA
AFDLZK
AREA FORECAST DISCUSSION...UPDATE FOR AVIATION
NATIONAL WEATHER SERVICE LITTLE ROCK AR
545 PM CST TUE DEC 22 2009
.AVIATION...
OVERALL MVFR CEILINGS ACROSS AR. PATCHY IFR CONDITIONS WITH FOG AND
SHOWERS. AREAS OF VFR CONDITIONS MAINLY OVER SOUTH AR. SURFACE FLOW
FROM THE SOUTH 4 TO 10 KNOTS. LOW LEVEL JET TO AFFECT NORTH AND
CENTRAL AR WITH WIND SHEAR POSSIBLE SURFACE TO 2K FT. OVERNIGHT...
INCREASING AREAS OF IFR CEILINGS AND VISIBILITY TO AFFECT ALL TAF
SITES. ALSO INCREASING LIGHT RAIN AND SHOWERS AFTER MIDNIGHT ACROSS
ALL OF AR...AS A STORM SYSTEM OVER THE SOUTHERN PLAINS MOVES CLOSER
TO AR. (59)
&&
.PREV DISCUSSION... /ISSUED 347 PM CST TUE DEC 22 2009/
.SHORT TERM...TONIGHT THROUGH FRIDAY
A POWERFUL STORM SYSTEM IN THE ROCKIES WILL MOVE INTO THE
SOUTHERN PLAINS ON WEDNESDAY...AND WILL APPROACH ARKANSAS
WEDNESDAY NIGHT/EARLY THURSDAY BEFORE TURNING TO THE NORTH.
AHEAD OF THE SYSTEM...AREAS OF HEAVY RAIN AND SOME SEVERE WEATHER
ARE IN THE FORECAST.
A FEW SHOWERS WERE ALREADY DEVELOPING THIS AFTERNOON...WITH
SHOWERS/ISOLATED THUNDERSTORMS POPPING UP MORE READILY OVERNIGHT.
THE LATEST SOUNDINGS SHOW PLENTY OF DRY AIR ALOFT...WITH THE
INTRODUCTION OF MOISTURE CREATING EVAPORATION AND COOLING. THIS
WILL MAKE IT EASIER FOR ICE TO FORM...WITH SOME HAIL POSSIBLE INTO
WEDNESDAY MORNING.
PRECIPITATION WILL BECOME MORE WIDESPREAD ON WEDNESDAY AS THE
SYSTEM HEADS TOWARD THE REGION. RAIN AND SCATTERED THUNDERSTORMS
ARE IN THE FORECAST. WHILE THERE COULD BE HEAVY DOWNPOURS IN SPOTS...
DID NOT MENTION HEAVY RAIN UNTIL WEDNESDAY NIGHT/THURSDAY MORNING.
DURING THIS TIME FRAME...THE SYSTEM WILL DRAG A COLD FRONT INTO
ARKANSAS. RAIN WILL BE MORE CONCENTRATED/HEAVY AHEAD OF THE FRONT
IN WESTERN SECTIONS OF THE STATE WEDNESDAY EVENING...AND FARTHER
EAST LATER AT NIGHT/EARLY THURSDAY.
IN ADDITION TO THE RAIN...THERE COULD BE A SQUALL LINE NEAR THE
FRONT. GIVEN A LOT OF WIND ENERGY...THE LINE COULD BRING STRONG TO
DAMAGING WINDS...ESPECIALLY TO THE SOUTHERN HALF OF ARKANSAS. HIGH
0-1 KM HELICITY VALUES INDICATE THE POSSIBILITY OF AN ISOLATED
TORNADO. TORNADOES WILL BE MORE LIKELY SOUTH OF THE STATE IN
EASTERN TEXAS/LOUISIANA WHERE THE ATMOSPHERE IS MORE UNSTABLE AND
THE STORMS MORE SURFACE BASED.
AS THE SYSTEM DEPARTS TO THE NORTH LATE THURSDAY...IT WILL BE
FOLLOWED BY MUCH COLDER AIR. MOISTURE WILL EXIT QUICKLY...WITH NOT
MUCH LEFT BY THE TIME RAIN CHANGES TO SNOW. LEFT SMALL CHANCES FOR
LIGHT SNOW IN AREAS TOWARD THE MISSOURI BORDER.
MOISTURE WILL CONTINUE TO WRAPAROUND THE SYSTEM ON CHRISTMAS
DAY...AGAIN ACROSS THE FAR NORTH. THERE MAY BE A LITTLE LIGHT
SNOW...WITH A DUSTING POSSIBLE. CLEARING WILL TAKE PLACE IN
PORTIONS OF CENTRAL/SOUTHERN ARKANSAS...WITH BELOW NORMAL
TEMPERATURES.
&&
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
MODELS CONTINUE TO KEEP A HIGHLY AMPLIFIED PATTERN IN PLACE WHEN THE
PERIOD INITIATES. PATTERN HIGHLIGHTED BY RIDGES OVER THE WESTERN
CONUS AND ALONG THE EAST COAST WITH TROUGHING IN BETWEEN. VERY DEEP
UPPER LOW OVER THE UPPER MIDWEST INITIALLY BUT PATTERN BECOMES MORE
BLOCKY WITH TIME AND KEEPS BROAD CYCLONIC FLOW IN PLACE THROUGH THE
MAJORITY OF THE PERIOD. WILL BLEND FORECAST SOLUTIONS THIS AFTERNOON
BUT WITH THE ECMWF CONTINUING TO BE THE BEST FIT AND WITH IT OUT
PERFORMING THE GFS OF LATE...WILL LEAN IN ITS DIRECTION.
DEEP UPPER LOW WILL CONTINUE TO SPIN OVER THE UPPER MIDWEST/GREAT
LAKES THROUGH THE WEEKEND BEFORE FINALLY LIFTING OUT LATE IN THE
PERIOD. MOISTURE ROTATING AROUND THIS FEATURE WILL CONTINUE TO BRUSH
THE NORTHERN MOST COUNTIES WITH MORE CLOUDS VERSUS THE REMAINDER THE
AREA BUT NO PRECIPITATION EXPECTED ANYWHERE ALTHOUGH CONDITIONS WILL
BE BREEZY. TEMPERATURES WILL CONTINUE TO RUN BELOW NORMAL THROUGH
THE PERIOD WITH THE MAV/MEX NUMBERS LOOKING REASONABLE AND GENERALLY
ACCEPTED.
HIGH PRESSURE WILL DOMINATE FOR MONDAY AND DRY CONDITIONS WILL
CONTINUE. FORECAST GETS A LITTLE MORE INTERESTING FOR LATE IN THE
PERIOD AS ECMWF STARTS TO BRINGS PRECIPITATION BACK TO THE AREA WITH
LOW PRESSURE DEVELOPING IN THE GULF ACCOMPANIED BY AN ADVANCING
SHORTWAVE TROUGH.
COLD AIR WILL LIKELY BE ESTABLISHED BY THIS POINT AND THERMAL
STRUCTURE SUGGESTS WINTER PRECIP POSSIBLE MONDAY NIGHT AND OVER THE
FAR SOUTH. GFS ON THE OTHER HAND HAS BACKED OFF THIS SCENARIO UNTIL
AFTER THE EXTENDED PERIOD AND IS SLIGHTLY WARMER. SINCE WE ARE
TALKING A WEEK OR MORE OUT...WILL TAKE A WAIT AND SEE APPROACH BUT
SCENARIO WILL NEED TO BE MONITORED OVER THE NEXT SEVERAL DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 48 57 51 54 / 80 90 100 90
CAMDEN AR 53 63 55 56 / 80 90 90 90
HARRISON AR 47 58 49 50 / 80 90 100 90
HOT SPRINGS AR 52 63 53 54 / 80 90 100 90
LITTLE ROCK AR 51 61 53 55 / 80 90 90 90
MONTICELLO AR 53 63 55 58 / 80 90 100 90
MOUNT IDA AR 52 63 52 53 / 80 90 100 90
MOUNTAIN HOME AR 47 57 49 50 / 80 90 100 90
NEWPORT AR 48 57 52 55 / 80 90 100 90
PINE BLUFF AR 52 62 55 57 / 80 90 100 90
RUSSELLVILLE AR 50 61 51 52 / 80 90 100 90
SEARCY AR 50 59 53 55 / 80 90 100 90
STUTTGART AR 51 60 54 57 / 80 90 100 90
&&
.LZK WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY
MORNING FOR 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.
&&
$$
SHORT TERM...46 / LONG TERM...56
