Area Forecast Discussion
Issued by NWS Little Rock, AR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KLZK 240548 AAA
AFDLZK

AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NATIONAL WEATHER SERVICE LITTLE ROCK AR
1245 AM CDT FRI APR 24 2015

.AVIATION...

OVERALL VFR FLIGHT CONDITIONS ARE EXPECTED OVERNIGHT...WITH ONLY
PATCHY MVFR CEILINGS IN SPOTS. TOWARD MORNING A WARM FRONT AND SOME
UPPER LEVEL ENERGY WILL MOVE INTO AR FROM THE SOUTHWEST...AND HELP
DEVELOP ISOLATED SHOWERS AND POSSIBLY A FEW THUNDERSTORMS. WINDS
WILL BE E TO SE AT 5 TO 10 MPH OVERNIGHT. ON FRIDAY...VFR CEILINGS
WILL BE SEEN WITH AREAS OF MVFR ALONG WITH MORE SHOWERS AND
THUNDERSTORMS. WINDS WILL BECOME E TO SE AT 5 TO 15 MPH. (59)

&&

.PREV DISCUSSION... /ISSUED 243 PM CDT THU APR 23 2015/

SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT...

THE SURFACE FRONT THAT PUSHED THROUGH ARKANSAS IS NOW LOCATED ACROSS
LOUISIANA...AND THIS FRONT WILL PUSH BACK NORTHWARD INTO ARKANSAS
TOMORROW AS A WARM FRONT. THIS BOUNDARY WILL BE THE FOCUS OF
CONVECTIVE ACTIVITY DURING THE DAY. LOCAL WRF MODEL SHOWS THE
BOUNDARY TO BE ORIENTED FROM WEST CENTRAL AR...TO JUST SOUTH OF
LITTLE ROCK...THRU PINE BLUFF...TO SE AR BY MIDDAY. THIS ROUGHLY
CORRESPONDS TO THE ENHANCED RISK AREA OUTLINED IN THE LATEST SPC
BULLETIN.

THE MOST SUBSTANTIAL CONVECTION IS EXPECTED TO OCCUR IN THE WARM
SECTOR AND ALONG THE BOUNDARY. OUR LOCAL WRF MODEL STARTS TO FIRE
OFF MORE SIGNIFICANT CONVECTION BY AROUND 1-2 PM IN WESTERN
AR...WITH THESE STORMS REACHING CENTRAL AR BY AROUND 4-5 PM.

NAM FORECAST SOUNDINGS SHOW A LOT OF MOISTURE IN THE WARM SECTOR
WITH LI VALUES IN THE AFTERNOON IN THE -3 TO -4 RANGE...AND CAPE
VALUES GENERALLY AT 1000 J/KG OR LESS. WITH A SOUTHERLY SURFACE FLOW
THERE IS A BIT OF DIRECTIONAL SHEAR IN THE LOWER LEVELS...BUT ABOVE
THAT ITS MOSTLY SPEED SHEAR.

I AM THINKING THAT HAIL WILL BE THE PRIMARY THREAT TOMORROW
AFTERNOON AND EVENING. IF A STORM GROWS SUBSTANTIALLY LARGE
ENOUGH...THERE COULD BE SOME SEVERE WINDS AS WELL. WHILE THERE
SHOULD NOT BE A LARGE THREAT FOR TORNADOES...WITH SOME DIRECTIONAL
SHEAR IN THE LOWER LEVELS IT CANNOT BE RULED OUT.

BEYOND FRIDAY WE SHOULD SEE A NICE WARM UP...WITH TEMPS IN THE 80S
ACROSS MOST OF THE STATE ON SATURDAY. ON SUNDAY ANOTHER BOUNDARY
WILL BE APPROACHING AND RAIN CHANCES WILL BE INCREASING AGAIN.

LONG TERM...MONDAY THROUGH THURSDAY

WEATHER DURING THE LONG TERM WILL HINGE ON THE EVOLUTION OF AN UPPER
LOW THAT WILL START THE PERIOD CENTERED SOMEWHERE NEAR THE NEW
MEXICO/TEXAS PANHANDLE BORDER. THAT IS TO SAY THAT UNCERTAINTY IS
HIGH AS THE BEHAVIOR OF SUCH FEATURES IS TYPICALLY NOT WELL MODELED
WITH RESPECT TO TIMING. MODELS OFTEN TIMES MOVE CLOSED UPPER LOWS
EASTWARD TOO QUICKLY.

THAT BEING SAID...MADE ONLY SLIGHT CHANGES TO THE FORECAST TO
REFLECT LATEST TIMING...TEMPERATURE...AND PRECIPITATION TRENDS SEEN
IN THE MORNING MODEL RUNS. THE CLOSED UPPER LOW WILL BEGIN MONDAY
SITUATED NEAR THE NEW MEXICO/TEXAS PANHANDLE BORDER...WITH CURRENT
FORECASTS SHOWING IT OVER THE ARKLATEX REGION BY TUE MORNING. AHEAD
OF THIS SYSTEM...SHOWERS AND THUNDERSTORMS WILL SPREAD NORTH AND
EAST INTO ARKANSAS. THE BIG QUESTION IS HOW FAR ACROSS THE FORECAST
AREA THIS PRECIPITATION WILL MAKE IT. HAVE SLIGHT CHANCE POPS IN THE
FORECAST FOR NORTHERN ZONES...WITH CHANCE POPS ACROSS CENTRAL AND
SOUTHERN ARKANSAS...WHICH IS HEAVY-HANDED TOWARDS THE EURO BUT ALSO
HAS SOME ASPECTS OF THE GFS FORECAST IN THERE AS WELL. THE EURO
SOLUTION WOULD MEAN DRY CONDITIONS FROM THIS WEEKEND THROUGH THE END
OF THE LONG TERM PERIOD ACROSS NORTHERN ARKANSAS...WHEREAS THE GFS
HAS A MORE WIDESPREAD PRECIPITATION SHIELD. A BLENDED APPROACH SEEMS
REASONABLE FOR NOW UNTIL CERTAINTY IN THE TRACK OF THE CLOSED LOW
INCREASES...AS WELL AS THE INFLUENCE OF ANOTHER NRN STREAM DIVING
SOUTH INTO THE BACKSIDE OF THE UPPER LOW AS IT MOVES EAST OF
ARKANSAS ON WEDNESDAY.

TEMPERATURES WILL REMAIN AROUND OR SLIGHTLY BELOW NORMAL THROUGH THE
LONG TERM.


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

$$







USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.