National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS64 KTSA 182303
AFDTSA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
603 PM CDT SAT MAY 18 2013

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
FOR THE 0Z TAFS... VFR CONDITIONS WILL PREVAIL THROUGH THE ENTIRE
FORECAST PERIOD AT ALL TAF SITES. GUSTY SOUTHERLY WINDS WILL
CONTINUE AREAWIDE THROUGH THIS EVENING... WITH A VERY MOIST
AIRMASS CREATING HAZY CONDITIONS. KFSM IS EXPECTED TO DECOUPLE
FROM STRONG UPPER LEVEL WINDS... CREATING LLWS OVERNIGHT.
THUNDERSTORM CHANCES WILL INCREASE ACROSS EASTERN OKLAHOMA TOWARD
THE END OF THIS FORECAST.


&&

.PREV DISCUSSION... /ISSUED 316 PM CDT SAT MAY 18 2013/

DISCUSSION...
THE STAGE IS SET FOR A SIGNIFICANT OUTBREAK OF SEVERE WEATHER
ACROSS PARTS OF EASTERN OKLAHOMA AND NORTHWEST ARKANSAS LATE
SUNDAY...WITH A REPEAT PERFORMANCE IN SOME AREAS MONDAY. ALL MODES
OF SEVERE WEATHER WILL BE POSSIBLE WITH SOME HIGH END EVENTS
LIKELY.

THIS AFTERNOON...WATER VAPOR IMAGERY SHOWS LARGE SCALE WESTERN
U.S. THROUGH...WITH ATTENDANT DRY LINE AT THE SFC IN GENERAL
VICINITY OF OK/TX PANHANDLE BORDERS INTO SW KANSAS. SEVERE STORMS
SHOULD DEVELOP ALONG DRY LINE SHORTLY...THEN MOVE EAST AND
POTENTIALLY INTO PARTS OF EASTERN OK LATE THIS EVENING OR TONIGHT.
STORMS SHOULD BE ON A DOWNWARD TREND IN INTENSITY BY THEN AS THEY
ENCOUNTER RELATIVELY STRONG CAP...THOUGH SOME LG HAIL AND WIND
THREAT WILL EXIST IN FAR WESTERN COUNTIES.

NEGATIVE TILT UPPER TROUGH FORECAST TO MOVE INTO CENTRAL PLAINS
SUNDAY...AGAIN WITH EXTREMELY UNSTABLE AIRMASS IN PLACE OVER MUCH
OF THE AREA. DRY LINE WILL MIX FARTHER EAST SUNDAY AFTERNOON...WITH
SOME INDICATIONS IT COULD REACH AS FAR EAST AS I-35 BY 00Z. STRONG
SPEED MAX ROTATING AROUND BASE OF TROUGH PUTS GOOD PORTION OF
NORTHEAST OK IN A FAVORABLY SHEARED ENVIRONMENT FOR ROTATING
SUPERCELLS THAT REMAIN DISCRETE FOR A SIGNIFICANT AMOUNT OF
TIME. THERE ARE SOME DIFFERENCES IN THE FORECAST POSITION OF THE
SPEED MAX THAT COULD BE CRITICAL TO DETERMINING THE BEST LOCATION
FOR STRONG TORNADOES...BUT REGARDLESS IT WILL BE A POTENTIALLY
DANGEROUS LATE AFTERNOON AND EVENING...ESPECIALLY ALONG AND NORTH
OF I-44. STORMS WILL EVENTUALLY GROW INTO AN MCS WHICH WILL MOVE
EAST SUNDAY NIGHT WITH A CONTINUES THREAT OF SEVERE WEATHER EAST
INTO NW ARKANSAS WELL AFTER DARK.

THE ABOVE MENTIONED MCS WILL LIKELY PRODUCE AN OUTFLOW BOUNDARY
WHICH WILL BE IMPORTANT IN DETERMINING GREATEST SEVERE POTENTIAL
FOR MONDAY. NAM HAS BEEN THE MOST AGGRESSIVE WITH THIS FEATURE
THOUGH ITS MOST RECENT RUNS HAVE BACKED OFF A LITTLE IN SOUTHWARD
PUSH. CURRENT THINKING IS THIS BOUNDARY SHOULD BE PRESENT IN SOME
FORM NEAR I-40 CORRIDOR...WITH WIND PROFILES ONCE AGAIN FAVORING
SUPERCELLS AND MORE SIGNIFICANT SEVER WEATHER. LOCATION OF THE
GREATEST THREAT WILL BE REFINED FURTHER. STRONG SIGNAL OF ANOTHER
MCS MONDAY NIGHT INTO TUESDAY MORNING NORTH OF I-40 WITH SOME
HEAVY RAIN AND FLOODING POTENTIAL BY THEN.

SFC COLD FRONT WILL REMAIN IN THE GENERAL AREA BY TUESDAY WITH
UPPER TROUGH MOVING EAST. THIS SHOULD LEAD TO A LESSENING SEVERE
THREAT OVER MOST OF THE AREA...WITH POSSIBLE EXCEPTION OF SE
OKLAHOMA AND PARTS OF WESTERN ARKANSAS. PRECIP CHANCE WILL REMAIN
HIGH THROUGH MUCH OF TUESDAY BEFORE THE FRONT FINALLY PUSHES SOUTH
TUESDAY NIGHT.

SHOULD SEE A DRY DAY WEDNESDAY BUT BOUNDARY WILL LIKELY DRIFT BACK
NORTH LATER IN THE WEEK WITH THUNDERSTORM CHANCES RETURNING. BY
THIS TIME THE UPPER LEVEL FLOW WILL BE MUCH LESS FAVORABLE FOR
SEVERE STORMS BUT COULD SUPPORT SLOW MOVING SUMMER-LIKE CONVECTION
WITH AN ATTENDANT THREAT FOR HEAVY RAINFALL.

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&

$$

AVIATION...06