Flash Flood and Hail in Oklahoma, June 4, 2002

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OKLAHOMA
320 PM CDT TUE JUN 4 2002

INITIAL THUNDERSTORMS IN CENTRAL KANSAS HAVE PUSHED AN OUTFLOW
BOUNDARY SOUTHWARD AND IT IS CURRENTLY LOCATED FROM NORTH CENTRAL
OKLAHOMA THROUGH EXTREME SW OKLAHOMA.  COLD FRONT IS LAGGING BEHIND
THIS BOUNDARY AND HAS MADE A GOOD PUSH SOUTHWARD ACROSS THE TEXAS
PANHANDLE.  THUNDERSTORMS HAVE REDEVELOPED ALONG OUTFLOW BOUNDARY
WITH ENTIRE LINE MAKING SLOW PROGRESS EASTWARD.  UPPER LEVEL SUPPORT
IS BEING PROVIDED BY APPROACHING UPPER LOW CURRENTLY MOVING INTO
CENTRAL NM.

EXPECT WIDESPREAD SHOWER/THUNDERSTORM DEVELOPMENT OVERNIGHT ALONG
AND NORTH OF SAGGING COLD FRONT/OUTFLOW BOUNDARY.  APPROACHING
TROUGH AXIS...FAVORABLE UPPER JET DYNAMICS...AND SLOW MOVING
BOUNDARY WILL ALL PLAY A ROLE IN PRODUCTION OF HEAVY RAIN.  MODEL
QPF PLACEMENT VARIES...HOWEVER BELIEVE HEAVIEST RAINS OVERNIGHT WILL
OCCUR NORTH OF AN OKEMAH...TAHLEQUAH...BERRYVILLE LINE.  ISOLATED
AMOUNTS WILL LIKELY EXCEED FLASH FLOOD GUIDANCE VALUES AND A FFA
WILL BE POSTED TO ADDRESS THIS CONCERN.  SEVERE THREAT APPEARS TO BE
LIMITED TO INITIAL STAGES OF THE EVENT WITH GRADUAL TRANSITION TO
HEAVY RAINS.

EXPECT SLOW MOVEMENT OF BOUNDARY WITH PRECIP CHANCES CONTINUING INTO
WEDNESDAY.  PLACEMENT AND AMOUNTS OF TUESDAY NIGHT PRECIP WILL BE
MONITORED FOR ANY EXTENSION OF FFA.  COLD FRONT WILL CONTINUE
SOUTHWARD THROUGH WEDNESDAY NIGHT TAKING PRECIP CHANCES WITH IT.
FAVORED MORE MODEST FWC TEMPS ON THURSDAY WITH RESIDUAL MOISTURE
HAMPERING WARM UP.

DRY WEATHER AND A SLOW WARMING TREND EXPECTED THROUGH THE EARLY PART
OF THE WEEKEND.  NEXT COLD FRONT IS SLATED FOR SUNDAY/MONDAY
TIMEFRAME AND WILL CONTINUE MENTION OF PRECIP.

THANKS SURROUNDING OFFICES FOR COORDINATION EFFORTS.

FORECASTER = 07

TUL  65  76  58  82 /  90  60  10   0
FSM  70  81  61  82 /  60  70  30  10
MLC  69  79  61  81 /  70  70  20   0
BVO  60  74  57  81 /  90  50  10   0
FYV  66  75  55  78 /  80  70  20   0
BYV  66  76  56  78 /  80  70  20   0
MIO  65  74  58  80 /  90  60  10   0
MKO  68  77  58  82 /  80  70  20   0
F10  68  77  59  80 /  80  60  10   0
HHW  74  84  64  83 /  60  70  30  10

.TSA...
AR...FLASH FLOOD WATCH TONIGHT FOR ZONES ARZ001>002...ARZ010>011.

OK...FLASH FLOOD WATCH TONIGHT FOR ZONES OKZ054>071.

ARZ001-002-010-011-019-020-029-OKZ049-053>076-051200-

EASTERN OKLAHOMA / NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
100 PM CDT TUE JUN 4 2002

...A CHANCE OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING
ACROSS PARTS OF NORTHEAST OKLAHOMA...

A COLD FRONT...CURRENTLY LOCATED FROM NORTHERN OKLAHOMA INTO
NORTHERN MISSOURI...WILL MOVE SLOWLY SOUTH THROUGH TONIGHT. THE
FRONT IS FORECAST TO MOVE INTO WEST CENTRAL ARKANSAS AND SOUTHEAST
OKLAHOMA BY SUNRISE WEDNESDAY. NUMEROUS SHOWERS AND THUNDERSTORMS
ARE EXPECTED TO DEVELOP ALONG AND BEHIND THE FRONT AS IT MOVES
ACROSS NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS TONIGHT.

A FEW STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE LATE THIS
AFTERNOON AND EARLY THIS EVENING ACROSS PARTS OF NORTHEAST OKLAHOMA.
LARGE HAIL AND DAMAGING STRAIGHT-LINE WINDS COULD ACCOMPANY A FEW OF
THE STORMS AS THEY DEVELOP IN A VERY UNSTABLE AIRMASS. THE SEVERE
WEATHER THREAT WILL DIMINISH THIS EVENING AS THE AIRMASS STABILIZES
SOMEWHAT...BUT THERE WILL BE A THREAT OF HEAVY RAINFALL AS STORMS
REPEATEDLY DEVELOP ALONG AND NORTH OF THE SLOW-MOVING COLD FRONT.

.SPOTTER ACTIVATION...
SPOTTER ACTIVATION MAY BE NEEDED ACROSS PARTS OF NORTHEAST OKLAHOMA
AFTER 4 PM.

.DISCUSSION...
THUNDERSTORMS WERE DEVELOPING AND INCREASING IN INTENSITY ALONG AN
OUTFLOW BOUNDARY EXTENDING FROM NORTH CENTRAL OKLAHOMA INTO
SOUTHEAST KANSAS EARLY THIS AFTERNOON. THIS BOUNDARY WILL EVENTUALLY
MOVE INTO NORTHEAST OKLAHOMA ACROSS PAWNEE...OSAGE...AND WASHINGTON
COUNTIES AS A SURFACE COLD POOL DEEPENS ACROSS KANSAS AND EXPANDS
SOUTHWARD. IF THE BOUNDARY CAN MOVE INTO NORTHEAST OKLAHOMA BEFORE 5
OR 6 PM...THEN A FEW SEVERE THUNDERSTORMS WILL BE POSSIBLE WITH CAPE
VALUES AROUND 2500 J/KG. MARGINAL WIND SHEAR WILL LIMIT THE
INTENSITY AND COVERAGE OF ANY SEVERE CONVECTION THIS EVENING. THE
RISK OF SEVERE WEATHER WILL DIMINISH AFTER 10 PM.

A COLD FRONT IN CENTRAL KANSAS WILL CATCH UP TO THE OUTFLOW BOUNDARY
THIS EVENING AND MOVE SLOWLY SOUTH INTO NORTHEAST OKLAHOMA AND
NORTHWEST ARKANSAS TONIGHT. AS AN UPPER LEVEL DISTURBANCE MOVES EAST
OUT OF NEW MEXICO...NUMEROUS SHOWERS AND THUNDERSTORMS WITH VERY
HEAVY RAIN WILL DEVELOP ALONG AND NORTH OF THE FRONT. THE RESULTING
MESOSCALE CONVECTIVE SYSTEM /MCS/ COULD PRODUCE EXCESSIVE
RAINS...MAINLY ACROSS NORTHEAST OKLAHOMA.

RISK TABLE
VALID THROUGH 1200 UTC WEDNESDAY

AREA 1...ALONG AND NORTH OF A LINE FROM OKEMAH TO JAY
THUNDERSTORM PROBABILITY...100
SEVERE PROBABILITY IF STORMS OCCUR...35
SIGNIFICANT SEVERE PROBABILITY IF STORMS OCCUR...10

RISK AREAS DEFINE THE GREATEST SEVERE POTENTIAL. PROBABILITIES ARE IN
PERCENT. SIGNIFICANT SEVERE IS DEFINED AS F1 OR GREATER WIND/TORNADO
DAMAGE AND/OR GOLFBALL SIZE HAIL OR LARGER.

.OTHER HAZARDS...
VERY HEAVY RAINFALL IS POSSIBLE TONIGHT AS THE SLOW-MOVING COLD
FRONT MOVES SOUTH ACROSS THE AREA. THE MOST LIKELY AREA TO RECEIVE
HEAVY RAIN WILL BE ACROSS NORTHEAST OKLAHOMA AFTER MIDNIGHT.