Severe Thunderstorm Warning 298, NWS Tulsa, OK

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
254 AM CDT THU JUL 27 2000

THUNDERSTORM COMPLEX OVER MISSOURI HAS SHOWN SIGNS OF WEAKENING PAST
FEW HOURS...BUT MORE CONVECTION WAS DEVELOPING IN SOUTHEAST KANSAS
NORTH OF THE MAIN OUTFLOW BOUNDARY. LEADING EDGE OF CONVECTION HAS
ALREADY MOVED INTO NORTHWEST ARKANSAS AND THE NORTHEAST CORNER OF
OKLAHOMA AT THIS TIME...AND EXPECT THE ACTIVITY WILL CONTINUE MOVING
SOUTH THIS MORNING. SOME ISOLATED HIGH-BASED CONVECTION WAS ALSO
DEVELOPING IN SOUTHWEST ARKANSAS AND SOUTHEAST OKLAHOMA. GIVEN
CURRENT TRENDS...PLAN ON GOING LIKELY POPS ACROSS NORTHERN ZONES FOR
LINGERING SHOWERS/STORMS EARLY THIS MORNING WITH ONLY 20 POPS ACROSS
EXTREME SOUTHEAST OKLAHOMA. FIRST PERIOD POPS ARE SUBJECT TO LARGE
CHANGES THOUGH BASED ON RADAR TRENDS AT ZONE RELEASE TIME.

CHALLENGES IN LATER PERIODS DEAL WITH TIMING AND LOCATION OF
CONVECTIVE CLUSTERS THAT ARE EXPECTED TO DEVELOP AND MOVE SOUTH OR
SOUTHEAST NEXT TWO DAYS. MOST FAVORED GENESIS REGION EXPECTED TO BE
JUST SOUTH OF A COLD FRONT LATER TODAY AND AGAIN ON FRIDAY. WOULD
THEREFORE EXPECT MCS DEVELOPMENT SOMEWHERE ACROSS KANSAS THURSDAY
EVENING AND ACROSS SOUTHERN KANSAS OR NORTHERN OKLAHOMA FRIDAY
EVENING. WILL INCLUDE HIGHEST POPS IN NORTHERN ZONES THROUGH FRIDAY
NIGHT WHERE SOUTHWARD MOVING CONVECTIVE COMPLEXES SEEM MOST LIKELY
TO TRACK.

COLD FRONT TO MOVE SLOWLY ACROSS NORTHEAST OKLAHOMA FRIDAY EVENING
AND INTO SOUTHEAST OKLAHOMA ON SATURDAY. SLIGHTLY COOLER
TEMPERATURES AND DECREASING RAIN CHANCES EXPECTED BEHIND THE
FRONT...WHILE THREAT OF CONVECTION CONTINUES IN AREAS ALONG AND
AHEAD OF FRONT. WILL FOLLOW TRENDS OF PREVIOUS FORECAST AND END RAIN
CHANCES SATURDAY NIGHT ACROSS THE NORTH AND SUNDAY NIGHT ACROSS THE
SOUTH.

AFTERNOON TEMPERATURES HIGHLY DEPENDENT ON PERSISTENCE OF CLOUD
COVER AND ON STRENGTH OF CONVECTIVE OUTFLOW. COOLEST READINGS
EXPECTED ACROSS NORTHERN ZONES WHERE OUTFLOW AND DEBRIS CLOUDS WILL
KEEP TEMPERATURES IN 80S NEXT FEW DAYS...WITH HIGHS IN THE 90S
EXPECTED IN SOUTHERN ZONES.

FCSTID = 9

...FIRST PERIOD POPS BELOW SUBJECT TO CHANGE...

TUL   88  73  88  70 /  60  30  50  60
FSM   92  70  92  70 /  30  10  40  50
MLC   92  72  92  71 /  40  10  30  50
BVO   87  69  86  66 /  70  30  50  60
FYV   86  68  86  68 /  60  30  50  60
BYV   86  67  85  67 /  60  30  50  60
MIO   87  68  86  67 /  70  30  50  60
MKO   90  72  92  71 /  40  10  30  50
F10   91  73  88  70 /  50  30  50  60
HHW   93  69  94  71 /  20  10  20  40

.TUL...
AR...NONE.
OK...NONE.

ARZ001-002-010-011-019-020-029-OKZ049-053>076-281100-

EASTERN OKLAHOMA AND NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
600 AM CDT THU JUL 27 2000

...ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE ACROSS PARTS OF
   NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS THIS MORNING AND AGAIN
   LATE TONIGHT...

..SYNOPSIS...
A RIDGE OF HIGH PRESSURE ALOFT REMAINS OVER THE ROCKIES PUTTING THE
PLAINS STATES IN A NORTH TO NORTHWEST FLOW.  AT THE SURFACE AN
OUTFLOW BOUNDARY WAS LOCATED FROM PONCA CITY TO FORT SMITH. THIS
BOUNDARY WILL WASH OUT TODAY.  HOWEVER...ANOTHER BOUNDARY...A COLD
FRONT...LOCATED NEAR THE KANSAS-NEBRASKA BORDER WILL PUSH SOUTH
TOWARD THE OKLAHOMA-KANSAS BORDER LATE TONIGHT.

.PRIMARY HAZARD...
ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE THIS MORNING TO THE NORTH
OF THE OUTFLOW BOUNDARY OR ACROSS NORTHEAST OKLAHOMA.  ISOLATED
SEVERE THUNDERSTORMS WILL AGAIN BE POSSIBLE LATE TONIGHT TO THE
NORTH OF A TULSA TO FAYETTEVILLE LINE.  THE MAIN THREAT FROM THE
THUNDERSTORMS WILL BE MARGINALLY SEVERE HAIL AND DAMAGING WINDS.

.DISCUSSION...
A COMPLEX OF SHOWERS AND THUNDERSTORMS MOVED SOUTH OUT OF KANSAS AND
MISSOURI THIS MORNING LEAVING AN OUTFLOW BOUNDARY FROM PONCA CITY TO
FORT SMITH.  STORMS HAVE BEEN FORMING TO THE NORTH OF THIS BOUNDARY
AND THEN ARE MOVING SOUTH.  ENOUGH INSTABILITY EXISTS FOR A STORM OR
TWO TO BE SEVERE.  THESE STORMS SHOULD DISSIPATE THIS MORNING.
HOWEVER...MORE STORMS ARE EXPECTED TONIGHT.  THE STORMS TONIGHT WILL
FORM ALONG THE COLD FRONT IN KANSAS AND WILL PUSH SOUTH IN THE
NORTHERLY FLOW ALOFT.  SOME OF THESE STORMS MAY MOVE INTO NORTHEAST
OKLAHOMA AND NORTHWEST ARKANSAS LATE TONIGHT.  AGAIN ENOUGH
INSTABILITY WILL EXIST FOR A FEW STORMS TO BE SEVERE.

.SPOTTER ACTIVATION...
SPOTTERS AND CIVIL DEFENSE AGENCIES WILL NEED TO MONITOR THE LATEST
WEATHER CONDITION THIS MORNING AND AGAIN LATE TONIGHT.

AN UPDATED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AT 1 PM.