Flood in Oklahoma, May 30 to 31, 2001

EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
510 AM CDT WED MAY 30 2001

ZONES ALREADY SENT. MODELS ARE OF VERY LITTLE HELP THIS MORNING
AS NONE OF THEM ARE HANDLING THE ONGOING COMPLEX VERY WELL. 06Z ETA
SEEMS TO HAVE THE BEST HANDLE AS IS TO BE EXPECTED SO WILL BASE THE
FORECAST MAINLY ON THIS SOLUTION.

HAVE CANCELLED THE FLASH FLOOD WATCH FOR THIS MORNING AS THE
HEAVIEST RAINS ARE SHIFTING SOUTH OF THE WATCH AREA AND
REDEVELOPMENT OF HEAVY RAIN IS NOT EXPECTED THIS MORNING. COMPLEX
APPEARS TO BE ON A DOWNWARD SLIDE NOW AND EXPECT THIS TO CONTINUE
WITH THE ACTIVITY ON THE WESTERN END OF THE COMPLEX LIKELY TO
MAINTAIN ITSELF THE BEST THE NEXT SEVERAL HOURS.

BIG QUESTION IS HOW MUCH AIRMASS RECOVERY WE WILL SEE TODAY. 06Z ETA
SUGGESTS SOME CLEARING LATER THIS MORNING AND AFTERNOON BEHIND THE
COMPLEX RESULTING IN SIGNIFICANT DESTABILIZATION. OUTFLOW BOUNDARY
FROM THE CURRENT COMPLEX IS LIKELY TO RESIDE IN SOUTHEAST OKLAHOMA
THIS AFTERNOON AND WILL PROVIDE THE FOCUS FOR THE MOST VOLATILE
DEVELOPMENT THIS AFTERNOON. WIND PROFILES WILL BE FAVORABLE FOR
TORNADIC SUPERCELLS NEAR THE OUTFLOW BOUNDARY WHERE LOW LEVEL FLOW
WILL BE MAXIMIZED. WILL LIKELY SEE SCATTERED DEVELOPMENT FURTHER
NORTH ALONG THE COLD FRONT SO WILL NEED TO KEEP POPS IN ALL DAY.
SOME OF THESE STORMS MAY ALSO BE SEVERE BUT THE BEST ACTION WILL BE
IN THE SOUTH SO WILL ONLY MENTION SEVERE IN THAT AREA.

AFTERNOON STORMS LIKELY TO ONCE AGAIN ORGANIZE INTO A MESOSCALE
CONVECTIVE COMPLEX THIS EVENING WITH MOST OF THE ACTIVITY SHIFTING
SOUTH AND EAST OF THE FORECAST AREA AFTER MIDNIGHT. COLD FRONT WILL
MOVE THROUGH BY EARLY THURSDAY ENDING ALL RAIN CHANCES AND USHERING
IN DRIER AIR. MAY SEE SOME STRATOCUMULUS AROUND THURSDAY SO KEPT
SKIES PARTLY CLOUDY.

AVN AND ETA EXTENSION BOTH SWING A STRONG VORT LOBE AROUND THE
BACKSIDE OF THE DEEPENING UPPER MIDWEST CLOSED UPPER LOW FRIDAY.
FRONTOGENESIS WILL OCCUR WITH LOW LEVEL FLOW BACKING TO THE
SOUTHWEST AND WEST AHEAD OF THE FRONT DURING THE DAY FRIDAY.
ALTHOUGH SURFACE DEWPOINTS WILL GENERALLY REMAIN IN THE 50S TO
AROUND 60...COLD TEMPERATURES ALOFT WILL COMBINE WITH STRONG
INSOLATION AT THE SURFACE (TEMPERATURES WARMING WELL INTO THE 80S)
TO CREATE AT LEAST A MODERATELY UNSTABLE AIRMASS AHEAD OF THE FRONT.
EXPECT SCATTERED TO BROKEN CONVECTION TO DEVELOP ALONG THE FRONT BY
LATE AFTERNOON AND ADVANCE SOUTHEAST ACROSS THE FORECAST AREA.
SEVERE STORMS LOOK TO BE A GOOD BET ONCE AGAIN WITH THIS EVENT.

COOLDOWN BEHIND THIS FRONT WILL BE VERY BRIEF WITH RETURN FLOW
ALREADY SETTING UP BY SATURDAY AFTERNOON. WILL KEEP THINGS DRY
SATURDAY THROUGH TUESDAY WITH A WARMING TREND PER ECMWF AND MOST
OTHER MEDIUM RANGE MODELS AND DISCARD THE MRF WHICH IS THE BIG
OUTLIER AMONG THE MODELS.

WENT WARMER THAN GUIDANCE FOR MAXIMUMS TODAY WITH SOME SUNSHINE
EXPECTED BY LATE MORNING AND AFTERNOON THEN STAYED CLOSE TO GUIDANCE
IN THE LATER PERIODS.

FCSTID = 5
TUL   82  60  77  57 /  50  20  10  10
FSM   83  63  80  60 /  70  60  20   0
MLC   86  63  80  60 /  70  50  20   0
BVO   80  57  76  53 /  40  20  10  10
FYV   76  60  75  50 /  70  40  10   0
BYV   76  60  75  50 /  70  40  10   0
MIO   78  59  75  52 /  60  20  10  10
MKO   84  62  78  58 /  70  30  10   0
F10   84  61  78  57 /  50  20  10  10
HHW   88  64  82  62 /  60  70  30  10

.TSA...
AR...NONE.
OK...NONE.

PLATE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
150 AM CDT WED MAY 30 2001

TIME(CDT)  .....CITY LOCATION..... STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0144 AM    TULSA                     OK    FLOOD
05/30/01   TULSA                           SPOTTER REPORT OF
                                           HARVARD ALMOST
                                           IMPASSABLE AT 71ST ST
                                           AND 81ST ST.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
238 AM CDT WED MAY 30 2001

TIME(CDT)  .....CITY LOCATION..... STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0231 AM    KIEFER                    OK    FLOOD
05/30/01   CREEK                           EMERGENCY MANAGEMENT
                                           REPORT OF WATER A FOOT
                                           DEEP OVER HIGHWAY 75.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
308 AM CDT WED MAY 30 2001

TIME(CDT)  .....CITY LOCATION..... STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0255 AM    BEGGS                     OK    FLOOD
05/30/01   OKMULGEE                        HIGHWAY 16 AND BUSINESS
                                           HIGHWAY 75 UNDERPASSES
                                           CLOSED DUE TO HIGH
                                           WATER.  EMERGENCY
                                           MANAGEMENT REPORT.

0300 AM    COWETA                    OK    FLOOD
05/30/01   WAGONER                         SEVERAL ROADS
                                           IMPASSABLE.  POLICE
                                           DEPARTMENT REPORT.

ARZ001-002-010-011-OKZ054>070-301000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TULSA OK
310 AM CDT WED MAY 30 2001

THE TORNADO AND SEVERE THUNDERSTORM WATCHES WHICH HAVE BEEN IN
EFFEC&T FOR MUCH OF NORTHEAST OKLAHOMA AND THE NORTHWEST CORNER OF
ARKANSAS HAVE BEEN CANCELLED. SHOWERS AND THUNDERSTORMS WILL
CONTINUE ACROSS THE AREA EARLY THIS MORNING BUT THE THREAT OF SEVERE
WEATHER HAS DIMINISHED.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
422 AM CDT WED MAY 30 2001

TIME(CDT)  .....CITY LOCATION..... STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0400 AM    BEARDEN                   OK    1 INCH HAIL
05/30/01   OKFUSKEE                        SHERIFFS OFFICE REPORT.

0400 AM    OKEMAH                    OK    .75 INCH HAIL
05/30/01   OKFUSKEE                        SHERIFFS OFFICE REPORT.

ARZ001-002-010-011-019-020-029-OKZ049-053>076-311100-

EASTERN OKLAHOMA/NORTHWEST ARKANSAS HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TULSA OK
600 AM CDT WED MAY 30 2001

...A FEW SEVERE THUNDERSTORMS EXPECTED THIS AFTERNOON AND TONIGHT...

A COMPLEX OF THUNDERSTORMS WAS LOCATED ACROSS NORTH CENTRAL ARKANSAS
AND EXTENDED INTO EASTERN OKLAHOMA EARLY THIS MORNING. THIS AREA OF
THUNDERSTORMS BROUGHT HEAVY RAINS AND SEVERE WEATHER TO MUCH OF
NORTHEAST OKLAHOMA OVERNIGHT. AN OUTFLOW BOUNDARY FROM THIS
CONVECTION EXTENDED FROM JUST SOUTH OF MCALESTER INTO CENTRAL
ARKANSAS. SATELLITE IMAGERY SHOWED A CLEARING TREND FROM THE
SOUTHWEST...AND THE LACK OF CLOUDS THIS MORNING WILL HELP TO
DESTABILIZE THE ATMOSPHERE AGAIN TODAY. SEVERE THUNDERSTORMS ARE
EXPECTED TO DEVELOP ALONG THE OUTFLOW BOUNDARY THIS MORNING AND
AFTERNOON. WIND PROFILES SUPPORT SUPERCELLS...MAINLY SOUTH OF A LINE
FROM OKEMAH TO FORT SMITH. THE MAIN THREAT FROM THESE STORMS WILL BE
ISOLATED TORNADOES AND LARGE HAIL. NORTH OF THIS LINE...ISOLATED
SEVERE THUNDERSTORMS ARE EXPECTED THIS AFTERNOON. THE MAIN THREAT
FROM THESE STORMS WILL BE LARGE HAIL...WITH A SECONDARY THREAT OF
DAMAGING WINDS.

.SPOTTER ACTIVATION...
SPOTTER ACTIVATION WILL BE NECESSARY AGAIN LATER TODAY ACROSS
EASTERN OKLAHOMA AND NORTHWEST ARKANSAS.

.DISCUSSION...
A NEGATIVELY TILTED UPPER TROUGH IS FORECAST TO MOVE EAST INTO
CENTRAL ARKANSAS BY TONIGHT. STRONG UPPER LEVEL DIVERGENCE
ASSOCIATED WITH THE UPPER LOW AND JET WILL SUPPORT THE DEVELOPMENT
OF WIDESPREAD SHOWERS AND THUNDERSTORMS AGAIN TODAY. THUNDERSTORMS
WILL INITIATE THIS MORNING ON AN OUTFLOW BOUNDARY LEFT OVER FROM
LAST NIGHTS CONVECTION. THIS OUTFLOW BOUNDARY IS EXPECTED TO BE NEAR
THE RED RIVER VALLEY THIS MORNING...AND MOVE NORTH A LITTLE THROUGH
THE DAY. CLEARING IS EXPECTED THIS MORNING...WHICH WILL MAKE THE
ATMOSPHERE VERY UNSTABLE BY THIS AFTERNOON. SURFACE BASED CAPES ARE
EXPECTED TO APPROACH 5000 J/KG...AND LIFTED INDEX VALUES WILL BE
NEAR -10 TO -12 C. THE GREATEST THREAT FOR TORNADOES WILL BE WITH
SUPERCELLS THAT ARE ABLE FORM ALONG THE BOUNDARY. AT THIS TIME...IT
APPEARS THAT WILL BE ACROSS FAR SOUTHEAST OKLAHOMA.

NORTH OF THE OUTFLOW BOUNDARY...THE ATMOSPHERE HAS BEEN WORKED OVER
FROM PREVIOUS CONVECTION. ISOLATED SEVERE STORMS ARE
EXPECTED...ESPECIALLY IF CLOUDS DIMINISH AS MUCH AS EXPECTED. THE
MAIN THREAT WITH THESE STORMS WILL BE LARGE HAIL...THOUGH THERE
COULD BE ISOLATED SUPERCELLS.

THREAT TABLE
VALID THROUGH 6 AM THURSDAY

THREAT AREA 1...SOUTH OF AN OKEMAH TO FORT SMITH LINE
THUNDERSTORM PROBABILITY...80
SEVERE PROBABILITY IF STORMS OCCUR...100
SIGNIFICANT SEVERE PROBABILITY IF STORMS OCCUR...50

THREAT AREA 2...NORTH OF A LINE FROM OKEMAH TO FORT SMITH
THUNDERSTORM PROBABILITY...50
SEVERE PROBABILITY IF STORMS OCCUR...30
SIGNIFICANT SEVERE PROBABILITY IF STORMS OCCUR...10

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

.OTHER HAZARDS...
RECENT HEAVY RAINS HAVE SATURATED THE GROUND...AND ANY ADDITIONAL
RAIN WILL AGGRAVATE ANY FLOODING PROBLEMS. THE GOOD NEWS IS THAT THE
HEAVIEST RAINS TODAY ARE EXPECTED TO BE ACROSS SOUTHEAST
OKLAHOMA...WHERE NOT AS MUCH RAIN HAS FALLEN. HOWEVER WITH ANY
STORMS THAT DEVELOP...HEAVY RAIN WILL CAUSE LOCALIZED FLASH FLOODING.

RELATED GRAPHICAL INFORMATION CAN BE FOUND AT...
WWW.SRH.NOAA.GOV/TULSA

SJT