Severe Thunderstorm Warning 539, NWS Norman, OK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
135 AM CDT SUN AUG 19 2007

.UPDATE...
UPDATED GRIDS TO BETTER REFLECT STRONG WINDS AND HEAVY RAINS
ASSOCIATED WITH TROPICAL DEPRESSION ERIN. THE CENTER OF
CIRCULATION IS EXPECTED TO MOVE TO THE NORTHEAST DURING THE EARLY
MORNING HOURS WITH HIGH WINDS AND HEAVIEST RAINS OCCURRING TO THE
EAST AND NORTHEAST OF THE CIRCULATION.

&&

.PREV DISCUSSION... /ISSUED 927 PM CDT SAT AUG 18 2007/

UPDATE...
CENTER OF TROPICAL DEPRESSION ERIN HAS BEGUN TO MOVE INTO FAR
SOUTHWEST OK/WEST N TEXAS. ERIN WILL CONTINUE TO MOVE NE
OVERNIGHT... MOVING INTO CENTRAL OK BY MORNING. WIDESPREAD RAIN AND
SOME THUNDERSTORMS WILL CONT OVERNIGHT WITH MOST OF THE RAIN
OCCURRING ON THE E/NE SIDE OF THE DEPRESSION. HAVE ADJUSTED POPS TO
SHOW THIS SCENARIO. WITH THE LOSS OF THE SUN... THE POTENTIAL FOR
ANY FURTHER SEVERE/TORNADIC STORMS WILL CONT TO DECREASE AND LIKELY
END OVER THE NEXT HOUR OR SO. FOCUS WILL SHIFT TO HEAVY RAIN AND
FLOODING POTENTIAL OVERNIGHT. WILL CONT WITH A FLASH FLOOD WATCH BUT
EXTEND INTO CENTRAL OK. WILL KEEP CURRENT END TIME OF 14Z.
HOWEVER... WATCH MAY NEED TO BE EXTENDED IN TIME ON SUNDAY. WILL
SEND UPDATES AS SOON AS POSSIBLE.

MAXWELL

PREV DISCUSSION... /ISSUED 156 PM CDT SAT AUG 18 2007/

SHORT TERM...
LOW-LEVEL CENTER OF T.D. ERIN REMAINS WELL DEFINED IN SFC/RADAR/
SATELLITE DATA FIELDS. SYSTEM LIKELY TO REMAIN STRONGER AND MORE
CONCENTRATED AT LOW LEVELS THAN MOST IF NOT ALL OF THE MODEL
PROGS. DIURNAL CONVECTION TO CONTINUE THIS EVENING E/NE OF CENTER
WHERE PW VALUES REMAIN AOA 2 INCHES. TYPICAL DAY/NIGHT TRENDS
SUGGEST THIS CONVECTION WILL LESSEN IN COVERAGE/INTENSITY THIS
EVENING BEFORE REDEVELOPING OVERNIGHT IN A MORE CONCENTRATED AREA
SOMEWHERE NEAR THE CENTER. LATTER MOST LIKELY TO BE IN THE SW
QUADRANT OF OK BUT EXACT LOCATION HARD TO PIN DOWN. CONSIDERED
EXPANDING FLASH FLOOD WATCH E/NE TOWARD CENTRAL OK... BUT WITH
EXPECTED CONTRACTION OF HEAVIER PRECIP CLOSER TO THE CENTER
OVERNIGHT WE WILL LEAVE THE WATCH AREA INTACT. LATER SHIFTS MAY
NEED TO EXPAND WATCH DEPENDING ON PRECIP TRENDS THIS EVENING AND
OVERNIGHT. POPS ARE INCREASED MAINLY SW OVERNIGHT... BUT LIKELY
POPS AND LOCALLY HEAVY RAIN ARE EXPANDED E/NE INTO CENTRAL OK. POPS
ON SUN ARE INCREASED TO LIKELY OVER MUCH OF THE HEART OF THE
CWA... BENEATH THE SLOW-MOVING LOW/MID LEVEL CENTER... ALONG WITH
CONTINUED MENTION OF LOCALLY HEAVY RAIN GIVEN TROPICAL NATURE OF
BOTH AIRMASS AND THE RESPONSIBLE SYSTEM. WILL FOLLOW THE HPC 6-H
QPF CLOSELY. HIGH TEMPS LOWERED DUE TO CLOUDS/PRECIP BUT LOWS
EXPECTED TO REMAIN ON THE WARMER SIDE DUE TO LOW-LEVEL
WINDS/CLOUDS/MOISTURE.

LONG TERM...
NOT MUCH CHANGE TO FORECAST FOR MON AND BEYOND. CHANGING OF THE
GUARD EARLY NEXT WEEK - SO TO SPEAK - AS ERIN REMNANTS PROCEED E
WHILE CURRENT S-FL UPPER LOW MOVES W TOWARD TX. NET RESULT FOR S
PLAINS IS PERSISTING BREAK IN THE SUBTROPICAL RIDGE... WHICH LEADS
TO HIGH TEMPS BEING KEPT A LITTLE BELOW CLIMATOLOGY. DESPITE THE
BREAK IN THE UPPER RIDGE OVERHEAD... PRECIP CHANCES APPEAR LIMITED
DUE TO LACK OF A FRONT OR OTHER FOCUSING MECHANISM.

CURRENT TPC/HPC PROJECTIONS OF MAJOR HURRICANE DEAN INDICATE THE
STORM - AND ATTENDANT EFFECTS - WILL REMAIN S OF HERE THROUGH AT
LEAST NEXT SAT. THERE IS SOME CONCERN THAT THE W-WARD MOVING UPPER
LOW AHEAD OF THE HURRICANE COULD BE THE WILD CARD AND ALTER THE
MID- LEVEL STEERING FLOW AHEAD OF DEAN ENOUGH TO NUDGE IT A TAD
FARTHER N. THIS IS NOT SEEN IN THE CURRENT MODEL DATA THOUGH...
AND THUS IT APPEARS LIKELY AT THIS TIME THAT ANY AFFECT ON THE
OK/NTX AREA WOULD BE LIMITED TO REMNANTS OF THE STORM RECURVING
AND COMING BACK ACROSS EARLY IN THE WEEK OF 26 AUG. REFER TO
LATEST FORECASTS AND DISCUSSIONS BEING ISSUED BY TPC/NHC.

&&

.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK  73  91  73  93 /  30  10  10  10
HOBART OK         74  93  73  94 /  20  10  10  10
WICHITA FALLS TX  76  93  73  94 /  20  10  10  10
GAGE OK           72  95  71  94 /  10  10  10  10
PONCA CITY OK     75  92  75  94 /  30  10  10  10
DURANT OK         73  92  73  91 /  20  10  10  10

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH UNTIL 9 AM CDT THIS MORNING FOR OKZ016>030-
     033>040-044.

     WIND ADVISORY UNTIL 7 AM CDT THIS MORNING FOR OKZ015>019-022>025-
     027>029-035-037>040-044-045.

TX...FLASH FLOOD WATCH UNTIL 9 AM CDT THIS MORNING FOR TXZ083>089.

&&

26/32

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORMAN OK
104 AM CDT SUN AUG 19 2007

OKZ004>048-050>052-TXZ083>090-191200-
HARPER-WOODS-ALFALFA-GRANT-KAY-ELLIS-WOODWARD-MAJOR-GARFIELD-NOBLE-
ROGER MILLS-DEWEY-CUSTER-BLAINE-KINGFISHER-LOGAN-PAYNE-BECKHAM-
WASHITA-CADDO-CANADIAN-OKLAHOMA-LINCOLN-GRADY-MCCLAIN-CLEVELAND-
POTTAWATOMIE-SEMINOLE-HUGHES-HARMON-GREER-KIOWA-JACKSON-TILLMAN-
COMANCHE-STEPHENS-GARVIN-MURRAY-PONTOTOC-COAL-COTTON-JEFFERSON-
CARTER-JOHNSTON-ATOKA-LOVE-MARSHALL-BRYAN-HARDEMAN-FOARD-WILBARGER-
WICHITA-KNOX-BAYLOR-ARCHER-CLAY-
104 AM CDT SUN AUG 19 2007

THIS HAZARDOUS WEATHER OUTLOOK COVERS NORTHERN...WESTERN...
CENTRAL...AND SOUTHERN OKLAHOMA...AND WESTERN NORTH TEXAS.

.DAY ONE...TONIGHT...

THUNDERSTORM OUTLOOK...
THUNDERSTORMS WILL OCCUR ACROSS PARTS OF OKLAHOMA AND WESTERN NORTH
TEXAS OVERNIGHT. ISOLATED SEVERE STORMS POSSIBLE.

DISCUSSION...
WIDESPREAD RAIN AND SCATTERED THUNDERSTORMS WILL CONTINUE TO MOVE
ACROSS OKLAHOMA AND WESTERN NORTH TEXAS AS TROPICAL DEPRESSION ERIN
MOVES FROM SOUTHWEST INTO CENTRAL OKLAHOMA OVERNIGHT. DUE TO STRONG
WIND SHEAR ASSOCIATED WITH ERIN AND SUFFICIENT INSTABILITY...
ISOLATED SEVERE STORMS WILL BE POSSIBLE THROUGH THE EARLY MORNING
HOURS MAINLY ACROSS PARTS OF SOUTHERN AND CENTRAL OKLAHOMA. WIND
GUSTS ABOVE 60 MPH WILL BE POSSIBLE... ALONG WITH FREQUENT CLOUD TO
GROUND LIGHTNING AND TORRENTIAL RAINFALL. THE STRONG WIND SHEAR MAY
ALSO PRODUCE A BRIEF FUNNEL CLOUD OR TORNADO. HOWEVER... THE
POTENTIAL FOR THESE HAS DECREASED FROM SATURDAY EVENING. LOCALLY
HEAVY RAINFALL LEADING TO FLOODING IS ALSO A CONCERN WITH THE VERY
EFFICIENT RAIN PRODUCING SHOWERS IN THE TROPICAL AIRMASS.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT SUNDAY AUG 19.
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE
              NWS NORMAN COUNTY WARNING AREA...100 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...40 PERCENT.

OTHER HAZARDOUS WEATHER...
VERY HEAVY TO EXCESSIVE RAINFALL WILL OCCUR ACROSS PORTIONS OF
SOUTHWEST AND CENTRAL OKLAHOMA AND PORTIONS OF WESTERN NORTH
TEXAS... WHICH WILL LEAD TO FLASH FLOODING. FOR ADDITIONAL
INFORMATION SEE THE FLASH FLOOD WATCH PRODUCT.

STRONG SOUTH TO SOUTHEAST WINDS WILL OCCUR ACROSS PARTS OF SOUTHERN
AND CENTRAL OKLAHOMA TO THE EAST OF THE CENTER OF TROPICAL
DEPRESSION ERIN THROUGH THE EARLY MORNING HOURS. WIND GUSTS TO
AROUND 55 MPH ARE LIKELY... WITH OCCASIONAL GUSTS ABOVE 60 MPH
POSSIBLE. BE PREPARED FOR SUDDEN INCREASES IN WIND SPEED AS ERIN
MOVES NORTHEAST INTO CENTRAL OKLAHOMA. FOR ADDITIONAL INFORMATION
SEE THE WIND ADVISORY PRODUCT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...

THUNDERSTORM OUTLOOK...
THE REMAINS OF TROPICAL STORM ERIN WILL CONTINUE TO PRODUCE SHOWERS
AND ISOLATED THUNDERSTORMS OVER THE AREA SUNDAY. HEAVY RAIN WILL BE
THE MAIN CONCERN.

OTHER HAZARDOUS WEATHER...
ALTHOUGH TEMPERATURES WILL NOT BE AS HOT SUNDAY WITH THE
CLOUDS AND SHOWERS ASSOCIATED WITH THE REMNANTS OF TROPICAL STORM
ERIN...TEMPERATURES ARE EXPECTED TO BE QUITE WARM AGAIN OVER THE
EARLY AND MIDDLE PART OF NEXT WEEK. HEAT INDEX READINGS WILL ONCE
AGAIN REACH THE 100 TO 105 RANGE OVER PORTIONS OF OKLAHOMA AND NORTH
TEXAS TUESDAY AND WEDNESDAY.

THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AT 7 AM
SUNDAY.

30/25

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
248 AM CDT SUN AUG 19 2007

OKZ018-019-025-028-029-190845-
LOGAN OK-KINGFISHER OK-OKLAHOMA OK-CLEVELAND OK-MCCLAIN OK-
248 AM CDT SUN AUG 19 2007

...SIGNIFICANT WEATHER ADVISORY...

THIS SIGNIFICANT WEATHER ADVISORY IS FOR CLEVELAND...KINGFISHER...
LOGAN...MCCLAIN AND OKLAHOMA COUNTIES.

THE LEADING EDGE OF AN AREA OF STRONG TO SEVERE THUNDERSTORMS WAS
LOCATED FROM 8 MILES SOUTHWEST OF DOVER TO 21 MILES SOUTHWEST OF
CRINER AT 248 AM CDT. THIS AREA WILL SLOWLY SHIFT EAST. WIND GUSTS
ABOVE 50 MPH... FREQUENT LIGHTNING... AND VERY HEAVY RAIN LEADING TO
FLOODING IS LIKELY. BRIEF FUNNEL CLOUDS OR TORNADOES WILL ALSO BE
POSSIBLE.

MAXWELL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
301 AM CDT SUN AUG 19 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0254 AM     TSTM WND GST     WATONGA                 35.85N 98.41W
08/19/2007  M82 MPH          BLAINE             OK   AWOS

            MEASURED AT WATONGA AIRPORT

&&

EM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
324 AM CDT SUN AUG 19 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0320 AM     FLASH FLOOD      4 ESE MOUNTAIN VIEW     35.08N 98.68W
08/19/2007                   KIOWA              OK   AMATEUR RADIO

            WATER RESCUES OCCURRING APPROXIMATELY 1 MILE S OF HWY 9
            ON COUNTY RD 2420. A 0.5 SECTION OF HWY 9 STILL CLOSED.
            STINKING CREEK OUT OF ITS BANKS.

&&

EM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
326 AM CDT SUN AUG 19 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0255 AM     TSTM WND DMG     EL RENO                 35.53N 97.95W
08/19/2007                   CANADIAN           OK   BROADCAST MEDIA

            POWER POLES DOWNED ON I-40 NEAR COUNTRY CLUB ROAD.

&&

EM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
342 AM CDT SUN AUG 19 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0330 AM     FLASH FLOOD      1 W TUTTLE              35.29N 97.83W
08/19/2007                   GRADY              OK   PUBLIC

            SEVERAL FEET OF WATER COVERING HWY 37

&&

EM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
349 AM CDT SUN AUG 19 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0345 AM     FLASH FLOOD      EL RENO                 35.53N 97.95W
08/19/2007                   CANADIAN           OK   BROADCAST MEDIA

            HWY 81 CLOSED NEAR I-40 DUE TO WATER. SEMI AND CAR
            STRANDED. REPORTED BY KOCO TV.

&&

EM