FXUS64 KOUN 300510 AFDOUN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 1110 PM CST MON NOV 29 2004 UPDATED FORECAST TO ADD IN SOME SLEET ACROSS PARTS OF SOUTHWEST OKLAHOMA INTO WESTERN NORTH TEXAS. PCPN BREAKING OUT OVER THE AREA IN RESPONSE TO THE STRONG FRONTOGENETIC FORCING SPREADING INTO THE REGION. DRIER AIR AT MID LEVELS OVER WEST CENTRAL OKLAHOMA WILL TEND TO LIMIT THE NORTHERN EXTENT OF THE HEAVIER PCPN. MEANWHILE... SURFACE TEMPERATURES OVER SW OK AND WRN NTX ARE STILL ABOVE FREEZING... BUT WITH VERY COLD TEMPS ALOFT ASSOCIATED WITH THE UPPER SYSTEM... EX: -34C AT H5 OVER ABQ... AND DECENT LIFT EVIDENT... WILL SEE COLUMN COOL FAIRLY QUICKLY. CALLS MADE TO THE SEYMOUR AREA INDICATED SOME RAIN AND SLEET NOW OCCURRING. && 32 ________________________________________________ 912 PM CST MON NOV 29 2004 EASTWARD PROGRESSION OF FREEZING TEMPERATURES INTO CENTRAL OKLAHOMA HAS BEEN A BIT SLOWER THAN EARLIER EXPECTED... WHICH IN TURN WILL SLOW THE TRANSITION OF DRIZZLE INTO FREEZING DRIZZLE. HOWEVER... PCPN IN CENTRAL AND SOUTHEAST OKLAHOMA HAS BEEN FAIRLY ISOLATED... AMOUNTING ONLY TO DRIZZLE OR LIGHT RAIN. MEANWHILE... LIGHT SNOW CONTINUES ACROSS NORTHWEST OKLAHOMA... WITH OCCASIONALY MODERATE SNOW LIKELY OCCURRING NEAR THE KANSAS BORDER. RADAR ECHOES HAVE BEEN INCREASING OVER WEST TEXAS... FROM CHILDRESS TO NEAR LUBBOCK... IN A RELATIVELY DEEP ZONE OF FROTOGENETIC FORCING. HOWEVER... SURFACE OBS AT CHILDRESS NOT YET INDICATING ANY PCPN OR REDUCED VISIBILITIES. AS THE UPPER SYSTEM COMES OUT TONIGHT... AREA OF FRONTOGENETIC FORCING WILL SPREAD NORTHEAST ACROSS THE FA. WHILE THAT SHOULD AID EXPANSION OF PCPN OVER THE AREA... MODELS ALSO INDICATE QUITE A BIT OF DRIER AIR AT MID LEVELS ALSO SPREADING INTO MUCH OF THE WESTERN 2/3 OF THE FA. THIS WOULD TEND TO KEEP PCPN A LITTLE LIGHTER. CURRENT LAYOUT OF WINTER WEATHER ADVISORIES STILL LOOK REASONABLE. ALTHOUGH TEMPS ARE A LITTLE SLOW TO FALL OVER CENTRAL OKLAHOMA... SUBFREEZING TEMPS SHOULD STILL SPREAD INTO THE AREA BY NEAR OR A LITTLE AFTER MIDNIGHT. && 32 _______________________________________________ 300 PM CST MON NOV 29 2004 .UPDATE... TONIGHT IS MAIN FORECAST CONCERN. CLOSED UPPER LOW ACROSS FOUR CORNERS AREA THIS AFTN WILL OPEN UP AND BEGIN TO SHEAR OUT/BECOME POS TILTED AS IT MAKES ITS WAY ENE OVERNIGHT TONIGHT INTO TUESDAY MORNING. SATELLITE IMAGERY SHOWS LARGE DRY SLOT MAKING ITS WAY AROUND UPPER LOW ALREADY AFFECTING PRECIP ACROSS SRN PLAINS. THIS WILL ALSO CREATE PROBLEMS TONIGHT IN AMOUNTS AND TYPE OF PRECIP. THIS DRY LAYER LOOKS TO OCCUR WHERE BEST SNOW GROWTH OCCURS AND WILL LIKELY CONTRIBUTE TO A BAND/AREA OF LIGHT FREEZING DRIZZLE FOR A WHILE THIS EVENING FROM NC INTO CENTRAL AND SOUTHWEST OK AND PORTIONS OF WESTERN NORTH TEXAS. AS UPPER WAVE MOVES ACROSS LATER TONIGHT THIS LAYER AGAIN BECOMES SATURATED AND PRECIP TRANSITIONS BACK TO SNOW. LIGHT RAIN SHOULD CONT OVER PORTIONS OF SC/SE OK AS SFC TEMPS THERE WILL REMAIN ABOVE FREEZING AND COLUMN IS WARMER. EVEN WITH LIGHTER AMOUNTS EXPECTED OVERNIGHT...WITH MON AFTN AMOUNTS OF 2 INCHES ALREADY ON THE GROUND... PARTS OF NW OK MAY SEE 4 INCH TOTALS BY EARLY TUE. ONE TO TWO INCHES COULD FALL ACROSS WESTERN AND NORTH CENTRAL OK OVERNIGHT. WILL THEREFORE EXTEND SNOW ADVISORY FARTHER SOUTH AND EAST AND WILL GO WITH WINTER WX ADVISORY FOR AREAS MENTIONED ABOVE... INCLUDING OKC AND WICHITA FALLS... FOR POSSIBLE FREEZING DRIZZLE THIS EVENING CHANGING TO LIGHT SNOW AFTER MIDNIGHT. PRECIP COULD END AS A LIGHT FREEZING DRIZZLE AGAIN TUE MORNING. SOUTH CENTRAL AND SOUTHEAST OK COULD ALSO SEE TRANSITION TO RAIN/SNOW MIX OR SNOW LATE TONIGHT BUT ANY WINTERY PRECIP SHOULD NOT AMOUNT TO MUCH. LIGHT PRECIP MAY LINGER FOR A FEW HOURS TUE MORNING... BUT SHOULD END ACROSS AREA BEFORE NOON WITH SOME CLEARING BY AFTN. THE REMAINDER OF THE WEEK LOOKS MORE TRANQUIL WITH A COUPLE OF REINFORCING SHOTS OF COOLER AIR. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 29 40 25 52 / 60 30 10 0 HOBART OK 27 41 24 53 / 60 20 0 0 WICHITA FALLS TX 30 44 27 54 / 60 30 0 0 GAGE OK 22 39 18 49 / 60 20 0 0 PONCA CITY OK 27 38 23 49 / 60 30 10 0 DURANT OK 35 45 30 55 / 60 40 10 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...SNOW ADVISORY TONIGHT OKZ004>018-021>022-033>036. WINTER WX ADVISORY TONIGHT AND EARLY TUESDAY OKZ019-020-023>030-037>039-044. TX...WINTER WX ADVISORY TONIGHT AND EARLY TUESDAY TXZ083>089. && $$ 30