Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 141138 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 638 AM CDT SUN SEP 14 2014 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 326 AM CDT SUN SEP 14 2014 CHANCE FOR THUNDERSTORMS TONIGHT REMAINS THE PRIMARY FORECAST CONCERN. MEAN MID LEVEL TROUGH WAS OVER THE NORTHERN PLAINS THIS MORNING...WITH JET EXTENDING FROM ALBERTA INTO SOUTH DAKOTA AND MINNESOTA AND ON TOWARD THE GREAT LAKES. SHORTWAVE WAS NOTED IN CENTRAL ALBERTA...AND IS FORECAST TO DIVE INTO EASTERN SOUTH DAKOTA OVERNIGHT. FORCING FOR ASCENT WILL COMMENCE AHEAD OF THIS FEATURE OVER THE PLAINS BEGINNING THIS EVENING...WITH MAXIMUM FORCING NEAR 09Z BEFORE WAVE SWINGS TO THE EAST MONDAY MORNING. TWO DISTINCT AREAS OF PRECIPITATION SHOULD RESULT TONIGHT...BOTH ELEVATED IN NATURE. ONE AREA IS EXPECTED IN SOUTH DAKOTA AND NORTHEAST NEBRASKA UNDER DIVERGENT UPPER FLOW REGIME NEAR JET SEGMENT ASSOCIATED WITH VORTICITY MAXIMUM. MAINLY SHOWERS ARE EXPECTED HERE AS INSTABILITY PROFILES ARE RELATIVELY WEAK. FARTHER SOUTH...WARM ADVECTION PROCESSES WITH INCREASING LOW LEVEL JET RIDING OVER SURFACE WARM FRONT IN NORTHERN KANSAS WILL LEAD TO A MARKED INCREASE IN INSTABILITY AS HIGH THETA-E AIR IS DRIVEN NORTH. COOLING ALOFT WHERE LOWERING HEIGHTS OVERSPREAD EASTERN NEBRASKA WILL LEAD TO STEEP LAPSE RATES OVER THE SOUTHERN HALF OF THE CWA AFTER MIDNIGHT. FORECAST SOUNDINGS SUGGEST UP TO 1500 J/KG OF ELEVATED CAPE AND NEAR ZERO INHIBITION WILL JUXTAPOSE WITH 40KT OF SHEAR IN AREAS NEAR AND SOUTH OF A LINCOLN TO RED OAK LINE OVERNIGHT. WHILE MOISTURE PROFILES ARE NOT IMPRESSIVE...THERE IS CERTAINLY ENOUGH FOR THE POTENTIAL FOR A FEW STRONG THUNDERSTORMS WITH HAIL IN THE SOUTHERN HALF OF THE CWA. INTENSITY OF STORMS WILL FADE WITH TIME LATE TONIGHT AS LOW LEVEL JET BECOMES MORE WESTERLY AND SHORTWAVE BEGINS MOVING EAST. COULD SEE LINGERING STORMS IN OUR SOUTHEAST THROUGH THE MORNING BEFORE MOVING OUT OF OUR AREA MONDAY AFTERNOON. NORTHERLY LOW LEVEL FLOW SHOULD CLEAR CLOUDS THEN...WITH THERMAL TROUGH SETTLING OVER THE CWA. SHOULD SEE HIGHS GAINING ONLY ABOUT 10 TO 15 DEGREES FROM MORNING LOWS. HIGH PRESSURE WILL SETTLE OVER THE REGION MONDAY NIGHT BUT WILL QUICKLY SHIFT EAST BY TUESDAY MORNING. THUS ONLY A BRIEF PERIOD OF DECENT RADIATIONAL COOLING IS EXPECTED BEFORE SOUTHERLY WINDS START TO KICK IN AGAIN. HAVE LOWS IN THE LOW TO MID 40S TUESDAY MORNING WITH TEMPS REBOUNDING BACK TOWARD 70 TUESDAY AFTERNOON UNDER PLENTY OF SUNSHINE. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 326 AM CDT SUN SEP 14 2014 NORTHWEST FLOW ALOFT WILL BEGIN THE LONGER TERM PERIOD...BUT A SOMEWHAT PROGRESSIVE FLOW PATTERN WILL BRING RIDGING INTO THE PLAINS BY THURSDAY BEFORE ANOTHER TROUGH MOVES INTO THE REGION BY FRIDAY OR SATURDAY. A WEAK SHORTWAVE RIDING THROUGH CENTRAL NEBRASKA AND KANSAS COULD TRIGGER SOME CONVECTION IN OUR SOUTH ON WEDNESDAY...BUT BETTER CHANCES FOR PRECIPITATION WILL WAIT UNTIL LONGER WAVE TROUGH APPROACHES LATE IN THE WEEK. WILL HAVE INCREASING CHANCES FOR THUNDERSTORMS FRIDAY INTO SATURDAY. TEMPERATURES THROUGH THE WEEK SHOULD AVERAGE THE 70S WITH FEW 80S LIKELY FRIDAY BEFORE CLOUDS/PRECIP INVADE. && .AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 621 AM CDT SUN SEP 14 2014 CLEAR SKIES WITH INCREASING SOUTHERLY WINDS ARE EXPECTED THIS MORNING. CLOUDS WILL INCREASE BUT SHOULD REMAIN IN THE VFR CATEGORY THROUGH THE AFTERNOON AND INTO THE EARLY EVENING. AN UPPER LEVEL DISTURBANCE WILL DROP SOUTH OUT OF THE DAKOTAS OVERNIGHT PRODUCING WIDESPREAD SHOWERS ACROSS THE AREA. A FEW THUNDERSTORMS ARE POSSIBLE AT KLNK AND KOMA LATE THIS EVENING AND THROUGH THE OVERNIGHT AS A WARM FRONT LIFTS NORTH OUT OF KANSAS. WINDS WILL TURN FROM THE SOUTH TO THE EAST THIS EVENING AND EVENTUALLY NORTHEAST OVERNIGHT. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DERGAN LONG TERM...DERGAN AVIATION...KERN

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