Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 221207 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 607 AM CST SAT NOV 22 2014 .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 339 AM CST SAT NOV 22 2014 WITH A COLD FRONT SLAMMING THROUGH THE REGION SUNDAY...SMALL RAIN CHANCES WITH MILD TEMPERATURES AHEAD...THEN COLDER WITH POTENTIAL FOR LIGHT SNOW BEHIND...ARE THE PRIMARY FORECAST CONCERNS. SHALLOW TROUGHING IN THE MID LEVELS WAS NOTED ACROSS THE MIDDLE OF THE COUNTRY THIS MORNING. UPPER LOW/TROUGH WAS NOTED IN NORTHERN MEXICO AND ANOTHER DEVELOPING LOW/TROUGH WAS SEEN MOVING INTO SOUTHWEST CANADA AND THE PACIFIC NORTHWEST. THESE TWO FEATURES ARE FORECAST TO COMBINE IN TO A DEEPER TROUGH EXTENDING FROM NORTH DAKOTA INTO OKLAHOMA BY SUNDAY AFTERNOON...BEFORE SHIFTING EAST TO THE GREAT LAKES AND LOWER MISSISSIPPI VALLEY REGION ON MONDAY. AN EXITING SHORTWAVE THIS MORNING WILL TEND TO TURN SURFACE WINDS TO THE SOUTHWEST DURING THE DAY BEFORE LOWERING PRESSURES IN THE HIGH PLAINS INDUCE SOUTHERLY FLOW AGAIN TONIGHT. LOW CLOUDS AND FOG COVERING MOST OF EASTERN NEBRASKA AND WESTERN IOWA THIS MORNING ARE FORECAST BY MOST MODEL OUTPUT TO SCOUR OUT FROM WEST TO EAST THROUGH THE DAY. HOWEVER MODELS TEND TO HAVE A HARD TIME DEALING WITH THICK LOW LEVEL MOISTURE...AND FORECAST WINDS WILL PARALLEL BACK EDGE OF CLOUDS LEADING TO SLOWER EROSION. THUS AM NOT CONVINCED CLEARING LINE WILL WORK ALL THE WAY TO EAST OF THE MISSOURI RIVER THIS AFTERNOON. THIS WILL LIKELY LIMIT HIGH TEMPERATURES SOMEWHAT...BUT LOW LEVEL THETA-E ADVECTION SHOULD PUSH TEMPERATURES WELL INTO THE 40S AND LOWER 50S EVEN WHERE CLOUDS PERSIST. AS WINDS TURN BACK TO THE SOUTH THIS EVENING...A MORE PRONOUNCED SURGE IN LOW LEVEL HIGH THETA-E AIR IS EXPECTED ACROSS ALL OF EASTERN NEBRASKA AND WESTERN IOWA. WEAK LIFT AHEAD OF MID LEVEL TROUGH SHOULD LEAD TO AREAS OF RAIN IN OUR SOUTH WHERE LAYER MOISTURE IS DEEPEST...WITH FOG AND DRIZZLE LIKELY ACROSS THE REST OF THE AREA. GIVEN SURFACE DEW POINTS WELL INTO THE 30S AS FAR NORTH AS NORTHEAST NEBRASKA...DO NOT EXPECT ANY PROBLEMS WITH FREEZING PRECIPITATION. AS UPPER LOW/TROUGH MOVES INTO THE PLAINS EARLY SUNDAY...ATTENDANT COLD FRONT SHOULD BE PUSHING INTO NORTHEAST NEBRASKA BY 12Z. LIGHT RAIN WILL CONTINUE TO BE POSSIBLE ALONG AND AHEAD OF THE FRONT UNTIL IT PASSES TO OUR SOUTHEAST SUNDAY AFTERNOON. STRONG COLD ADVECTION WILL FOLLOW WITH 850 TEMPERATURES DROPPING SOME 10C FROM 12Z TO 00Z. THUS MOST AREAS WILL SEE HIGHS IN THE MORNING OR EARLY AFTERNOON...RANGING FROM NEAR 40 NORTH TO THE LOWER 50S SOUTH...WITH FALLING AFTERNOON TEMPERATURES ON GUSTY NORTHWEST WINDS. SHORTWAVE ROTATING SOUTHEAST ON BACK SIDE OF LOW/TROUGH WILL LIKELY PRODUCE AREAS OF LIGHT SNOW IN NORTHEAST NEBRASKA INTO WEST CENTRAL IOWA LATER SUNDAY NIGHT INTO MONDAY BEFORE EXITING TO THE EAST. CORE OF ASSOCIATED LIFT IS EXPECTED TO STAY TO OUR NORTHEAST SO AM NOT EXPECTING MORE THAN A DUSTING OF SNOW. BUT TEMPERATURES WILL CERTAINLY BE COLDER WITH LOWS IN THE 20S AND HIGHS IN THE 30S ON MONDAY. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 339 AM CST SAT NOV 22 2014 IT STILL LOOKS LIKE THE MAJORITY OF NEXT WEEK WILL REMAIN FAIRLY COOL AND MAINLY DRY. UPPER TROUGH PASSING THROUGH THE PLAINS MONDAY WILL SETTLE OVER THE EASTERN THIRD OF THE COUNTRY...KEEPING OUR AREA UNDER NORTHWEST FLOW ALOFT AND PRONE TO REINFORCING SHOTS OF COLD AIR. ONE POTENTIALLY MORE SIGNIFICANT SHORTWAVE WAS NOTED BY GFS/ECMWF DROPPING INTO THE PLAINS TUESDAY OR TUESDAY NIGHT. WARM ADVECTION AHEAD OF THIS WAVE SHOULD BRING THE WARMEST DAY OF THE WEEK ON TUESDAY WHEN HIGHS COULD APPROACH 40. THERE IS A SMALL CHANCE FOR LIGHT SNOW...BUT AGAIN MOST OF THE ENERGY/LIFT WILL RIDE NORTHEAST OF OUR AREA. THEN COLDER AIR WILL FOLLOW FOR WEDNESDAY AND BEYOND. THANKSGIVING LOOKS LIKE THE COLDEST DAY OF THE WEEK WHEN SURFACE HIGH PRESSURE SETTLES OVER THE MISSOURI RIVER VALLEY LEADING TO LIMITED MIXING AND HIGHS ONLY IN THE 20S. && .AVIATION...
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(12Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 603 AM CST SAT NOV 22 2014 LIFR CONDITIONS START OFF THE PERIOD AT KOMA AND KLNK WHILE KOFK REMAINS ON THE EDGE OF THE LOWER CIGS. EXPECT KOFK TO BECOME VFR BY 15Z AS SOUTHWEST WINDS INCREASE AND DRIER AIR SPREADS EAST. LESS CERTAIN ON TIMING AT KOMA AND KLNK BUT TREND TOWARD VFR 15Z-18Z. LOWER CIGS MAY REDEVELOP AFTER 00Z IN ADVANCE OF COLD FRONT WHICH WILL MOVE INTO THE AREA AFTER 06Z.
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&& .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DERGAN LONG TERM...DERGAN AVIATION...FOBERT

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