Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 252321 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 621 PM CDT WED MAR 25 2015 .SHORT TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 332 PM CDT WED MAR 25 2015 COOL TEMPERATURES WITH A COUPLE OF PRECIP CHANCES TO END THE WEEK...THEN THE START OF A WARMING TREND SATURDAY ARE THE MAIN STORIES IN THE FORECAST. COLD FRONT HAD MOVED WELL SOUTH OF OUR AREA OVERNIGHT AND WAS CURRENTLY NEAR THE KANSAS/OKLAHOMA BORDER WHERE SCATTERED THUNDERSTORMS WERE FIRING. SOUTHWEST FLOW ALOFT AHEAD OF MID LEVEL TROUGH AND OVER TOP OF COOL SURFACE LAYER WAS PRODUCING SCATTERED RAIN SHOWERS OVER SOUTHERN AND SOUTHEAST NEBRASKA INTO SOUTHWEST IOWA. THIS AREA WAS SLOWLY SINKING SOUTH WITH APPROACH OF TROUGH AXIS...AND WILL LIKELY SEE SOME ACTIVITY CONTINUING INTO THE EVENING BEFORE FOCUS SHIFTS SOUTH AND EAST. COOL NORTH TO NORTHWEST WINDS WILL TEND TO DRY OUT LOWER ATMOSPHERE LATER THIS EVENING...SO EXPECT DECREASING CLOUDS OVERNIGHT. TEMPERATURES IN THE 20S ARE EXPECTED FOR LOWS. ON THURSDAY...A POTENT MID LEVEL CLIPPER SYSTEM WILL DIVE INTO THE PLAINS...AND TRACK IS A LITTLE FARTHER EAST THAN PREVIOUS MODEL RUNS. THUS CORE OF POTENTIAL PRECIPITATION IS RIGHT ACROSS EASTERN NEBRASKA AND PARTS OF WESTERN IOWA. QUICK BUT STRONG WARM ADVECTION AHEAD OF THIS SHORTWAVE WILL PRODUCE SUFFICIENT LIFT FOR SATURATION AND PRECIP BY NOON OR SO IN NORTHEAST NEBRASKA...THEN TRACKING SOUTHEAST THROUGH THE REST OF THE CWA IN THE AFTERNOON AND EVENING. FORECAST SOUNDINGS ARE STILL SHOWING A SUFFICIENT WARM LAYER NEAR THE SURFACE TO SUPPORT MELTING THUS RAIN...BUT PERIODS OF ROBUST LIFT WILL LIKELY LEAD TO BURSTS OF SNOW WHICH COULD REACH THE GROUND BEFORE MELTING. THUS WILL CONTINUE WITH A RAIN/SNOW MENTION...BUT NOT EXPECTING ACCUMULATION. PRECIP WITH THIS SYSTEM SHOULD BE OUT OF OUR AREA BY MIDNIGHT THURSDAY NIGHT. A QUICK RETURN TO SOUTHERLY LOW LEVEL FLOW WILL FOLLOW OVERNIGHT AS YET ANOTHER SHORTWAVE MOVES ACROSS THE NORTHERN PLAINS. THIS SYSTEM WILL THEN DIVE SOUTHEAST FRIDAY EVENING...AND COULD BRUSH FAR EASTERN NEBRASKA AND WESTERN IOWA WITH LIGHT PRECIPITATION BEFORE EXITING SATURDAY MORNING. SOUNDINGS AT THIS TIME FAVOR RAIN IN THE EVENING WITH AN EVENTUAL CHANGE TO SNOW AS WET BULB COOLING OCCURS IN THE SURFACE LAYER. QPF LOOKS LOW AS WE ARE ON THE EDGE OF THIS PRECIP SHIELD...THUS ANY SNOW THAT DOES OCCUR SHOULD NOT ACCUMULATE TOO MUCH. WE WILL SEE MORE SUNSHINE ON SATURDAY WITH GRADUALLY RISING HEIGHTS AND WARMING IN THE LOWER ATMOSPHERE. THE MORE ROBUST WARMING WILL STILL BE TO OUR WEST...BUT A REBOUND BACK INTO THE 50S STILL LOOKS ON TRACK FOR MOST OF OUR AREA. .LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 332 PM CDT WED MAR 25 2015 THE WARMING TREND WILL CONTINUE INTO THE LONGER TERM PERIOD AS FLOW ALOFT TURNS MORE WEST OR NORTHWEST AS OPPOSED TO NORTHERLY...AND A GENERAL RISE IN HEIGHTS OCCURS. THERE MAY BE SOME HICCUPS IN THIS SCENARIO AS MODELS ARE DIFFERING ON STRENGTH OF SHORTWAVES ROLLING THROUGH THE FLOW. THE FIRST OF THESE DIFFERENCES COMES SATURDAY NIGHT AND SUNDAY. GFS ROLLS A STRONG SHORTWAVE THROUGH THE NORTHERN PLAINS AND KEEPS PRECIPITATION TO OUR NORTHEAST SATURDAY NIGHT...AND IS LESS AGGRESSIVE WITH SUBSEQUENT POST-FRONTAL COOLING. ECMWF IS FARTHER SOUTH AND STRONGER...AND DEVELOPS A LARGE AREA OF RAIN ACROSS EASTERN NEBRASKA AND WESTERN IOWA ON SUNDAY. THE CANADIAN MODEL IS CLOSE TO THE GFS IN REGARDS TO TIMING...BUT PRODUCES RAIN ACROSS THE AREA SATURDAY NIGHT. FOR NOW WILL FOLLOW THIS SCENARIO WITH LOW POPS SATURDAY NIGHT...BUT COULD EASILY SEE THAT TIMING SLIPPING BACK INTO PART OF SUNDAY. BEYOND SUNDAY...WILL KEEP OUR CURRENT DRY FORECAST GOING FOR THE MOST PART AS TIMING AND STRENGTH OF SHORTWAVES WILL BE NEARLY IMPOSSIBLE TO PIN DOWN TO ONE 12-HOUR PERIOD. OTHERWISE EXPECT TEMPERATURES IN THE 60S SUNDAY THEN WARMING INTO THE 70S MOST AREAS MONDAY AND TUESDAY. A SLIGHT COOLDOWN IS LIKELY ON WEDNESDAY...BUT WE SHOULD STILL REACH THE 60S. && .AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 620 PM CDT WED MAR 25 2015 VFR CONDITIONS THROUGH THE PERIOD. COULD BE SOME LIGHT SHOWERS THAT AFFECT THE TAF SITES 20-24Z THURSDAY AFTERNOON. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DERGAN LONG TERM...DERGAN AVIATION...DEWALD

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