Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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900 FXUS63 KOAX 120851 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 251 AM CST FRI FEB 12 2016 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 250 AM CST FRI FEB 12 2016 PCPN CHANCES/AMOUNTS FROM LATE TONIGHT INTO SUNDAY MORNING...THEN HIGH TEMPS ON SUNDAY WILL PROVIDE THE MAIN FORECAST CHALLENGES. LARGE SCALE MID TROPOSPHERIC PATTERN FEATURES A RIDGE EXTENDING FROM ARIZONA AND SOUTHERN CALIFORNIA UP INTO BRITISH COLUMBIA AND ALBERTA. A CLOSED LOW WAS OVER JAMES BAY. OUR AREA WAS IN FAIRLY STRONG NORTHWEST FLOW. JET MAX OF AROUND 125 KNOTS WAS NOTED AT 300 MB AT 00Z OVER EASTERN MONTANA...PUNCHING SOUTHEAST. THERE WERE HEIGHT FALLS OF AROUND 40 METERS NOTED AT KOAX...BUT THE SHORTWAVE TROUGH ASSOCIATED WITH THESE HAD ALREADY PUSHED DOWN ACROSS MISSOURI. LOOKING UPSTREAM...HEIGHT FALLS WERE NOTED EXTENDING BACK SOUTHWEST FROM THAT CLOSED LOW OVER JAMES BAY INTO SOUTHERN MANITOBA ACCORDING TO RECENT MODEL INITIALIZATIONS AS OF ABOUT 06Z. STRONGER HEIGHT FALLS WERE MOVING INTO THE NORTHWEST UNITED STATES AND WESTERN CANADA. TODAY...EXPECT SOME DECREASE IN CLOUD COVER...ESPECIALLY FOR THE EASTERN HALF OF THE FORECAST AREA. RIDGE OF COLD HIGH PRESSURE AT THE SURFACE WILL BUILD SOUTHWARD FROM CANADA TODAY AND BY 00Z SATURDAY SHOULD STRETCH FROM WESTERN MANITOBA DOWN INTO OKLAHOMA AND ARKANSAS. TEMPS THIS AFTERNOON ARE EXPECTED TO BE STEADY OR SLOWLY FALL. BY 12Z SATURDAY THAT SURFACE RIDGE SHOULD BE OVER MINNESOTA... IOWA AND MISSOURI. ISENTROPIC UPGLIDE/LIFT WILL INCREASE IN THE 285-295 KELVIN LAYER TONIGHT WITH LIGHT SNOW POSSIBLY MOVING INTO THE WESTERN PARTS OF NORTHEAST NEBRASKA PRIOR TO SUNRISE SAT. GENERAL MODEL CONSENSUS IS THAT SOME LIGHT SNOW SHOULD SPREAD ACROSS THE NORTHERN AND EASTERN PARTS OF THE FORECAST AREA SAT. A STRONGER SYSTEM/SHORTWAVE TROUGH IN THE NORTHWEST FLOW IS EXPECTED TO MOVE SOUTHEAST ACROSS THE NORTHERN PLAINS SATURDAY NIGHT. THE MAIN LIFT AND DEEPER MOISTURE WITH THAT IS CURRENTLY EXPECTED TO BE OFF TO OUR NORTH AND EAST. WILL KEEP SOME SNOW CHANCES GOING FOR OUR NORTHERN AND EASTERN ZONES SATURDAY NIGHT... THEN MOSTLY IN WESTERN IOWA SUNDAY MORNING. POPS SUNDAY MORNING ARE LOWER THAN PREVIOUS FORECAST AND IF TRENDS CONTINUE...MAY BE ABLE TO REMOVE SNOW CHANCES COMPLETELY FOR SUNDAY IN THE NEXT FEW FORECAST CYCLES. DOWNSLOPE FLOW SHOULD LEAD TO WARMING SUNDAY...ESPECIALLY WESTERN ZONES...AS A MILDER AIRMASS SPREADS IN FROM THE WEST. CURRENTLY HAVE HIGHS SUNDAY MAINLY IN THE UPPER 30S TO MID 40S...BUT A BIT COOLER NORTH AND EAST OF OMAHA. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 250 AM CST FRI FEB 12 2016 A MID TROPOSPHERIC RIDGE IS EXPECTED TO BE IN PLACE BETWEEN 120-140 DEGREES WEST LONGITUDE AT THE START OF THIS PERIOD...WITH THE CENTRAL PLAINS IN NORTHWEST FLOW. BY WEDNESDAY...THE LONGER RANGE MODELS BUILD THAT RIDGE EASTWARD INTO THE ROCKY MOUNTAIN REGION. IT APPEARS THE RIDGE WILL BUILD EVEN FARTHER EAST BY THURSDAY... AS A TROUGH DIGS OFF THE CALIFORNIA COAST. MODEL AGREEMENT STARTS TO DIVERGE BY FRIDAY...WITH DIFFERENCES IN TIMING OF SHORTWAVE TROUGHS. MUCH OF THIS PERIOD SHOULD BE DRY. THE 00Z ECMWF DID BRING SOME PCPN INTO OUR AREA MONDAY NIGHT...BUT GFS SUGGESTED IT WOULD BE MAINLY DRY. WILL KEEP A DRY FORECAST GOING...BUT MAY NEED TO ADJUST LATER. THE OVERALL TREND THOUGH IS FOR WARMER TEMPS NEXT WEEK...WHICH COULD CONTINUE INTO THE 8 TO 14 DAY PERIOD. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1139 PM CST THU FEB 11 2016 05Z SURFACE ANALYSIS SHOWS A FILLING SURFACE LOW OVER NERN KS /S OF BIE/ WITH AN INVERTED TROUGH EXTENDING ALONG A KLNK-KOFK LINE. WEAK WINDS ALONG THIS TROUGH HAVE RESULTED IFR CIGS AND SOME VISIBILITY RESTRICTION IN FOG AT KOFK. THIS SHOULD BE A SHORT- TERM CONDITION AS SURFACE WINDS ARE EXPECTED TO INCREASE FROM THE NORTH OVER THE NEXT COUPLE OF HOURS. EXPECT MVFR CIGS TO PERSIST /WITH SOME BRIEF FLUCTUATIONS -- BOTH UP AND DOWN/ INTO FRIDAY MORNING. BY MID TO LATE MORNING...MVFR CIGS SHOULD BREAK AT KOFK AND KOMA AS A SURGE OF DRIER POLAR AIR MOVES INTO THE REGION FROM THE NORTH. MVFR CIGS WILL HOLD A BIT LONGER AT KLNK...BUT SHOULD EVENTUALLY MIX OUT BY MID AFTERNOON. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...MILLER LONG TERM...MILLER AVIATION...MEAD

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