Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 031717 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 1217 PM CDT SUN MAY 3 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 320 AM CDT SUN MAY 3 2015 TODAY...STORMS SHOULD CONTINUE EASTWARD OUT OF THE FORECAST AREA EARLY THIS MORNING. HIGH RES MODELS ARE IN GOOD AGREEMENT WITH THAT. STORMS LAST EVENING DID PRODUCE SOME LARGE HAIL AND A FEW SPOTS RECEIVED STRONG WINDS AS STORMS MIXED DOWN A STRONG LOW LEVEL JET. AS OF AROUND 07Z RUC MODEL INITIALIZATION SHOWED WINDS AT AROUND 1 KM AGL OF AROUND 40-50 KNOTS STRETCHING FROM WESTERN OKLAHOMA INTO SOUTHEAST NEBRASKA AND PARTS OF IOWA. THESE WINDS WILL DECREASE THIS MORNING. COLD FRONT AS OF 08Z STRETCHED FROM NORTHEAST MINNESOTA BACK INTO WESTERN SOUTH DAKOTA. THAT FRONT WILL MOVE SOUTHEAST INTO NORTHEAST NEBRASKA THIS AFTERNOON. LOOK FOR HIGHS IN THE MID TO UPPER 80S AT MOST SPOTS TODAY WITH A FEW HIGHS AROUND 90 POSSIBLE. THIS WILL CREATE CAPE VALUES FROM 1500 TO 2500 J/KG BY MID AFTERNOON. EXPECT CAP TO BREAK NEAR THE FRONT BY MID/LATE AFTERNOON. SOME MODELS ALSO HINT AT THE CAP WEAKENING FARTHER SOUTH...BUT WITH A LACK OF FOCUS AT THAT TIME WILL KEEP HIGHEST POPS CLOSER TO THE FRONT. SOME SEVERE STORMS APPEAR POSSIBLE...WITH LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS. GENERALLY USED A BLEND OF SHORT RANGE GUIDANCE FOR TONIGHT WITH THE HIGHEST WEIGHT GIVEN TO THE 00Z HIGH RES WRF-ARW MODEL. LIKE SOME OF THE OTHER MODELS...IT DEVELOPED STORMS LATE AFTERNOON THEN MOVED THEM SOUTH AND EAST. SOME STORMS MAY CONTINUE TO BE SEVERE IN THE EVENING. COVERAGE SHOULD DECREASE AFTER MIDNIGHT. CONVECTION WILL LIKELY FORCE THE FRONT DOWN AT LEAST AS FAR AS SOUTHEAST NEBRASKA AND MAYBE INTO NORTHEAST KANSAS BY 12Z MONDAY. MOST MODELS SHOW LIFT OCCURRING OVER THE BOUNDARY DURING THE DAY MONDAY WITH PCPN COVERAGE INCREASING...SO HAVE POPS INCREASING TO MATCH THAT. TWO CLUSTERS OF STORMS MAY TAKE SHAPE BY LATE AFTERNOON OR EARLY EVENING. ONE NEAR THE NEBRASKA/SOUTH DAKOTA BORDER AND ANOTHER LIFTING FROM NORTHERN KANSAS THROUGH OUR AREA AND TOWARD CENTRAL IOWA MONDAY NIGHT. TUESDAY...WE MAY SEE SOMEWHAT OF A BREAK IN THE WIDESPREAD PCPN... AT LEAST OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. HAVE POPS RANGING FROM 15 TO 50 PERCENT...HIGHEST IN NORTHEAST NEBRASKA. SOUTHERLY FLOW WILL INCREASE AND HELP A WARM FRONT LIFT NORTH OF THE AREA. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 320 AM CDT SUN MAY 3 2015 PATTERN WILL BE ACTIVE MUCH OF THIS PERIOD. A LARGE MID TROPOSPHERIC TROUGH SHOULD BE OVER THE WESTERN UNITED STATES AT THE START OF THIS PERIOD WITH EMBEDDED SHORTWAVES. ONE OF THESE WAVES WILL LIFT ACROSS MID AMERICA WEDNESDAY/WEDNESDAY NIGHT...WHILE A CLOSED LOW STARTS TO DIG SOUTHWARD FROM THE PACIFIC NORTHWEST. THIS WILL GENERALLY KEEP OUR AREA IN SOUTHWEST FLOW WITH A DECENT SUPPLY OF LOW LEVEL MOISTURE FOR SHOWERS AND STORMS TO WORK WITH. MODEL AGREEMENT STARTS TO FALL OFF BY DAY 7...SO CONFIDENCE FALLS TO AVERAGE BY DAY 7. TEMPERATURES AND PCPN SHOULD BE AT OR ABOVE NORMAL FOR THIS PERIOD. && .AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1211 PM CDT SUN MAY 3 2015 SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO INCREASE IN AREAL COVERAGE THIS AFTN ALONG A COLD FRONT PUSHING THRU ERN NEB. IT IS POSSIBLE THAT A FEW STORMS MAY APPROACH OR BECOME SEVERE LATE THIS AFTN. HAVE ADDED TEMPO GROUPS AT ALL TERMINALS FOR POSSIBLE LATE AFTN/EARLY EVENING MVFR CONDITIONS. VFR CONDITIONS THEN PREVAILING THIS EVENING THRU THE REST OF THE FCST PD. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...PEARSON/MILLER LONG TERM...MILLER AVIATION...DEE

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