Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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742 FXUS63 KOAX 091118 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 518 AM CST TUE FEB 9 2016 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 310 AM CST TUE FEB 9 2016 PRIMARY FORECAST CONCERN IS PRECIPITATION CHANCES TONIGHT INTO WEDNESDAY. A DEEP-LAYER CYCLONE CENTERED OVER THE UPPER GREAT LAKES EARLY THIS MORNING WILL DE-AMPLIFY AS IT GRADUALLY SHIFTS EWD TO OFF THE ATLANTIC SEABOARD BY ABOUT THURSDAY. DURING THIS TIME FRAME...AN UPSTREAM RIDGE WILL REMAIN QUASI-STATIONARY OVER WRN NORTH AMERICA...WITH THE PREVAILING MID-LEVEL FLOW FROM THE ROCKIES THROUGH MS VALLEY BECOMING MORE NWLY. IN THE NEAR-TERM (TODAY)...WINDS HAVE REMAINED GUSTY EARLY THIS MORNING WITH SUSTAINED SPEEDS OF 15-20 MPH WITH GUSTS TO 25-30 MPH. WHILE NOT NEARLY AS WINDY AS SUNDAY AND MONDAY...WE WILL LIKELY SEE GUSTY WINDS CONTINUING THROUGH TODAY...ESPECIALLY ALONG AND EAST OF THE MISSOURI RIVER. INCREASING CLOUDS FROM THE WEST AND LITTLE CHANGE TO THE CHARACTER OF THE LOW-LEVEL THERMODYNAMIC ENVIRONMENT WILL RESULT IN HIGHS MAINLY IN THE 20S. 00Z MODEL GUIDANCE IS IN REASONABLE AGREEMENT IN SUGGESTING THAT A LOW-AMPLITUDE CLIPPER-TYPE SYSTEM WILL TRAVERSE THE CANADIAN PRAIRIE PROVINCES TONIGHT BEFORE DIVING SEWD INTO THE UPPER MS VALLEY AND EVENTUALLY OH VALLEY WEDNESDAY INTO WEDNESDAY NIGHT. THIS UPPER-AIR SYSTEM WILL BE ATTENDED BY A MIGRATORY SURFACE CYCLONE AND A CHINOOK-TYPE WARM FRONT WHICH IS FORECAST TO SHIFT EWD THROUGH THE NRN AND CNTRL PLAINS TONIGHT INTO WEDNESDAY. THEREAFTER...A TRAILING COLD FRONT WILL PUSH SWD THROUGH THE MID- MO VALLEY WEDNESDAY NIGHT. THE RESPONSE TO STRENGTHENING LOW TO MID-TROPOSPHERIC FRONTOGENESIS WILL FOSTER A N-S-ORIENTED BAND OF PRECIPITATION OVER THE DAKOTAS TODAY WHICH WILL SUBSEQUENTLY SPREAD SSEWD THROUGH THE MID-MO VALLEY TONIGHT INTO WEDNESDAY. FORECAST SOUNDINGS SUGGEST THAT SNOW WILL BE THE PREDOMINANT P-TYPE...THOUGH A WARM NOSE CENTERED AROUND 850 MB MAY ALLOW SOME SLEET TO MIX IN TOWARD THE END OF THE EVENT. THE SYSTEM WILL BE RELATIVELY FAST MOVING WITH THE HIGHEST SNOW ACCUMULATIONS OF AROUND AN INCH MOST LIKELY BEING OVER OUR WRN IOWA COUNTIES. SKIES WILL BEGIN TO CLEAR FROM THE WEST BY AFTERNOON...POTENTIALLY RESULTING IN HIGHS RANGING FROM LOWER 40S SW TO LOWER 20S OVER OUR W-CNTRL IA COUNTIES. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 310 AM CST TUE FEB 9 2016 FRIDAY INTO SATURDAY...MEDIUM-RANGE MODELS ARE IN GENERAL AGREEMENT THAT A SERIES OF MID TO UPPER-LEVEL SPEED MAXIMA TRANSLATING FROM CNTRL CANADA INTO THE OH VALLEY WILL CONTRIBUTE TO THE RE- INTENSIFICATION OF THE LARGE-SCALE TROUGH PRESENT OVER ERN NORTH AMERICA. THESE DATA SUGGEST THAT WE WILL BE ON THE WRN FRINGE OF A SURGE OF COLD CONTINENTAL AIR PLUNGING EQUATORWARD...THE IMPACTS OF WHICH WILL BE LIKELY FELT ON SATURDAY WITH HIGHS IN THE TEENS AND 20S. A FEATURE THAT WE WILL BE WATCHING FOR THIS UPCOMING WEEKEND IS A SHORT-WAVE TROUGH WHICH IS FORECAST TO MOVE ONTO THE PACIFIC NW COAST FRIDAY NIGHT OR SATURDAY. THIS SYSTEM WILL THEN AMPLIFY AS IT PROGRESSES THROUGH THE NRN INTER-MOUNTAIN REGION SATURDAY BEFORE REACHING THE GREAT PLAINS SUNDAY. THE ECMWF AND CANADIAN MODELS ARE MORE PROGRESSIVE WITH THIS SHORT-WAVE TROUGH THAN THE DETERMINISTIC GFS AND GEFS MEAN. HOWEVER...IT IS WORTH NOTING THAT THE LATTER TWO HAVE TRENDED CLOSER TO THE ECMWF SOLUTION OVER THE PAST 24 HOURS. THE UPSHOT IS THAT WE SHOULD AN INCREASE IN PRECIPITATION CHANCES LATER THIS WEEKEND. && .AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 517 AM CST TUE FEB 9 2016 VFR CONDITIONS THROUGH MOST OF THE PERIOD. NORTHWEST WINDS CONTINUE TODAY AT 15 TO 25 KNOTS. SHOULD START TO DIMINISH TO 12 KNOTS OR LESS BY 19-22Z...THEN BECOMING LIGHT AND VARIABLE. MVFR CONDITIONS COULD RETURN AT KOFK/KLNK BY 08-10Z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...MEAD LONG TERM...MEAD AVIATION...DEWALD

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