Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 291459 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 959 AM CDT MON JUN 29 2015 .UPDATE... ISSUED AT 953 AM CDT MON JUN 29 2015 VISIBLE SATELLITE INDICATES A QUITE EXTENSIVE SMOKE LAYER OVERHEAD FROM WILDFIRES IN CANADA...SIGNIFICANTLY MORESO THAN THAN YESTERDAY WHICH JUST A VERY THIN PLUME. THIS SMOKE IS RESULTING IN HAZY SKIES...WHICH IS ALSO ALLOWING FOR A MUCH MORE SLOWER RISE IN TEMPS...WHICH WILL ALSO IMPACT HIGH TEMPERATURES. PILOT REPORTS INDICATE THE SMOKE LAYER IS FROM ABOUT 4500 TO 10000 AGL...WHICH IS LOWER THAN WE WOULD HAVE THOUGHT. INITIALLY THOUGHT THOUGHT THERE WOULDN`T BE A NOTICEABLE SMELL AT THE SURFACE...BUT AT LEAST ONE REPORT OF A SMOKY SMELL HAS BEEN RECEIVED SO FAR. WE DID CUT BACK DAYTIME TEMPS BY ONE OR TWO DEGREES...AND MAY NEED TO CUT BACK EVEN MORE BASED ON DIURNAL RISES THE NEXT HOUR OR TWO. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 349 AM CDT MON JUN 29 2015 THE RETURN OF MORE SIGNIFICANT RAIN CHANCES TUESDAY NIGHT INTO WEDNESDAY IS THE PRIMARY FORECAST CONCERN. NORTH-NORTHWEST UPPER FLOW PATTERN CONTINUES OVER THE NORTHERN AND CENTRAL PLAINS THIS MORNING...AND WILL REMAIN IN PLACE THROUGH TONIGHT BEFORE SHORTWAVE ENERGY BEGINS TO SUPPRESS WESTERN RIDGE. THE RESULT WILL BE UNSETTLED NORTHWEST FLOW REGIME INTO MID WEEK AND BEYOND. AT THE SURFACE...HIGH PRESSURE OVER THE HIGH PLAINS WILL SLIDE SOUTHEAST TODAY...KEEPING EASTERN NEBRASKA AND WESTERN IOWA IN NORTHWEST TO NORTH LOW LEVEL FLOW. THIS WILL TRANSLATE INTO MODEST LOW LEVEL MIXING...AND WHEN COMBINED WITH PLENTY OF SUNSHINE...WE SHOULD SEE HIGHS THIS AFTERNOON APPROACHING 90 IN MANY SPOTS. SURFACE FLOW BECOMES SOUTHWESTERLY OVERNIGHT AS PRESSURES BEGIN TO LOWER IN THE NORTHERN PLAINS IN RESPONSE TO SHORTWAVE DROPPING INTO MINNESOTA AND WISCONSIN. STRONG 90KT 300MB JET ON BACK SIDE OF THIS SHORTWAVE WILL SLAM INTO WESTERN IOWA TONIGHT...SIMILAR TO PATTERN OF SATURDAY NIGHT/SUNDAY MORNING WHEN ISOLATED THUNDERSTORMS BUBBLED UP IN WESTERN IOWA. COULD SEE SAME SCENARIO LATER TONIGHT...SO WILL MAINTAIN OUR CURRENT SLIGHT CHANCE POPS FOR AREAS NEAR AND EAST OF THE MISSOURI RIVER. ANY ACTIVITY THAT DOES FIRE WILL BE EXITING TO THE SOUTH TUESDAY MORNING. ATTENTION THEN TURNS TO STRONGER SHORTWAVE CURRENTLY OFF THE OREGON COAST SCHEDULED TO ROLL THROUGH THE NORTHERN ROCKIES AND INTO THE NORTHERN HIGH PLAINS TUESDAY AFTERNOON...THEN INTO NORTHEAST NEBRASKA WEDNESDAY MORNING. LOWERING SURFACE PRESSURES ACROSS MUCH OF THE REGION WILL COMMENCE TUESDAY WITH APPROACH OF SHORTWAVE... INDUCING GENERAL SOUTHERLY FLOW AND MINOR MOISTURE RETURN INTO OUR AREA. PRECIPITATION CHANCES ARE EXPECTED TO INCREASE MARKEDLY TUESDAY NIGHT WHEN LOW LEVEL JET INCREASES AS WAVE MOVES CLOSER. EXPECT AXIS OF HIGHEST CHANCES TO LIE FROM NORTHEAST NEBRASKA INTO SOUTHWEST IOWA...JUST NORTHEAST OF TIGHTEST GRADIENT OF LOW LEVEL BAROCLINIC ZONE WHERE ISENTROPIC UPGLIDE IS MAXIMIZED. MOISTURE PROFILES FROM VARIOUS MODEL SOUNDINGS SUGGEST LOW LEVEL MOISTURE WILL BE LIMITED...THUS LIMITED INSTABILITY FOR SEVERE STORMS. SYSTEM IS SCHEDULED TO BE MOVING OFF TO THE SOUTHEAST WEDNESDAY MORNING...TAKING MOST PRECIP WITH IT. LINGERING SHOWERS ARE CERTAINLY POSSIBLE...ESPECIALLY IN THE MORNING...BUT WOULD EXPECT THE BALANCE OF WEDNESDAY TO BE DRY FOR MOST AREAS. EAST TO NORTHEAST SURFACE WINDS BEHIND WAVE/SURFACE LOW WILL KEEP TEMPERATURES SEVERAL DEGREES COOLER THAN THE NEAR 90 FORECAST MONDAY/TUESDAY. HAVE HIGHS CLOSER TO 80 IN OUR NORTH AND EAST...WITH MIDDLE 80S INTO SOUTHEAST NEBRASKA. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 349 AM CDT MON JUN 29 2015 NORTHWEST UPPER FLOW PATTERN WILL CONTINUE INTO FRIDAY WHEN ANOTHER AND STRONGER SHORTWAVE SETTLES INTO OUR AREA. GFS HAS COME AROUND TO ECMWF SOLUTION IN SHOWING THIS WAVE DEEPENING JUST TO OUR EAST ON FRIDAY...THEN DRIFTING FARTHER EAST SATURDAY AS YET ANOTHER IMPULSE APPROACHES FROM THE NORTHWEST. WILL SEE INCREASE IN THUNDERSTORM CHANCES BEGINNING LATER WEDNESDAY NIGHT...AND ESPECIALLY THURSDAY AFTERNOON/NIGHT... AS FIRST WAVE MOVES INTO THE PLAINS AND MOISTURE/INSTABILITY MODESTLY INCREASE. AGAIN SEVERE THREAT APPEARS RELATIVELY LOW WITH BEST MOISTURE PACIFIC IN NATURE AT MID LEVELS. WE SHOULD BE ON BACK SIDE OF SYSTEM FRIDAY AFTERNOON WHEN PRECIP CHANCES WILL DECREASE FROM NORTH TO SOUTH. SHORTWAVE RIDGING BETWEEN UPPER IMPULSES SUGGESTS A DRY DAY SATURDAY BEFORE A REINTRODUCTION OF THUNDER CHANCES SATURDAY NIGHT AND SUNDAY. && .AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 633 AM CDT MON JUN 29 2015 VFR CONDITIONS ARE EXPECTED THROUGH THE TAF CYCLE...WITH A FEW CU POSSIBLY BRUSHING KOMA TODAY. WINDS WILL BECOME NORTHWESTERLY AND PEAK AROUND 8-10KT THIS AFTERNOON...THEN BECOME LIGHT AGAIN TONIGHT. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ UPDATE...DEWALD SHORT TERM...DERGAN LONG TERM...DERGAN AVIATION...MAYES

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