152 FXUS63 KOAX 300941 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 441 AM CDT THU MAY 30 2013 .DISCUSSION... FORECAST CONCERNS TODAY WILL BE EXTENT OF ADDITIONAL RAINFALL TODAY INTO THE WEEKEND AND AT 06Z...A LARGE AREA OF CONVECTION WAS ONGOING ACROSS THE PLAINS...COVERING MUCH OF KANSAS...EASTERN NEBRASKA/WESTERN IOWA...INTO MINNESOTA AND THE DAKOTAS...AND BY 09Z...MUCH OF THIS HAD SHIFTED OUT OF THE AREA. THE 00Z OAX SOUNDING WAS IMPRESSIVE...SATURATED TO AROUND 480MB AND HAD PRECIPITABLE WATER OF 1.9 INCHES...OR 220% OF NORMAL. THIS WOULD BE THE SECOND HIGHEST PWAT FOR OAX/OMA IN MAY WHICH WAS 2.05 INCHES OBSERVED MAY 18....1988. MU CAPE WAS AROUND 1800J/KG AND 0-2KM SRH WAS 256M2/S2. ON THE 00Z UA MAPS...THE STRONG 130KT H3 JET WAS DIVING FROM OREGON TOWARD NEW MEXICO. 40-50DM HT FALLS WERE OVER THE PLAINS WITH A BROAD H5 TROF FROM THE WRN PLAINS ACROSS THE ROCKIES INTO THE PACIFIC NORTHWEST. THE H7 PATTERN WAS SIMILAR AND VERTICALLY STACKED COMPARED TO THE H5 PATTERN WITH HIGH H7 DEWPOINTS OF 6 AT KOUN AND 7DEGC AT OAX. OF NOTE AT H85 WAS ABUNDANT DEEP MOISTURE THROUGH THE PLAINS AND A 40-50KT SOUTH FLOW ACROSS THE PLAINS...AHEAD OF LOW PRESSURE OVER SOUTHEAST COLORADO INTO THE WESTERN HIGH PLAINS. TODAY...THE IDEAL HEAVY RAIN CONDITIONS HAVE SHIFTED OUT OF THE AREA. THE FORECAST AREA REMAINS UNDER THE INFLUENCE OF CYCLONIC FLOW RELATED TO THE SLOW MOVING CLOSED LOW OVER SOUTH DAKOTA AND UPPER LEVEL DIVERGENCE. DEEPER MOISTURE WILL LINGER OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA THIS MORNING...SHIFT EAST...AND THEN SHIFT WEST OVERNIGHT. THERE WILL BE ADDITIONAL SHOWERS AND THUNDERSTORMS DEVELOPING WITH THE CONTINUED WARM ADVECTION PATTERN AND LITTLE INHIBITION. THERE IS A STRONG H5 SPEED MAX MOVING INTO KANSAS THIS MORNING AND THIS COULD ENHANCE THE STRENGTH OF THE STORMS TODAY. THE LINCOLN TO OMAHA AREAS SHOULD BE ON THE NORTHWEST EDGE OF THE PRECIPITATION...SO HAVE LEFT PART OF THE FLASH FLOOD WATCH IN PLACE. THE PRECIPITABLE WATER VALUES WILL DROP SIGNIFICANTLY DURING THE DAY CLOSER TO 1 INCH AND H85 DEWPOINTS WILL LOWER AS WELL. STRONG TO SEVERE STORMS MAY DEVELOP ALONG THIS MOISTURE GRADIENT AS INSTABILITY INCREASES TO 1000 TO 2000 J/KG THIS AFTERNOON. THERE IS SOME LOW LEVEL SHEAR TO WORK WITH...HOWEVER DRYING WILL BE TAKING PLACE AS BULK SHEAR IS INCREASING IN THE FAR SOUTHEAST PART OF THE FORECAST AREA. THE AREA IS STILL IN THE SLIGHT RISK AND THIS SEEMS REASONABLE FOR ISOLATED SEVERE STORMS. MOISTURE...INSTABILITY AND SHEAR PARAMETERS CAN BE LOOKED AT DURING THE DAY TO GET A BETTER ASSESSMENT ON HOW MUCH OF A THREAT THERE WILL BE. TONIGHT...LEFT IN SOME SCATTERED SHOWERS AND THUNDERSTORMS AS SOME DEEPER MOISTURE RETURNS AND THERE IS AN AREA OF FRONTOGENESIS THAT MOVES IN. CYCLONIC FLOW CONTINUES FRIDAY AND SATURDAY WITH A FEW INSTABILITY SHOWERS AND THUNDERSTORMS. TEMPERATURES LOOKS TO BE ON THE CHILLY SIDE WITH A BRISK WEST WIND SATURDAY...WITH HIGHS ONLY IN THE 60S FOR MUCH OF THE AREA. FINALLY...THERE IS A REPRIEVE FROM THE PRECIPITATION SATURDAY NIGHT THROUGH SUNDAY NIGHT...HOWEVER RAIN CHANCES RETURN FOR MONDAY WITH MORE ACTIVE WEATHER AND BELOW NORMAL TEMPERATURES THROUGH WEDNESDAY. && .AVIATION... 06Z TAFS FOR KOFK...KOMA AND KLNK. ALL THREE TAF SITES WILL CONTINUE TO BE IN A VERY WET PATTERN THROUGH THE FIRST 6-8 HOURS OF THE TAF PERIOD WITH WIDESPREAD RAIN AND NUMEROUS EMBEDDED THUNDERSTORMS. OUTSIDE OF THE THUNDERSTORM ACTIVITY CONDITIONS MAY BE VFR OR MVFR...BUT LOWERING TO IFR WITH HEAVY RAIN IN THUNDERSTORMS. EXPECT A DECREASE IN THE RAIN/THUNDER AFTER 12Z AND IMPROVING CONDITIONS. DN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NEZ045-052-053- 066>068-078-088>093. IA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR IAZ043-055-056-069- 079-080-090-091. && $$ ZAPOTOCNY