Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 250441 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 1141 PM CDT FRI JUL 24 2015 .UPDATE... ISSUED AT 917 PM CDT FRI JUL 24 2015 CLUSTER OF CONVECTION THAT FIRED ALONG THE COLD FRONT HAS WEAKENED WITHIN THE LAST HOUR AS IT PUSHES OUT OF OUR AREA. KOAX 00Z UPPER SOUNDING REVEALED 6021 J/KG OF CAPE...BUT WET BULB ZERO HEIGHTS WERE ALSO ABOUT 13041 AGL...LIKELY RESULTING IN SIGNIFICANT MELTING OF HAIL BEFORE IT HIT THE GROUND. STORMS PULSED UP AND DOWN VERY QUICKLY...WITH MARGINAL WIND SHEAR TO GET LARGER HAIL TO DEVELOP. WE DID HAVE SEVERAL PEA SIZE HAIL REPORTS...AND ONE NICKEL SIZE HAIL REPORT NEAR BEATRICE. WINDS ALSO GUSTED TO 60 MPH AND DOWNED A FEW TREES NEAR PLATTSMOUTH. FOCUS SHIFTS TO THE WEST WITH STRONG STORMS DEVELOPING IN CENTRAL NEBRASKA. THESE STORMS SHOULD CONTINUE TO DEVELOP EASTWARD THROUGH THE PLATTE RIVER VALLEY OVERNIGHT...THUS HAVE INCREASED POPS IN THIS AREA TO 50 TO 60 PERCENT. EFFECTIVE SHEAR OVERNIGHT SHOULD REMAIN SOMEWHAT WEAK AT 25 TO 30 KNOTS...BUT VERY STRONG INSTABILITY REMAINS ESPECIALLY SOUTHERN HALF OF THE FORECAST AREA. THUS ANY STORMS OVERNIGHT MAY STILL CONTAIN GUSTY WINDS...AND MARGINALLY SEVERE HAIL DUE TO HIGH WET BULB ZERO VALUES PREVIOUSLY MENTIONED. FORTUNATELY...THIS ADDITIONAL RAINFALL SHOULD OCCUR OVER AREAS THAT DID NOT RECEIVE RAIN EARLIER THIS EVENING. HOWEVER...THAT LINE OF STORM DID PRODUCE RAINFALL OF 1 TO 2 INCHES...THUS WILL HAVE TO WATCH A NARROW CORRIDOR THAT SAW THE STRONGER STORMS THIS EVENING. UPDATE ISSUED AT 715 PM CDT FRI JUL 24 2015 THUNDERSTORMS ERUPTED ALONG THE COLD FRONT WITHIN THE LAST HOUR TAKING ADVANTAGE OF 5000-6000 J/KG OF CAPE...ALTHOUGH EFFECT SHEAR IS WEAK AT 20-25 KNOTS. STORMS HAVE BEEN VERY QUICK TO PULSE UP...BUT ALSO PULSE RIGHT BACK DOWN. && .SHORT TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 320 PM CDT FRI JUL 24 2015 VERY HOT AND HUMID WEATHER WILL GIVE WAY TO CHANCES OF SHOWERS AND THUNDERSTORMS OVER THE NEXT COUPLE OF DAYS. SUBJECTIVE 12Z UPPER AIR ANALYSIS INDICATES BROAD UPPER-LEVEL RIDGE OVER THE CENTRAL US...WITH A SHORTWAVE TROUGH RIDING AROUND THE EDGE OF THE RIDGE OVER THE WESTERN GREAT LAKES...WITH WEAK UPPER-LEVEL JET AROUND 75KT EXTENDING FROM NV INTO ND. 850MB MOISTURE WAS ABUNDANT ACROSS THE CENTRAL US...WITH 12-20C DEWPOINTS FROM THE MID-MO RIVER VALLEY SOUTHWARD. SURFACE LOW AT 20Z WAS CENTERED IN SOUTHWEST CO...WITH SECONDARY LOW IN NORTHERN MN...AND BOUNDARY EXTENDING BETWEEN THE TWO THROUGH NORTHWEST IA/EASTERN NEB/CENTRAL KS. MAIN FORECAST CONCERN IS CONVECTIVE POTENTIAL THIS EVENING AND TONIGHT...AND AGAIN TOMORROW. WILL LET HEAT ADVISORY RIDE AS IS THROUGH 8PM...WITH WIDESPREAD AREA OF HEAT INDICES OF 105 OR GREATER. ELEVATED SHOWERS ONGOING IN CENTRAL NEB ARE MOVING INTO MORE FAVORABLE AIRMASS OVER EASTERN NEB...BUT HAVE SHOWN SIGNS OF WEAKENING. SHORT-TERM CONVECTIVE-ALLOWING MODELS HAVE TENDED TO KEEP THE CWA MAINLY PRECIP-FREE UNTIL LATER THIS EVENING...AFTER 03Z OR EVEN 06Z...WITH THUNDERSTORMS EXPANDING OUT OF WESTERN NEB INTO CENTRAL/EASTERN NEB AS THEY BOTH MOVE IN AND DEVELOP ALONG THE BOUNDARY. HINTS OF THIS ACTIVITY ARE ALREADY APPARENT...WITH CONVECTIVE INITIATION SHOWING IN NORTHWEST KS. THAT SAID...FEW MODELS ARE PICKING UP ON THE ELEVATED SHOWER/ISOLATED THUNDER ACTIVITY THAT IS ONGOING. DID STILL DECREASE POPS FROM 00- 06Z...THOUGH KEPT A SLIGHT CHANCE MENTION UNTIL 03Z FOR THAT ELEVATED SHOWERS/STORMS. CONTINUED THE CHANCES FOR SHOWERS/STORMS THROUGH TOMORROW NIGHT...THOUGH DID KEEP CHANCES ON THE LOWER SIDE...AS CONFIDENCE IS ON THE LOW SIDE FOR WHERE AND WHEN SHOWERS/STORMS WILL BE GOING. SHOWERS/STORMS SHOULD CLEAR OUT OF THE AREA THROUGH SUNDAY MORNING...LEAVING MAINLY FAIR WEATHER FOR AT LEAST THE AFTERNOON HOURS AS THE SURFACE FRONT FINALLY PUSHES SOUTH OF THE AREA. RESPITE IS SHORT-LIVED AS BOUNDARY BEGINS TO RETURN NORTHWARD MONDAY...BRINGING A CHANCE FOR SHOWERS/STORMS AT LEAST INTO SOUTHEAST TO CENTRAL NEB BY AROUND MONDAY MORNING AND INTO THE AFTERNOON. TEMPERATURES ALSO WILL RETURN TO A WARMING TREND. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 320 PM CDT FRI JUL 24 2015 THINK CHANCES OF SHOWERS/STORMS ON MONDAY NIGHT WILL SKIRT THE NORTHWESTERN CWA AT BEST...WITH FOCUS MORE LIKELY TO BE FURTHER NORTH AT THE NOSE OF THE LOW-LEVEL JET AND CLOSER TO THE APPROACHING UPPER-LEVEL TROUGH. FAIRLY SUBSTANTIAL TROUGH IS PROGGED TO MOVE ACROSS THE NORTHERN CONUS ON TUESDAY...DRAGGING A COLD FRONT THROUGH THE PLAINS. CURRENT PROGS ADVANCE THE FRONT MAYBE INTO NORTHEAST NEB BY 00Z WED. IN THE WARM SECTOR AHEAD OF THE FRONT...EXPECT TEMPS TO JUMP WELL INTO THE 90S...AND HAVE CONTINUED TO PUSH TEMPERATURES UP TO MATCH EXPECTATIONS. ALSO KEPT POPS OUT OF THAT WARM SECTOR...WHICH SHOULD BE STRONGLY CAPPED ON TUESDAY...AND LIMITED SLIGHT CHANCE POPS TO ALONG AND BEHIND THE FRONT. CHANCES INCREASE ACROSS THE AREA ON TUESDAY NIGHT AS THE FRONT MOVES THROUGH...WITH SOME POPS LINGERING INTO WED MORNING. BEHIND THE FRONT...COOLER AND DRIER AIRMASS SPILLS INTO THE CWA TO END THE WEEK. && .AVIATION...
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(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1138 PM CDT FRI JUL 24 2015 LINE OF POTENTIALLY SEVERE STORMS IS JUST WEST OF KLNK...SHOULD IMPACT THAT LOCATION 05-06Z. STORMS SHOULD REACH KOMA BY 06-07Z. WILL FORECAST A 2 HOUR WINDOW OF STORMS...THEN LINGERING SHOWERS THAN COULD LAST UNTIL 10-12Z. STILL THINKING THAT KOFK MAY BE TOO FAR NORTH TO GET ANY PRECIP WITH THIS FIRST ROUND. SHOULD SEE NEW THUNDERSTORM DEVELOPMENT LATER IN THE TAF PERIOD...18-23Z AT KOFK...AND 20-03Z AT KLNK/KOMA.
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&& .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ UPDATE...DEWALD SHORT TERM...MAYES LONG TERM...MAYES AVIATION...DEWALD

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