Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 311712
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1212 PM CDT SUN AUG 31 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 340 AM CDT SUN AUG 31 2014

TSTMS THE NEXT 24 HOURS AND THE SEVERE WEATHER POTENTIAL MAINLY
THIS AFTN AND EVENING ARE THE PRIMARY FORECAST CONCERNS. WE WILL
MAY ALSO NEED A FLASH FLOOD WATCH AT SOME POINT LATER TODAY.

UPPER AIR CHARTS FROM LAST EVENING HAD THE FOLLOWING MAIN FEATURES
OF INTEREST. AT 300 MB A JET SEGMENT OF AROUND 105 KNOTS WAS NEAR
THE CA/OR BORDER AND ANOTHER WAS JUST OFF SHORE. 12 HOUR HEIGHT
FALLS OF UP TO 60 METERS WERE NOTED AT 500 MB WITHIN THE TROUGH
OVER THE URN AND CONTROL ROCKIES. RIDGE AT 700 MB STRETCHED FROM
THE FOUR CORNERS REGION INTO THE WRN HIGH PLAINS. 700 MB AND
850 MB MOISTURE WAS A BIT LACKING IN THE REGION...WITH THE 00Z
KOAX SOUNDING ONLY HAVING 0.91 INCHES OF PRECIPITABLE WATER.

ISOLD TO SCT CONVECTION MAY MOVE ACROSS THE FCST AREA THIS
MORNING...WHICH MAY COMPLICATE CONVECTIVE INITIATION LATER TODAY.
STORMS THIS MORNING WILL BE ELEVATED AND SHOULD BE MOSTLY BELOW
SEVERE LIMITS. STORMS SHOULD GET GOING EARLY/MID AFTN IN NCTRL NE
AND THEN MOVE/DEVELOP EWD INTO ERN NE DURING THE MID TO LATE AFTN.
DEVELOPMENT INITIALLY MAY BE TIED TO THE COLD FRONT AND POSSIBLY
NEAR A PRE-FRONTAL TROUGH AS UPPER LEVEL LARGE SCALE LIFT MOVES
IN FROM THE WEST. SFC DEWPOINTS WILL INCREASE INTO THE 65-70
DEGREE RANGE WHILE TEMPERATURES CLIMB INTO THE 80S. THIS SHOULD
YIELD ML CAPE VALUES OF 2000-3000 J/GAG. MODELS FCST PRECIPITABLE
WATER VALUES TO REACH CLOSE TO 2 INCHES BY LATE AFTERNOON. STORMS
MAY INITIALLY BE SOMEWHAT DISCRETE THEN FORM INTO CLUSTERS AND/OR
LINEAR STRUCTURES DURING THE EVENING. TORNADO RISK WILL BE SLIGHTLY
ENHANCED NEAR ANY LOW LEVEL CONVERGENCE ZONES...BUT THE LACK OF A
WARM FRONT IN OUR AREA MAY BE A LIMITING FACTOR.

STORM CHANCES CONTINUE MOST AREAS TONIGHT BUT WILL BE DECREASING
FROM NORTHWEST TO SOUTHEAST AS THE NIGHT GOES ON. HEAVY RAIN
POTENTIAL SHOULD BE HIGHEST FROM 6 PM TO 2 AM. LOOK FOR LOWS
TONIGHT MAINLY IN THE 60S...COOLEST NORTHWEST/WARMEST SOUTHEAST.
A COLD FRONT SHOULD EXTEND FROM WRN WI THROUGH SERN IA AND THEN
INTO CNTRL KS BY 12Z MONDAY. STORMS COULD LINGER IN SERN NE AND
SWRN IA AT LEAST MONDAY MORNING. ENERGY MOVING SEWD FROM THE DKTS
COULD BRING SOME SHOWERS/THUNDERSTORMS TO MAINLY NERN NE MONDAY
NIGHT...SO KEPT SOME POPS GOING THERE IN THE EVENING AND SPREAD
THEM TO ALL OF THE AREA LATER MONDAY NIGHT.

TUESDAY LOOKS MAINLY DRY. HIGH PRESSURE WILL INITIALLY BE OVER THE
AREA BUT SLIDE SEW DURING THE DAY. SOUTHERLY WINDS WILL INCREASE
AND HELP PUSH HIGHS TO THE LOWER AND MID 80S.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 AM CDT SUN AUG 31 2014

THINKING FROM THE PAST FEW DAYS IN THIS PERIOD HAS NOT CHANGED
MUCH. INITIALLY FAST ZONAL FLOW AT 500 MB WILL BE IN PLACE ACROSS
THE NRN UNITED STATES. THIS FLOW BECOMES MORE SOUTHWESTERLY AS A
TROUGH DEVELOPS FROM CANADA TO NRN CA BY THURSDAY.

STORM CHANCES SHOULD INCREASE THURSDAY NIGHT INTO SATURDAY BEHIND
A COLD FRONT THAT WILL MOVE THROUGH THE AREA THURSDAY. 00Z GFS AND
ECMWF HAVE SOME DIFFERENCES IN PCPN COVERAGE LATE IN THE WEEK.
DECIDED TO KEEP ABOUT AN EVEN BLEND OF THE MODELS FOR NOW IN THOSE
PERIODS.

.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1125 PM CDT SAT AUG 30 2014

VFR CONDITIONS WITH SCATTERED TO BROKEN HIGH CLOUDS ARE FORECAST
THROUGH MID MORNING. LOW LEVEL WIND SHEAR IS LIKELY 09Z TO 15Z AT
ALL TAF SITES AS SOUTHWESTERLY LOW LEVEL JET KICKS UP TO 40 TO
50KT RANGE. GUSTY SOUTH WINDS 15 TO 25KT ARE EXPECTED AFTER 15Z
AHEAD OF A COLD FRONT MOVING INTO EASTERN NEBRASKA. THUNDERSTORMS
ARE FORECAST TO FIRE ALONG THAT FRONT AFTER 21Z...MOST LIKELY JUST
SOUTHEAST OF KOFK AREA. STRONG STORMS COULD MOVE THROUGH KOMA AND
KLNK TAF SITES AFTER 00Z.

&&

.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1215 PM CDT SUN AUG 31 2014

A GENERALLY WEAK LINE OF CONVECTION WORKING ALONG MO RIVER SHOULD
EXIT KOMA TAF SITE SHORTLY AFTER VALID START TIME WITH MID/HIGH
CLOUDS GRADUALLY CLEARING EASTWARD AS WELL. HOWEVER...WITH
APPROACHING UPPER TROUGH...CLOUDS COULD FILL IN QUICKLY. TSTM
REDEVELOPMENT STILL LIKELY THIS AFTN AS TROUGH/FRONT APPROACH.
ALTHOUGH DEVELOPMENT COULD BE DELAYED SLIGHTLY WITH LAG IN HEATING
DUE TO MORNING/MIDDAY CLOUDS...STRONG/SEVERE STORMS STILL EXPECTED
TOWARD 00Z. HOWEVER...AXIS OF STRONGEST COULD BE SE OF KOFK...SO
STRONGER WIND GUSTS WITH CONVECTION WERE RESERVED FOR KOMA AND
KLNK. BESIDES THE STRONG WIND GUSTS...STORMS COULD ALSO CONTAIN
HAIL WHICH WAS NOT INCLUDED IN TAF FORECASTS. STORMS COULD LINGER
BEHIND FRONT WELL INTO THE EVENING...ALTHOUGH WOULD EXPECT
COVERAGE AND STRENGTH TO BE LESS THAN EARLY EVENING ACTIVITY. LOW
CLOUDS WERE ALSO EXPECTED TO FILTER IN BEHIND THE FRONT LATE
TONIGHT INTO LABOR DAY MORNING...AND A PERIOD OF MVFR CIGS WERE
INCLUDED AT ALL SITES.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$

SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...CHERMOK



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