FXUS63 KOAX 210833
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
333 AM CDT TUE JUN 21 2011
.DISCUSSION...
WEATHER IS BECOMING MUCH LESS VOLATILE ACROSS THE AREA...THOUGH NOT
NECESSARILY QUIET. SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES UPPER
LOW CENTERED IN NORTHWEST KS...WITH WV IMAGERY INDICATING THE LOW
HAD PROGRESSED INTO CENTRAL NEB BY 07Z. A FEW WEAK SHRA/TSRA WERE
UNDER THE UPPER LOW IN CENTRAL NEB...WITH STRONGER CONVECTION WELL
EAST OF THE AREA. SURFACE LOW AT 07Z WAS CENTERED IN SOUTHEAST
NEB/NORTHEAST KS...WITH COLD FRONT EXTENDING SOUTHWARD THROUGH
EASTERN KS INTO CENTRAL OK...AND WITH INVERTED TROUGH EXTENDING
NORTHWARD THROUGH EASTERN NEB INTO EASTERN/CENTRAL SD. UPPER LOW
WAS NEARLY STACKED...WITH 850MB LOW CENTERED IN SOUTH CENTRAL
NEB/NORTH CENTRAL KS...AND MOISTURE HAD WRAPPED AROUND THE LOW INTO
ND/WESTERN WY.
MAIN FORECAST CONCERNS INCLUDE LINGERING SHOWERS UNDER AND BEHIND
THE UPPER LOW...AND COOLER TEMPERATURES. UPPER LOW IS PEAKING IN
INTENSITY THIS MORNING AND IS BECOMING STACKED...BUT UPPER-LEVEL
FLOW IS NOT ALL THAT STRONG. THE LOW WILL ONLY MOVE SLOWLY ACROSS
THE CENTRAL US FOR THE NEXT COUPLE OF DAYS...REACHING NORTH CENTRAL
IA BY 12Z WEDNESDAY AND LAKE MICHIGAN BY 12Z THURSDAY. SHOWERS AND
THUNDER BENEATH AND BEHIND THE LOW WILL AFFECT MUCH OF THE CWA
TODAY AND TONIGHT. INSTABILITY WILL BE SUFFICIENT TODAY TO
SUPPORT A FEW RUMBLES OF THUNDER...BUT SEVERE THREAT SHOULD REMAIN
WELL EAST AHEAD OF THE UPPER LOW. WITH 850MB WINDS APPROACHING
40KT BEHIND THE LOW TODAY...MAY SEE GUSTY CONDITIONS...ESPECIALLY
WEST OF THE MISSOURI RIVER...BUT SHOULD REMAIN BELOW ADVISORY
CRITERIA. TEMPS ARE MUCH COOLER BEHIND THE UNSEASONABLY STRONG
LOW...AND HAVE DROPPED TEMPS IN THE NORTH IN PARTICULAR FOR TODAY.
SHOWERS SHOULD BE ABLE TO HANG ON IN THE NORTHERN AND EASTERN CWA
THROUGH TONIGHT AND WEDNESDAY...KEEPING CONDITIONS COOL THERE IN
PARTICULAR. HAVE LOWERED HIGHS EVERYWHERE...BUT PARTICULARLY IN
THE NORTHERN CWA...THROUGH THURSDAY.
BY THURSDAY...UPPER LOW WILL HAVE MOVED FAR ENOUGH EAST TO PULL ITS
SHOWERS AND PERSISTENT CLOUDS AWAY FROM THE CWA. HOWEVER...ECMWF IS
CONSISTENT IN ITS LAST FEW RUNS IN DEVELOPING CONVECTION FROM
EASTERN KS INTO THE NEB/IA BORDER LATE THURSDAY NIGHT AS LOW-LEVEL
JET RETURNS MOISTURE TO THE REGION AND LOW-LEVEL RIDGING SLIDES
EASTWARD. GFS AND GEM ARE DRY...WITH RIDGING STILL LINGERING IN THE
AREA...AND SREF HAS JUST ONE MEMBER WITH PRECIP IN THE AREA.
THUS...PRECIP POTENTIAL LATE THURSDAY NIGHT IS LOW CONFIDENCE. KEPT
SLIGHT CHANCE POP IN THE SOUTHERN CWA...BUT DID DECREASE ITS
COVERAGE WITH LOW CONFIDENCE AND LACK OF SUPPORT FROM ANY OTHER
SOLUTIONS. ALSO DECREASED POPS DURING THE DAY ON FRIDAY TO SLIGHT
CHANCE...WITH LOW CONFIDENCE IN COVERAGE AS UPPER-LEVEL FORCING
REMAINS WELL WEST.
MADE NO CHANGES BEYOND FRIDAY.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
WITH UPPER AND SURFACE LOW TRACKING NNE THROUGH EASTERN NEBRASKA...
CONFIDENCE IN WIND FORECAST AT KOFK NOT HIGH AS A SLIGHT WWD TRACK
WOULD BRING WIND BACK AROUND TO SOUTHEAST AS OPPOSED TO NW. IN
ADDITION...SHOWERS/TSTMS SPINNING AROUND SYSTEM ALSO CREATES A
RATHER LOW CONFIDENCE IN PRECIPITATION TIMING. 06Z TAFS INCLUDED A
TEMPO TSRA AT KOFK THIS MORNING AS STRONGER ACTIVITY WAS MORE
CLOSELY TIED TO UPPER LOW. TEMPO GROUPS IN SHRA WERE CARRIED AT
KLNK/KOMA THIS MORNING WITH MENTION OF CB BUT NO THUNDER. FEEL SOME
INCREASE IN SHOWERS/TSTMS COULD OCCUR THIS AFTERNOON DUE TO
HEATING...BUT UPPER LOW AND BETTER INSTABILITY WILL BE SHIFTING ENE
OF THE REGION SO STRONGEST ACTIVITY SHOULD BE N THROUGH E OF TAF
SITES. MVFR CEILINGS WRAPPING AROUND BACK SIDE OF UPPER/SURFACE LOW
COULD OVERSPREAD TAF SITES THIS MORNING. LOWER CEILINGS COULD
REMAIN IN AT KOFK ALL DAY WITH SOME POSSIBILITY OF THEM EVEN
LOWERING INTO IFR CATEGORY THIS MORNING AND THEN AGAIN TUE NIGHT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
MAYES/CHERMOK