FXUS63 KOAX 011956
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
256 PM CDT FRI JUL 1 2011
.SHORT TERM...TONIGHT.
STRONG AND COMPACT SHORTWAVE CURRENTLY OVER NORTH CENTRAL
NEBRASKA CONTINUES TO PROGRESS NORTHEAST INTO EASTERN SD. AHEAD OF
THIS...SFC CDFNT EXTENDS FROM EXTREME SERN SD THRU NERN NEB AND
INTO NORTHWEST KANSAS. ATMOSPHERE REMAINS WELL CAPPED AHEAD OF THE
SFC FRONT BUT IF ANY STORMS CAN GET THRU THE CAP...THEY COULD
QUICKLY BECOME SEVERE WITH STRONG 0-6KM BULK SHEAR ON THE ORDER OF
50KTS AND HIGH CAPE VALUES. WITH MAIN UPPER FORCING PUSHING NEWD
ACROSS ERN SD...FEEL THAT CHANCES OF TSTMS ALONG AND BEHIND THE
SFC CDFNT ACROSS EASTERN NEBRASKA AND SOUTHWEST ARE RATHER
SMALL...BUT DO EXIST.
.LONG TERM...SATURDAY THROUGH FRIDAY.
TYPICAL FOR THE SEASON TIMING OF THUNDERSTORM CHANCES MAIN
FORECAST CHALLENGE. SATURDAY PERIOD WAS LEFT DRY AS WEAK FRONT
SHOULD SHOVE BETTER INSTABILITY SOUTH OF THE FORECAST AREA WITH
RETURN FLOW STARTING TO DESTABILIZE WRN NEBRASKA...BUT TO OUR WEST...
AHEAD OF NEXT TRANSITORY SHORTWAVE TROUGH. THIS THROUGH AND
ATTENDANT INSTABILITY THAT IS FORECAST TO SPREAD OVER THE FORECAST
AREA LATE SATURDAY NIGHT SHOULD GENERATE SHOWERS/TSTMS. INCREASED
POPS INTO LIKELY CATEGORY NW ZONES WHICH WILL LIKELY BE ON NE SIDE
OF INSTABILITY GRADIENT AS LOW LEVEL JET DIURNALLY VEERS. HOW MUCH
CONVECTION LINGERS ON SUNDAY STILL IN QUESTION AS BACKING LOW LVL
JET SHOULD KEEP BETTER INSTABILITY FOCUSED TO OUR WEST.
HOWEVER...WITH THE WEAK UPPER WAVE CONTINUING TOWARD AREA...FELT
MODEST CHANCE POPS WERE WARRANTED. EVEN ABSENT PRECIP...APPEARS
ENOUGH RESIDUAL CLOUDS COULD LINGER TO LIMIT HEATING AND LOWERED
TEMPERATURES TO A BLEND OF COOL NAM AND SOMEWHAT WARMER GFS. WITH
WAVE CROSSING AREA SUNDAY EVENING EXTENDED SMALL POPS SUNDAY NIGHT
ACROSS ERN 1/2. A DRY FORECAST WAS KEPT MON/MONDAY NIGHT WITH LTL
CHANGES TO TEMPS.
AFTER THAT UPPER RIDGE OVER ROCKIES LEANS A LITTLE EWD AND
FLATTENS WITH ANY FRONTAL PASSAGE FOR AREA WEAK WITH LITTLE
APPARENT SUPPORT. SINCE 00Z ECMWF USHERED IN A WEAK BOUNDARY
TUESDAY...A 1/2 DAY-FULL DAY FASTER THAN 12Z GFS...KEPT IN SMALL
TSTM CHANCES TUESDAY. WITH GFS KEEPING SOME SEMBLANCE OF A FRONT
IN FORECAST AREA VICINITY IN WED-FRIDAY PERIOD TOUGH TO PIN DOWN
WHICH DAY WOULD RUN HIGHEST CHANCES AND EVEN IF A CHANCE WOULD BE
WARRANTED EACH DAY. DECIDED TO NOT PULL ANY PRECIP MENTION IN TUE-
WED NIGHT TIME FRAME AND KEPT THURSDAY AND FRIDAY DRY SINCE TIMING
COULD VERY WELL CHANGE WITH LATER RUNS. DID OPT TO KEEP/INCREASE
NIGHTTIME POPS TO CHANCE CATEGORY NRN ZONES TUE AND WED NIGHTS AND
WENT WITH SLGT CHC POPS THU NGT AS CLIMATOLOGICALLY PATTERN WOULD
SUGGEST SOME NOCTURNAL TSTMS WILL OCCUR WITH BOUNDARY IN THE AREA.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
CDFNT WILL BE PASSING THRU TAF SITES EARLY IN THE TAF PERIOD TURNING
WINDS TO THE NORTHWEST. SCT TSTMS ARE POSSIBLE ALONG AND BEHIND THE
BOUNDARY THIS EVENING BUT HAVE LEFT CHANCES OUT OF THE TAF SITES FOR
NOW AS ACTIVITY...IF ANY...WILL LIKELY BE SCATTERED. SOME REDUCED
VISIBILITIES ARE POSSIBLE DURING THE EARLY MORNING HOURS AS HIGH
PRESSURE BUILDS INTO THE AREA.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
KERN/CHERMOK