FXUS63 KOAX 212016
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
316 PM CDT THU APR 21 2011
.DISCUSSION...
OVERALL PATTERN REMAINS RELATIVELY COOL AND ACTIVE FOR EASTERN
NEBRASKA AND WESTERN IOWA FORECAST AREA NEXT 7 DAYS. FOR THIS EVENING
MOST OF THE CONVECTION SHOULD HOLD TO OUR SOUTH NEAR/NORTH OF H85
FRONT THAT WAS IN NRN OKLAHOMA PER 12Z SUBJECTIVE ANALYSIS.
HOWEVER...WEAK WAVE MOVING E OF NEBR PANHANDLE PER EARLY AFTN
SATELLITE IMAGERY COULD SPREAD A FEW MOSTLY LIGHT SHOWERS TO
MAINLY NWRN AREA THROUGH EVENING WITH SPRINKLES POSSIBLE
ELSEWHERE. LATER TONIGHT AS STRONGER TROUGH APPROACHES INSTABILITY
IS PULLED INTO SERN NEBR THUS HIGHER POPS WARRANTED THERE AND IN
NWRN FORECAST AREA CLOSER TO UPPER WAVE EJECTING INTO NEBRASKA.
HOWEVER...HOW FAR NORTH ACTIVITY WILL SPREADS BY 12Z SOMEWHAT UP
IN THE AIR AND MODEST POPS WERE KEPT FARTHER N AND EAST AS WELL.
CEILINGS SHOULD BE LOWERING AND DRIZZLE PROBABLE AS WELL. THIS
NEXT TROUGH WILL ATTEMPT TO SHOVE DRY LINE THROUGH THE FORECAST
AREA BY EARLY AFTERNOON ALLOWING DECREASING/ENDING POPS AND
CLEARING...PER 12Z GFS/ECMWF. HOWEVER...A SIGNIFICANT PIECE OF
ENERGY LAGS BEHIND WHICH COULD ALLOW FOR A LESS AGGRESSIVE PUSH TO
CLEARING/MILDER TEMPS PER 12Z NAM AND/OR ALLOW SOME
CLOUDS/SCATTERED LIGHT PRECIP TO LEAK INTO NWRN ZONES LATE.
FORECAST WAS BASED ON MORE PROGRESSIVE AND WARMER GFS/ECMWF THUS
MANY TEMPERATURES WERE RAISED AND POPS LIMITED TO MAINLY IA
COUNTIES AFTER 18Z.
CLOUDS AND COOLER TEMPERATURES LOOK TO PUSH SOUTH ACROSS FORECAST
AREA EARLY SATURDAY AT LEAST WITH PROBABLY NOT MUCH TEMPERATURE
RECOVERY SUNDAY AS SOUTHWESTERLY UPPER FLOW SHOULD KEEP AN
ABUNDANCE OF CLOUD COVER. SEVERAL WAVES LIFTING NE OUT OF THIS
SOUTHWESTERLY FLOW WILL BRING PRECIPITATION CHANCES BACK INTO THE
FORECAST AREA BEGINNING SUNDAY AND CONTINUING INTO MIDWEEK WITH
MONDAY CURRENTLY PEGGED AS THE HIGHEST PROBABILITY DAY. THIS
WARRANTED TRIMMING OF MAX TEMPS MONDAY WITH RELATIVELY HIGH
PROBABILITY FOR LINGERING CLOUDS/LOW CLOUDS WARRANTING TEMPERATURE
CUT ON TUESDAY AS WELL. UNCERTAIN HOW A TRAILING WAVE MOVING
ACROSS PLAINS ON WEDNESDAY WILL IMPACT AREA AS IT APPEARS BULK OF
ENERGY WILL LIFT OUT IN MONDAY/TUESDAY PERIOD. THUS A DRY DAY WAS
FORECAST ACROSS MOST OF THE AREA ON WEDNESDAY WITH THIS PACKAGE. BOTH
GFS/ECMWF SUGGEST EVEN LOWER PRECIP CHANCES BY NEXT THURSDAY WITH
WARMING TEMPERATURES. USING A BLEND BETWEEN COOLER ECMWF AND QUITE
WARM GFS PUTS HIGHS ABOVE MEX GUIDANCE MIXING TO H85 WHICH SHOULD
HAPPEN GIVEN DECENT WRLY COMPONENT TO SFC WINDS.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
EXPECT VFR CONDITIONS TO REMAIN VFR UNTIL ABOUT 22/00Z WHEN
CONDITIONS BEGIN TO DETERIORATE. LLVL MOISTURE WILL ENVELOP ERN NEB
AND PUSH CIG LEVELS DOWN TO MVFR RANGE LASTING TILL ABOUT 22/06Z.
AFTER THAT IFR CIGS/MVFR VSBYS WILL PREVAIL AT ALL SITES THE REST OF
THE FCST PD. GIVEN LOW CONFIDENCE FOR PCPN DEVELOPMENT/AREAL
COVERAGE...HAVE OPTED TO NOT INCLUDE PROB30 GROUPS IN THE LATTER
HALF OF FCST.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
CHERMOK/DEE