FXUS63 KOAX 152007
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
307 PM CDT MON MAR 15 2010
.SHORT TERM...TONIGHT THROUGH THURSDAY. PESKY LOW CLOUDS REMAIN
FORECAST PROBLEM POSING THE MAIN CHALLENGE TO TEMPERATURES FOR THE
FIRST 2 DAYS OF THE SHORT TERM.
FORECAST AREA CAUGHT IN BETWEEN WEATHER SYSTEMS WITH VERY LIGHT
FLOW ALOFT NOTED ON 12Z OAX SOUNDING. 18Z STLT IMAGERY SHOWED LOW
CLOUDS COVERED MUCH OF NEBR...SD...WRN MN AND ERN ND WITH A WEAK
UPPER TROUGH MOVG TWD NERN ND. AFT 18Z LOW CLOUDS WERE ERODING OVR
WRN NEBR AND MODELS HINT AT SOME POSSIBLE LOW CLOUD EROSION SW TO
ECNTRL ZONES ON TUE AT VARYING LEVELS AOB 850 MB DEPENDING ON
MODEL...BUT GENERALLY LEFT IN MOCLOUDY SKIES THRU TUE MOST AREAS
BASED ON UPSTREAM CONDITIONS AND CONTD NWLY COOL ADVCTN FLOW. IN
ADDITION...WITH UPPER TROUGH FORECAST TO DROP ALMOST DUE
SOUTH...SOME MID CLOUD GENERATION ALSO LIKELY. IN FACT...WITH WEAK
QG FORCING NOTED PER NAM/GFS...AND SOMEWHAT STEEPER 1000-700 MB
LAPSE RATES...A STRAY SHOWER OR TWO CAN/T BE RULED OUT TUE. ATTM
INCLUDED AN ISOLD RW--. WITH EXPECTED LOW CLOUDS TNGT/TUE
PERSISTENCE LOOKS ABOUT THE BEST FOR TEMPS VS. MAV/MET...ALTHOUGH
PERHAPS HIGHS ON TUE MAY BE A DEG OR SO COOLER THAN TDA SINCE
MODEST COOL ADVCTN WAS NOTED AT 850 MB WITH ABOVE MENTIONED WAVE.
AS WAVE DROPS SOUTH OF THE AREA ON WED WOULD EXPECT A GRADUAL
CLEARING FM N TO S OVER CWA...BUT LINGERED CLOUDS A BIT LONGER
INTO THE AFTN AND THUS LOWERED MAX TEMPS A BIT ECNTRL/SE. DECENT
WARMING APPEARS IN STORE ON THU AS FLATTENING UPPER RIDGE SPREADS
OVER FCST AREA. TIMING OF FRONT MAY LIMIT WARMING NRN ZONES BUT
EVEN THERE READINGS COULD APPROACH MEX AS INVERSION BECOMES LESS
SHALLOW THU MORNING IN RESPONSE TO WSW WINDS JUST OFF THE SFC.
IDEAL WARMING SETTING UP FOR SWRN ZONES WITH SW LOW LVL FLOW AHEAD
OF COLD FRONT. MIXING TO 850 MB USING NAM/GFS AVE WOULD YIELD
UPPER 60S. THOSE COULD EVEN BE CONSERVATIVE AS IT WAS NOTED THAT
MID 60S WERE OBSERVED TDA IN NERN IA/WI WITH 850 MB TEMPS COOLER
AND NE SFC WINDS...PLUS LAST YEAR AROUND THIS TIME WE WERE IN THE
MID/UPR 70S.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
GLOBAL MODELS STILL HAVE CONSIDERABLE DIFFICULTY WITH SHORTWV ENERGY
DIVING SEWD OUT OF BC INTO THE NRN ROCKIES AND EVENTUALLY ACROSS THE
PLAINS FOR THE LATE PART OF THE WEEKEND. 00Z 15 MAR OPERATIONAL
GUIDANCE WAS IN FAIR AGREEMENT...BUT 12Z OPERATIONAL RUNS OF THE
CANADIAN AND GFS HAVE BROKE WITH CONTINUITY TOWARD A STRONGER
SYSTEM. 00Z GFS ENSEMBLE AND NAEFS DID LEND SOME SUPPORT FOR THE
LATEST GFS /PARTICULARLY THE CANADIAN RUNS OF THE NEFS BUT ALSO A
COUPLE OF GFS RUNS AS WELL/. NEVERTHELESS...UNTIL BETTER CONTINUITY
CAN DEVELOP BETWEEN THE GLOBAL MODELS WILL TEND TO FAVOR THE MORE
CONSISTENT EC AND EC ENSEMBLES FOR THIS FORECAST PACKAGE.
THUS HAVE MADE LITTLE CHANGE TO THE GOING FORECAST THROUGH THE
PERIOD. CURRENT THINKING AND GRIDS WILL REFLECT A CDFNT DROPPING SWD
THRU THE FA THURS NIGHT AND CLEARING THE AREA BY MID DAY ON FRI.
PERSISTENT MID LVL FRONTOGENESIS BEHIND THE FNT SHLD LEAD TO A
FRONTAL CIRCULATION AND EVENTUAL PRECIP BY FRI MRNG /MAINLY OVR THE
NRN CWA/. AS THIS FRONTAL ZONE DROPS SWD THRU THE DAY ON
FRI...PRECIP SHLD ALSO DROP SWD THRU THE DAY. HAVE INCREASED POPS
INTO THE LIKELY CAT DURING THE DAY ON FRI AS THIS IS WHEN THERE IS
THE GREAT AMOUNT OF AGREEMENT IN PRECIPITATION. MOST OF THE PRECIP
THRU THE DAY ON FRI S OF HIGHWAY 92 STILL LOOKS TO BE RA...BUT CLD
STILL SEE A MIX N OF THAT AS COLD AIR DROPS INTO THE REGION. PRECIP
IS THEN LIKELY TO CONT INTO FRI NIGHT OVR THE CNTRL AND SRN CWA.
SOME OF THE SRN CWA MAY CONT TO SEE A MIX INTO FRI EVNG...BUT AFTER
MIDNIGHT MOST LOCATIONS SHLD BE SN. PRECIP WL LIKELY BE ENDING BY
EARLY SAT MRNG...BUT CONT SOME SCHC POPS INTO SRN/ERN CWA ON SAT.
COLD WEATHER WILL THEN CONT THRU NEXT MON AND WENT WELL BELOW CLIMO.
OPERATIONAL MEX SEEMS TO WARM DUE TO CLIMO ON DAYS 6 AND 7 AND ALSO
SIG MODEL VARIABILITY. THUS HAVE GENERALLY USED HPC NUMBERS AND
ADJUSTED DOWNWARD FROM THERE.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VERY LIGHT UPPER LEVEL WINDS WILL RESULT IN PERSISTENT CLOUDINESS
THROUGH 18Z TUESDAY. EXPECT CIGS WILL DROP INTO THE IFR AND
POSSIBLY LIFR CATEGORY AGAIN TONIGHT AFTER DARK...THEN LIFT ABOVE
1000 FEET TUESDAY MORNING. RESIDUAL MOISTURE IN THE SOIL AND COOL
TEMPERATURES SHOULD LEAD TO MORE LIGHT FOG DEVELOPMENT LATE TONIGHT
AS WELL...SIMILAR TO EARLY THIS MORNING.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
CHERMOK/BOUSTEAD/NIETFELD
Back to Main Forecast Discussion Page |
