FXUS63 KOAX 012027
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
327 PM CDT FRI APR 1 2011
.DISCUSSION...
WEAK ISENTROPIC UPGLIDE AROUND 295K IS EXPECTED OVERNIGHT AND WILL
CAUSE SOME VARIABLE MID LEVEL CLOUDINESS ACROSS THE AREA. A FEW
SPRINKLES ARE NOT COMPLETELY OUT OF THE QUESTION...BUT PROBABILITY
OF THAT SEEMS LOW ENOUGH TO LEAVE THE FORECAST DRY. NORTHWEST WINDS
SHOULD DECREASE TO LESS THAN 10 KNOTS BY 8 PM...THEN BECOME LIGHT
AND VARIABLE LATER TONIGHT. LOWS SHOULD BE MOSTLY IN THE 30S.
MILLER
WINDS WILL BACK TO THE SOUTHEAST SATURDAY AND INCREASE THROUGH
THE DAY IN RESPONSE TO PRESSURE FALLS ALONG THE WESTERN HIGH
PLAINS. THE PRESSURE FALLS WILL BE A RESULT OF A LARGE-SCALE
TROUGH MOVING INTO THE WESTERN US FROM THE EASTERN PACIFIC. WE
SHOULD SEE A GOOD DEAL OF SUN ON SATURDAY LEADING TO DECENT
MIXING...AND WITH A DRY ATMOSPHERE AND GROUND...WE HAVE INCREASED
THE HIGHS FOR MOST AREAS. WARM AIR AND MOISTURE ADVECTION WILL
INCREASE ON SATURDAY NIGHT AS THE SURFACE LOW DEEPENS AND MOVES
OFF THE HIGH PLAINS. MODELS DO INDICATE THAT ELEVATED INSTABILITY
WILL INCREASE OVERNIGHT OVER THE EASTERN CWA...BUT SO WILL THE
MID-LEVEL TEMPERATURES. THIS ALONG WITH WEAK LARGE-SCALE SUPPORT
AND LIMITED MASS CONVERGENCE LED TO REMOVING POPS FROM THE
FORECAST FOR SATURDAY NIGHT. WE ALSO SIGNIFICANTLY INCREASED LOWS
GIVEN THE STRONG ADVECTION AND SOME INCREASE IN CLOUDS. MODELS ARE
STILL STRUGGLING WITH THE TIMING OF THE STRONG COLD FRONT THAT
WILL MOVE THROUGH THE FA ON SUNDAY AND WE CURRENTLY PREFER A
LITTLE FASTER MOTION PER ECMWF/NAM/SREF GIVEN THE POSITIVE TILT OF
THE UPPER LEVEL TROUGH ASSOCIATED WITH THE FRONT. THUS WE WILL
LIKELY HAVE FALLING AFTERNOON TEMPERATURES IN THE NORTHWEST FA.
WILL MAINTAIN THE VERY WARM READINGS OVER THE SOUTHERN CWA GIVEN
THE VERY WARM READINGS JUST OFF THE SURFACE AT 12Z. WE MAY SEE A
GOOD 30 DEGREE SPREAD IN HIGHS ACROSS THE FA ON SUNDAY. WE ALSO
REMOVED ANY POPS FROM SUNDAY AS WELL WITH LITTLE SUPPORT FOR
PRECIP ON THE LARGE-SCALE...AND INSUFFICIENT MOISTURE IN OUR FA
FOR CONVECTION ALONG THE COLD FRONT. LARGE-SCALE FORCING FOR
ASCENT DOES INCREASE ON SUNDAY NIGHT ALONG WITH INCREASED
FRONTOGENESIS AS THE MID-LEVEL FRONT MOVES THROUGH THE FA. THIS
ALONG WEAK STABILITY AND SUFFICIENT MOISTURE SHOULD LEAD TO SOME
SHOWERS BEHIND THE FRONT SUNDAY NIGHT AND WILL MAINTAIN SOME MID
CHANCE POPS. SOME POTENTIAL FOR WET SNOWFLAKES TO MIX IN OVER
NORTHEAST NEB AFTER MIDNIGHT AS THE COLDER AIR RUSHES IN BUT WE
EXPECT NO ACCUMULATION. WITH THE POSITIVE TILT TO THE SYSTEM WE
SHOULD SEE MOISTURE AND LIFT QUICKLY EXIT THE AREA ON MONDAY AND
WE HAVE ENDED POPS BY 18Z WITH DRY CONDITIONS AFTER THAT. MONDAY
IS LIKELY TO BE A COLD RAW DAY WITH VERY WINDY CONDITIONS.
CONDITIONS QUIET DOWN FOR TUESDAY THROUGH THURSDAY WITH THE
PROGRESSIVE PATTERN LEADING TO A FLAT RIDGE EXPANDING EAST ACROSS
THE CENTRAL US. TEMPERATURES WILL SLOWLY RECOVER DURING THIS TIME.
THE NEXT SIGNIFICANT TROUGH WILL MOVE INTO THE WESTERN US LATE
NEXT WEEK AND WILL START TO INFLUENCE THE CWA TOWARD THE END OF
THIS FORECAST. WILL INCLUDE SOME SCHC POPS FOR DAY 7...BUT IT MAY
ACTUALLY END UP BEING MORE NEXT WEEKEND BEFORE WE SEE
PRECIPITATION FROM THIS SYSTEM.
BOUSTEAD
&&
.AVIATION...
18Z TAFS
GUSTY NORTHWEST WINDS WILL DECREASE QUICKLY THIS EVENING AND CUMULUS
CLOUDS SHOULD DISIPATE. SOME VARIABLE MID LEVEL CLOUDINESS EXPECTED
OVERNIGHT...WITH CEILINGS ABOVE 7000 FEET. HIGH PRESSURE AT THE
SURFACE WILL MOVE EASTWARD TONIGHT AND SATURDAY...WITH SOUTHEAST
WINDS INCREASING SATURDAY.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$