FXUS63 KOAX 152055
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
255 PM CST TUE FEB 15 2011
.SHORT TERM...TONIGHT THROUGH FRIDAY. WEAK WAVE MOVING THROUGH
THE REGION WILL BE EAST OF THE FORECAST AREA BY EARLY THIS
EVENING...AS AN ADVANCING WARM FRONT ESSENTIALLY WASHES OUT.
LATEST MODELS ARE SUGGESTING THAT ALL OF THE LOW LEVEL MOISTURE
SHOULD BE EAST OF THE AREA AS WELL...THUS SIGNIFICANTLY LOWERED
CLOUD FORECAST OVERNIGHT. STILL COULD BE AREAS OF FOG IN SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA THOUGH WERE HIGHER DEWPOINTS WILL
REMAIN OVERNIGHT AS THE NIGHT WEARS ON.
SOUTHERLY FLOW ON WEDNESDAY WILL TAP INTO HIGH LOW LEVEL MOISTURE
TO OUR SOUTH ON WEDNESDAY THOUGH...WITH INCREASING CLOUDS AS WE
HEAD INTO THE AFTERNOON. THE NAM ENVELOPS THE FORECAST AREA WITH
BOUNDARY LAYER SATURATED CONDITIONS WEDNESDAY NIGHT...WHILE THE GFS
LIMITS THE WESTWARD EXTENT OF THIS MOISTURE. NEVERTHELESS...FEEL
THAT SOME PATCHY DRIZZLE WILL BE POSSIBLE ACROSS SOUTHEAST NEBRASKA
AND SOUTHWEST IOWA THAT COULD LINGER INTO THURSDAY MORNING.
TEMPERATURES WEDNESDAY SHOULD WARM INTO THE 52 TO 62 DEGREE
RANGE...WITH THE COOLER READINGS STILL OVER NORTHEAST NEBRASKA
WHERE SOME VERY MINOR SNOW COVER STILL EXISTS. LOWS WEDNESDAY
NIGHT SHOULD BE FAIRLY MILD...WITH MOSTLY CLOUDY OR CLOUDY
CONDITIONS...AND READINGS IN THE LOWER 30S TO MID 40S ACROSS THE
FORECAST AREA.
A TROUGH IS FORECAST TO MOVE INTO THE REGION THE THURSDAY AFTERNOON.
TEMPS THIS DAY WILL BE TRICKY. LOW CLOUDS AND PATCHY DRIZZLE IN
THE MORNING IN THE SOUTHEASTERN FORECAST AREA COULD HINDER THE
WARMUP THERE JUST A BIT. THE WEST NORTHWESTERLY FLOW BEHIND THE
TROUGH SHOULD HELP TO BOOST TEMPS IN NORTHEAST NEBRASKA TO THE
LOWER 60S...AND TEMPS IN SOUTH CENTRAL NEBRASKA COULD REACH THE
UPPER 60S...BUT BELOW RECORD VALUES.
COOLER AIR FILTERS BACK ACROSS THE REGION ON FRIDAY BEHIND THE
FRONT WITH HIGHS BACK INTO THE 40S...BUT STILL ABOVE NORMAL. THE
NAM12 IS ABOUT THE ONLY MODEL THAT HINTS AT SOME POSSIBLE
SPRINKLES IN THE PLATTE RIVER VALLEY THURSDAY EVENING BEHIND THE
COLD FRONT. JUST NOT ENOUGH OTHER MODEL SUPPORT TO MENTION IN THE
FORECAST AT THIS TIME.
70
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY. FORECAST CHALLENGES CONTINUE
TO BE PRECIPITATION TYPE FROM SATURDAY NIGHT INTO MONDAY MORNING.
CONFIDENCE WITH MODEL SOLUTIONS IS ON THE LOW SIDE IN THE EXTENDED
PERIODS DUE TO FAIRLY DIFFERENT TIMING DETAILS...AND THERMAL PROFILES
THAT HAVE A BIG IMPACT ON PRECIP TYPE. THERE IS SOME AGREEMENT WITH
THE OVERALL PATTERN OF AN ANCHORING UPPER TROF NEAR THE WEST COAST
AND BROAD UPPER RIDING OVER THE CENTRAL US. THIS PUTS THE FORECAST
AREA IN SOUTHWEST FLOW WITH INCREASING MOISTURE ADVECTION INTO THE
REGION. VERTICAL MOTION MAINLY AS A RESULT OF ISENTROPIC LIFT
PROGRESSIVELY INCREASES STARTING SATURDAY AND CONTINUING INTO SUNDAY
NIGHT. AS UPPER LOW MOVES INTO PLAINS SUNDAY...DPVA AIDS THE LIFT
AND CHANCES FOR PRECIPITATION APPEAR TO INCREASE.
MOST OF THE FORECAST AREA SHOULD BE IN THE SYNOPTIC SCALE WARM
SECTOR IN THE LOWER TO MIDDLE TROPOSPHERE...THUS TEMPERATURES AROUND
850 MB WILL BE FAIRLY WARM AND WELL ABOVE 0C MOST AREAS. HOWEVER
THE CHALLENGE IS MORE WITH THE LOCATION OF THE SURFACE WARM FRONT
AND THE COOLER SURFACE AIR TO THE NORTH. ECMWF HAS CONSISTENTLY
KEPT THE WARM FRONT TO OUR SOUTH WHILE THE GFS ADVERTISES A MORE
NORTHERN POSITION...CUTTING THROUGH THE OAX FORECAST AREA. EVEN
WITH THE COOLER ECMWF SOLUTION...BELIEVE THE SOUTHERN THIRD OF THE
FORECAST AREA WILL REMAIN WARM ENOUGH FOR MOSTLY A RAIN EVENT
THROUGH THE WEEKEND. THE NORTHERN THIRD MAY BE FAR ENOUGH INTO THE
COLDER SURFACE AIR AND COOLER MID LEVEL TEMPERATURES SHOULD SUPPORT
MOSTLY LIGHT SNOW. IN THE MIDDLE...INCLUDING THE INTERSTATE-80
CORRIDOR... THERE WILL BE SOME CHANCE FOR MORE OF A MIX OF RAIN/SNOW
AND PERHAPS EVEN FREEZING RAIN ESPECIALLY SUNDAY MORNING.
ABOVE MENTIONED WARM FRONT POSITION AS WELL AS PRECIPITATION WILL
HAVE A LARGE INFLUENCE ON TEMPERATURES...AND LEANED TOWARD A
CONSENSUS.
NIETFELD
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$