FXUS63 KOAX 120946
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
346 AM CST FRI NOV 12 2010
.DISCUSSION...
WIDESPREAD PRECIPITATION CONTINUES OVER THE SOUTHEAST HALF OR SO OF
OUR CWA IN AREA OF STRONG ISENTROPIC UPGLIDE IN 295-305K LAYER.
PRECIP HAS BEEN MAINLY RAIN...BUT REPORTS OF WET SNOWFLAKES AND ICE
PELLETS HAVE BEEN RECEIVED. NOT EXPECTING WIDESPREAD FROZEN
PRECIPITATION AND CERTAINLY NO ACCUMULATIONS THIS MORNING AS
TEMPERATURES REMAIN ABOVE FREEZING ACROSS ALL OF THE CWA. MUCH OF
THE PRECIP HAS ENDED FOR THE TIME BEING IN NORTHEAST NEBRASKA AS
RIGHT REAR QUAD OF UPPER JET STREAK LIFTS TO THE NORTHEAST.
HOWEVER IT LOOKS LIKE MORE PRECIPITATION IS ON THE WAS AS
WELL-DEFINED BAROCLINIC LEAF STRUCTURE NOTED ON WATER VAPOR IMAGERY
ROUNDS BASE OF UPPER TROUGH AND ROLLS NORTHEAST. THAT SYSTEM WAS IN
EASTERN NEW MEXICO THIS MORNING...AND SHOULD BE OVER NEBRASKA LATER
THIS AFTERNOON. THIS WILL HELP DEEPEN SURFACE LOW IN NORTHERN TEXAS
TODAY...WHICH WILL RIDE NORTHEAST THROUGH NORTHERN MISSOURI AND INTO
IOWA LATER TONIGHT. NAM IS FARTHER WEST WITH SURFACE LOW
TRACK...THUS WILL KEEP PRECIP IN OUR AREA LONGER SATURDAY...WITH
GFS/ECMWF LIFTING PRECIP OUT FASTER. AM NOT EXPECTING MUCH
DIFFERENCE IN POTENTIAL SNOW AMOUNTS WITH EITHER SOLUTION AS THE
SLOWER/FARTHER WEST NAM LINGERS WARM SURFACE LAYER LONGER THAN GFS...
THUS DURATION OF SNOW LOOKS TO BE SIMILAR.
RAIN WILL BE PROMINENT PRECIP TYPE THROUGH THE DAY ASIDE FROM A MIX
WITH SNOW DURING THE EARLY MORNING. TEMPERATURES WILL NOT MOVE MUCH
DURING THE DAY...HOLDING IN THE UPPER 30S TO MIDDLE 40S AS NORTHEAST
FLOW MAINTAINS GENERAL THERMAL PATTERN ACROSS THE CWA. AS SURFACE
LOW MOVES INTO MISSOURI TONIGHT...SURFACE FLOW WILL BECOME NORTHERLY
ACROSS THE NORTHERN CWA...BRINGING COLDER AIR INTO THE AREA. THIS
SHOULD BE THE START OF OUR CHANGE OVER TO SNOW...BEGINNING IN
NORTHEAST NEBRASKA DURING THE EVENING...THEN TO WEST CENTRAL IOWA
AND WESTERN PARTS OF SOUTHEAST NEBRASKA BY MIDNIGHT. A SLOW CHANGE
FROM WEST TO EAST WILL COMMENCE AFTER MIDNIGHT...WITH THE INTERSTATE
80 CORRIDOR SEEING SNOW BEFORE 12Z SATURDAY. PLENTY OF MOISTURE
WILL GET WRAPPED AROUND SYSTEM IN WARM CONVEYOR BELT EXTENDING FROM
MISSOURI INTO NORTHWEST IOWA. COMBINATION OF LIFT...MOISTURE...AND
COOLING NEAR-SURFACE TEMPS SUGGESTS OUR NORTHEAST CWA WILL HAVE THE
BEST CHANCE FOR ACCUMULATIONS ABOVE AN INCH OR SO...BASICALLY JUST
NORTH OF THE METRO AREA FROM TEKAMAH THROUGH ONAWA AND POINTS NORTH.
HAVE ABOUT A HALF INCH OF SNOW FROM OMAHA THROUGH LINCOLN AND UP TO
NORFOLK....WITH NEARLY 2 INCHES FORECAST NEAR/NORTH OF ONAWA IN
MONONA COUNTY IOWA. HIGHER AMOUNTS AND POSSIBLE HEADLINES ARE
FORECAST BY OFFICES SERVING NORTHWEST IOWA INTO SOUTHWEST MINNESOTA.
EXPECT LINGERING SNOWS SATURDAY MORNING IN OUR NORTHEAST CWA WITH
ADDITIONAL ACCUMULATIONS LESS THAN A HALF INCH.
FOR THE REST OF THE FORECAST...LITTLE WAS CHANGED FROM AFTERNOON
PACKAGE. WE REMAIN UNDER BROAD TROUGH REGIME WITH SEVERAL IMPULSES
RIDING THROUGH THAT FLOW. AND EACH OF THOSE BRINGS A LITTLE MORE
COLD AIR. MAY SEE FLURRIES OR LIGHT SNOW ON SUNDAY THEN AGAIN
MONDAY...BUT MODELS ARE ALL OVER THE PLACE WITH TRACK AND TIMING OF
SHORTWAVES. GFS/ECMWF ARE BEGINNING TO CONVERGE ON POSSIBLE SNOW ON
WEDNESDAY BUT TIMING AND LOCATION STILL HAVE TO BE WORKED OUT.
DERGAN
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
RAIN HAD OVERSPREAD THE AREA AT 06Z AND CONDITIONS ARE EXPECTED TO
DETERIORATE THROUGH 12Z AS LOWER LAYER SATURATES. WIDESPREAD IFR
CIGS AND VSBYS IN LIGHT RAIN OR A MIX OF RAIN AND SNOW LIKELY AFTER
12Z AND THROUGH THE REMAINDER OF THE FORECAST AS SURFACE WAVE OVER
THE SOUTHERN PLAINS LIFTS TOWARD THE LOWER MISSOURI VALLEY.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$