FXUS63 KOAX 260928
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
328 AM CST SAT FEB 26 2011
.DISCUSSION...
SNOW CHANCES TODAY...FREEZING DRIZZLE POTENTIAL TONIGHT...THEN
PRECIP CHANCES/TYPES SUNDAY AND SUNDAY NIGHT...ARE THE PRIMARY
FORECAST CONCERNS.
LIGHT SNOW CONTINUED TO FALL ACROSS MUCH OF THE CWA THIS MORNING AS
RIGHT ENTRANCE REGION OF 130KT 300MB JET WAS INDUCING ISENTROPIC
UPGLIDE ACROSS OUR AREA. MUCH OF THE BEST ACCUMULATING SNOW HAS BEEN
LIFTING NORTH THROUGH THE CWA OVERNIGHT...AND WAS FOCUSING ON
NORTHEAST NEBRASKA AND WEST CENTRAL IOWA. PATCHY FREEZING DRIZZLE
WAS ALSO REPORTED FROM TIME TO TIME IN OUR SOUTHWEST CWA. AND THEN
MORE SNOW WAS NOTED IN SOUTHWEST SOUTH DAKOTA AND NORTHWEST
NEBRASKA...AND THIS WAS MOVING EAST WITH WEAK UPPER IMPULSE
TRANSLATING EAST THROUGH SOUTH DAKOTA. ALL THE ABOVE IS EXPECTED TO
CONTINUE THROUGH THE MORNING AND INTO THE AFTERNOON...WITH HIGHEST
CHANCES FOR ACCUMULATION OVER OUR NORTHERN CWA WHERE ISENTROPIC
UPGLIDE IS MAXIMIZED AND SNOW TO THE WEST WILL EVENTUALLY ARRIVE.
SNOW AMOUNTS SHOULD REMAIN AROUND AN INCH OR LESS IN MOST AREAS.
SURFACE CHARTS SHOWED HIGH PRESSURE SETTLING THROUGH MINNESOTA THIS
MORNING...AND IS FORECAST INTO ILLINOIS THIS AFTERNOON. SOUTHERLY
LOW LEVEL FLOW ON THE BACK SIDE OF THIS HIGH WILL PROVIDE FOR WEAK
WARM ADVECTION OVERNIGHT. AND EXPANSIVE DECK OF LOW CLOUDS FROM
NEBRASKA INTO OKLAHOMA WILL PROVIDE FOR LOW LEVEL MOISTURE RETURN.
LIFT OVER THIS MOIST BOUNDARY LAYER WILL INCREASE OVERNIGHT AS LOW
PRESSURE INTENSIFIES IN THE LEE OF THE ROCKIES WITH APPROACH OF
UPPER LOW MOVING ACROSS THE FOUR CORNERS AREA. ONLY LOW LEVEL
MOISTURE NOTED ON FORECAST SOUNDINGS...SO EXPECT AT LEAST PATCHY
FREEZING DRIZZLE TO DEVELOP ACROSS THE CWA TONIGHT AND SUNDAY
MORNING. CURRENT FORECAST HAS THIS HANDLED WELL SO WILL NOT CHANGE.
UPPER LOW MOVING INTO THE PLAINS SUNDAY AFTERNOON AND NIGHT IS AGAIN
HANDLED SIMILARLY BY GFS AND ECMWF. HOWEVER THIS MORNING THESE
MODELS ARE TAKING TRACK A BIT FARTHER SOUTH THAN YESTERDAY. SURFACE
LOW IS FORECAST TO HUG THE KANSAS/OKLAHOMA BORDER THROUGH THE DAY
SUNDAY...THEN SWEEP THROUGH SOUTHERN MISSOURI SUNDAY NIGHT. THIS
TRACK ALLOWS COLDER AIR TO SETTLE INTO OUR SOUTHERN CWA...BUT
TEMPERATURES WILL REMAIN ABOVE FREEZING WELL INTO THE NIGHT. AND
PRECIPITATION SHIELD SHOULD BE FARTHER SOUTH AS WELL. THUS WILL
MAINTAIN A CHANCE FOR PRECIPITATION IN OUR SOUTHEAST HALF WHILE
REMOVING CHANCES IN THE NORTHWEST. RAIN IS THE MOST LIKELY PRECIP
TYPE BEGINNING SUNDAY AFTERNOON...WITH A TRANSITION FROM RAIN TO
SNOW ALONG INTERSTATE 80 SUNDAY EVENING...THEN IN THE FAR SOUTHEAST
AFTER MIDNIGHT. SPEED OF UPPER LOW SHOULD TAKE PRECIP EAST OF OUR
AREA BY MONDAY MORNING...AND LIMIT AMOUNTS OF SNOW TO WELL UNDER AN
INCH.
THE REST OF THE WEEK WILL BE DRY AS PER PREVIOUS FORECAST. HOWEVER
THE GFS AND ECMWF SUGGEST A FRONTAL SYSTEM MAY BRING PRECIP TO THE
AREA AROUND THURSDAY. TEMPERATURES SHOULD WARM INTO THE 40S BY MID
WEEK UNDER WEAK MID LEVEL RIDGING.
DERGAN
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
WEAK SHORTWAVES WILL CONTINUE TO AFFECT THE AREA INTO TONIGHT WITH
PERIODS OF MVFR CIGS AND PATCHY MVFR VSBYS IN LIGHT SNOW AS UPPER
JET REMAINS ACROSS THE REGION. SURFACE FLOW WILL BECOME SOUTHERLY
AFTER 18Z AS HIGH PRESSURE SHIFTS EAST.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$