FXUS63 KOAX 040848
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
248 AM CST FRI FEB 4 2011
.DISCUSSION...
COMPLEX FORECAST SCENARIO OVER THE NEXT FEW DAYS WITH MIXED WINTRY
PRECIPITATION POSSIBLE ON SATURDAY AS SURFACE LOW MOVES THROUGH
THE DAKOTAS...WITH WARM AIR ADVECTION ALOFT AHEAD OF THE NEXT COLD
SURGE. AHEAD OF THIS FEATURE...WEST SOUTHWEST WINDS SHOULD HELP BOOST
TEMPS INTO THE UPPER 20S TO MID 30S TODAY...WHICH WILL HELP INCREASE
LOW LEVEL BOUNDARY LAYER MOISTURE DUE TO SOME MELTING. AM CONCERNED
THAT FOG WILL DEVELOP OVERNIGHT...WITH THE POTENTIAL FOR SOME LIGHT
FREEZING DRIZZLE ACROSS THE MISSOURI RIVER VALLEY AS ISENTROPIC
LIFT ON THE 280K LAYER WITHIN AN AREA OF LOW PRESSURE CONDENSATION
DEFICITS IS PRESENT AHEAD OF A VERY WEAK SURFACE TROUGH. THIS
MIXED BAG OF PRECIP WILL STILL BE POSSIBLE SATURDAY...AS A WARM
BUBBLE ALOFT SLIDES THROUGH THE REGION. COULD SEE THE ENTIRE
SPECTRUM ON SATURDAY...WITH FREEZING RAIN OR SLEET IN THE
MORNING...BUT THEN CHANGING TO RAIN AS TEMPERATURES WARM IN THE
SOUTH AND WEST...BUT CHANGING TO SNOW IN THE NORTH AS COLDER AIR
BEGINS TO FILTER IN ON THE BACKSIDE OF A SURFACE LOW PRESSURE
CENTER THAT IS FORECAST TO MOVE INTO CENTRAL IOWA BY DAYBREAK
SUNDAY. THIS SETS THE STAGE FOR SOME LIGHT SNOW SATURDAY NIGHT
THROUGH SUNDAY NIGHT AS A SECONDARY UPPER CLIPPER MOVES INTO THE
REGION...AS THE SURFACE LOW SLOWLY MOVES THROUGH THE MID
MISSISSIPPI RIVER VALLEY. SNOWFALL AMOUNTS ARE FORECAST TO REMAIN
VERY LIGHT...AND SNOW SHOULD END ALTOGETHER BY DAYBREAK MONDAY AS
SURFACE LOW SHIFTS FAR ENOUGH EAST.
FOCUS THEN SHIFTS TO AN ARCTIC AIR MASS THAT CONTINUES TO OVERSPREAD
THE REGION MONDAY THROUGH THURSDAY OF NEXT WEEK...WITH PERIODIC
REINFORCING SURGES OF PROGRESSIVELY COLDER AIR. TRIED TO TWEAK
TEMPERATURES THROUGH MID WEEK BASED ON LATEST GFS AND ECMWF
TRENDS...BOTH OF WHICH ARE COMING IN SIGNIFICANTLY COLDER WHICH IS
SOMEWHAT CONCERNING. TRENDED TEMPERATURES DOWN...BUT MAY NOT HAVE
TRENDED DOWN FAR ENOUGH. THERE ALSO APPEARS TO BE ANOTHER SYSTEM
COMING OUT OF THE ROCKIES MONDAY NIGHT AND TUESDAY NOW...ABOUT 24
HOURS EARLIER THAN PREVIOUSLY FORECAST...THUS ADDED A SLIGHT CHANCE
OF SNOW TO SOUTHEAST NEBRASKA FOR THIS PERIOD...AND PUSHED IT JUST
A LITTLE FURTHER SOUTH OF THE FORECAST AREA BY TUESDAY NIGHT.
LATEST 00Z ECMWF PUSHES TEMPS TOWARD 10 TO 20 BELOW BOTH WEDNESDAY
AND THURSDAY MORNING...AND WILL HAVE TO MONITOR THIS TREND...
ALTHOUGH TRYING TO TIME AN ARCTIC SURGE THIS FAR OUT IS A SIGNIFICANT
CHALLENGE...WHICH WOULD BE DEPENDENT ON CLOUD COVER TOO.
DEWALD
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE FORECAST PERIOD...
ALTHOUGH MAY HAVE TO CONSIDER SOME MVFR FOG BY 05/06Z AND BEYOND.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$