FXUS63 KOAX 082101
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
301 PM CST SAT JAN 8 2011
.SHORT TERM...TONIGHT THROUGH TUESDAY.
HIGH PRESSURE RIDGE EXTENDED FROM THE EASTERN DAKOTAS AND
MINNESOTA ACROSS IOWA INTO NORTHERN MISSOURI EARLY THIS AFTERNOON.
BROAD AREA OF LIGHT SNOW STRETCHED FROM WESTERN SOUTH DAKOTA INTO
CENTRAL PARTS OF NEBRASKA WITH THE EASTERN EDGE BRUSHING SOME
WESTERN COUNTIES OF THE CWA IN NORTHEAST NEBRASKA.
MAIN CONCERN WILL BE THE DEVELOPING SNOW EVENT FOR THE AREA AS
UPPER WAVE OVER THE NORTHERN ROCKIES TRANSLATES EAST DURING THE
PERIOD. MODELS NOT TOO DIFFERENT IN EVOLUTION OF THE SYSTEM WITH
AREAS TO OUR WEST SEEING EXPANDING AREA OF SNOW TONIGHT THEN
FOCUSING OVER NORTHERN PARTS OF THE CWA ON SUNDAY. SNOW THEN
CONTINUES ACROSS MOST OF THE AREA SUNDAY NIGHT INTO MONDAY NIGHT
BEFORE DIMINISHING LATE MONDAY NIGHT. LATEST THINKING IS FOR A
PROLONGED PERIOD OF SNOW ACCUMULATION WITH AMOUNTS IN THE 6-10
INCH RANGE BEFORE ENDING TUESDAY.
HAVE OPTED FOR ADVISORY HEADLINES AT THIS TIME AS AMOUNTS ARE NOT
EXPECTED TO MEET 12/24 HOUR CRITERIA AS WELL AS LACK OF STRONG
WINDS OR OTHER PRECIP TYPES TO COMPOUND TRAVEL PROBLEMS. DRY LOW
LEVELS WILL LIKELY HINDER SNOW DEVELOPMENT INITIALLY IN THE EAST.
NORTHWEST PART OF THE CWA EXPECTED TO SEE ACCUMULATING SNOW FIRST
AS DEEPER LAYER SATURATION OCCURS LATE TONIGHT...THUS ADVISORY IS
SPLIT INTO TWO GROUPS WITH THE NORTHWEST AREA STARTING AT 6AM
SUNDAY AND SECOND GROUPING FOR EASTERN AND SOUTHERN AREAS 6PM
SUNDAY. MAIN PERIOD OF SNOWFALL STILL LOOKS TO BE FROM SUNDAY
NIGHT THROUGH MONDAY BEFORE VERTICAL MOTION WEAKENS AS ENERGY
MOVES EAST OF AREA. EURO CONTINUES TO INDICATE STRONGER SURFACE
WINDS MONDAY NIGHT INTO TUESDAY THAN THE GFS OR NAM. SINCE CURRENT
WINDS ARE BASED ON NAM WILL HAVE TO ACCOUNT FOR THE STRONGER WINDS
IN LATER FORECASTS IF THIS TREND CONTINUES.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY.
EXTENDED FORECAST FOCUS IS MAINLY TEMPERATURES...AT LEAST FOR THE
BEGINNING OF THE EXTENDED...AS ARCTIC HIGH PRESSURE BUILDS DOWN
ACROSS CENTRAL PLAINS BEHIND OUR WELL-ADVERTISE PROLONGED SNOW
EVENT. WITH FRESH SNOW COVER WOULD EXPECT TEMPERATURES TO FALL
BELOW ZERO MOST AREAS BY WEDNESDAY MORNING...ALTHOUGH AIRMASS OVER
WESTERN CANADA THIS MORNING WAS NOT EXTRAORDINARILY COLD. THUS
ALTHOUGH LOWS WERE LOWERED A BIT BASED ON LAST SEVERAL RUNS OF
GUIDANCE...DID NOT GO QUITE AS LOW AS 12Z MEX JUST YET BECAUSE OF
CURRENT UPSTREAM TEMPS WELL INTO CANADA WERE MOSTLY ABOVE NORMAL.
LEANED TOWARD THE SLIGHTLY SLOWER SOLUTION OF 00Z ECMWF IN MOVG SFC
HIGH EWD ON THURSDAY...THUS KEPT TEMPERATURES A BIT COLDER THAN MEX
THEN. MODERATING TEMPERATURES STILL APPEAR IN ORDER FRIDAY AHEAD OF
NEXT ARCTIC FRONT WHICH IS SHOVED THROUGH FORECAST AREA FRIDAY NIGHT
BASED ON 00Z GFS MEAN. HOWEVER...ATTM DID NOT QUITE AGREE WITH MILD
H85 TEMPERATURES FOR FRIDAY PER 00Z ECMWF. INCLUDED SMALL SNOW POPS
WITH THIS FRONT FRI/FRI NGT NRN/NERN 1/2 ALTHOUGH MAIN ENERGY ALOFT
APPARENTLY WILL STAY PRETTY FAR TO OUR N. REINFORCING SHOT OF
ARCTIC AIR ON DAY 7...ALTHOUGH BASED ON LATEST MODEL DATA...QUICKLY
MODERATING.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VARIABLE FLIGHT CATEGORIES ARE EXPECTED OVER THE NEXT 24 HOURS. WE
WILL BEGIN WITH VFR OVER THE SITES AS DRY AIR MOVES IN FROM THE EAST
AS SFC HIGH PRESSURE MOVES SEWD OVER THE ERN DAKOTAS AND ERN NEB.
CIGS SHOULD BEGIN TO FALL TO MVFR AND EVENTUALLY IFR ONCE ATMOSPHERE
BECOMES SATURATED AND SNOW MOVES IN FROM WEST TO EAST. THE HEAVIEST
SNOWFALL OF THE PERIOD WL LIKELY OCCUR OVERNIGHT INTO SUNDAY MORNING
WITH A FEW INCHES OF ACCUMULATION POSSIBLE AT ALL THREE TAF SITES.
WINDS WILL BE OUT OF THE SOUTHEAST AT AROUND 10KTS SO NOT LOOKING
FOR MUCH BLOWING SNOW. VISIBILITIES WILL BE REDUCED IN AREAS OF SNOW
HOWEVER.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY FROM 6 PM SUNDAY TO 6 AM CST TUESDAY FOR
NEZ034-044-045-051>053-066>068-078-088>093.
WINTER WEATHER ADVISORY FROM 6 AM SUNDAY TO 6 PM CST MONDAY FOR
NEZ011-012-015>018-030>033-042-043-050-065.
IA...WINTER WEATHER ADVISORY FROM 6 PM SUNDAY TO 6 AM CST TUESDAY FOR
IAZ043-055-056-069-079-080-090-091.
&&
$$
FOBERT/CHERMOK/KERN