FXUS63 KOAX 250414
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1014 PM CST THU DEC 24 2009

.UPDATE...
ALL OF THE FORECAST AREA NOW IN A BLIZZARD WARNING OR WILL BE AT
MIDNIGHT. 

&&

.DISCUSSION...

SYSTEM CONTINUES TO PRODUCE BANDS OF SNOW. SNOW LIKELY TO CONTINUE
THROUGH FRIDAY. WINDS ARE STRONG ENOUGH TO CREATE LOW VISIBILITY
AND BLIZZARD OR NEAR BLIZZARD CONDITIONS. NO OTHER CHANGES TO
FORECAST.

&&

.PREV DISCUSSION... /ISSUED 442 PM CST THU DEC 24 2009/ 

..LET IT SNOW...LET IT SNOW...LET IT SNOW...AND LET THE CHRISTMAS
2009 BLIZZARD COMMENCE...

SHORT TERM...TONIGHT THROUGH SUNDAY. HAVE UPGRADED A LARGE
PORTION OF THE AREA TO A BLIZZARD WARNING...BASED ON HIGHER WINDS
THAN MODELS INDICATING ALREADY OCCURRING...ALONG WITH THE
COMBINATION OF HEAVY SNOW SETTING UP THAT IS EXPECTED TO MOVE
THROUGH THE REGION. STORM TOTAL SNOWFALL WILL RANGE FROM 6 TO
16...WITH THE HEAVIEST AXIS OF SNOW ORIENTED ALONG THE MISSOURI
RIVER. AFTER SOME CONCERN THAT THIS MIGHT BE SHIFTING EAST...THOSE
CONCERNS HAVE DECREASED SIGNIFICANTLY. IN OTHER WORDS...WE ARE
STICKING WITH OUR ORIGINAL THINKING. IF ANYTHING...WE MAY BE LIGHT
ON THE SNOWFALL...AS SNOWFALL TO LIQUID RATIOS ARE PROGGED TO BE
HIGHER THAN WHAT WEVE USED THUS FAR. HAVING SAID THAT...WITH SUCH
STRONG WINDS...AND POTENTIALLY STRONGER SUSTAINED WINDS THAN THE
LAST EVENT...MEASURING ACCURATELY IS GOING TO BECOME INCREASINGLY
DIFFICULT. 

INITIALLY...THE AXIS OF HEAVIEST SNOW...AT LEAST AN INCH PER HOUR...
WILL BE ORIENTED ALMOST SOUTH TO NORTH...AND THEN NORTHWEST TO
SOUTHEAST AS THE SURFACE LAW DRAWS NORTHEAST...THEN RETROGRADES TO
THE WEST AS THE TWO STREAMS BEGIN TO PHASE WITH EACH OTHER...EVENTUALLY
BECOMING ONE SYSTEM. SYNOPTICALLY...THERE WAS EXCELLENT MODEL AGREEMENT
TODAY BETWEEN NAM/GFS...PROVIDING THAT BOOST OF CONFIDENCE THAT WE
LACKED...ESPECIALLY AFTER THE MODEL FIASCO AT 00Z YESTERDAY. 

DUE TO A VTEC GLITCH...WE DID EXTEND THE BLIZZARD WARNING UNTIL
12Z SATURDAY...BUT FEEL THAT CONDITIONS WILL DEFINITELY BE
IMPROVING SOMETIME FRIDAY NIGHT. SOME LIGHT SNOW WILL ALSO LINGER
SATURDAY...BUT NOT MUCH ADDITIONAL MEASURABLE SNOW. THUS...THE
ENDING OF THE VARIOUS HEADLINES WILL LIKELY NEED ADJUSTMENT AT
SOME POINT...BUT WELL CROSS THAT BRIDGE MUCH LATER. ALSO...WE DID
LEAVE A COUPLE OF COUNTIES OUT OF THE BLIZZARD WARNING...IN
SOUTHEAST NEBRASKA DUE TO LIGHTER AMOUNTS OF SNOW...AND IN WEST
CENTRAL IOWA...DUE TO SOME CONCERN ABOUT STRENGTH OF WINDS AS YOU
HEAD FURTHER NORTHEAST. THOSE 4 COUNTIES MAY REQUIRE AN UPGRADE TO
A BLIZZARD WARNING.

LONG TERM...SUNDAY NIGHT THROUGH THURSDAY. DEEP AND SLOW-MOVING
STACKED LOW WILL PULL AWAY EAST OF THE GREAT LAKES BY SUNDAY
NIGHT...WITH SFC HIGH AND MID- TO UPPER-LEVEL RIDGING DEVELOPING
IN THE CNTRL US. WITH FRESH SNOW COVER ON THE GROUND...EXPECT SUN
NT/MON/MON NT TEMPS TO STAY QUITE COOL UNDER CLEARER SKIES AND
LIMITED MIXING. HAVE KEPT TEMPS WELL BELOW GUIDANCE. RIDGING IS
SHORT-LIVED AS SRN STREAM UPPER WAVE IS PROGGED TO MOVE ACROSS THE
SWRN STATES...BEFORE LIFTING NEWD TOWARD THE OH VALLEY. ECMWF
REMAINS DEEPER AND MORE AGGRESSIVE WITH PRECIP ASSOCIATED WITH THE
WAVE...WITH GFS SOLUTION FASTER/BROADER/WEAKER AND GFS ENSEMBLE
MEMBERS TRENDING SLOWER. LEANED TOWARD ECMWF SOLUTION FOR
NOW...AND INSERTED SCHC POPS ON TUES NT AND WED FOR SNOW MAINLY IN
THE SERN HALF OF THE CWA. INCREASED CLOUDS FOR TUES THROUGH WED NT
AS WELL...AS CLOUDIER CONDITIONS ARE LIKELY EVEN IF PRECIP TIMING
CHANGES SLIGHTLY. ECMWF/GFS HINT AT THE SRN STREAM WAVE BEING
ABSORBED INTO A DEEPENING ERN US TROUGH. RESULT FOR THE CWA WOULD
TREND DRIER BUT COLDER...AND HAVE NUDGED EXTENDED GRIDS IN THAT
DIRECTION.

AVIATION...
LIFR CONDITIONS EXPECTED...WITH BLIZZARD CONDITIONS DEVELOPING
IMMEDIATELY AT LNK/OMA...AND EVENTUALLY AT OFK.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...BLIZZARD WARNING UNTIL 6 AM CST SATURDAY FOR NEZ015-033-034-
     043>045-050>053-065>068-078-088>093.

     WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR NEZ011-012-
     016>018-030>032-042.

     BLIZZARD WARNING UNTIL 6 AM CST SATURDAY FOR NEZ011-012-016>018-
     030>032-042.

IA...BLIZZARD WARNING UNTIL 6 AM CST SATURDAY FOR IAZ043-055-056-069-
     079-080-090-091.

&&

$$

SHORT TERM...99