FXUS63 KOAX 110424
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1024 PM CST FRI DEC 10 2010
.UPDATE...
UPDATED TO ISSUE SOME WINTER HEADLINES...LOWS TONIGHT AND PRECIP
AMOUNTS TNGHT AND SAT.
&&
.DISCUSSION...
VERY LITTLE TIME FOR DISCUSSION TONIGHT...BUT LATEST TRENDS FM THE
MODELS AND PER EVNG WV IMAGERY...THE SYSTEM IS TAKING A MORE SRN
ROUTE THRU THE PLAINS. THE SYSTEM ALSO IS LOOKING STRONGER THAN
PROGGED FOR OUR AREA. RAIN OVER NE NEB IS EXPECTED TO QUICKLY
CHANGE TO SNOW AFTER MIDNIGHT. AS THE UPPR LVL SYSTEM STARTS TO
CLOSE OFF AND DROP THRU WRN IA...DEFORMATION BAND IS EXPECTED TO
DVLP FM NE NEB INTO NW IA. THIS IS WHERE WE ARE EXPECTING OUR
HEAVIES ACCUMULATIONS. STG H6 FRONTOGENESIS AND WEAK STABILITY
WILL ALLOW FOR GOOD UVV FOR A 6 TO 12 HR TIME FRAME. QUICK GARCIA
METHOD ALLOWS FOR 3 TO 6 IN OVR FAR NE NEB...AND THIS SEEMS TO
AGREE WELL WITH MOST MODEL SOLUTIONS. DEFORMATION BAND...ONCE IT
DVLPS ON SAT MRNG...THEN EXPECTED TO DROP SWD THRU THE DAY ON SAT
WITH SN MOVG INTO TQE THEN OMA BY MID AFTN. GFS AND RUC ARE FAIRLY
CONSISTENT IN 925 MPH WINDS OF NEARLY 50 KT WHICH WILL LIKELY GIVE
NEAR HIGH WIND WARNING CRITERIA GUSTS DURING THE DAY ON SAT. THIS
COUPLED WITH THE NEW SNOW WILL CREATE BZ CONDS OVER NE NEB. THUS
HAVE ISSUED A BLIZZARD WARNING. SNOWFALL IS EXPECTED TO TAPER
FARTHER SOUTH DUE TO LIMITED MOISTURE AND THE DYNAMICS SHLD START
TO SHIFT EWD. AMOUNTS IN OMAHA ARE LIKELY TO BE LESS THAN AN
INCH. WHERE WE HAVE 1 TO 3 INCHES IN THE FORECAST /WHICH IS
BASICALLY A OFK TO HNR LINE/ WENT WITH A WINTER WEATHER ADVISORY
FOR SNOW AND BLOWING SNOW. KEPT THE WIND ADVISORY FARTHER S. HAVE
ALSO KEPT SOME MENTION OF SNOW AND BLOWING SNOW INTO SAT EVNG.
OTHERWISE HAVE INCREASED WIND SPEEDS IN THE GRIDS AND ALSO
INCREASED OVERNIGHT LOWS IN OUR SRN AND ERN CWA. WITH SRLY
WINDS...TMPS SHLD HOLD STEADY UNTIL THE FNT GETS HERE.
NO OTHER CHANGES PLANNED ATTM. WSW AND NPW ALREADY OUT. WILL GET
THE FORECAST UPDATED BY 1045 PM.
BOUSTEAD
&&
.PREV DISCUSSION... /ISSUED 258 PM CST FRI DEC 10 2010/
SHORT TERM...TONIGHT THROUGH MONDAY.
SFC OBS SHOWING LOW PRESSURE CENTERED OVER WRN SD STRENGTHENING IN
RESPONSE TO APPROACHING SHORTWAVE TROF CROSSING ERN MT PER WV IMAGERY
AND PROFILERS. MAIN ISSUES ARE SWD PUSH OF ARCTIC AIRMASS INTO THE
LOWER 48 TONIGHT/SAT ALONG WITH GUSTY NW WINDS AND POSSIBLE -SN.
NAM/GFS/CMC IN PRETTY GOOD AGREEMENT CAA SURGE SHOULD MAKE IT INTO
THE CWA AROUND 06Z TONIGHT AND QUICKLY SPREAD SWD THRU THE DAY SAT.
APPEARS THAT WIND ADVISORY CRITERIA WILL BE MET INITIALLY OVER THE
NRN CWA WITH FROPA...THEN REST OF CWA AROUND 12Z SAT. PRESSURE
GRADIENT PROGGED TO REMAIN TIGHT THROUGHOUT THE DAY...THUS WILL KEEP
WIND ADV HEADLINE IN EFFECT TILL LATE SAT AFTN. APPEARS THAT WIND
CHILL VALUES WILL NOT BE AN ISSUE UNTIL SAT NIGHT/SUNDAY MORNING TIME
FRAME...AND WILL LIKELY RESULT IN HEADLINES WITH VALUES EXPECTED TO
DROP TO THE 20 BELOW RANGE. FORTUNATELY...BRUNT OF SHORTWAVE FORCING
WILL PHASE WITH BEST AVAILABLE MOISTURE GENERALLY NORTHEAST OF THE
CWA. BUFKIT/COBB DATA PRETTY MUCH SHOWING CHANGE FROM -RA TO -SN WILL
BE QUICK THRU THE CWA LATE TONIGHT. -SN ACCUMULATION...AN INCH OR
LESS...IS PROBABLE AND GENERALLY ANTICIPATE THIS FROM ABOUT KNOX
COUNTY TO THE OMAHA METRO IN ERN NEB...MONONA/HARRISON/SHELBY CO IN
W-CNTRL IA. MODELS HANG ONTO BITTERLY COLD AIRMASS THRU SUNDAY.
SLIGHT WARMING THEN ON MONDAY WHEN LOW AMPLITUDE UPPER RIDGE TRIES TO
BUILD EWD INTO THE CNTRL PLAINS.
LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
HIGHLY AMPLIFIED UPPER FLOW STARTS OFF THE EXTENDED PERIOD WITH DEEP
TROUGH IN THE EAST AND RIDGING WEST...THEN FLOW BECOMES MORE ZONAL
DURING THE PERIOD AS SERIES OF WAVES MOVE THROUGH AND FLATTEN THE
RIDGE. SOME LIGHT PRECIP POSSIBLE AROUND TUESDAY OR WEDNESDAY AS
BAROCLINIC ZONE SETS UP OVER THE PLAINS BUT HAVE TRENDED DRY FOR NOW
BASED ON HPC GUIDANCE. TEMPERATURES LOOK TO STAY ON THE COLD SIDE
AND MAY NEED TO ADJUST DOWN IN LATER FORECASTS DEPENDING ON EXTENT
AND AMOUNT OF SNOWFALL THAT OCCURS OVER THE NEXT FEW DAYS.
AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS ARE EXPECTED THROUGH ABOUT 06Z. SOUTH TO SOUTHWEST
WINDS AHEAD OF A STRONG LOW PRESSURE SYSTEM WILL BRING VFR CIGS/SHRA
TO EASTERN NEBRASKA TAF SITES DURING THE EVENING. AS THE SYSTEM
MOVES EAST AFTER 06Z...A STRONG ARCTIC COLD FRONT WILL PASS KOFK
NEAR 07Z AND KOMA/KLNK BY 10Z. NORTHWEST WINDS 20 TO 30 KTS WILL
GUST TO 40KTS THROUGH 18Z BEHIND THE COLD FRONT. LIGHT SNOW COULD
ALSO ACCOMPANY THE STRONG WINDS CREATING MVFR VSBYS AT TIMES. CIGS
WILL ALSO DROP INTO THE FL010-020 RANGE BEHIND THE COLD FRONT. A
BRIEF PERIOD OF FREEZING RAIN IS POSSIBLE FOR ABOUT AN HOUR WITH THE
COLD FRONT...BUT AMOUNTS ARE EXPECTED TO BE QUITE LIGHT AT THE
SURFACE. HOWEVER MODERATE ICING IS LIKELY IN CLOUD LAYERS SFC-FL170
FROM 06Z THROUGH 18Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY FROM 9 AM SATURDAY TO MIDNIGHT CST
SATURDAY NIGHT FOR NEZ034-045.
WIND ADVISORY FROM 6 AM TO 9 PM CST SATURDAY FOR NEZ051>053-
066>068-078-088>093.
WIND ADVISORY FROM 2 AM TO 9 PM CST SATURDAY FOR NEZ030-042-043-
050-065.
WINTER WEATHER ADVISORY FROM 3 AM SATURDAY TO MIDNIGHT CST
SATURDAY NIGHT FOR NEZ016-017-031>033-044.
BLIZZARD WARNING FROM 3 AM SATURDAY TO MIDNIGHT CST SATURDAY
NIGHT FOR NEZ011-012-015-018.
IA...WINTER WEATHER ADVISORY FROM 9 AM SATURDAY TO MIDNIGHT CST
SATURDAY NIGHT FOR IAZ043-055-056-069.
WIND ADVISORY FROM 6 AM TO 9 PM CST SATURDAY FOR IAZ079-080-090-
091.
&&
$$