Winter Storm Warning 5, NWS Omaha, NE

Fremont County, IA, Harrison County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Shelby County, IA, Cass County, NE, Douglas County, NE, Gage County, NE, Jefferson County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Richardson County, NE, Saline County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Washington County, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
340 AM CST FRI DEC 21 2007

.DISCUSSION...
FIRST NEED TO ADDRESS FOG POTENTIAL THIS MORNING. 09Z OBSERVATIONS
SHOWED LOWEST VISIBILITES FARTHER EAST. 06Z NAM LOW LEVEL RH PROGS
KEEP IT THAT WAY. WILL STILL MENTION SOME FOG EASTERN ZONES...AND
CONTINUE THE ADVISORY IN SOUTHWEST IOWA. AT THIS TIME...IT DOES
NOT APPEAR AN ADVISORY IS NEEDED IN EASTERN NEBRASKA. WILL REISSUE
IF NEEDED. OTHERWISE...

MAIN FORECST CONCERN IS PCPN AND WIND WITH SYSTEM MOVING THROUGH
TONIGHT AND SATURDAY. POTENTIAL IMPACT SEEMS TO BE HIGHER TO THE
SOUTH AND EAST...SO CAN SEE WHY HEADLINES WERE ISSUED THERE. IT
STILL LOOKS LIKE MAINLY 1 TO 3 INCHES OF SNOW AT MOST IN OUR AREA...
ALTHOUGH IT APPEARS THERE COULD BE SOME BANDING SATURDAY MORNING.
THAT JUST ABOUT ALWAYS SEEMS TO ADD TO SOME LOCALLY HIGHER AMOUNTS.
DID NOT HAVE A MODEL PREFERENCE...AND IF ANYTHING LEANED TOWARD A
BLEND OF THE 03Z NCEP SREF AND THE 00Z ECMWF.

UPPER AIR CHARTS FROM 00Z SHOWED THE SYSTEM OVER THE ROCKIES WITH
500 MB 12 HOUR HEIGHT FALLS OF UP TO 130 METERS. JET MAX OF 115 KTS
WAS OVER UTAH. EACH MODEL RUN HAS HANDLED THIS SYSTEM JUST A LITTLE
DIFFERENTLY. NOT CONFIDENT THAT THEY EVEN HAVE A GOOD HANDLE ON IT
NOW. WATER VAPOR IMAGERY SHOWED A STRONG SYSTEM IN THE PACIFIC IN
THE VICINITY OF 40-50 N AND 140-150 W AND ANOTHER IN THE GULF OF
ALASKA. SHORTWAVE TROUGH NOW OVER ALBERTA WAS MOVING EAST...BUT
THE MODELS TRY TO DIG IT SOUTHEAST AND MERGE IT/PHASE IT WITH THE
SYSTEM NOW OVER CALIFORNIA. WILL STAY CLOSE TO PREVIOUS FORECAST...
BUT DID CHANGE TIMING A BIT. IT DOES NOT LOOK LIKE MUCH QPF WILL
OCCUR BEFORE 06Z TONIGHT. LEFT LIKELY POPS IN FOR LATER TONIGHT AND
SATURDAY MORNING. WITH STRONG WINDS DEVELOPING...LEFT MENTION OF
BLOWING SNOW. INITIAL PCPN COULD BE MIXED IN THE SOUTHEAST ZONES
AND COULD EVEN SEE SOME FREEZING DRIZZLE. WONT MENTION THAT AT
THIS TIME SINCE BIGGER PROBLEMS WILL PROBABLY BE WIND AND BLOWING
SNOW.

SINCE THINGS APPEAR TO BE STARTING A LITTLE LATER...THE PCPN WILL
PROBABLY CONTINUE LATER. SO INCREASED POPS A LITTLE FOR SATURDAY
AFTERNOON. EXPECT A NONDIURNAL TEMPERATURE CURVE TONIGHT AND
SATURDAY. TRIED TO DEPICT THIS IN THE HOURLY TEMPERATURES.
TEMPERATURES SHOULD DROP OFF BEHIND THE FRONT AND LOWS MAY NOT
OCCUR UNTIL MID MORNING SATURDAY. IT DOES NOT LOOK LIKE THERE WILL
BE MUCH RECOVERY DURING THE DAY...SO KEPT TEMPERATURES FAIRLY
CONSTANT.

DID NOT MAKE MANY CHANGES BEYOND MONDAY OTHER THAN JUST SOME MINOR
BLENDING.

&&

.AVIATION...
SFC RIDGE AXIS OVR CNTRL IA MAY BE CLOSE ENOUGH TO GIVE KOMA SOME
MVFR OR BRIEF IFR CONDS THRU 14Z...BUT WIDESPREAD IFR CONDS NO
LONGER LOOK LIKELY ATTM. OTHERWISE...SFC PRES GRADIENT WL CONT TO
INCREASE TODAY AS LO PRES DVLPS OVR THE WRN DAKOTAS. THIS SHLD ALLOW
FOR SERLY LO LVL FLOW TO DLVP AND INCREASE ACRS ALL 3 TAFS SITES
THRU THE DAY. WIDESPREAD IFR CONDS TO OUR E IS LIKELY TO START TO
PUSH WWD THRU THE DAY AND OVERSPREAD THE AREA BY LATE THIS AFTN.
UPPR LVL SYSTEM OVR THE WRN US WL START TO SPREAD EWD TONIGHT AND WL
MENTION SOME -SN AFTR 06Z SAT AT KOFK/KLNK BUT LEAVE KOMA DRY THRU
12Z SAT.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR IAZ043-055-
     056-069-079-080-090-091.

&&

DISCUSSION...MILLER
AVIATION...BOUSTEAD

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
148 PM CST FRI DEC 21 2007

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-221000-
MONONA-HARRISON-SHELBY-POTTAWATTAMIE-MILLS-MONTGOMERY-FREMONT-
PAGE-KNOX-CEDAR-THURSTON-ANTELOPE-PIERCE-WAYNE-BOONE-MADISON-
STANTON-CUMING-BURT-PLATTE-COLFAX-DODGE-WASHINGTON-BUTLER-
SAUNDERS-DOUGLAS-SARPY-SEWARD-LANCASTER-CASS-OTOE-SALINE-
JEFFERSON-GAGE-JOHNSON-NEMAHA-PAWNEE-RICHARDSON-
148 PM CST FRI DEC 21 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST
IOWA...WEST CENTRAL IOWA...EAST CENTRAL NEBRASKA...NORTHEAST
NEBRASKA AND SOUTHEAST NEBRASKA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

LIGHT SNOW AND STRONG WINDS WILL COMBINE TO PRODUCE HAZARDOUS
CONDITIONS LATER TONIGHT. NORTHWEST WINDS AND LIGHT
SNOW...POSSIBLY MIXED WITH FREEZING RAIN OR SLEET EARLY SHOULD
BEGIN AFTER MIDNIGHT IN NORTHWEST NEBRASKA...WITH NORTHWEST WINDS
INCREASING TO 25 TO 35 MPH WITH GUSTS TO 40 MPH.

A CONFERENCE CALL WILL BE HELD AT 230 PM THIS AFTERNOON FOR
EMERGENCY MANAGERS AND THE MEDIA AFFECTED BY WINTER STORM
CONDITIONS...MAINLY ALONG AND SOUTH OF A LINE FROM HARRISON TO
SAUNDERS AND SEWARD COUNTIES.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

SNOW IS EXPECTED TO END SATURDAY MORNING OVER NORTHEAST NEBRASKA...
WITH ACCUMULATIONS THERE EXPECTED TO BE MAINLY AROUND AN INCH OR
TWO. SNOW IS LIKELY ACROSS THE REMAINDER OF EASTERN NEBRASKA AND
SOUTHWEST IOWA DURING THE DAY SATURDAY. SNOWFALL AMOUNTS FROM 3
TO 5 INCHES ARE POSSIBLE BEFORE THE SNOW ENDS BY LATE SATURDAY
AFTERNOON OR EARLY SATURDAY EVENING.

STRONG NORTHWEST WINDS UP TO 40 MPH WILL CREATE AREAS OF BLOWING
SNOW...WHICH COULD CAUSE AREAS OF REDUCED VISIBILITY AND TRAVEL
PROBLEMS.

LISTEN FOR UPDATES ON THIS DEVELOPING WINTER WEATHER SITUATION.

SOME LIGHT SNOW IS POSSIBLE AGAIN BY TUESDAY NIGHT AND INTO THE
DAY ON WEDNESDAY.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTERS ARE ENCOURAGED TO REPORTS SNOWFALL AMOUNTS TO THE
NATIONAL WEATHER SERVICE IN OMAHA SATURDAY.

ZAPOTOCNY