Wind Advisory 9, NWS Omaha, NE

Fremont County, IA, Harrison County, IA, Mills County, IA, Monona County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Shelby County, IA, Antelope County, NE, Boone County, NE, Burt County, NE, Butler County, NE, Cass County, NE, Cedar County, NE, Colfax County, NE, Cuming County, NE, Dodge County, NE, Douglas County, NE, Knox County, NE, Lancaster County, NE, Madison County, NE, Otoe County, NE, Pierce County, NE, Platte County, NE, Sarpy County, NE, Saunders County, NE, Seward County, NE, Stanton County, NE, Thurston County, NE, Washington County, NE, Wayne County, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
318 AM CDT SAT APR 15 2006

.DISCUSSION...
SEVERE WEATHER THIS AFTERNOON/EVENING REMAINS THE PRIMARY FORECAST
CONCERN.

WINDS HAVE TURNED TO THE SOUTHEAST ACROSS THE CWA THIS MORNING...AND
WILL CONTINUE TO INCREASE THROUGH THE DAY AS LOW PRESSURE IN THE
HIGH PLAINS DEEPENS WITH APPROACH OF POTENT UPPER LEVEL WAVE. THAT
WAVE WAS APPROACHING THE FOUR CORNERS REGION THIS MORNING.  00Z
UPPER AIR CHARTS SHOWED 100-130M HEIGHT FALLS WITH THIS SYSTEM...AND
NUMEROUS LIGHTNING STRIKES SPREADING INTO COLORADO AHEAD OF IT LEND
TO ITS STRENGTH.  SURFACE PRESSURE FALLS WERE POINTING TO NORTHEAST
COLORADO AS EVENTUAL LOW CENTER...AND 00Z GFS/NAM CONCUR. IN FACT...
GFS AND NAM ARE IN BETTER AGREEMENT WITH SURFACE LOW TRACK THIS
AFTERNOON...BUT NAM IS STILL A TAD SLOWER PUTTING LOW CENTER IN
NORTH CENTRAL NEBRASKA AT 00Z SUNDAY WHILE GFS HAS THE LOW IN
NORTHEAST NEBRASKA. BOTH MODELS SEEM TO BE OVERDOING LOW LEVEL
MOISTURE RETURN...PAINTING LOW TO MID 60S SURFACE DEW POINTS
COVERING MUCH OF THE CWA THIS AFTERNOON. LATEST SURFACE OBS FROM
SOURCE REGION OF NORTHERN MISSOURI SUGGEST MID 50S ARE MORE LIKELY.
850 DEW POINTS ALSO LOOKED TO BE 2 OR 3C TOO HIGH THIS AFTERNOON.
THIS SAME SCENARIO OF OVER-FORECASTING LOW LEVEL MOISTURE PLAYED
ITSELF OUT WITH OUR LAST SEVERE WEATHER EPISODE.

HOWEVER EVEN WITH SOMEWHAT LIMITED MOISTURE...SEVERE PARAMETERS ARE
STILL IMPRESSIVE.  MODIFYING FORECAST SOUNDINGS FOR EXPECTED
MOISTURE/TEMPERATURES THIS AFTERNOON STILL YIELD CAPES APPROACHING
1500 J/KG. BULK SHEAR OF 50KT WITH MODEST INSTABILITY WILL FAVOR
SUPERCELL STORMS WITH LARGE HAIL AND DAMAGING WINDS LIKELY.
TORNADOES ARE POSSIBLE AS 0-1KM HELICITY IS FORECAST INTO THE
150-200 RANGE...BUT HIGHER LCL HEIGHTS WITH LOWER DEW POINTS MAY
HINDER DEVELOPMENT.

EXPECT SOME ELEVATED CONVECTION TO GET GOING LATER THIS MORNING AS
LARGE SCALE ASCENT OVERSPREADS THE REGION WITH APPROACHING WAVE.
THIS SHOULD LIFT NORTHEAST THROUGH THE AFTERNOON...ALLOWING SUNSHINE
TO WORK ON LOW LEVEL ATMOSPHERE. WARM FRONT CURRENTLY IN NORTHERN
KANSAS SHOULD LIFT NORTH OF INTERSTATE 80 THIS AFTERNOON AS DRY LINE
ADVANCES EAST WITH SURFACE LOW. EXPECT INITIAL AFTERNOON DEVELOPMENT
ALONG THE DRYLINE FROM NEAR ALBION TO BEATRICE AROUND 21Z WITH
STORMS GENERALLY TRACKING NORTHEAST.  SEVERE THREAT WILL CONTINUE
THROUGH THE EVENING BEFORE LINE OF STORMS LIFTS NORTHEAST OF THE CWA
BY 06Z OR SO. WRAP-AROUND SHOWERS SHOULD CONTINUE OVERNIGHT WITH
SOME LINGERING RAIN SUNDAY MORNING. MOST OF THE PRECIP WILL BE EAST
OF THE CWA BY SUNDAY AFTERNOON.

HAVE MADE VERY FEW CHANGES TO THE REST OF THE FORECAST AS MAIN
HIGHLIGHTS WERE HANDLED WELL IN PREVIOUS RENDITION. NEXT WAVE WILL
EJECT INTO THE PLAINS MONDAY/TUESDAY BRINGING A CHANCE FOR
THUNDERSTORMS THEN. FOR THE MIDDLE PART OF THE WEEK...GFS LOOKS TO
BE TRENDING TOWARD ECMWF SOLUTION IN TAKING UPPER LOW THROUGH THE
NORTHERN PLAINS RATHER THAN LINGERING IT IN THE CENTRAL PART OF THE
COUNTRY. THIS WOULD LEAD TO LESS OF A SHOWER CHANCE WEDNESDAY AND
THURSDAY...BUT ONLY SMALL CHANCES GOING NOW SO THOSE WERE LEFT
UNCHANGED.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

DERGAN

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1135 AM CDT SAT APR 15 2006

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-160645-
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-
1135 AM CDT SAT APR 15 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN
NEBRASKA AND SOUTHWEST IOWA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SEVERE THUNDERSTORMS ARE LIKELY THIS AFTERNOON AND EVENING OVER MUCH
OF EASTERN NEBRASKA AND SOUTHWEST IOWA. SEVERE THUNDERSTORMS WILL
LIKELY DEVELOP BETWEEN 4 AND 5 PM FROM AROUND OR JUST NORTHEAST OF
A COLUMBUS TO BEATRICE LINE. THE ACTIVITY IS EXPECTED TO TRACK
FAIRLY QUICKLY NORTHEAST...SPREADING ACROSS NORTHEAST NEBRASKA BY
7 PM OR SO AND THEN INTO SOUTHWEST IOWA.

SUPERCELL THUNDERSTORMS WITH LARGE HAIL AND TORNADOES ARE
ESPECIALLY POSSIBLE ON THE SOUTHERN END OF THIS AREA OF EXPECTED
DEVELOPMENT. STORMS ON THE NORTHERN END WILL LIKELY BE MORE IN
CLUSTERS AND INITIALLY BE LARGE HAIL PRODUCERS BUT AN ISOLATED
TORNADO ALSO REMAINS POSSIBLE. THE SEVERE THREAT WILL TURN MORE
TOWARD HIGH WINDS AND LARGE HAIL BY MID EVENING ALTHOUGH AN
ISOLATED TORNADO THREAT CONTINUES.

MODERATE INSTABILITY AND HIGH SHEAR VALUES WILL BE PRESENT OVER
MUCH OF THE OUTLOOK AREA BY LATE AFTERNOON. WHEN COMBINED WITH A
WARM FRONT FORECAST TO PUSH INTO SOUTHEAST NEBRASKA...AND A DRY
LINE MOVING IN FROM NORTH CENTRAL KANSAS...THE NECESSARY
INGREDIENTS FOR SUPERCELLS WILL BE PRESENT.

THE SEVERE THREAT SHOULD DIMINISH OR SHIFT EAST OF THE AREA LATE THIS
EVENING.

EVEN ABSENT THUNDERSTORMS...STRONG SOUTHEAST WINDS OF 25 TO 35 MPH
WITH GUSTS OVER 40 MPH CAN BE EXPECTED THIS AFTERNOON...ESPECIALLY
ALONG AND NORTH OF A LINE FROM ALBION TO NEBRASKA CITY TO CLARINDA IOWA.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THUNDERSTORMS ARE AGAIN POSSIBLE ON TUESDAY...WITH SOME STORMS
POSSIBLY SEVERE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL WILL BE REQUIRED THIS AFTERNOON AND
EVENING ACROSS MOST OF EASTERN NEBRASKA AND SOUTHWEST IOWA.

CHERMOK