Winter Storm in Iowa, April 6 to 7, 2003

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
330 AM CDT SUN APR 6 2003

FCST CHALLENGE BESIDES SNOW AMOUNTS WITH DVLPG STORM IS HOW TO
HANDLE FAR SERN ZONES.  GFS/ETA ARE PRETTY CLOSE IN LIFTING
NEGATIVELY TILTED 500 MB TROF INTO CNTRL PLAINS THEN CLOSING IT OFF
VCNTY OF ERN NEBR TNGT AND ARE ACCEPTABLE.

SHORT TERM...CURRENT WINTER STORM WARNING TDA/TNGT LOOKS GOOD MOST
OF CWA WITH MAIN CHALLENGE PINNING DOWN SNOW AMOUNTS.  QPF
CONVERSION FM 00Z ETA SUPPORTS GENERAL 6-10 INCH AMOUNTS WHICH MAY
BE LOCALLY ENHANCED WITH FRONTOGENETICAL BANDING OR CONVECTION
...SPCLY LATER THIS AM.  WL ADJUST WORDING SLIGHTLY TO ACCOUNT FOR
HEAVIEST AMOUNTS SRN ZONES TDA AND NRN ZONES TNGT.  CURRENT LACK OF
LOW LVL MSTR WOULD INDICATE A STG POSSIBILITY THAT WITH LIFT/EVAP
COOLING PCPN TYPE FAR SE WOULD BE FROZEN MUCH OF EVENT AND THIS IS
BACKED TO A LARGE DEGREE BY FCST SOUNDINGS.  HOWEVER...1000-500 MB
THICKNESS VALUES ARE A BIT WORRISOME AS THEY REMAIN RELATIVELY HIGH
FOR SNOW AND BUFKIT DOES SUGGEST SOME SLEET POSSIBILITY.  WITH
CURRENT CONVECTIVE NATURE TO PCPN SPREADING NWD WL MENTION SLEET IN
SERN ZONES.  THE SLEET...PSBL RAIN MIX AND SLGTLY WARMER TEMPS WOULD
LMT ACCUMULATIONS FAR SERN NEBR AND SO WL ADJUST SNOW AMOUNTS
DOWNWARD THERE AND CHANGE WINTER STORM WATCH TO WINTER WX ADVSRY
THRU TNGT.  OTRW WOULD EXPECT LTL TEMP CHANGE TDA. ALTHO WINDS COULD
BE BRISK AND CREATE SOME DRIFTING...OVERALL TRENDS AFT ONSET OF PCPN
WOULD BE FOR THEM TO GRADUALLY DECREASE LATE THIS AFTN INTO TNGT AND
THEY DONT APPEAR TO BE A MAJOR PLAYER WITH THIS STORM.

BOTH GFS AND ETA SLOW UPR LOW OVR FCST AREA MONDAY AND PIVOT AROUND
UPR ENERGY LATER THAT DAY INTO MON NGT.  THIS WOULD ALLOW NOT ONLY
FOR DEFORMATION BAND OF DECREASING INTENSITY SNOW TO LINGER INTO
MONDAY...BUT ALSO DELAY WARMUP A DAY OR SO.  MADE ADJUSTMENTS FOR
THAT INCLUDING ADDITIONAL SNOW AMOUNTS ON MONDAY...MAINLY N...AND
TRIMMED BACK TEMPS MON THROUGH TUE.  SINCE WINDS SHOULD BE
DECREASING TNGT INTO MONDAY WL NOT EXTD WARNING INTO MONDAY ATTM.

MADE LTL CHANGES TO REST OF FCST.  KNOCKED A FEW DEGREES OFF OF
TEMPS ON WED AS TUE COULD BE COOLER THAN EARLIER THOUGHT WITH
LESS MELTING BUT OTHERWISE WARMUP STILL EXPECTED.

THANKS FOR THE COORDINATION FSD...EAX...GID AND TOP.

.OMA...WINTER STORM WARNING TODAY AND TONIGHT FOR THE ENTIRE OAX CWA
EXCEPT NEZ088>093 WHERE A WINTER WEATHER ADVSRY WL BE POSTED FOR TDA
AND TONIGHT.

CHERMOK

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-061800-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1145 AM CDT SUN APR 6 2003

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

.DAY ONE...TODAY AND TONIGHT

A WINTER STORM WARNING REMAINS IN EFFECT FOR A LARGE PART OF
EASTERN NEBRASKA AND SOUTHWEST IOWA THROUGH TONIGHT.  A WINTER
WEATHER ADVISORY CONTINUES FOR THE SOUTHERN PART OF SOUTHEAST
NEBRASKA.  A MIXTURE OF SNOW...SLEET AND SOME FREEZING RAIN WILL
AFFECT THE AREA ALONG AND NORTH OF INTERSTATE 80...WITH A MIXTURE
OF RAIN AND SNOW OR SLEET TO THE SOUTH.  A FEW THUNDERSTORMS ARE
ALSO POSSIBLE INTO THIS EVENING OVER SOUTHEAST NEBRASKA.

TOTAL SNOWFALL AMOUNTS WITH THIS SYSTEM THROUGH TONIGHT ARE
EXPECTED TO RANGE FROM 6 TO 12 INCHES IN A LARGE PART OF THE
WARNING AREA...AND MAINLY LESS THAN 4 INCHES IN THE ADVISORY
AREA.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

SOME LIGHT SNOW WILL LINGER OVER THE AREA MONDAY....MAINLY NORTH
OF A LINE FROM COLUMBUS TO OMAHA.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTER REPORTS OF SNOW AMOUNTS WOULD BE VERY HELPFUL TODAY
AND TONIGHT.

MILLER