River Flood Warning 17, NWS Indianapolis, IN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
535 AM EST SUN FEB 21 2010

.AVIATION...DISCUSSION FOR THE 12Z TAFS.

OVERVIEW...POOR FLYING CONDITIONS AS MVFR CONDITIONS ARE EXPECTED TO
DETERIORATE TO IFR OR LIFR DURING THIS FORECAST PERIOD.

ONGOING MVFR CONDITIONS EXPECTED TO DETERIORATE AS RADAR TRENDS
SUGGEST RA ACROSS ILLINOIS TO PUSH EAST ACROSS CENTRAL INDIANA. IFR
OR WORSE CEILINGS OVER CENTRAL ILLINOIS ON THE NORTH SIDE OF THE
WARM FRONT ARE EXPECTED TO PUSH ACROSS CENTRAL INDIANA BY MID
MORNING ALONG WITH ONGOING RAIN FOR MUCH OF THE DAY.

AS THE TAF SITES WILL REMAIN ON THE NORTH SIDE OF THE WARM FRONT
THROUGH MUCH OF THE DAY...NO IMPROVEMENT IS EXPECTED. NAM 300K
ISENTROPIC SURFACE SHOWS STRONG UPGLIDE LATE THIS AFTERNOON AND
TONIGHT ACROSS CENTRAL INDIANA. FURTHERMORE AS THE LOW PRESSURE OVER
OKLAHOMA APPROACHES INDIANA...A STRONG LLJ OF 35-50 KNTS WILL BE IN
PLACE ACROSS INDIANA THIS EVENING AIDING RA DEVELOPMENT. FORECAST
SOUNDINGS AND TIME HEIGHT SECTIONS SHOW VERY MOIST LOWER LEVELS
ALONG WITH GOOD LIFT THROUGH MUCH OF THE PERIOD.

&&

.SHORT TERM...
MAIN FOCUS OF SHORT TERM CONTINUES TO BE THE SYSTEM PROGGED FOR
TONIGHT/TOMORROW MORNING.

LATEST MODELS ARE CONTINUING WITH THE MORE NORTHERLY TRACK OF
AFOREMENTIONED SYSTEM. THIS WOULD TAKE THE 700MB LOW JUST NORTH OF
CENTRAL INDIANA. CONFIDENCE IN ALL RAIN EVENT HAS
INCREASED...HAVING A HARD TIME FINDING ANY SUPPORT FOR ANY WINTER
PRECIP ACROSS THE NORTHERN COUNTIES AS WELL. ABOVE FREEZING FORECAST
SOUNDINGS AND WARM SURFACE TEMPERATURES ARE MAKING IT HARD TO
JUSTIFY ANY TYPE OF WINTRY MIX AT THIS TIME.

TIME CROSS SECTIONS ARE INDICATING THE STRONGEST LIFT BETWEEN MON
00Z AND MON 12Z. SO...STARTED INCORPORATING INCREASED POPS FURTHER
EAST A BIT EARLIER...AROUND SUN 18Z. OTHERWISE...AGREE WITH
CURRENT TREND IN GRIDS. WILL NOT SEE A CHANGE OVER TO SNOW OR
RAIN/SNOW MIX UNTIL MONDAY AFTERNOON...WHEN COLD AIR ON THE BACK
SIDE FILTERS IN. SO...KEPT A SLIGHT CHANCE FOR SNOW SHOWERS
THROUGH TUESDAY TO ACCOUNT FOR WRAPAROUND MOISTURE. NORTHERN
PORTIONS OF AREA COULD SEE A DUSTING OF SNOW.

OTHERWISE...AS FAR AS TEMPS...STUCK CLOSE TO GUIDANCE AND WENT
WITH A BLEND.

LONG TERM...TUESDAY THROUGH SATURDAY
ARCTIC AIRMASS IN PLACE OVER THE REGION FOR MUCH OF THE EXTENDED AS
EASTERN U S UPPER TROUGH REESTABLISHES WITH POLAR VORTEX DIVING INTO
THE GREAT LAKES MIDWEEK. POLAR VORTEX ARRIVES OVER THE LOWER
GREAT LAKES WEDNESDAY AND THURSDAY WITH A REINFORCING SHOT OF COLD
AIR AND ADDITIONAL OPPORTUNITIES FOR SNOW SHOWERS. APPEARS LOW
LEVEL WIND FIELDS ALSO BECOME FAVORABLE FOR SOME LAKE MICHIGAN
ENHANCEMENT TO SNOW SHOWERS BY THURSDAY AS THE POLAR VORTEX MOVES
OFF TO THE EAST...ESPECIALLY OVER NORTHEAST COUNTIES.

POLAR AND SUBTROPICAL JETS WILL PHASE WITH LOW PRESSURE DEVELOPING
AND DEEPENING RAPIDLY OFF THE NEW ENGLAND COAST THURSDAY NIGHT. THIS
MAY SERVE TO KEEP SNOW SHOWERS AND CLOUDS ACROSS THE REGION ON THE
BACK SIDE OF THE POLAR VORTEX INTO FRIDAY BEFORE HIGH PRESSURE CAN
TAKE HOLD. UNDERCUT MOS GUIDANCE FOR TEMPS THROUGH THE PERIOD WITH
HIGHS IN THE UPPER 20S AND 30S.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

SHORT TERM...TDUD
LONG TERM...RYAN
AVIATION...JP

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
854 AM EST SUN FEB 21 2010

INZ021-028>031-035>049-051>057-060>065-067>072-221400-
CARROLL-WARREN-TIPPECANOE-CLINTON-HOWARD-FOUNTAIN-MONTGOMERY-
BOONE-TIPTON-HAMILTON-MADISON-DELAWARE-RANDOLPH-VERMILLION-PARKE-
PUTNAM-HENDRICKS-MARION-HANCOCK-HENRY-VIGO-CLAY-OWEN-MORGAN-
JOHNSON-SHELBY-RUSH-SULLIVAN-GREENE-MONROE-BROWN-BARTHOLOMEW-
DECATUR-KNOX-DAVIESS-MARTIN-LAWRENCE-JACKSON-JENNINGS-
854 AM EST SUN FEB 21 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL INDIANA.

.DAY ONE...TODAY AND TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

RAIN WILL TRANSITION TO SNOW ON MONDAY NIGHT AS COLDER AIR FILTERS
BACK INTO THE REGION. SNOW ACCUMULATIONS WILL BE MINIMAL. CHANCES
FOR LIGHT SNOW WILL CONTINUE THROUGH THURSDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

&&

MORE INFORMATION...ALONG WITH OTHER WEATHER...HYDROLOGICAL AND
CLIMATE INFORMATION CAN BE FOUND...AT HTTP://WEATHER.GOV/IND (ALL
LOWERCASE)