River Flood Warning 160, NWS Indianapolis, IN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
702 PM EDT WED MAY 7 2008

.AVIATION...

DISCUSSION FOR 00Z TAFS.

ACTIVE WEATHER PATTERN WILL BRING RAIN TO ALL TAF SITES FOR THE
MAJORITY OF THE NEXT 24 HOURS. CURRENTLY A SHIELD OF STEADY
MODERATE RAIN IS MOVING INTO THE AREA FROM THE SOUTH. IT SHOULD
OVERTAKE ALL SITES BY 02Z WITH VSBY IN THE MVFR CATEGORY. CIGS
WILL BE GENERALLY IN THE IFR CATEGORY. THE HEAVIEST RAIN AXIS WILL
SLOWLY SHIFT NORTHWARD OVERNIGHT SOT THAT CONDITIONS WILL
GRADUALLY GET WORSE TOWARDS 09Z...THEN SOME IMPROVEMENT AFTER 09Z
AT BMG. BETWEEN 12-14Z THE RAIN SHIELD SHOULD EXIT THE AREA AND
LEAVE SOME MVFR CIGS AND A FEW SCATTERED SHOWERS. THIS MVFR WILL
PERSIST UNTIL 19-21Z WHEN MORE RAIN AND THUNDERSTORMS MOVE BACK
IN.

&&

.PREV DISCUSSION... /ISSUED 230 PM EDT WED MAY 7 2008/

DISCUSSION...TONIGHT AND THURSDAY

SHORT TERM...SFC ANALYSIS EARLY THIS AFTERNOON SHOWS A CD FRONT
STRETCHING FROM EASTERN WI ACRS CENTRAL IL TO SRN MO. AN AREA OF LOW
PRES WAS FOUND NEAR TX/OK BOARDER. H2O VAPOR IMAGERY SHOWS A STREAM
OF GULF MOISTURE PUSHING ACRS THE LWR MISSISSIPPI RVR VALLEY INTO
MO...IL...TN..KY AND INDIANA. DEWPOINT TEMPS ACRS THE FA HAVE
REACHED THE MIDDLE 50S AND RADAR MOSAICS SHOW SCT TSRA ACRS SRN
INDIANA WITH MORE DEVELOPMENT AHEAD OF THE FRONT ACRS SRN IL AND SRN
MO.

GOOD RAIN EVENT IN STORE FOR THE NEXT 24 TO 36 HRS AS AN UPPER LOW
OVR THE SRN PLAINS WL PUSH ACRS THE OHIO VALLEY. GFS 300K ISENTROPIC
SFC SHOWS VERY STRONG UPGLIDE TONIGHT ALONG VERY STEEP INCLINE.
MOISTURE WILL NOT BE A PROBLEM AS MIXING RATIOS ALONG THIS SFC ARE
NEAR 8 G/KG AND WE CAN ALREADY SEE THE EFFECT IN THE DEW POINTS ACRS
THE AREA AND FROM THE H2O IMAGERY. GOOD 50 KNT LLJ WL BE STREAMING
INTO THE OHIO VALLEY TONIGHT AIDING THE LIFT. TOPPING THIS ALL
OFF...TIME HEIGHT SECTIONS SHOW GOOD FRONTOGENESIS AND LOWER LVL Q
VECTOR CONVERGENCE IS QUITE IMPRESSIVE. THUS WL GO WITH CATEGORICAL
POPS TONIGHT AND EARLY ON THURSDAY. BEST DYNAMICS BEGIN TO TAPER OFF
ON THURSDAY AFTERNOON...HENCE WL BEGIN A DECREASING TREND IN THE
POPS DURG THE AFTERNOON.

AS FOR TEMPS...WL LEAN WARMER BY A DEGREE OR TWO ON LOWS GIVEN THE
MOIST FLOW EXPECTED ALONG WITH DEWPOINTS ALREADY AT OR ABOVE MAVMOS
LOWS. GIVEN THE EXPECTED CLOUDS AND RAIN...THE COOLER MAVMOS APPEARS
TO HAVE A BETTER HANDLE THAN THE WARMER METMOS AND WL STICK CLOSE TO
THE MAVMOS.

LONG TERM...FRIDAY THROUGH WEDNESDAY

TODAYS SYSTEM EXITS STATE BY DAYBREAK FRIDAY THOUGH CONSIDERABLE
CLOUD COVER SHOULD LINGER DURING DAY IN COLD ADVECTION AND MODELS
WEAK SECOND WAVE MOVING ACROSS. FRIDAY MAX TEMPS NEAR GUIDANCE BUT
BELOW SEASONAL NORMS. WAVES PASSAGE AND SURFACE HIGH PRESSURE TO
BRING PARTLY CLOUDY CONDITIONS FRIDAY NIGHT INTO SATURDAY BEFORE
NEXT SYSTEM ARRIVES. MODEL RUNS HAVE BEEN WAVERING ON TRACK OF
WEEKEND WEATHER SYSTEM THOUGH TIMING APPEARS TO LOCK IN TO ONSET
SATURDAY NIGHT SO HAVE SLOWED PCPN START BY 12 HOURS. GFS HAS
TRACKED SURFACE AND UPPER SYSTEM FURTHER NORTH ON 06Z RUN AND BACK
FURTHER SOUTH ON 12Z RUN. THOUGH THIS SHOULD NOT IMPACT LIKELY
POTENTIAL FOR PCPN IT DOES IMPACT FCST TEMPS AND THREAT FOR THUNDER
SUNDAY. HAVE CONTINUED CURRENT FCST OF THUNDER POSSIBLE WITH SLIGHT
UPWARD ADJUSTMENT ON TEMPS GIVEN LAST NIGHT SOLNS BETWEEN EURO AND
GFS BEING SIMILAR AND SOMEWHAT FURTHER NORTH IN TRACK. MODELS AGREE
ON LULL IN PCPN EARLY NEXT WEEK BEFORE NEXT SYSTEM MIDWEEK. HAVE
COORDINATED WITH ADJACENT OFFICES IN BEGINNING NEXT PCPN TUE NIGHT.

&&

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

AVIATION...LAJ

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
708 AM EDT WED MAY 7 2008

INZ021-028>031-035>049-051>057-060>065-067>072-081030-
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-
708 AM EDT WED MAY 7 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL INDIANA.

.DAY ONE...TODAY AND TONIGHT.

THUNDERSTORMS ARE EXPECTED TODAY AND TONIGHT. HEAVY RAIN IS
POSSIBLE TONIGHT AND TOMORROW WITH OVER AN INCH AN A HALF
ACCUMULATED RAINFALL POSSIBLE. DEADLY CLOUD TO GROUND LIGHTNING
WILL BE THE MAIN THREAT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

THUNDERSTORMS ARE EXPECTED ON THURSDAY AND ALSO ON SATURDAY AND SUNDAY.
DEADLY CLOUD TO GROUND LIGHTNING WILL BE THE MAIN THREAT.

.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)

KOCH