Graphic for MPD #0154

MESOSCALE PRECIPITATION DISCUSSION 0154
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
236 AM EDT SAT APR 29 2017

AREAS AFFECTED...SOUTHEAST MO...SOUTHERN IL...SOUTHERN
IN...SOUTHWEST OH...NORTHERN KY

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 290635Z - 291235Z

SUMMARY...TRAINING THUNDERSTORMS WITH INTENSE RAINFALL RATES WILL
CONTINUE PAST DAWN...WITH AREAS OF SIGNIFICANT FLASH FLOODING
LIKELY.

DISCUSSION...RADAR IMAGERY SHOWS AN AXIS OF TRAINING THUNDERSTORMS
EXTENDING FROM SOUTHEAST MO EAST ACROSS SOUTHERN IL...FAR SOUTHERN
IN AND ACROSS THE OH RIVER INTO FAR NORTHERN KY. THE ACTIVITY
REMAINS FOCUSED ALONG AND GENERALLY NORTH OF A STATIONARY FRONTAL
ZONE...HOWEVER SOME OF THE CONVECTION HAS ADVANCED INTO THE VERY
MOIST AND UNSTABLE WARM SECTOR SOUTH OF THE BOUNDARY AS NOTED WITH
SEVERAL SMALLER SCALE OUTFLOW BOUNDARIES ADVANCING EAST-SOUTHEAST
TO THE SOUTH OF THE OH RIVER. STRONG WARM ADVECTION OVER THE FRONT
CONTINUES AS A FOCUSED LOW LEVEL JET OF 50 TO 60 KTS INTERACTS
WITH THE BOUNDARY AND CONTINUES TO TRANSPORT AN ANOMALOUSLY MOIST
AND UNSTABLE AIRMASS NORTHEAST FROM THE LOWER MS VALLEY
REGION...WITH PWATS OF 1.5 TO 1.7 INCHES AND OVER 2000 J/KG OF
MUCAPE.

THE SATELLITE PRESENTATION OF THE CONVECTION IS VERY IMPRESSIVE
WITH THE EXPERIMENTAL GOES-16 10.3 MICRON/IR IMAGERY DEPICTING A
VERY LARGE AREA OF VERY COLD CONVECTIVE CLOUD TOPS...REACHING
NEARLY -80C...WITH NUMEROUS OVERSHOOTING TOPS EMBEDDED WITHIN THE
CONVECTIVE MASS. THIS IS INDICATIVE OF VERY STRONG FORCING WHICH
IS ENHANCED NOT ONLY IN THE LOW LEVELS GIVEN THE LOW LEVEL JET AND
ISENTROPIC ASCENT...BUT ALSO BROADLY DIFFLUENT FLOW ALOFT
ASSOCIATED WITH RIGHT-ENTRANCE REGION JET DYNAMICS.

SIGNIFICANT FLASH FLOODING WILL BE A MAJOR CONCERN THIS MORNING
ACROSS THE OH VALLEY AS TRAINING THUNDERSTORMS ARE EXPECTED TO
CONTINUE. THE LOW LEVEL FLOW WILL TEND TO VEER SOMEWHAT THROUGH
DAWN WHICH WILL ALLOW THE CONVECTION TO TEND TO FOCUS IN A GENERAL
W/E FASHION. GIVEN THE LEVEL OF CONVECTIVE ORGANIZATION AND COLD
POOL ENHANCEMENT...SOME BOWING OF THE CONVECTION A LITTLE SOUTH OF
DUE EAST WILL BE EXPECTED AS WELL...AND ESPECIALLY OVER AREAS OF
NORTHERN KY. RAINFALL RATES OF OVER 2 INCHES/HR CAN BE
EXPECTED...WITH ADDITIONAL RAINFALL TOTALS OF 3 TO 6 INCHES
POSSIBLE THROUGH DAWN.

ORRISON

ATTN...WFO...ILN...ILX...IND...JKL...LMK...LSX...PAH...RLX...

ATTN...RFC...LMRFC...NCRFC...OHRFC...

LAT...LON   39808480 39528318 38618270 37988294 37708363
            37558463 37418666 37168804 37068894 37178967
            37739028 38329001 38938922 39248820 39648659
           


Last Updated: 236 AM EDT SAT APR 29 2017