Graphic for MPD #0067
MESOSCALE PRECIPITATION DISCUSSION 0067
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1000 PM EST TUE FEB 28 2017

AREAS AFFECTED...SOUTHEAST IL...SOUTHERN IND...SOUTHWEST OH

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

VALID 010300Z - 010800Z

SUMMARY...LINE OF EXPANDING MDT TO HVY RAINFALL APPROACHING AREAS
OF SATURATED SOILS AND GIVEN RATES NEAR 1.0"/HR MAY LEAD TO
LOCALIZED FLASH FLOODING CONCERN OVER THE NEXT FEW HOURS.

DISCUSSION...RADAR MOSAIC DENOTES A LINE OF INCREASING CONVECTION
EXITING SOUTHEAST IL EXPANDING A BIT WITH INCREASED MST
CONVERGENCE AND FLUX.  THIS WARM SECTOR BAND HAS DEVELOPED A
NARROW SFC MST CONVERGENCE BAND WHERE WINDS NORTH ARE BACKED AND
ARE RELATIVELY SLOWER WITH A WEAK SURFACE INFLECTION BETWEEN 1H2
AND FOA.  LOWER LEVEL PROFILE SUPPORTIVE OF MODEST 1000-1250 J/KG
MLCAPE AND WITH LOW 60S TDS AND COLUMN TPWS IN THE 1.25"
RANGE...THERE IS SUFFICIENT SUPPORT FOR RAIN RATES IN THE
1-1.25"/HR RANGE.  500-1000MB THICKNESS FIELDS SUPPORT EASTWARD
FORWARD PROPAGATION OF THE LINE THOUGH INDIVIDUAL DEEPER CELLS MAY
TRANSLATE A BIT NORTH ALLOWING FOR NARROW AREAS OF MAXIMIZED
TOTALS POSSIBLY AS HIGH AS 1.5".  BACKYARD TIPPING GAUGE AND NWS
MESONET OBSERVATIONS DENOTE 1 HOUR TOTALS ARE IN THE .9-1.25"
RANGE ACROSS S CENTRAL IL.  CURRENTLY VAD 850MB LLJ WINDS ARE
AROUND 50KTS PROVIDING STRONG FLUX INTO THIS LINE/BOUNDARY...BUT
IS FORECAST TO STEADILY INCREASE TO 60-65 KTS BY 06Z LIKELY TO
INCREASE RAINFALL EFFICIENCY AS THE CELLS REACH SE IN/SW OH.  THIS
AREA HAS COMPROMISED  FFG VALUES DUE TO PRIOR RAINFALL TODAY AND
SUGGEST THE SOILS COULD  ONLY SUPPORT 1 HR RATES OF .5" AND 3HR
LESS THAN 1.0". 

HI-RES GUIDANCE PARTICULARLY THE RECENT RUNS OF THE HRRR PRESENT
THE CURRENT RADAR OBSERVATIONS THE BEST AND SUGGEST THIS LINE TO
TRACK JUST SOUTH OF KIND TOWARD CMH THOUGH THIS APPEARS A BIT TOO
FAR NORTH AND WITH STRENGTHENING LLJ SUSPECT SOME SW BACKBUILDING
ON THE SW EDGE OF THE LINE POSSIBLE AND C-VECTORS TO SUPPORT A
SLIGHT SEWARD TREND FOR FORWARD PROPAGATION EVEN FURTHER INTO
LOWERED FFG.

NOTE: THERE IS ALSO INCREASING THREAT FOR BAND OF WARM SECTOR
CONVECTION EXPANDING OUT OF THE CONFLUENCE OF THE MS/OH RIVERS IN
THE NEXT FEW HOURS THAT WOULD TRANSLATE INTO THE OHIO RIVER
VALLEY. AS SUCH A SECOND DISCUSSION MAY BE FORTHCOMING DEPENDENT
ON NEXT FEW HOURS OF EVOLUTION/EXPANSION.

GALLINA

ATTN...WFO...ILN...ILX...IND...LMK...PAH...

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

LAT...LON   40228291 39488281 38788468 38448578 38018750
            38038887 39468751 39888575 40118464


Last Updated: 1000 PM EST TUE FEB 28 2017