National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FOUS30 KWBC 200151
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
949 PM EDT SUN MAY 19 2013

...VALID 03Z MON MAY 20 2013 - 00Z TUE MAY 21 2013...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
30 ENE BIL 55 SW MLS 35 SSW MLS 15 NE MLS 35 NNW GDV 30 WNW ISN
10 SSW KD50 15 WNW CWEI 15 N CWPO 20 NNE CWGN 25 E HCO 10 S TVF
30 NNE JKJ JKJ 15 WNW FAR 35 SW RDR 15 N K46D 35 WSW K46D
15 E BIS 20 SSW KY19 20 ENE HEI 25 E 2WX 45 SSE 2WX 35 NNW RCA
35 NE IKA 10 N GCC 10 E BYG 30 WSW PIN 15 NNE GEY 40 S BIL
30 ENE BIL.

MADE SOME SLIGHT CHANGES TO THE PREVIOUS ISSUANCE..BUT STILL SEE A
THREAT FOR SOME FLOODING PROBLEMS PORTIONS OF THE NORTHERN PLAINS
BACK INTO THE NORTHERN ROCKIES..AND ESPECIALLY SO WHERE FF
GUIDANCE VALUES ARE QUITE LOW IN ND AND SOUTH-CENTRAL MT.  MOIST
INFLOW WILL CONTINUE TO FUEL DEFORMATION/DYNAMIC COOLING RAINS ON
THE BACKSIDE OF THE FAIRLY INTENSE AND SLOW MOVING CLOSED H5 LOW
OVER THE NORTHERN HI PLAINS AT THIS TIME.  THE REALLY HIGH PWS
WILL LIKELY REMAIN WELL TO THE SOUTH AND EAST WITH THE EXPECTED
CONVECTIVE DEVELOPMENT OVER THE MIDWEST AND UPPER MS VALLEY..BUT
LONG DURATION OF THE EVENT COULD POSE THE BIGGER CONCERN.  EXPECT
SOME 0.50-1.00 INCH RAINFALL AMOUNTS IN A 3-6 HOUR PERIOD..BUT
WITH SOME 1-2 INCH TOTALS POSSIBLE THIS ENTIRE PERIOD.



SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
10 ESE AXA FCM 15 ESE HZX 15 NE EVM 20 NE ELO 40 NNW CKC
30 W CYQT 10 S CYQT 45 NW CMX ARV 15 SW VOK 25 S MXO 25 S FFL
40 ESE LWD 15 E CSQ 10 ESE AXA.

SEE AN INCREASING POTENTIAL FOR SOME FLOODING PROBLEMS PORTIONS OF
THE MIDWEST INTO THE NORTHWESTERN GREAT LAKES..WITH THE MIDWEST
THREAT LIKELY THRU 06Z OR SO AND THE THREAT EXTENDING THRU THE
REMAINDER OF SUNDAY NIGHT IN THE NORTHWESTERN LAKES.  WEAKENING
BUT STILL DEFINEABLE MCV LIFTING NORTHEASTWARD INTO NORTHWESTERN
MO AT THIS TIME SHOULD HELP TO ENHANCE THE CONVECTIVE POTENTIAL
NEXT SEVERAL HOURS OVER IA AND INTO THE LATER SUNDAY NIGHT HOURS
IN THE NORTHWESTERN LAKES..WITH A WEAK FRONTAL BOUNDARY/EARLIER
OUTFLOW BOUNDARY TENDING TO FOCUS THE ACTIVITY.  AIRMASS OVER THE
MIDWEST IS QUITE UNSTABLE..LI`S AS LOW AS -10..AND MOIST..WITH PWS
ABOVE 1.50 INCHES..WITH A POTENTIAL K INDEX OF 48 AT DVN ATTESTING
TO THESE VERY MOIST AND UNSTABLE CONDITIONS.  WITH A CONTINUED
SOUTH-SOUTHWESTERLY LOW LEVEL JET OF 40+ KTS FORECAST INTO THE
REGION AT LEAST INTO 06Z..THE VERY MOIST AND UNSTABLE CONDITIONS
SHOULD PERSIST.  EXPECT THE POTENTIAL FOR SOME 1-2 INCH/HOUR
RAINFALL AMOUNTS ESPECIALLY OVER THE MIDWEST UNTIL ABOUT 06Z OR
SO..WITH LESSER RAINFALL RATES CONTINUING LATER SUNDAY NIGHT INTO
THE NORTHWESTERN LAKES REGION.

TERRY
$$