EXCESSIVE RAINFALL DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
959 AM EDT MON APR 25 2011
 
...VALID 15Z MON APR 25 2011 - 12Z TUE APR 26 2011...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...
 

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
30 S OJC 20 ENE CDJ 35 S OTM 10 SSW MPZ 15 ESE EOK 20 N IJX AAA
10 S IKK 15 NE IRS ARB 25 SE MTC 10 ESE CXDI CYSN 20 ENE IAG
20 WNW ROC 30 ESE BUF JHW GKJ 15 N AKR 10 NE MFD 10 SW MNN WMO
20 NNE LOU FTK 25 NNE HOP 25 ESE NQA GLH 20 SE BAD 15 NW OCH
10 SSW PSN 20 E CRS 20 W 3T1 15 WSW PRX 30 SE AQR 15 NW AQR
10 NNW ADH 10 NNW SNL 20 SSW BVO 30 S OJC.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE
FROM
55 N JLN SZL 40 NNE DMO 25 NNW COU 30 E COU 15 N SET CMI
25 NW GUS 15 SSE ASW 15 E FWA 30 ESE FWA 20 SE AID 25 S BMG
20 ESE PAH 20 WNW UTA 25 WNW LLQ 35 W ELD 30 N DTN 40 NW DTN
15 WSW TXK 30 E DEQ 20 WNW MWT 10 SE FSM JSV 15 E MKO 15 SSE GCM
55 N JLN.

HIGH RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
40 NNE SGF AIZ 20 ENE VIH 25 SSW SUS CPS 30 S TAZ PRG 15 NE HUF
10 ESE HUF 10 SSW AJG 15 S HSB 25 SSE JBR 10 ESE SGT 25 SE M89
25 S M89 35 SSW M89 30 WSW M89 10 SE MWT 25 SSW RUE 10 W RUE
30 NW RUE 10 SE FYV 10 S XNA 20 NNW ROG 40 NNE SGF.

TOTAL RAINFALL AMOUNTS OF FIVE INCHES WILL BE POSSIBLE TO THE
RIGHT OF A LINE FROM 15 ENE JBR 20 SSE M19 SRC 20 N LRF
30 NNW LRF 20 ESE FLP 15 E UNO 30 SW FAM 25 SW SAR 15 SE SAR
10 WSW MDH CGI 20 SE POF 15 ENE JBR.

 
AFT LOOKING AT THE 06Z MDL GUIDANCE..12Z RAOBS AND RECENT
RADAR/SATL IMAGERY/TRENDS..SEE NO REASON TO DEVIATE FM EARLIER
ISSUANCE/THINKING.  THE MODEL QPF GUIDANCE CONTS TO ADVERTISE A
MAJOR EXCESSIVE RNFL EVENT..WITH THE STG DYNAMICS ASSOCTD WITH
CYCLOGENESIS OVR THE CNTRL U.S. AIDING THE SYNOPTIC SCALE LIFT. 
THERE IS STILL SOME UNCERTAINTY AS TO WHERE THE HVIEST RNFL AXIS
WL SET UP DUE TO ONGOING CNVCTN AND THE INTERACTION OF SYNOPTIC
AND MESOSCALE FORCING..BUT IN GENL XPC CONTG ISENTROPIC LIFT ALG
THE E/W ORIENTED BAROCLINIC ZONE AHD OF THE SFC LO AIDED BY FVBL
RT ENTRANCE REGION JET DYNAMICS..WITH A CONTG STG NWD MSTR FLUX
INTO THE FEATURE..TO SUPPORT THE HVY CNVCTV RAINS.  A 2ND LIFTING
MECHANISM WL BE FM A COMBO OF THE STG HGT FALLS AND ITS ASSOCTD
CYCLOGENESIS AS WELL AS THE EWD PUSH OF THE CDFNT.  BELIEVE THE
BEST COMBO OF ALL THE ABOVE MECHANISMS WOULD ARGUE FOR THE MID MS
VLY AREA BEING THE FOCUS FOR THE HEAVIEST ACTIVITY.  AMS IS
ALREADY QUITE MOIST AND UNSTABLE VCNTY OF THE LWR OH/MID MS
VLYS..AS PER THE OBSERVED K INDEX OF 40 AT LZK THIS MRNG.  XPC
WIDESPREAD 2 TO 3 INCH RAINS WITH THIS SYS..AND WOULD AGAIN NOT BE
SURPRISED TO SEE AMTS IN EXCESS OF 5 INCHES THRU THE PD OVR
LOCALIZED AREAS OF THE MID MS VLY.

TERRY
$$