NWS-SPC: Excessive Rainfall Likely Nebraska- South Dakota

I just put up the weather stuff as it comes across- whether the layperson can understand the jargon or not. Any questions- just use the comments feature below or email me.

The areas on the map below are forecast to get whacked with "excessive rainfall" from this Tuesday morning until 7 am Wednesday morning.

EXCESSIVE RAINFALL DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER
CAMP SPRINGS MD 1020 AM EDT TUE JUN 12 2007

...VALID 15Z TUE JUN 12 2007 - 12Z WED JUN 13 2007......

REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM DVL BVN ITR IEN WEI DVL.
SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM 25 ESE ASG 10 NNW GMJ 30 NW GMJ 25 SSW UKL 25 SW FOE 20 S FOE 25 NE UKL 50 ENE CNU 30 NNE JLN 15 WNW SGF 25 NW BPK 20 E HRO 25 SW HRO 25 ESE ASG.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM ABR ODX 45 N ITR D07 40 E N60 ABR.

HIGH RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM ONL 35 SSW IML PHP BIS ONL.

UPDATE...OVER THE NRN TO CNTRL PLAINS...NO CHANGES MADE TO THE PREVIOUS EXCESSIVE RAINFALL POTENTIAL OUTLOOK. SEE PREVIOUS DISCUSSION BELOW.

OVR SERN KS/SWRN MO/FAR NWRN AR... A SLIGHT RISK WAS ADDED FOR THEONGOING CONVECTION THAT HAS FIRED TO THE NORTH OF THE STNRY FRONTAL BNDRY STRETCHING FROM THE SRN PLAINS INTO THE LOWER MSVALLEY. THIS CONVECTION IS MOVG SLOWLY TO THE SOUTH ACRS REGIONS THAT RECEIVED HEAVY RAINFALL YESTERDAY. ISOLATED SHRT TERM PCPN AMTS OF 1"+ POSSIBLE WITH THIS CONVECTION. NOT A LOT OF CONFIDENCE WITH THE EVOLUTION OF THIS CONVECTION...WHICH BOTH THE NAM AND GFS ARE NOT DEPICTING WELL.

OUR FIRST IMPRESSION IS THAT THIS CONVECTION WILL WEAKEN BY EARLY AFTERNOON AS THE LOW LEVEL FLOW BACKS TO A MORE SELY DIRECTION PARALLEL TO THE STNRY FRONTAL BNDRY...REDUCING OVERRUNNING OF THIS BNDRY. THE THREAT REGION ACRS SW TX WAS DISCONTINUED AS CONVECTION THAT AFFECTED THIS REGION OVERNIGHT HAS WEAKENED.
...ORAVEC

PREVIOUS DISCUSSION......CNTRL/NRN PLNS...VRY STAGNANT MID/UPR FLOW REGIME WL CONT TO SUPPORT STG/DEEP LYR SRLY FLOW THRU THE REGION THAT WL TAP INTO AN EPAC/GULF MSTR SOURCE. MDLS SHOW PWS OF 1.50-1.75 INCHES THRU THE CNTRL U.S..THESE VALUES ARE 2-3 STDS ABV NRML. THIS MSTR COMBINED WITH A STG LLJ IS SUPPORTG MSTR FLUX ANOMALIES OF 3-5 STDS ABV NRML. VALUESOF THIS MAGNITUDE ALMOST ALWAYS SUPPORTS VRY HVY RNFL. SHRTWVENERGY EJECTG FM THE NRN ROCKIES WL PHASE WITH ENERGY COMG OUT OFTHE SRN ROCKIES WITH A POTENT UPR JET COUPLET FORMG OVR THE CNTRL HI PLNS THIS AFTN AND LIFTG ENEWD TNGT. THE ASSOCD SFC BNDRY WL PUSH INTO THE PLNS WITH THE ATMOS AHD OF THE BNDRY BCMG UNSTBL WITH LIS OF MINUS 2-4. BNDRY LYR MSTR CVRG WL ALSO INCRS. MDLS SHOW VRY SLOW CELL MOTIONS LATER TDA/TNGT THAT WL CONTRIBUTE TO SOME STNRY CNVCTN AND ASSOCD VRY HVY RNFL AMTS. CONCERNS FOR THIS AREA ARE THE ONGOING MCS OVR NEB...WHICH IF IT DOES NOT WEAKEN TDA...COULD IMPACT THE AREA BY BLOCKG MSTR FLUX NWD. ALSO...THEMIDLVL SHRTWV OVR THE SRN ROCKIES SEEMS TO BE MOVG NEWD QUICKER THAN THE LATEST GUID INDICATES AND THIS COULD RESULT IN AN ERLR START TO CNVCTN OVR THE CNTRL HI PLNS WHICH COULD ALSO RESULT INSOME BLOCKAGE OF MSTR FLUX INTO THE NRN PLNS AND HVIER RNFL AMTS A LITTLE FARTHER S THAN INDICATED. RNFL RATES OF TWO INCHES PER HRARE PSBL WITH A FEW SPOTS IN THE 4-5 INCH RNG....SWRN TX...ONGOING CNVCTN ACRS THE REGION WL SLOLY MOV NEWD THRU THE MRNG AND EVENTUALLY WEAKEN. THIS ACTVTY IS BEING FUELED BY DEEP EPAC/GULFMSTR WITH MDLS SHOW PWS ARND 1.50 INCHES. SHRTWV ENERGY MOVG THRU THE SRN ROCKIES WL MOV NEWD THIS MRNG WITH THE STGR HGT FALLS LIFTG NWD. XPCT LCLZD 1-2 INCH RNFL INTO THIS MRNG THAT WL CAUSE LCL RUNOFF PRBLMS...ESPCLY OVR THE HIER TERRAIN.
...ECKERT

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