Quantitative Precipitation Forecast
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
058
FOUS30 KWBC 220038
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
837 PM EDT WED SEP 21 2016

...VALID 01Z THU SEP 22 2016 - 12Z THU SEP 22 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
95 SSE HSE 25 SSW MRH 15 ENE ILM 20 WNW MYR 30 SSW FLO UDG
20 ESE HNZ 10 S WAL 80 ESE OXB.

MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
45 S BPI 50 W VEL 10 WNW U28 40 SE CNY 35 NNW CPW 20 SE CPW
30 W SKX 15 NW SAF 15 ENE 4SL 10 ESE FMN 15 SSW CEZ 20 S 4BL
40 WSW 4BL 10 ENE PGA 45 N GCN 35 ESE SGU 30 WSW CDC 75 WNW CDC
65 ENE TPH 15 ESE TPH 45 NNW TPH 45 NW P68 45 NE 9BB 15 N PIH
25 NW IDA 50 WNW IDA 45 E SUN 20 ESE SUN 20 NW SUN 30 ESE SNT
30 SE SMN 20 S BTM 25 SSW HLN 35 NE 3DU 30 SE GPI 20 NNE GPI
20 SSW CWFJ 30 SSE CTB 35 ESE GFA LWT 45 WNW JDN 40 NE OLF
35 W ISN 35 SSE OLF 50 S JDN 35 S BIL 55 NW RIW 45 S BPI.

MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
OTM 15 E ICL 45 S HSI 20 SSE ODX 30 NNW YKN 15 NE VVV
15 SSE AIT 10 WNW LNL 20 ENE SUE 30 WSW LDM ENW 30 E MLI OTM.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
10 S GHW 20 NE RZN 10 SE T08 10 SW ATW 10 WNW UNU 15 N DBQ
30 W DSM 10 W LNK 20 WSW OLU 30 ENE YKN 10 S GHW.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 SW MDZ 20 S ISW 15 NNW LNR 15 NNW ALO 20 W BNW DNS 10 S EST
HCD 20 WSW RPD 20 SW MDZ.


01Z UPDATE...


PLEASE REFER TO MPD #684 IN EFFECT UNTIL 0500Z FOR PORTIONS OF THE
UPR MS VALLEY.


...CENTRAL PLAINS AND MIDWEST / PARTS OF NE/SD/IA/MN/WI/IL...

TWO DISTINCT CONVECTIVE BANDS WERE NOTED AS 0F 00Z WITH A MORE
ELEVATED BAND JUST NORTH OF AN E/W FRONT ACRS SNR MN EXTENDING
ESEWD INTO WI..WHILE ANOTHER SLOW MOVING CLUSTER OF STORMS
CONTINUE TO FIRE NEAR THE WRN EDGE OF AN OLD OUTFLOW BNDRY FROM
EARLIER CONVECTION AND ON THE SRN EDGE OF STG MID LEVEL CAP.  A
WEAK S/WV NOTED ON SATL IMAGERY WORKING EWD FROM ERN NEB WILL HELP
TO RELEASE THE STGLY CAPPED INSTABILITY WORKING NEWD FROM WRN
IA/ERN NEB INTO THE FRONTAL ZONE/OUTFLOW BNDRY THIS EVENING WITH
THE MORE ORGANIZED STORMS AND POTNL FOR SLOWER MOVING E/W TRAINING
TO SETUP ACRS SRN MN..BUILDING SLOWLY S AND EWD THROUGH NRN IA
INTO WI LATER THIS EVENING.  RECENT HRRR SEEMS TO SUPPORT THIS
STGR AXIS ACRS SRN MN..WITH RECENT RADAR TRENDS SUGGESTING THE
MORE SRN AXIS FOR HEAVIER RAINFALL AS WELL.   STGLY DIFFLUENT
THICKNESS PATRN ALONG WITH 40 KTS OF SWLY FLOW ALL SUPPORT THE
POTNL FOR STG ORGANIZED CONVECTION WITH PWS IN EXCESS OF 1.75
INCHES BEING 2.5 TO 3 STANDARD DEVIATIONS ABOVE THE MEAN
INDICATIVE OF HEAVY RAIN RATES.  NO CHANGE WAS MADE TO THE MDT
RISK AREA BASED ON THE ABOVE..WITH HEAVY TO EXCESSIVE RAINFALL
AMOUNTS LIKELY IN THE VICINITY OF NORTHEAST NEBRASKA---CENTRAL TO
NORTHERN IA---SOUTHERN MN INTO SOUTHWEST WI.  LOCAL RAINFALL
AMOUNTS OVERNIGHT OF 2 TO 4"+ ARE POSSIBLE..ESPECIALLY OVER
PORTIONS OF SRN MN..NRN IA..INTO WRN/SW WI


...THE CAROLINAS AND SOUTHEAST VIRGINIA...

THE CLOSED LOW INITIALLY ALONG THE COASTAL NC/SC BORDER IS
EXPECTED TO BECOME INCREASINGLY SHEARED BUT HEAVIER RAIN BAND
NORTH OF THE UPR LOW HAS REMAINED RESILIENT.  THE MAIN SFC LOW
CONTINUES TO DROP SLOWLY SWD ACRS ERN SC...BUT MODEST ENELY FLOW
CONTINUES TO MAINTAIN LOCALLY HEAVY RAIN BANDS ACRS SE VA INTO NRN
NC..WHLE SOME WEAK INSTABILITY FARTHER SOUTH HAS ALLOWED FOR SOME
LOCALIZED CONVECTIVE CELLS OVER SRN NC.  WHILE THERE SHOULD BE A
GRADUAL WEAKENING OF THE HEAVIER RAIN BANDS OVERNIGHT AS THE
SYSTEM CONTINUES TO WEAK/SHEAR...GIVEN THAT MUCH OF SE VA AND NE
NC IS SATURATED FROM THE 5 TO 10+ INCH RAINS THAT HAS FALL OVER
THIS REGION..ANY ADDITIONAL RAIN WILL ONLY EXACERBATE EXISTING
FLOODING CONDITIONS.


...WESTERN U.S...

MODELS CONTINUE TO SHOW GOOD CONTINUITY AND AGREEMENT WITH THE
AMPLIFICATION OF THE UPPER TROF FROM THE PACIFIC
NORTHWEST---SOUTHWARD ALONG THE WEST COAST AND INLAND INTO THE
WESTERN PORTIONS OF THE GREAT BASIN.  THE MUCH ABOVE AVERAGE PW
VALUES THAT HAVE ALREADY PUSHED NORTHWARD INTO SOUTHERN
CALIFORNIA---THE SOUTHWEST AND THE SOUTHERN GREAT BASIN AHEAD OF
POST TROPICAL CYCLONE PAINE WILL CONTINUE TO PUSH NORTHEASTWARD
AHEAD OF THIS AMPLIFYING TROF ACROSS THE GREAT BASIN AND INTO THE
NORTHERN ROCKIES. THIS WILL BE SUPPORTING INCREASING PRECIP
COVERAGE THROUGH THE GREAT BASIN INTO THE NORTHERN ROCKIES WITH
WIDESPREAD MODERATE TO LOCALLY HEAVY PRECIP TOTALS EXPECTED. IN
THE 15Z UPDATE WE EXPANDED LOW PROBABILITIES AND MARGINAL RISK TO
INCLUDE MOISTURE ADVECTING INTO THE HIGHER TERRAIN OF SOUTHWEST
COLORADO AND NORTHERN NEW MEXICO...NOTING SUBSTANTIAL PW INCREASE
BETWEEN 00Z AND 12Z AND A MARGINALLY FAVORABLE HI-RES QPF SIGNAL.
ONE OF THE MORE INTRIGUING AREAS IS OVER PARTS OF NV/UT/ID...WHERE
THERE WILL BE SOME SENSE OF JET COUPLING THIS AFTERNOON AND A BIT
MORE SUBSTANTIAL HEIGHT FALLS SWINGING EASTWARD THROUGH NEVADA.
LAPSE RATES ARE STEEP...BUT MOISTURE MAY BE SUFFICIENT ONLY TO
GENERATE CAPE VALUES TOUCHING ON 500 J/KG...AND QUICK CELL MOTIONS
ARGUE FOR MAINTAINING ONLY LOW / MARGINAL PROBABILITIES OF
RAINFALL EXCEEDING FLASH FLOOD GUIDANCE.

SULLIVAN/BURKE/ORAVEC
$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.