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
000
FOUS30 KWBC 240146
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
945 PM EDT SAT AUG 23 2014

...VALID 03Z SUN AUG 24 2014 - 00Z MON AUG 25 2014...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 NNW COD 30 N WYS 25 NNE BTM 55 WNW GTF 25 ENE CWOE
40 ESE CWIK 40 NE BDE 10 SE CQM 10 SSW STC 10 E PQN 30 NNW ONL
30 E PHP 40 SSW KHZE 20 SSE GDV 25 NE PIN 15 ESE WRL 20 NNW COD.

MODERATE RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
40 SSE CWEH 30 E CYEN 10 SSE KD55 25 SW RDR 20 W K2D5 35 N BIS
25 E KS25 10 NE SDY 40 ESE JDN 40 W MLS 60 ESE BIL BIL
45 NNE BZN 30 NE GFA 40 SSE CWEH.

HIGH RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
50 SE HVR 55 SSW CWVN 30 WSW GGW 15 NW JDN 20 WSW JDN
55 WSW JDN 40 ESE LWT 25 NNE LWT 50 SE HVR.



...EASTERN FOOTHILLS OF THE NORTHERN ROCKIES INTO THE NORTHERN
PLAINS AND UPPER MISSISSIPPI VALLEY...

A SIGNIFICANT RAINFALL EVENT WAS UNDERWAY FROM THE THE EASTERN
FOOTHILLS OF THE NORTHERN ROCKIES EASTWARD INTO THE NORTHERN
PLAINS. BASED ON THE CURRENT GUIDANCE...RADAR/SATELLITE
TRENDS...AND 00Z SOUNDINGS...PULLED THE SLGT AND MDT RISK
NORTHWARD MAINLY IN PARTS OF THE DAKOTAS/EXTREME EASTERN MT WHERE
A DRY SLOT WAS NOSING INTO THE REGION.  OTHERWISE HAVE MADE NO
SIGNIFICANT CHANGE TO THE EXCESSIVE RAINFALL OUTLOOK ISSUED AT
18Z.

FLOW AROUND AN ANOMALOUS UPPER LEVEL FLOW WAS HIGHLY DIFLUENT AND
DIVERGENT AHEAD OF THE VORT MAX CURRENTLY LIFTING N/NNE ACROSS WRN
NE AND SWRN SD IS GENERATING A SEPARATE WIDESPREAD AREA OF
GENERALLY MODERATE RAINFALL ACROSS WRN SD AND WRN ND...WHILE
STEEPENING THETAE LAPSE RATES TO THE EAST WAS ENOUGH TO TRIGGER
DEEP CONVECTION AHEAD OF THE VORT MAX.  EAST OF THERE...AN
ENHANCED EXCESSIVE RAINFALL THREAT EXISTS ALONG THE N/NW PERIPHERY
OF THE INSTABILITY AXIS.  00Z SOUNDINGS FROM ABR AND BIS WERE 1.8
TO 2.0 INCHES...VALUES HIGHER THAN EARLIER FORECAST FROM THE ARW.

AS A RESULT OF THE ANOMALOUS COMBINATION OF FAVORABLE COOL-SEASON
DYNAMICAL FORCING ALONG WITH THE FAVORABLE THERMODYNAMIC
PROFILES...THE MODEL GUIDANCE...BOTH GLOBAL AND HIGH
RES...CONTINUE TO SHOW A STRONG SIGNAL FOR A SIGNIFICANT RAINFALL
EVENT ACROSS THE EASTERN FOOTHILLS OF THE NRN ROCKIES INTO THE NRN
PLAINS AND AT LEAST WRN PTNS OF THE UPPER MS VLY...WITH THE LATEST
SSEO MEAN PROBABILITIES OF EXCEEDING 3 AND 6 HOURLY FFG OVER 70
PERCENT IN THE HIGH RISK AREA ACROSS PORTIONS OF CENTRAL MT ALONG
THE WESTERN PERIPHERY OF THE TROWAL ZONE. 24 HOUR AREAL-AVERAGE
QPF WITHIN THE HIGH RISK AREA PER THE GLOBAL MODEL CONSENSUS
RANGES FROM 2.5 TO 5 INCHES...WHICH IS SUPPORTED BY THE SREF AND
GEFS PROBABILITIES OF 50% OR GREATER OF RECEIVING MORE THAN 3
INCHES IN 24 HOURS. AT THE SAME TIME...VIRTUALLY ALL OF THE HIGHER
RES GUIDANCE SHOW LOCALLY HIGHER AMOUNTS OF 6+ INCHES. FARTHER
EAST INTO THE DAKOTAS AND WRN MN...THE TOTAL RAINFALL IS EXPECTED
TO AVERAGE CLOSER TO 1-3 INCHES...HOWEVER GIVEN THE GREATER
INSTABILITY TO FEED OFF OF (ESPECIALLY IN THE EASTERN DAKOTAS AND
WRN MN)...THERE WILL MORE DEVIATION FROM THE MEAN WITH LOCALLY
HEAVIER...POTENTIALLY EXCESSIVE AREAS OF RAINFALL...SUPPORTED BY
THE ISOLATED 4-6+ INCH BANDS PER THE LATEST 4KM NAM CONEST... NSSL
WRF...AND WRF-ARW.

FOR FURTHER DETAILS REGARDING ANY ACTIVE MESOSCALE PRECIPITATION
DISCUSSIONS (MPD) WITHIN THE EXCESSIVE RAINFALL OUTLOOK AREA...
PLEASE REFER TO THE LINK FROM THE WPC HOME PAGE ABOVE THE TOP NEWS
OF THE DAY... OR GO DIRECTLY TO THE MPD PAGE:
WWW.WPC.NCEP.NOAA.GOV/METWATCH/METWATCH_MPD.PHP.

...IN TO NORTHERN KY...

MOTION OF THE STORMS ACROSS MUCH OF IN HAS BECOME HEAVILY COLD
POOL DRIVEN...RESULTING IN DIMINISHING RISK OF PROBLEMS DUE TO
PONDING OR RUN OFF.  THE 00Z SOUNDING FROM BNA SHOWED A MOIST
AIRMASS WAS ALREADY IN PLACE DOWN STREAM FROM THE CONVECTION IN
KY.  GIVEN THE ALIGNMENT OF THE CONVECTION COMBINED WITH THE
CONTINUED SOUTHWARD MOVEMENT...SOME PLACES MAY STILL HAVE BRIEF
RUN OFF OR PONDING PROBLEMS INTO THE LATE EVENING OUR EARLY
MORNING HOURS.
$$





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