721  
FGUS74 KHGX 202012  
ESFHGX  
210812-  
PROBABILISTIC HYDROLOGIC OUTLOOK  
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON, TX  
312 PM CDT THU APR 20 2017  
 
...ADVANCED HYDROLOGIC PREDICTION SERVICE (AHPS)  
PROBABILISTIC OUTLOOK FOR THE BRAZOS RIVER BASIN IN SOUTHEAST TEXAS...  
 
LITERAL:THE HOUSTON/GALVESTON NATIONAL WEATHER SERVICE OFFICE HAS  
IMPLEMENTED ADVANCED HYDROLOGIC PREDICTION SERVICE (AHPS) FOR THE  
BRAZOS RIVER BASIN IN SOUTHEAST TEXAS. AHPS ENABLES THE NATIONAL  
WEATHER SERVICE TO PROVIDE LONG-RANGE PROBABILISTIC OUTLOOKS.  
THIS SERVICE IS ALSO AVAILABLE ON THE INTERNET.  
 
IN THE TABLE BELOW...THE 90 THROUGH 10 PERCENT COLUMNS INDICATE THE  
CHANCE THE RIVER COULD RISE ABOVE THE LISTED STAGE LEVELS IN THE  
NEXT 90 DAYS. EXAMPLE: THE BRAZOS RIVER AT RICHMOND HAS A FLOOD  
STAGE OF 45 FEET. THERE IS A 50 PERCENT CHANCE THE RICHMOND  
FORECAST POINT WILL RISE ABOVE 38.8 FEET DURING THE NEXT 90 DAYS.  
 
CHANCE OF EXCEEDING STAGES AT SPECIFIC LOCATIONS  
VALID 04/19/2017-07/18/2017  
 
LOCATION FS(FT) 90% 80% 70% 60% 50% 40% 30% 20% 10%  
--------------------------------------------------------------------  
BRAZOS RIVER  
BRYAN 52.0 19.6 19.6 19.6 21.2 23.1 25.9 27.6 33.5 43.0  
EAST YEGUA CREEK  
DIME BOX 12.0 3.3 6.9 8.8 9.3 9.8 10.5 10.9 11.4 11.9  
MIDDLE YEGUA CREEK  
DIME BOX 10.0 2.9 8.3 9.4 9.8 10.2 10.9 11.3 12.6 13.3  
DAVIDSON CREEK  
LYONS 16.0 9.7 12.1 14.9 15.3 15.8 16.2 16.5 16.8 17.3  
NAVASOTA RIVER  
NORMANGEE 15.0 13.3 14.4 15.2 15.8 17.2 17.7 18.6 19.0 19.5  
LOWER BRAZOS RIVER  
HEMPSTEAD 50.0 35.2 23.3 35.2 38.0 41.3 45.4 50.3 52.5 53.9  
RICHMOND 45.0 33.3 33.3 33.5 36.2 38.8 42.6 45.4 46.7 51.0  
ROSHARON 43.0 36.3 36.3 36.5 38.8  
 
THIS LONG-RANGE PROBABILISTIC OUTLOOK CONTAINS NUMBERS THAT ARE  
CALCULATED USING MULTIPLE SCENARIOS FROM 50 YEARS OF HISTORICAL  
CLIMATOLOGICAL AND STREAM FLOW DATA. THESE NUMBERS ALSO TAKE  
INTO ACCOUNT CURRENT CONDITIONS OF THE RIVER AND SOIL MOISTURE.  
BY PROVIDING THE COMPLETE RANGE OF PROBABILISTIC NUMBERS...THE  
LEVEL OF RISK ASSOCIATED WITH LONG-RANGE PLANNING DECISIONS CAN  
BE DETERMINED.  
 
ADDITIONAL SUPPORTIVE DATA AND EXPLANATION ARE AVAILABLE ON THE  
INTERNET AT: WWW.SRH.WEATHER.GOV/CGI-BIN/AHPS.CGI!HGX  
(INTERNET ADDRESS IS ALL LOWER CASE).  
 
LONG-RANGE PROBABILISTIC OUTLOOKS ARE ISSUED AROUND THE THIRD  
THURSDAY OF EVERY MONTH.  

 
 
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