000 FGUS74 KEWX 050509 CCA ESFEWX TXC013-019-021-029-031-053-055-091-123-127-137-149-163-171-177- 187-209-255-259-265-271-285-287-299-323-325-385-453-463-465-491- 493-507-050830- HYDROLOGIC OUTLOOK...CORRECTED RAINFALL OCT-FEB NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 218 PM CST FRI MAR 4 2011 ...SPRING FLOOD OUTLOOK FOR SOUTH CENTRAL TEXAS... ...THE POTENTIAL FOR RIVER FLOODING WILL BE BELOW NORMAL THIS SPRING ACROSS THE HYDROLOGIC SERVICE AREA... ...EXISTING CONDITIONS... RAINFALL - RAINFALL HAS BEEN WELL BELOW NORMAL ACROSS THE WESTERN SECTIONS OF THE REGION SINCE OCTOBER 2010. ACROSS THE EASTERN PORTIONS OF THE AREA RAINFALL HAS BEEN LESS THAN 50 PERCENT OF THE AVERAGE. JANUARY WAS A WET MONTH...WITH ABOVE AVERAGE RAINFALL TOTALS FOR THE EASTERN SECTIONS OF SOUTH CENTRAL TEXAS WITH THE WEST REMAINING BELOW AVERAGE. MANY LOCATIONS WEST OF HIGHWAY 281 HAVE RECEIVED LESS THAN ONE INCH OF RAIN SINCE OCTOBER 2010. EAST OF HIGHWAY 281 MOST LOCATIONS HAVE RECEIVED 3 TO 6 INCHES. RAINFALL OCTOBER 1, 2010 TO FEBRUARY 28, 2011... RAINFALL(INCHES) NORMAL DEPARTURE FROM NORMAL AUSTIN MABRY 4.95 12.97 -8.02 AUSTIN BERGSTROM 6.09 13.77 -7.68 SAN ANTONIO 4.21 11.81 -7.60 DEL RIO 0.27 5.24 -4.97 SOIL MOISTURE - SURFACE MOISTURE REMAINS BELOW NORMAL OVER MOST OF THE HILL COUNTRY AND LOCATIONS ALONG OR NEAR THE RIO GRANDE. NEAR TO SLIGHTLY ABOVE NORMAL SURFACE MOISTURE CONDITIONS WERE PRESENT OVER THE EAST AND SOUTHEAST PARTS OF SOUTH CENTRAL TEXAS. GROUND WATER CONDITIONS - AQUIFER WATER LEVELS REMAIN NEAR SEASONAL AVERAGES...BUT BELOW VALUES OBSERVED AT THIS TIME LAST YEAR. THIS INCLUDES THE EDWARDS AQUIFER AND BARTON SPRINGS AQUIFER. RIVER FLOWS - RIVER FLOWS REMAIN NEAR OR SLIGHTLY BELOW NORMAL OVER MOST OF THE REGION. OVER THE WESTERN SECTIONS...SOME RIVER LOCATIONS ARE FLOWING MUCH BELOW NORMAL. RIVERS CURRENTLY CAN HANDLE A HIGHER THAN NORMAL VOLUME OF WATER DUE TO THE EXTENDED DRY SPELL. RESERVOIR CONDITIONS - RESERVOIRS AND LAKES REMAIN AT OR SLIGHTLY BELOW POOL LEVELS DUE TO LESS EVAPORATION AND LOW WINTER WATER USAGE. MEDINA LAKE IN MEDINA COUNTY REMAINS WELL BELOW NORMAL POOL DUE TO LESS INFLOW DURING THE SUMMER AND FALL OF 2010. INFLOWS REMAIN LOW INTO ALL AREA RESERVOIRS. ...DROUGHT CONDITIONS... SEVERE TO EXTREME DROUGHT CONDITIONS PREVAIL ACROSS THE RIO GRANDE AND RIO GRANDE PLAINS. THE AREAS IN EXTREME DROUGHT ARE LOCATED FROM DEL RIO TO NEAR ROCKSPRINGS TO UVALDE TO EAGLE PASS. MOST OF THE REMAINDER OF SOUTH CENTRAL TEXAS AND THE HILL COUNTRY ARE EXPERIENCING ABNORMALLY DRY TO MODERATE DROUGHT CONDITIONS. THESE CONDITIONS ARE EXPECTED TO PERSIST OR WORSEN THROUGH MAY. ...METEOROLOGICAL OUTLOOK... RAINFALL OPPORTUNITIES TEND TO INCREASE IN THE MARCH TO JUNE PERIOD BEFORE DRYER CONDITIONS ARRIVE IN JULY. DURING THE MARCH TO JUNE TIME FRAME IT IS COMMON FOR FRONTS TO STALL OVER THE REGION OR MOVE VERY SLOWLY. THESE SITUATIONS CAN CREATE SIGNIFICANT RAINFALL EVENTS. WITH LA NINA CONDITIONS EXPECTED THROUGH MAY...THEN A WEAKENING LA NINA INTO EARLY SUMMER...BELOW NORMAL PRECIPITATION WILL LIKELY CONTINUE. THERE ARE NO STRONG SIGNALS IN THE FORECAST THAT WOULD INDICATE THE WE WOULD...OR WOULD NOT...EXPERIENCE A SIGNIFICANT SPRING RAINFALL EVENT. THIS WILL HAVE TO BE MONITORED THROUGH JUNE. ...LONG TERM OUTLOOK... THE CLIMATE PREDICTION CENTER IS FORECASTING BELOW NORMAL SPRING RAINFALL AND ABOVE NORMAL TEMPERATURES THROUGH MAY. THE CURRENT LONG TERM OUTLOOK FOR SUMMER IS FOR NEAR NORMAL PRECIPITATION AND CONTINUED ABOVE NORMAL TEMPERATURES. THIS WOULD MAINTAIN RIVERS AT NEAR NORMAL OR BELOW NORMAL LEVELS. ...SPRING FLOOD OUTLOOK... RISES ON AREA RIVERS ARE COMMON IN SPRING DUE TO INCREASED RAINFALL. WITH DROUGHT CONDITIONS EXPECTED TO CONTINUE...MINOR FLOODING WOULD BE SEEN WITH HEAVY RAINFALL EVENTS...BUT SIGNIFICANT FLOODING IS NOT EXPECTED. INFORMATION USED TO COMPILE THIS FLOOD POTENTIAL OUTLOOK WAS PROVIDED COURTESY OF THE WEST GULF RIVER FORECAST CENTER...CLIMATE PREDICTION CENTER...THE UNITED STATES GEOLOGICAL SURVEY...THE U.S. DROUGHT MONITOR AND THE EDWARDS AQUIFER AUTHORITY. FOR MORE SPECIFIC HYDROMETEOROLOGICAL DATA... (ALL LOWER CASE) WEST GULF RIVER FORECAST CENTER...HTTP://WWW.SRH.NOAA.GOV/RFC/ AUSTIN/SAN ANTONIO FORECAST OFFICE...HTTP://WWW.SRH.WEATHER.GOV/EWX/ FOR DETAILED WEB INFORMATION CONCERNING RIVER STAGES AND FORECAST FOR SOUTH CENTRAL TEXAS... HTTP://WATER.WEATHER.GOV/AHPS2/INDEX.PHIP?WFO=EWX FOR PRECIPITATION ANALYSIS...HTTP://WATER.WEATHER.GOV/PRECIP/ FOR FORECAST PRECIPITATION...HTTP://WWW.SRH.NOAA.GOV/RFC/?N=WGRFCQPFPAGE $$ 10/31/08