NOAA Office of Satellite and Product Operations
Satellite Precipitation Message

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HIZ000-
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SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 03/16/21 0220Z
SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-683-1404
LATEST DATA USED: GOES 17 0200Z;SSMIS/AMSU;PHLI RAOB 00Z;RADAR 0135Z;FCS
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LOCATION...ISLAND OF OAHU IN THE STATE OF HAWAII...
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ATTN WFOS...HFO...
ATTN RFCS...AKRFC...
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EVENT...FLASH FLOODING OVER OAHU
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SATELLITE ANALYSIS AND TRENDS...SATELLITE IMAGERY IN THE VISIBLE CHANNELS SHOWS BLOSSOMING CONVECTIVE CLOUD ELEMENTS WITH DEVELOPING THUNDERSTORMS OVER OAHU AS UPPER LEVEL WINDS CARRY THE CIRRUS ANVIL TOPS OF THESE STORMS TO THE NORTHEAST, WHILE IR ANIMATION REVEALS COOLING TOPS OF THE STORMS. ADDITIONALLY, DIVERGENCE ALOFT IS EVIDENT BY THE EXPANDING NATURE OF THE CLOUD SYSTEM OVER OAHU. FIELDS OF SURFACE MOISTURE CONVERGENCE ARE STRONG OVER THE WESTERN HAWAIIAN ISLANDS; HOWEVER, THE GRADIENT BETWEEN THE MAXIMUM OVER NIIHAU AND THE MOLOKAI MINIMUM IS SIGNIFICANT BECAUSE THE DIVERGENCE PATTERN SEEN IN THE SURFACE MOISTURE CONVERGENCE CONTOUR NOW HAS SOMETIMES BEEN AN AREA WHERE EXCESSIVE RAIN OCCURS. THE ATMOSPHERE IS UNSTABLE WITH THE PHLI SOUNDING CAPE VALUE OF 2300 J/KG, NEGATIVELY-BUOYANT -7C LIFTED INDEX WITH PW QUANTITIES ESTIMATED BY SATELLITE SENSORS SSMIS/AMSU BETWEEN 1.3-1.4 INCHES OVER WHERE THE STORMS ARE DEVELOPING. THE BIG ISLAND HAS AN AREA OF CONVERGENCE AT THE SURFACE WITH PW VALUES 1.5 INCHES. SATELLITE IMAGERY SHOWS S/WV ENERGY MOVING AWAY FROM HAWAII AS AN UPPER TROUGH MOVES SOUTHEASTWARD TOWARD HAWAII, MEANWHILE AS UPPER WINDS SOUTH OF THE UPPER TROUGH MOVE FROM THE SW-TO-NE UPPER LEVEL DIVERGENCE OF MASS ALOFT, AS IT COMBINES WITH SURFACE CONVERGENCE, RESULTS IN UPWARD VERTICAL VELOCITY FIELDS THAT STRENGTHEN, GENERATE RISING CURRENTS OF AIR, RESULTING IN RAIN FALLING IN EXCESSIVE AMOUNTS, RESULTING IN MORE RAINFALL AND FLASH FLOODING. UNDER THIS PATTERN ALL HAWAIIAN ISLANDS ARE SUSCEPTIBLE UNTIL THIS STANDING ATMOSPHERIC WAVE MOVES AWAY FROM THE HAWAIIAN ISLANDS.
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SHORT TERM OUTLOOK VALID 0220-0820Z...HIGHER CONFIDENCE FACTOR
IN SHORT TERM OUTLOOK...0203Z RADAR ECHOES ARE STRONGER AND DBZ RADAR LEVELS ARE INCREASING ON THE NE SIDE OF OAHU AND OVER THE CENTRAL MAUKA AREAS OF THE ISLAND OF OAHU. FLASH FLOOD WARNINGS POSTED PRIOR TO THIS SATELLITE PRECIPITATION ESTIMATE OVER OAHU, IT IS BELIEVED THE THUNDERSTORMS WILL PERSIST WITH RAINFALL CONTINUING TO DEVELOP OVER THE ISLAND OF OAHU, BASED ON SATELLITE AND RADAR TRENDS; THEREFORE, FLASH FLOODING IS A CONTINUING CONCERN.
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....NESDIS IS A MEMBER OF NWSCHAT (NESDISSATELLITEPRECIP)....
....NESDIS IS A MEMBER OF 12 PLANET....
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FOR QUESTIONS AND COMMENTS CONCERNING THE SATELLITE
PRECIPITATION MESSAGES AND GRAPHICS PLEASE EMAIL
SSDPrecip@noaa.gov
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FOR PRECIP MESSAGES AND GRAPHICS ON THE WEB:
http://www.ospo.noaa.gov/Products/atmosphere/spe/
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FOR AUTOMATED SATELLITE PRECIPITATION ESTIMATES ON THE WEB:
http://www.star.nesdis.noaa.gov/smcd/emb/ff/CONUS.php
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LAT...LON 2233 16130 2230 15837 2233 15837 1891 15251 1885 15562

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