Flood Potential Outlook
Issued by NWS San Juan, PR
FGCA72 TJSJ 020917
National Weather Service San Juan PR
517 AM AST Thu Mar 2 2017
...Spring Flood Outlook...
...The flood risk is near average for the western half of Puerto
Rico while across the eastern half of Puerto Rico as well as
Vieques, Culebra and the U.S. Virgin Islands the flood risk is
Current Stream Flows... The average streamflow from the U.S.
Geological Survey (U.S.G.S.) river gauge network indicates most of
the streamflows across the western half of Puerto Rico between the
25th and the 75th percentile which is in the normal range. There are
a few outliers running above the 76th percentile which is above
normal or much above normal. Across the eastern half of Puerto Rico
most of the streamflows are running below the 24th percentile which
is below or well below normal. Most of them are located across the
Carraizo and La Plata basins. There is no streamflow data for the
U.S. Virgin Islands.
Past Rainfall...Shower activity during the past few months has been
observed over and north of the Cordillera Central, Sierra de
Luquillo as well as the outlying islands. Based on the Advance
Hydrologic Prediction Service (A.H.P.S.) rainfall deficits are
reported across the hydrologic service area. The 90-day rainfall
deficits across the eastern half of Puerto Rico are between 2 and
8 inches with isolated areas near 16 inches. However, there is
also a 90-day rainfall surplus of 4 to 8 inches observed across
the northwest and western interior of Puerto Rico. Across the U.S.
Virgin Islands, and based on primary climatological data sites
such as Henry E. Rohlsen AP in Saint Croix and Cyril E. King AP in
Saint Thomas, rainfall deficits are near 2 inches.
SOIL MOISTURE...Soil moisture data from the Puerto Rico Agricultural
Water Management (PRAGWATER) indicates drier soils across the eastern
and southern areas of Puerto Rico. In general, this is consistent
with the 90-day rainfall pattern.
Fire...The Fire season has so far been relatively normal for this
time of the year. Climatologically...the southern slopes of Puerto
Rico and Saint Croix experience the warmest temperatures and the
driest soils during this season. The fuels across these areas are
expected to become available with the most significant fire weather
threat expected to continue for preferred areas along the south coast
and the dry forest area in southwest PR...particularly Guanica...Cabo
Rojo and around Camp Santiago.
Reservoirs...Based on data from the Water Authority and the U.S.G.S.
the major water supply reservoirs across Puerto Rico are in optimum
conditions but decreasing. This decreasing trend is normal during
the dry season.
Reservoir/Lake Sites Normal Pool
Pool Elev. Elev.
QUEP4 :LAGO GUAJATACA 646 : 639.36:
ARCP4 :LAGO CAONILLAS 826 : 824.15:
ARGP4 :LAGO DOS BOCAS 295 : 293.45:
LCSP4 :LAGO CARITE 84 : 80.87:
NARP4 :LAGO LA PLATA 155 : 166.66:
DRAP4 :LAGO DE CIDRA 1322 : 1322.09:
PLOP4 :LAGO LOIZA 132 : 133.64:
PASP4 :LAGO PATILLAS 222 : 209.77:
Future Rainfall...Climatologically, the dry season continues across
the local islands through March with a transition during April and
the onset of the wet season on May. Based on the CariCOF outlook for
the Caribbean region there is a chance to near or above normal
rainfall June through August.
As a result of these factors, there is a near average flood risk
across the western half of Puerto Rico with a below average flood
risk across the eastern half of Puerto Rico and outlying islands.