The remnants of frontal boundary remained across the region. Moisture, in combination with daytime heating and local effects, resulted in showers and thunderstorms activity flooding roads and low areas.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS SJU wrote it up.
The remnants of frontal boundary remained across the region. Moisture, in combination with daytime heating and local effects, resulted in showers and thunderstorms activity flooding roads and low areas.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS San Juan, PR wrote its last area forecast discussion before the first event at Mar 25, 12:03 PM AST, 3 hours 22 minutes earlier.
Area Forecast Discussion
National Weather Service San Juan PR
1203 PM AST Sun Mar 25 2018
.UPDATE...Winds have shifted somewhat on the southeast side of the
boundary. They are now more easterly. This has induced a change in
shape of the boundary and allowed it to shift further south toward
San Juan and further northeast toward and over Aguadilla. In these
area showers have been light to moderate and relatively
persistent. The boundary is expected to move northwest into the
Atlantic northwest of Aguadilla. Showers should not grow in
intensity there for the time being.
Conditions are mostly cloudy over western Puerto Rico and
convection there should be delayed or pre-empted. Nevertheless
should sun break through heating is expected to set off more
showers south of the Cordillera Central or in the vicinity of
Mayaguez. Stability is expected to limit any thunderstorm
formation to single events if any and only over land areas in
western Puerto Rico.
&&
.AVIATION...MVFR/IFR conds persisting in NW PR and over TJBQ as
well as TIST should relent aft 25/17Z but CIGS blo 050 may cont
til aft 25/21Z in SHRA with mtn obscurations. Elsewhere conds
VFR. Drier air will move as far east as the ern third of PR by
26/02Z effectively ending MVFR/SHRA. SHRA to cont over Atlantic
waters for approach.
&&
.MARINE...Seas are showing signs of having peaked at both 41043
and 41053. Small craft advisories are still expected to be lifted
by 8 PM AST as seas drop below 7 feet in the northern portion of
our local outer Atlantic waters. The next northerly swell is still
expected to reach the local Atlantic waters Wednesday with seas
increasing near 8 feet and occasional seas up to 10 feet. The high
risk of rip currents will continue along the north coast of Puerto
Rico through at least Monday night.
&&
.HYDROLOGY...Rio Camuy appears to have trouble draining into the
ocean and is backed up near route 119. Emergency managers confirm
that if it rains much more it will expand onto the highway. It
looks like rain in this area is diminishing and should not
contribute much more to the river level.
&&
.PREV DISCUSSION... /issued 455 AM AST Sun Mar 25 2018/
SYNOPSIS...There is a chance for shower and thunder activity
across the forecast area through at least Wednesday. Expect
frequent passing showers across windward areas as well as
afternoon showers with thunderstorms developing over and south
of the Cordillera Central each day. A drier and stable air mass
is expected to encompass the area on Thursday.
SHORT TERM...Today through Tuesday...
The remnants of a frontal boundary will remain across the region
today before dissipates on Monday. Latest satellite images depicted
a layer of low to mid level cloudiness across the region in
association with the remnants boundary. This moisture in combination
with daytime heating and local effects will provide sufficient
instability across the forecast area today. Low levels winds will
continue from the northeast today. As a result the development of
scattered to numerous showers and isolated thunderstorms are
expected to be more prevalent across portions of central and
southwest sections of Puerto this afternoon. Rainfall will be
locally heavy at times especially over those sections of Puerto
Rico. Urban and small stream flooding will therefore be possible
this afternoon. Most of the shower and thunderstorm activity is
expected to diminish early Sunday evening, leaving partly cloudy
skies with isolated to scattered shower activity tonight through
early Monday morning.
The boundary remnants are expected to dissipate by Monday, resulting
in a decrease in available low level moisture across the region.
However, the east northeast low level wind flow will combine again
with daytime heating and the proximity of an upper level trough to
the west of the region to induce again the development of shower and
possible thunderstorm activity over central and southwest sections
of Puerto Rico as well as across the U.S. Virgin Islands. Model
guidance suggests that another weak frontal boundary will reach the
region late Tuesday and Wednesday, resulting in an increase in
moisture and showers across the forecast area.
LONG TERM...Wednesday thru Monday...
As a broad mid to upper level trough across the western Atlantic
shifts eastward into the central Atlantic, a ridge pattern aloft
will slowly build across the forecast area Wednesday and hold
through Sunday. This feature is then expected to erode early next
week as trofiness develops across the western Atlantic and into
the central Caribbean. At lower levels, a surface high pressure
north of the area will yield a northeasterly wind flow much of
the forecast period.
As a result, there is a chance for shower activity Wednesday
afternoon across SW PR as moisture prevails across the eastern
caribbean. Thursday onwards, under a building ridge, limited
moisture and northeasterly winds, expect dry and stable weather
conditions with pleasant temperatures. Although mainly fair
weather will continue Sun thru Mon, locally scattered showers
across the US Virgin islands and eastern Puerto Rico are likely.
AVIATION...SHRA/TSRA across NW puerto Rico will continue to
produce brief period of MVFR across TJBQ and TJMZ through at least
25/12z. VCSH are expected elsewhere across the local flying area
until 25/16z. Winds will increase to 10 to 15 knots after 25/12z
with sea breeze variations after 25/16z. SHRA/TSRA will develop
again across central and southwest sections of PR after 25/17z,
resulting in mountains obscurations and periods of MVFR across
TJBQ and TJMZ and possible TJPS through at least 25/23z
MARINE...A northerly swell will result in hazardous seas across
the offshore Atlantic waters throughout the day but subsiding
tonight into Monday morning. Seas up to 7 feet across the Atlantic
offshore waters and subsiding 4 to 6 feet by tonight. The next
northerly swell is expected to reach the local Atlantic waters
Wednesday with seas increasing near 8 feet and occasional seas up
to 10 feet.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 83 75 86 75 / 50 40 40 40
STT 84 74 85 74 / 50 20 40 40
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Monday night for North
Central-Northwest-San Juan and Vicinity-Western Interior.
VI...None.
AM...Small Craft Advisory until 8 PM AST this evening for Atlantic
Waters of Puerto Rico and USVI from 10 NM to 19.5N.
&&
SHORT TERM...WS
LONG TERM....WSPerspectivas sobre Condiciones Peligrosas del Tiempo Servicio Nacional de Meteorologia San Juan PR 449 AM AST domingo 25 de marzo de 2018 AMZ710>745-PRZ001>013-260900- San Juan y Vecindad-Noreste-Sureste-Este Interior- Norte Central-Interior Central-Ponce y Vecindad- Noroeste-Oeste Interior-Mayaguez y Vecindad-Suroeste-Culebra-Vieques- Aguas cercanas y lejanas a la costa del Atlantico y Caribe- 449 AM AST domingo 25 de marzo de 2018 Esta perspectiva sobre las condiciones peligrosas del tiempo es para Puerto Rico y las aguas costeras adyacentes del Atlantico. .Dia Uno...Hoy y Esta Noche .Tronadas...Desarrollo de tronadas con periodos de lluvias fuertes y vientos en rafagas breves son probables esta tarde, mayormente a traves de sectores del centro y suroeste de Puerto Rico. .Inundaciones...Lluvias fuertes podrian resultar en inundaciones urbanas y de riachuelos, mayormente a traves de sectores del noreste, centro y suroeste de Puerto Rico. .Vientos...Vientos sostenidos en exceso de 20 MPH se esperan sobre el lado noroeste de las aguas del Atlantico. .Oleaje...Se espera oleaje picado de 7 a 9 pies a traves de las aguas mar afuera del Atlantico. .Corrientes Marinas...Existe un riesgo alto de corrientes marinas para las playas del noroeste a norte central de Puerto Rico. .Dias dos a siete...lunes a sabado Desarrollo de tronadas con periodos de lluvias localmente fuertes se esperan a medida que los remanentes de una zona frontal continue a traves de la region el lunes. Inundaciones urbanas y de riachuelos son posibles en areas aisladas. Un riesgo moderado a alto de corrientes marinas continua para las playas orientadas hacia el norte de PR e islas adyacentes el lunes. .Comunicado sobre informacion reportada por observadores... No se anticipa activacion amplia de observadores, sin embargo, se les exhorta a los observadores a reportar inundaciones y corrientes marinas al Servicio Nacional de Meteorologia en San Juan. AMZ715-725-VIZ001-002-260900- San Tomas, San John e Islas Adyacentes- Santa Cruz-Aguas cercanas del Atlantico y aguas costeras adyacentes del Caribe- 449 AM AST domingo 25 de marzo de 2018 Esta perspectiva sobre las condiciones del tiempo peligrosas es para Puerto Rico y las aguas costeras adyacentes del Atlantico. .Dia Uno...Hoy y Esta noche .Inundaciones...Lluvias fuertes podrian resultar en acumulacion de agua en carreteras y en areas de pobre drenaje a traves de San Tomas y San John. .Oleaje...Oleaje picado de 5 a 6 pies se espera mayormente sobre las aguas mar afuera del Atlantico. .Corrientes Marinas...Existe un riesgo moderado de corrientes marinas para algunas de las playas orientadas hacia el norte de San Tomas y Santa Cruz. .Dias dos a siete...lunes a sabado Desarrollo de tronadas con periodos de lluvias localmente fuertes es posible a medida que los remanentes de una zona frontal continue a traves de la region el lunes. Acumulacion de agua en carreteras y en areas de pobre drenaje son posibles. .Comunicado sobre informacion reportada por observadores... No se anticipa activacion amplia de observadores, sin embargo, se les exhorta a los observadores a reportar inundaciones y corrientes marinas al Servicio Nacional de Meteorologia en San Juan.
The national radar mosaic for the moment the first event began.
2 flood. Local standard time, as filed.
Emergency managers reported road PR 119 was closed due to flood waters.
Local emergency manager reported that roads 2 and 656 were flooded and therefore closed at that intersection.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2018Every state in 2018This day in weather historyWarnings in Puerto Rico, March 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 745650, 745651.