Saint John, U.S. Virgin Islands

Regional Weather Alerts


     
Alert: Hydrologic Outlook
Area(s): Adjuntas, PR; Aguada, PR; Aguadilla, PR; Aguas Buenas, PR; Aibonito, PR; Anasco, PR; Arecibo, PR; Arroyo, PR; Barceloneta, PR; Barranquitas, PR; Bayamon, PR; Cabo Rojo, PR; Caguas, PR; Camuy, PR; Canovanas, PR; Carolina, PR; Catano, PR; Cayey, PR; Ceiba, PR; Ciales, PR; Cidra, PR; Coamo, PR; Comerio, PR; Corozal, PR; Culebra, PR; Dorado, PR; Fajardo, PR; Florida, PR; Guanica, PR; Guayama, PR; Guayanilla, PR; Guaynabo, PR; Gurabo, PR; Hatillo, PR; Hormigueros, PR; Humacao, PR; Isabela, PR; Jayuya, PR; Juana Diaz, PR; Juncos, PR; Lajas, PR; Lares, PR; Las Marias, PR; Las Piedras, PR; Loiza, PR; Luquillo, PR; Manati, PR; Maricao, PR; Maunabo, PR; Mayaguez, PR; Moca, PR; Morovis, PR; Naguabo, PR; Naranjito, PR; Orocovis, PR; Patillas, PR; Penuelas, PR; Ponce, PR; Quebradillas, PR; Rincon, PR; Rio Grande, PR; Sabana Grande, PR; Salinas, PR; San German, PR; San Juan, PR; San Lorenzo, PR; San Sebastian, PR; Santa Isabel, PR; Toa Alta, PR; Toa Baja, PR; Trujillo Alto, PR; Utuado, PR; Vega Alta, PR; Vega Baja, PR; Vieques, PR; Villalba, PR; Yabucoa, PR; Yauco, PR; Saint Croix, VI; Saint John, VI; Saint Thomas, VI
Effective: 2026-04-10 @ 10:19 am
Onset: 2026-04-10 @ 10:19 am -> 2026-04-11 @ 10:30 pm
Severity: Unknown
Certainty: Possible
Urgency: Future
Issued By: NWS San Juan PR on 2026-04-10 @ 10:19 am
Headline: Hydrologic Outlook issued April 10 at 11:19AM AST by NWS San Juan PR
Description: ESFSJU
A mid to upper level trough is expected to move across Hispaniola
 on Sunday, reaching Puerto Rico and the Virgin Islands late Sunday
 into Monday. The trough will also reflect at the surface, with the
 axis reaching the islands Monday night into early Tuesday.
The first round of showers is expected to reach the region Sunday
 night into early Monday. On Monday morning, showers and isolated
 thunderstorms will stream across the Virgin Islands and portions
 of eastern Puerto Rico. Then, in the afternoon, stronger activity
 is expected to develop for the interior, moving into portions of
 the south-central, west and southwest Puerto Rico. By late Monday
 into Tuesday, conditions are expected to be even more favorable for
 periods of heavy rain across the islands, but especially strong
 along St. Thomas and St. John, Vieques, Culebra, eastern and
 northern Puerto Rico.
Soils continue to be saturated along the east and south of Puerto
 Rico, but a break in recent rainfalls will allow for the soil to dry
 a little. Streams are mostly running near normal or high across the
 entire region.
Taking all these factors into consideration, the likelihood of
 urban and small stream flooding, isolated flash flooding,
 landslides and rapid river rises is increasing. While it is too
 early to determine how much rainfall will fall, the most likely
 scenario is for 1 to 3" each day, and isolated higher
 amounts. So far, the days with the highest potential for flooding
 are Monday and Tuesday, but above normal moisture will persist
 through late in the workweek.
At this time, the confidence in the forecast is medium, but
 increasing, especially since there has been some consistency between
 runs of the global guidance. However, some uncertainty still exist
 in the exact amounts, timing and locations most affected. It is also
 worth mentioning that cloud coverage could also impact the amounts
 of rainfall expected, as cloudy skies tend to inhibit heavy rain
 formation.
This product will be updated as necessary to reflect updates in the
 forecast.
Alert: Hydrologic Outlook
Area(s): Adjuntas, PR; Aguada, PR; Aguadilla, PR; Aguas Buenas, PR; Aibonito, PR; Anasco, PR; Arecibo, PR; Arroyo, PR; Barceloneta, PR; Barranquitas, PR; Bayamon, PR; Cabo Rojo, PR; Caguas, PR; Camuy, PR; Canovanas, PR; Carolina, PR; Catano, PR; Cayey, PR; Ceiba, PR; Ciales, PR; Cidra, PR; Coamo, PR; Comerio, PR; Corozal, PR; Culebra, PR; Dorado, PR; Fajardo, PR; Florida, PR; Guanica, PR; Guayama, PR; Guayanilla, PR; Guaynabo, PR; Gurabo, PR; Hatillo, PR; Hormigueros, PR; Humacao, PR; Isabela, PR; Jayuya, PR; Juana Diaz, PR; Juncos, PR; Lajas, PR; Lares, PR; Las Marias, PR; Las Piedras, PR; Loiza, PR; Luquillo, PR; Manati, PR; Maricao, PR; Maunabo, PR; Mayaguez, PR; Moca, PR; Morovis, PR; Naguabo, PR; Naranjito, PR; Orocovis, PR; Patillas, PR; Penuelas, PR; Ponce, PR; Quebradillas, PR; Rincon, PR; Rio Grande, PR; Sabana Grande, PR; Salinas, PR; San German, PR; San Juan, PR; San Lorenzo, PR; San Sebastian, PR; Santa Isabel, PR; Toa Alta, PR; Toa Baja, PR; Trujillo Alto, PR; Utuado, PR; Vega Alta, PR; Vega Baja, PR; Vieques, PR; Villalba, PR; Yabucoa, PR; Yauco, PR; Saint Croix, VI; Saint John, VI; Saint Thomas, VI
Effective: 2026-04-09 @ 10:19 am
Onset: 2026-04-09 @ 10:19 am -> 2026-04-11 @ 10:30 am
Severity: Unknown
Certainty: Possible
Urgency: Future
Issued By: NWS San Juan PR on 2026-04-09 @ 10:19 am
Headline: Hydrologic Outlook issued April 9 at 11:19AM AST by NWS San Juan PR
Description: ESFSJU
A mid to upper level trough is expected to move across Hispaniola
 on Sunday, reaching Puerto Rico and the Virgin Islands late Sunday
 into Monday. By Tuesday, the trough will be developing a closed
 low pressure system in the mid and upper level of the atmosphere,
 with a well defined trough (or possibly a low) developing at the
 surface. As a result, favorable conditions for periods of
 heavy rain are anticipated on Monday and Tuesday.
The first round of showers is expected to reach the region Sunday
 night into early Monday. On Monday morning, showers and isolated
 thunderstorms will stream across the Virgin Islands and portions
 of eastern Puerto Rico. Then, in the afternoon, stronger activity
 is expected to develop for the interior, moving into portions of
 the south-central, west and southwest Puerto Rico.
By Tuesday, if a low pressure develops in the lower levels,
 the steering winds will weaken significantly. As a result,
 showers will move slow from the Atlantic Ocean into portions of
 the east and north of Puerto Rico and the Virgin Islands.
At this time, soils continue to be saturated along the east and
 south of Puerto Rico, but a break in recent rainfalls yesterday
 and today will allow for the soil to dry a little. Streams are
 mostly running near normal or high across the entire region.
Taking all these factors into consideration, the likelihood of
 urban and small stream flooding, isolated flash flooding,
 landslides and rapid river rises is increasing. While it is too
 early to determine how much rainfall will fall, the most likely
 scenario is for 1 to 3" each day, and very isolated higher
 amounts. So far, the days with the highest potential for flooding
 are Monday and Tuesday, but above normal moisture will persist
 through late in the workweek.
At this time, confidence in the forecast is medium, since small
 changes in timing of arrival and position of the feature could
 affect the total precipitation received and the areas most
 affected.
Usually, by mid-April, the Early Wet Season unfold in the
 northeast Caribbean Islands. However, this year, the dry season
 never arrived. In fact, the Last 60 Days Percent of Normal from
 the National Water Prediction Service show 300 to 500% above
 normal precipitation for southern Puerto Rico, from Salinas to
 Lajas. Areas in the interior and north were also wetter than what
 is expected for February and March, with nearly 100 to 200% above
 normal.
Please, stay tuned for updates in the forecast this weekend. This
 product will be updated as necessary to reflect updates in the
 forecast. Additional information can be found in the Area Forecast
 Discussion (AFDSJU).