NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION. Privacy and Cookie policy

FXCA62 TJSJ 280908 AFDSJU

Area Forecast Discussion National Weather Service San Juan PR 508 AM AST Tue Nov 28 2023

SYNOPSIS
Current satellite derived precipitable water (PWAT) data shows a dry air mass over our region with values of 0.95 to 1.45 inches.
Ridging at all levels will continue to promote fair weather conditions across the local area through at least the rest of the workweek. Therefore, little to no significant shower development is anticipated. Moisture will recover to normal values during the weekend. Near normal and seasonal temperatures will prevail.



SHORT TERM
Today through Thursday...

Minimum temperatures were between the low to mid 70s across the lower elevations, and from the low to mid 60s across the higher elevations. Light passing showers and low-level cloudiness were observed across portions of the islands during the night hours.
Rainfall accumulations over land areas were just a few hundredths of an inch, mainly over southeastern Puerto Rico. Sunny to partly cloudy skies are expected to prevail across the region throughout the day.

Ridging at all levels will continue to promote fair weather conditions across the local area through the short term period.
Sinking drier air and relative warm 500 mb temperatures due to a broad mid-level ridge over the central Caribbean should continue to promote stable conditions today across the islands. The best moisture content is trapped below 850 mb and it was mainly due to the fragmented cloud layer around 5000 ft that moved over the region from previous days. The precipitable water content is expected to remain below normal levels, around 1.30 inches, decreasing further to 1.10 inches by Wednesday morning. Therefore, little to no significant shower development is anticipated. Moisture recovers slightly on Thursday, but only isolated to scattered showers are expected as the region remains under the influence of the ridge.

LONG TERM
Friday through Monday...

Current model guidance suggests below normal precipitable water (PWAT) values on Friday, although with patches of moisture reaching the region. By Saturday, moisture is forecast to increase to normal values as moisture from the tropical Atlantic filters into the area.
This trend is forecast to continue through the rest of the period with the exception of a dry patch on Sunday. A mid level ridge will start over the northern Caribbean to start the period before gradually moving westward and weakening during the weekend. At surface level, a high pressure will build north of the islands over the western Atlantic, gradually moving eastward through the period.
Most available moisture should remain below 800 mb, with drier air aloft through most of the period, although slightly more humid air aloft is present Friday and Saturday, as a nearby polar trough and a lower level weak front approaches the region. As moisture increases the chance of passing showers across windward sectors of the islands will increase. Sea breeze convergence, diurnal heating and local effects will also help promote afternoon convection across interior to sectors of the western/southwestern half of Puerto Rico, under east-northeast low level winds, during most of the period.

AVIATION
Mainly VFR conditions are expected across all terminals during the next 24 hours. Winds from the east at 10-15 knots with sea breeze variations aft 28/14z.

MARINE

A surface low with associated frontal boundary moving northeastward across the Western Atlantic and a high pressure ridge north of the region, will promote gentle to moderate easterly winds across the Northeast Caribbean. Another surface high pressure is forecast to build from the western to central Atlantic, promoting moderate to locally fresh winds and choppy seas by Thursday or Friday. Seas will be up to 5 ft before conditions deteriorate by the end of the workweek. A lingering but slowly fading NE swell will persist through today. Current CARICOOS buoys report seas at 2-3 ft with San Juan's, Arecibo's and Rincon's buoys reporting a 12-13s swell.

There is a moderate risk of rip currents for the northern coastline of Puerto Rico, from Rincon to Ceiba, most of Culebra's coastline, northwestern St. Thomas and easternmost St. Croix. Low risk elsewhere.

SJU WATCHES/WARNINGS/ADVISORIES
PR...None.
VI...None.
AM...None.

toggle option: (graph/table)

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Key West, FL,