669 
FXCA62 TJSJ 060848
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
448 AM AST Sun Nov 6 2022


.SYNOPSIS...

There is a significant improvement in weather conditions compared
to yesterday, however the upper level trough that brought so much
instability is still positioned in an area that is favorable for 
shower and thunderstorm development over the local area. Rainfall 
amounts in the forecast are not ones that would normally cause 
significant flooding, but again, soils are very saturated and 
isolated thunderstorms could easily cause localized flooding. Due 
to hazardous marine and coastal conditions, there are Small Craft 
Advisories and High Risk of Rip Current Advisories out for the 
local waters and beaches. A wet pattern of passing showers and 
afternoon convection is expected to continue into next weekend as 
abundant moisture and lighter wind flow prevails.


&&

.SHORT TERM...Today through Tuesday...

The shower activity that encompassed the day yesterday gradually 
diminished overnight, and the flooding gradually subsided across the 
local islands. At this moment, only a narrow band of showers and 
thunderstorms is affecting the Caribbean waters, to the southeast of 
St Croix. Otherwise, mainly fair weather is being observed. 

The latest guidance suggests better weather than we had in the 
original forecast, so adjustments were made after considering the 
guidance and the observations. The upper trough that brought so much 
instability is still positioned in an area that is favorable for 
shower and thunderstorm development over the local area. However, 
the surface low pressure will continue to move north, bringing an 
area of drier air to move into the local area, while the deeper 
moisture will be just east of the USVI. With this setup, the band of 
deeper moisture will continue to move north just east of the USVI 
today, but late tonight into Monday, some of that moisture could 
move into the local islands. This means the showers and 
thunderstorms could affect the USVI late tonight into Monday, while 
PR would observe mainly scattered showers, though an area of 
isolated thunderstorms could affect south and east PR on Sunday 
night into Monday as well. That being said, the amounts of rain are 
not quite as much as we observed yesterday, though saturated soils 
must be considered when thinking of potential flooding. 

The narrow band of deep moisture that could widen as the day 
progresses on Monday, having eastern PR under some moisture as well, 
then widening even more on Tuesday with a light southerly wind flow. 
This will favor some rain once again for southern and eastern PR as 
well as the USVI. By then, the upper trough is much broader and 
weaker than it is now, so rainfall amounts in the forecast are not 
ones that would normally cause significant flooding, but again, 
soils are very saturated and isolated thunderstorms could easily 
cause localized flooding. Overall, an improvement in the weather is 
expected today, with some additional generalized or scattered 
moderate showers on Monday and Tuesday, with some areas of isolated 
thunderstorms.


&&

.LONG TERM...Wednesday through Sunday...

A moist, southerly flow on Wednesday will promote passing showers
along the southern coastline of Puerto Rico followed by afternoon
convection across northern sections. Strong westerly winds will be
present aloft due to an upper level low over the Bahamian 
Islands, which will promote instability at the surface possibly 
aiding afternoon thunderstorm activity. There will be an abrupt 
backing of the lower level wind flow by Thursday, settling on a 
southeasterly direction. The environment still remains favorable 
with abundant moisture which will allow for passing showers and 
afternoon convection across northwestern Puerto Rico. 

Friday afternoon a tropical wave looks to be passing across the
Caribbean Sea at 15N with a westward track. This will further
prolong the ongoing wet pattern by providing moisture, especially
across the Caribbean waters. By this time the lower level wind
flow has become easterly, which will promote the greatest 
activity of the day across the interior/western sections of Puerto
Rico. Streamer formation is also expected downwind of the USVI, 
El Yunque, and the Cayey mountain range. The same pattern is 
expect for Saturday and Sunday, however a mid to upper level ridge
begins to build to the northwest of the region, possibly reducing
the strength of next weekends afternoon convection. Overall, a
wet, seasonal pattern is expected. 

&&

.AVIATION...VFR conds are expected today across the local 
terminals. VCSH is forecast across the USVI terminals as well as 
TJSJ, but significant TSRA development is not expected today over 
the terminals. CIGs at around FL060 could be observed today across
TIST, TISX and TJSJ. Winds will be generally light, at around 
10KT or less, with a strong southerly component.

&&

.MARINE....The arrival of a northerly swell and ongoing wave wind
energy will cause choppy seas across the local waters. Moderate 
to strong southerly winds will prevail today. Current buoy 
observations show that the northerly swell is beginning to build 
at 3.3 feet at 11 seconds, observed at the Arecibo Datawell 
Directional buoy. It is expected to peak out tonight and then 
linger for the next couple days. Unsettled weather conditions 
continue across the local waters, therefore there is a chance of 
thunderstorm activity that could produce strong winds and heavy 
rains. 

Due to seas in excess of 7 feet, there is a Small Craft Advisory 
for multiple marine zones; the Caribbean waters near the USVI, the
waters east of Puerto Rico near the USVI, the Anegada passage, 
and the Atlantic Offshore waters. There is a High Risk of Rip 
Currents across the northern coast of Puerto Rico and Culebra due 
to breaking waves heights around 6 feet. There risk is moderate 
elsewhere.


.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Flash Flood Watch through Monday afternoon for PRZ001>013.

     High Rip Current Risk through late Monday night for PRZ001-002-
     008.

     High Rip Current Risk until 6 AM AST early this morning for 
     PRZ003-007-011.

     High Rip Current Risk through late Monday night for PRZ005.

     High Rip Current Risk through Monday afternoon for PRZ012.

VI...Flash Flood Watch through Monday afternoon for VIZ001-002.

     High Rip Current Risk from this evening through Monday afternoon 
     for VIZ002.

&&

$$

SHORT TERM...JA
LONG TERM...RC
PUBLIC DESK...LIS