Scientific Forecaster Discussion
fxca62 tjsj 240800
Area forecast discussion
National Weather Service San Juan PR
issued by National Weather Service Miami Florida
400 am AST sun Sep 24 2017
Short term...deep tropical moisture coupled with a south to
southeast flow will keep precipitable water values well over 2
inches through the weekend. However, the air mass is relatively
stable at this time as a weak wave has moved west to hispanola.
Shower activity will be isolated through Sunday, except possibly
east of the Virgin Islands, which may be affected by a weak
incoming easterly wave by Sunday evening. This system may bring
as much as an inch of rain in isolated locations to the Virgin
Islands Sunday night and Puerto Rico Monday, but most areas will
see quite a bit less than that.
Communications are improving and some weather reports are coming
in. It is still difficult to ascertain conditions in the area
though. However, some gauges continue to report. There is only
one gage still showing flood conditions and that one is on the
west end of Puerto Rico.
Heat index values will be near 100 for the next few days, bringing
hot and sticky weather to the area. This will make recovery
efforts difficult and overall living unpleasant as electricity
remains out across the island.
Long term...the pattern will change Tuesday into Tuesday night.
Flow will become easterly and precipitable water values will drop
to around 1.75 inches. This will bring more seasonable winds and
relatively drier conditions to the forecast area.
Aviation...VFR conditions will prevail through Sunday evening,
with isolated MVFR cigs/vsbys in isolated to scattered showers.
Marine...southeast winds will continue through Monday night.
Shower activity will be isolated to scattered today, but
increasing showers and thunderstorms will move in from the east
Sunday night into Monday. More seasonable easterly winds will
Preliminary point temps/pops...
sju 87 79 87 79 / 20 20 30 60
stt 84 82 84 83 / 20 60 40 50