Code: Select all
juan pr
703 am ast tue sep 14 2004
. Synopsis ... Tropical depression eleven was located near 16. 6 north
62. 2 west and is moving west northwest at about 10 knots. an upper
level trough extends southwest over puerto rico from a long wave
trough now in the central atlantic. it is adding some shear to the
environment in which the tropical depression must grow ... but is also
enhancing convection in the area.
. Discussion ... Tropical depression number 11 has come
together very quickly. during the last several hours cloud top
temperatures have reached -84 degrees celsius in a round of very
vigorous activity. winds in saint martin were also gusty as a band
showers moved west across the area ... they had winds of 16 gust to 29
kt.
Moisture will be good across the island. the 06z sounding from san
juan was 2. 15 inches. precipitable water levels were also this high
over isabela ... but have dropped to 1. 7 inches since. possibly
subsidence is beginning to set up over the outer fringes of the
system. it does not look like moisture will decrease closer in to
the system.
While surface winds are increasing around the system and flow is
beginning to turn more northeast over the virgin islands ... flow has
been very light over puerto rico so far. winds should begin to back
and increase this afternoon. this will place northeast flow over the
island this afternoon at the time of maximum heating and in the
excellent moisture. therefore strong convection and very heavy rains
are possible over southwest puerto rico this afternoon.
The system is forecast to move at 305 degrees and pass very near
culebra.. but at the present time movement looks to be more westerly
and with high pressure at mid levels just north of the dominican
republic there may be some left moving pressure in the track. as
usual with these systems the strongest winds are in the northern
portion of the storm ... and if the track is farther south ... this will
place puerto rico in the stronger winds. for the present all
interest would be best served to prepare for the worst possible
scenario ... high winds and torrential rains ... from a rapidly
developing system.
With the current movement toward the west northwest our local waters
are in the path of the developing swell. that swell will also travel
under the winds from this system as it moves towards us ... allowing
the swell to grow even more. although winds are not as high as with
ivan ... seas in the area may reach levels that are higher than
experienced with ivan due to the new systems proximity and path.
therefore a coastal flood watch has been issued for zones 2 ... 5... 12
and 13 of puerto rico and all of the u. s. virgin islands. would
expect swell to grow in saint croix first. high tide will also be
somewhat problematic tonight and tomorrow night in fajardo as water
levels will be around 1. 7 feet above mean lower low water
level ... which is just inches below the highest tide that will be
experienced this month. coastal flooding may be possible on the
northern shores of puerto rico as well ... but have waited until the
path is more certain and wind levels are better known to issue. this
flooding would also occur on wednesday rather than today.
The system will be leaving our coastal waters on thursday according
to the gfs and by that time it will be close to hurricane strength.
we will probably feel the effects of this storm for quite some time
as moisture in the area stays abundant through saturday. this could
continue to spell trouble for us if we are also drenched with heavy
rains from soon - to - be jeanne. the specter of flooding could
therefore remain through the end of the week. winds on the other
hand should be over by late thursday no matter what the track of
tropical depression 11 takes.
This discussion was made before the models and the dvorak t numbers came out showing that Jeannie is born.