A rainy pattern for eastern caribbean

[cycloneye]

puerto rico and u. s. virgin islands forecast discussion
national weather service san juan pr
320 pm ast mon oct 18 2004

. synopsis ... at upper levels ... high pressure is about 225 miles
southwest of san juan. it will sink south and dissipate as a weak
short wave moves north of the dominican republic. a stronger short
wave will dig in over cuba on thursday and overwhelm this weaker
wave. that shortwave will weaken and move east during the weekend.
during the middle of the following week a long wave trough will move
into position north of puerto rico.

at mid levels ... high pressure persists over the area until thursday
when a broad but weak trough settles in over eastern cuba. this
trough remains there until it pulls northeast and away from the area
over the weekend. during the following week a long wave trough
settles in from the northeast over the area. heights remain at or
above 585 dm.

at lower levels ... the weak wave that passed by puerto rico is now
over the dominican republic. dryer air will follow. a second wave
will enter the eastern caribbean wednesday and lower level flow will
turn southeast and south until saturday. on sunday high pressure
will ridge north of the area from georgia. the resulting northerly
flow will drive moisture south of the area monday and tuesday.

a surface low that crosses 20 north on 27 october northeast of the
windward islands ... can be traced to a system that comes out of the
itcz around friday of this week.

&&

. discussion ... the morning sounding showed a wetter and less stable
airmass over the area. this will shortly be followed by a short
interlude of drier air. after tuesday the moist layer will deepen to
more than 10 thousand feet and relative humidities will generally
increase through friday. models continue to show very favorable
conditions for rain beginning on thursday and continuing through
saturday. furthermore the models have not settled on the exact
solution for the upper air troughing to occur west of the area
thursday through saturday. the latest run has returned to a solution
with a sharp trough on friday morning that has a northerly jet over
florida and a southwest jet from haiti. models place puerto rico and
the u. s. virgin islands in a significant area of divergence aloft
friday morning. it is at this time that southerly flow ... 700 mb
theta - e and relative humidity at 850 mb reach a maximum. therefore
it would be safe to assume that thursday night and friday will both
have considerable quantities of rain ... and the specter of flooding
returns. since flow is southerly would expect the southern slopes of
puerto rico to be hit the hardest. amounts over the virgin islands
will be significant but would expect much less rain there ... with
some nuisance type flooding possible. it is still too early to
determine how much rain will fall in the area ... though would expect
thursday through saturday to be mostly cloudy and temperatures
somewhat lower each of those days.

after saturday ... the low pressure that the gfs continues to
develop near the itcz and move almost north northwest across 20
north near 57 west on tuesday of next week ... will not directly
affect the area ... but will cause northerly flow to wrap around over
the forecast area ... bringing in much drier air and the end of the
heavy rains. this drier air will become most noticeable on monday.
it now looks like a band of moisture ahead of the drier air ... much
like a front ... will cross over the area on sunday. afterward showers
will be sparse the remainder of the week

After a few days of great weather with the trade winds and dry air changes will arrive to Puerto Rico,The virgin islands and the Leewards,But nothing cyclonic that may form this combination of tropical wave,cold front,upper trough for Puerto Rico,the virgin islands and the leewards.Looks like the umbrellas will be used in the next few days.

[rainstorm]

stay dry

[Wnghs2007]

Stay safe and dry Cycloneye

[Sanibel]

There's a huge bank of convection out there east of the Windwards.

A wisp of a thin wave looks to be taking place in the west Caribbean.


It's nice and humid here tonight and warm...

[cycloneye]

afdsju

puerto rico and u. s. virgin islands forecast discussion
national weather service san juan pr
555 am ast tue oct 19 2004

. discussion ... mid to upper level height falls already taking place
and gfs continues to show a steady digging of short wave energy over
much of the central and eastern caribbean and southwest north
atlantic today and wednesday ... with a deep layered trough setting up
just to our west and northwest by wednesday night and thursday...
then lingering through friday ... and probably still close enough
saturday to have affects on the local weather.

at lower levels ... evolving scenario still a bit unclear ... but still
looks like a broad low level trough will develop over the central
and eastern caribbean tonight and wednesday ... then hang around into
thursday ... before shifting west of local area friday and saturday.

all of this troughiness will coincide with a general increase in
available moisture and instability locally. thus ... still looks like
an increasingly unsettled weather pattern for the local islands...
probably beginning as early as wednesday and then continuing through
friday and probably saturday ... with a significant amount of
cloudiness and showers and thunderstorms expected. as mentioned
monday ... feel that the potential for at least some localized
flooding should gradually increase as well ... especially given the
antecedent soil and river conditions locally.

[cycloneye]

The latest forecast for Puerto Rico is for bad weather from friday night going into all the weekend from 98L combining with an upper trough.



. thursday night ... variably cloudy early in the evening then becoming
mostly cloudy. scattered showers then widespread showers and
isolated thunderstorms in the late evening and overnight. lows 75
lower elevations ranging to 69 higher elevations. south winds 5 to
10 mph. chance of rain 80 percent.
. friday ... mostly cloudy. widespread showers. isolated thunderstorms
then occasional thunderstorms late in the morning then occasional
thunderstorms with heavy rainfall. highs 85 lower elevations ranging
to 79 higher elevations. chance of rain 80 percent.
. friday night ... cloudy. widespread showers and occasional
thunderstorms with heavy rainfall then numerous showers and
scattered thunderstorms with heavy rainfall in the late evening and
overnight. lows 75 lower elevations ranging to 69 higher elevations.
chance of rain 80 percent.
. saturday ... mostly cloudy. numerous showers. scattered thunderstorms
with heavy rainfall then scattered thunderstorms in the afternoon.
highs 86 lower elevations ranging to 80 higher elevations. chance of
rain 70 percent.
. saturday night ... mostly cloudy early in the evening then becoming
variably cloudy. numerous showers and scattered thunderstorms then
scattered showers and isolated thunderstorms in the late evening and
overnight. lows 77 lower elevations ranging to 71 higher elevations.
chance of rain 70 percent.
. sunday ... variably cloudy. scattered showers and isolated
thunderstorms. highs 87 lower elevations ranging to 81 higher
elevations. chance of rain 50 percent.
. sunday night ... variably cloudy early in the evening then becoming
partly cloudy. scattered showers. isolated thunderstorms early in
the evening. lows 77 lower elevations ranging to 71 higher
elevations. chance of rain 50 percent.

[cycloneye]

puerto rico and u. s. virgin islands forecast discussion
national weather service san juan pr
430 pm ast tue oct 19 2004

. discussion...
as previously advertised ... there is a developing short wave upper
level trough that is expected to deepen over the northeast caribbean
the next several days. if it deepens as depicted by the latest gfs
model guidance ... this will put the northeast caribbean on the
eastern side of the trough axis ... especially by thursday. during
this same time frame ... increasing low level moisture is expected to
approach the northeast caribbean. currently there is an area of
convection stretching from about 55 west eastward to about 45
west ... centered about 15 north. this is the combination of the itcz
and a weak wave introduced today near 54 west. while the
aforementioned upper level trough continues to deepen wednesday
night into thursday ... some of the low level moisture will approach
the northeast caribbean as the low level flow starts to become
southeast. after that ... the low level flow on thursday is expected
to become nearly due south and low level moisture convergence is
expected over the northeast caribbean ... with the anticipated
increase in convection starting late thursday into friday.

[Wnghs2007]

Dang going to get wet there. Keeps looking wetter and wetter as time goes on.

[cycloneye]

puerto rico and u. s. virgin islands forecast discussion
national weather service san juan pr
555 am ast wed oct 20 2004

. discussion ... water vapor imagery showing mid to upper level trough
continuing to dig in just to our west and northwest and this trough
is expected to continue to deepen and then linger there through
friday/friday night ... and will probably still be close enough
saturday to have affects on the local weather.

at lower levels ... broad low level trough will continue to develop
over the central and eastern caribbean today and tonight ... and then
hang around through at least thursday night ... before shifting west
of the local area friday and saturday.

as we have been advertising for a few days ... all of this troughiness
will coincide with a general increase in available moisture and
instability locally. so ... we will have an increasingly unsettled
weather pattern for the local islands ... beginning today and then
continuing through friday and probably saturday ... with a significant
amount of cloudiness and showers and thunderstorms expected. still
feel that the potential for at least some localized flooding should
increase as well over the next couple of days ... especially given the
antecedent soil and river conditions locally.

Here it comes.

[msbee]

cloudy skies here this morning Luis, but patches of sun breaking through.
And I am hearing rumbles of thunder in the distance.
Last night we saw a fair amount of lightning also.
no rain yet.

[cycloneye]

000
fxca62 tjsj 211025
afdsju

puerto rico and u. s. virgin islands forecast discussion
national weather service san juan pr
620 am ast thu oct 21 2004

. discussion...
tutt continues from central carib ne across w half of hispaniola
and into sw atlc this morning and continues to induce broad upper
lift and ventilation across the ne carib and adjacent atlc ... with
this upper pattern expected to persist through saturday evening.
abundant low to mid level moisture to the se of tutt axis prevails
across the region this morning and will maintain unstable
conditions ... with moisture forecast to maximize across the local
area friday through saturday for heavy rain potential. broad low
pressure across the caribbean and adjacent tropical atlc this
morning ... with local islands hovering around 1010 mb. stlt imagery
this morning suggests a llvl trough from the mona passage
southward ... while another trough is along about 57 west and a
reflection of upper low cut off there and gradually lifting nne.
the resultant effect of this low level troughing has been to create
a broad zone of abundant tropical moisture between 68 west and 50
west and south of 19 - 20 north. se to sse steering flow will advect
all this moisture nnw next 36 - 48 hours and under the influence of
the tutt to produce very active and unsettled weather across the ne
carib. best dynamics for deep convection may occur just to our e and
se during that time ... but will be close enough to generate deep
convection as is evidenced by 50k ft tops locally overnight.

heavy precip has already begun to affect e sections of p. r. and
vieques early this morning and will likely shift nnw during the day.
urban and stream flooding are thus likely today with isolated areas
of flash flooding ... and evening river flooding also very possible.
this rainfall will then set the stage for additional heavy rains
friday through saturday ... when flash flooding will be more easily
realized ... and thus more likely. local spotters ... and emergency
managers are requested to coordinate with the nws during this time
frame. rainfall amounts of 2 - 4 inches will be scattered today ... with
isolated amounts of 5 - 7 inches possible. higher atmospheric moisture
content friday and saturday could produce even higher localized
precip amounts then.


http://www.srh.noaa.gov/radar/loop/DS.p ... tjua.shtml


Here we are with flash flood watches and warnings.It's a cloudy and rainy morning in eastern Puerto Rico.

[caribepr]

It's cloudy and raining here as well, but I am loving it! Still cool at 9 a.m. - one of those *wanna stay in bed and read all day with a cup of tea* mornings we get like a gift. And from the looks of things, more to come. (Sorry, we don't get the floods here - unless extreme- and we can enjoy this pattern more)

[schmita]

Cloudy, swirling winds and lots of rain this morning and more to come from the looks of things. Nice and cool too ![/img]

[msbee]

[quote="caribepr"]It's cloudy and raining here as well, but I am loving it! Still cool at 9 a.m. - one of those *wanna stay in bed and read all day with a cup of tea* mornings we get like a gift.

and that's exactly what I did, caribepr......stayed in bed and I have been reading all day.
It's a holiday here..Everything is closed, so it's a perfect day to stay home and do nothing except maybe eat a bowl of hot soup LOL

Luis, does it look like St. Maarten will have the same pattern of
weather that you foerecast for PR? rain all thought the weekend?

[cycloneye]

It's cloudy and raining here as well, but I am loving it! Still cool at 9 a.m. - one of those *wanna stay in bed and read all day with a cup of tea* mornings we get like a gift.

and that's exactly what I did, caribepr......stayed in bed and I have been reading all day.
It's a holiday here..Everything is closed, so it's a perfect day to stay home and do nothing except maybe eat a bowl of hot soup LOL

Luis, does it look like St. Maarten will have the same pattern of
weather that you forecast for PR? rain all thought the weekend?

Yes St Marteen is on the same boat.

[msbee]

thanks Luis
I couldn't tell which way this weather was moving or even IF it is moving.
I thought maybe it might clear St. Maarten first if it was moving more West.

[caribepr]

Late afternoon and still beautifully cool! I walked home from work and people were out smiling and working on things with not a drop of sweat to be seen (unlike SOME LUCKY TYPES who got to lie abed and read all day !) A young friend who recently moved here from Montana was ecstatic "This is the first morning I woke up and was COLD!" I didn't tell her, oopsy, you've acclimated, it wasn't even down to 70!

[cycloneye]

000
fxca62 tjsj 212057
afdsju

puerto rico and u. s. virgin islands forecast discussion
national weather service san juan pr
445 pm ast thu oct 21 2004

synopsis...
broad mid to upper level upper level trough (tutt) continues to
extend from the west atlantic southward into the southwest caribbean
and eastward across hispanola. this is inducing a moist
southwesterly wind flow over the local region and good upper level
dynamics. as a result very unstable conditions will be maintained
over the area. in the low levels ... a frontal trough across the west
atlantic extends south across eastern cuba and continues to slowly
drift east southeast towards hispanola. meanwhile a broad induced
low level trough remains in place across the central caribbean and
extends northward across hispanola and the northeast caribbean. this
overall pattern is maintaining a good low level south southeast wind
flow across the local region resulting in a continuous influx of
tropical moisture.

&&

. discussion...
the low level trough will continue to aid in bringing copious
amounts moisture across the northeast caribbean overnight through
friday. the latest satellite imagery and doppler radar depicted
considerable amounts of cloudiness with embedded showers and
thunderstorms extending from across central caribbean northeast over
the local region and into the atlantic. the latest gfs guidance
suggests that the upper trough will continue to deepen during the
next 24 - 36 hours across the west atlantic and therefore maintain
good upper level dynamics and unstable conditions over the area.
present water vapor imagery confirms this as a 75 - 80 kt jet max is
apparent on west side of trough as it digs further south. the model
guidance also suggest good theta - e and omega values over the local
area for the next 24 - 36 hours. local 12z soundings across the region
depicted high precipitable water values (>2. 00 inches) with deep
moisture content from surface to upper levels. the low level flow
will become more southerly and therefore increase moisture
convergence over the entire northeast caribbean at least through
saturday. with this in mind ... a wet weather pattern was maintained
well into the weekend with the most intense amount of activity
expected on friday into saturday.


Plenty of rain for the Puerto Rico,Virgin islands area this weekend.

[cycloneye]

discussion...
tutt has weakened and drifted n past 24 hours and will eventually
merge with longwave trough across the w atlc and into sw carib. this
has shifted upper dynamics out of the local area for the next 24
hours. additionally ... drier mid level air and mild divergence there
has left the local area more stable than previously anticipated...
and this accounts for yesterdays afternoon stabilization which will
linger into tonight. although ample llvl moisture remains in place
across the entire region ... lack of llvl convergence will continue to
limit convection across the area today and tonight ... until
convergence zone currently across the e and se carib shifts n into
the local area saturday morning for a return to active weather.
deepening low across the nw atlc will push a weak trough into the
local area saturday night through sunday to act similar to a weak
front to provide lift and llvl convergence through sunday. have thus
altered forecast for next 24 hours significantly to drop rain
chances. abundant morning sunshine across p. r. today should yield
sea breezes and diurnal convection across the northern slopes and ne
sections by afternoon ... with otherwise limited activity. heavy
precip potential and possible watches are then expected saturday.

Still the weekend looks wet for Puerto Rico.

[msbee]

yep
rain has cleared out here also
partlly cloudy skies but looks like a decent day shaping up.
My backyard rain gauge measured 1.5 inches from yesterday.
a good amount of liquid sunshine
Barbara