Re: Caribbean - Central America Weather
Posted: Tue Jun 02, 2020 6:30 am
Area Forecast Discussion
National Weather Service San Juan PR
413 AM AST Tue Jun 2 2020
.SYNOPSIS...A seasonable weather pattern will continue across the
area during the next several days with isolated to scattered
passing showers across portions of eastern Puerto Rico and the
USVI during the overnight and early morning hours followed by the
development of afternoon convection across the western half of
Puerto Rico. Winds are expected to increase by the second half of
the work week as a broad surface high pressure settles across the
central Atlantic. A more unsettled weather pattern is possible by
early next week as a mid to upper-level trough amplifies north of
the area and deeper moisture moves in.
&&
.SHORT TERM...Today through Thursday...
Near normal to slightly below normal moisture is expected today and
even drier for Wednesday and Thursday, which is a change from what
the model guidance was suggesting yesterday. However, today, the
available moisture will be sufficient to cause the development of
locally induced showers and thunderstorms, particularly over western
Puerto Rico this afternoon. In addition, a mid to upper level trough
is present over the local islands, and it will be in its most
favorable position for thunderstorm support this afternoon, but not
so much for Wednesday and Thursday. In fact, for Wednesday and
Thursday, we should be in the subsident side of the upper trough
according to the GFS model, along with much drier than normal
moisture for the time of year. Therefore, we lowered the chances of
showers and thunderstorms across Puerto Rico for Wednesday and
Thursday. The shower and thunderstorm activity expected today could
cause urban and small stream flooding across the west to northwest
sections of Puerto Rico. The prevailing wind flow in will be mainly
from the east, at around 10-15 mph, with occasional gusts during the
daytime hours from today through Thursday.
.LONG TERM...Friday through Tuesday...
Shower activity is expected to remain limited across the local
area through Sunday as the moisture content is expected to remain
below normal with precipitable water values expected to range
between 1.3 and 1.5 inches. Broad surface high pressure across the
Central Atlantic is expected to result in a moderate easterly wind
flow. This will push occasional patches of low-level moisture
into the region, resulting brief isolated to locally scattered
shower activity across portions of eastern Puerto Rico and the
USVI during the overnight and early morning hours followed by the
development of afternoon shower and isolated thunderstorm activity
across western Puerto Rico. However, given the below normal
moisture content expected, significant rainfall activity is
unlikely.
Latest model guidance suggests that the synoptic scale pattern
changes by early next week as a mid to upper-level trough
amplifies north of the area. This will allow for deeper moisture
to pool in. Therefore, if model guidance is correct on this
general scenario, then more unsettled conditions with an increase
in shower and thunderstorm activity is possible.
&&
.AVIATION...VFR conditions expected through 02/16Z. Thereafter,
SHRA/TSRA is expected near TJBQ and TJMZ, some of which could
affect the terminals, while ISOL/SCT SHRA is expected elsewhere,
causing brief VCSH. Winds will continue from the East at 10 to 15
knots with occasional gusts and sea breeze variations, becoming
calm to light and vrb aft 02/23Z.
&&
.MARINE...Tranquil marine conditions expected to continues through
Wednesday with seas generally expected to remain below 5 feet.
Choppy seas are then expected by the second half of the work week
as winds increase. There is a moderate risk of rip currents for
some of the northern beaches of Puerto Rico as well as the eastern
most beaches of Culebra, Vieques, and Saint Croix.
&&
.FIRE WEATHER...Latest surface observations continue to indicate
very dry soils across the southern coastal plains of Puerto Rico
with KBDI values at Camp Santiago and Cabo Rojo at 733 and 594,
respectively, along with ten-hour fuel moisture at around 9%. For
today, expect a drier air mass to move across the area. This
should allow relative humidity values to dip into the mid 40s to
lower 50s. Sustained winds are also expected to peak around 15
mph with frequent higher gusts. Therefore, an elevated fire danger
risk once again is expected for the southern coastal plains and a
Fire Danger Statement (RFDSJU) has been issued accordingly.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 90 78 / 20 10 20 20
STT 89 79 88 79 / 30 20 20 20
National Weather Service San Juan PR
413 AM AST Tue Jun 2 2020
.SYNOPSIS...A seasonable weather pattern will continue across the
area during the next several days with isolated to scattered
passing showers across portions of eastern Puerto Rico and the
USVI during the overnight and early morning hours followed by the
development of afternoon convection across the western half of
Puerto Rico. Winds are expected to increase by the second half of
the work week as a broad surface high pressure settles across the
central Atlantic. A more unsettled weather pattern is possible by
early next week as a mid to upper-level trough amplifies north of
the area and deeper moisture moves in.
&&
.SHORT TERM...Today through Thursday...
Near normal to slightly below normal moisture is expected today and
even drier for Wednesday and Thursday, which is a change from what
the model guidance was suggesting yesterday. However, today, the
available moisture will be sufficient to cause the development of
locally induced showers and thunderstorms, particularly over western
Puerto Rico this afternoon. In addition, a mid to upper level trough
is present over the local islands, and it will be in its most
favorable position for thunderstorm support this afternoon, but not
so much for Wednesday and Thursday. In fact, for Wednesday and
Thursday, we should be in the subsident side of the upper trough
according to the GFS model, along with much drier than normal
moisture for the time of year. Therefore, we lowered the chances of
showers and thunderstorms across Puerto Rico for Wednesday and
Thursday. The shower and thunderstorm activity expected today could
cause urban and small stream flooding across the west to northwest
sections of Puerto Rico. The prevailing wind flow in will be mainly
from the east, at around 10-15 mph, with occasional gusts during the
daytime hours from today through Thursday.
.LONG TERM...Friday through Tuesday...
Shower activity is expected to remain limited across the local
area through Sunday as the moisture content is expected to remain
below normal with precipitable water values expected to range
between 1.3 and 1.5 inches. Broad surface high pressure across the
Central Atlantic is expected to result in a moderate easterly wind
flow. This will push occasional patches of low-level moisture
into the region, resulting brief isolated to locally scattered
shower activity across portions of eastern Puerto Rico and the
USVI during the overnight and early morning hours followed by the
development of afternoon shower and isolated thunderstorm activity
across western Puerto Rico. However, given the below normal
moisture content expected, significant rainfall activity is
unlikely.
Latest model guidance suggests that the synoptic scale pattern
changes by early next week as a mid to upper-level trough
amplifies north of the area. This will allow for deeper moisture
to pool in. Therefore, if model guidance is correct on this
general scenario, then more unsettled conditions with an increase
in shower and thunderstorm activity is possible.
&&
.AVIATION...VFR conditions expected through 02/16Z. Thereafter,
SHRA/TSRA is expected near TJBQ and TJMZ, some of which could
affect the terminals, while ISOL/SCT SHRA is expected elsewhere,
causing brief VCSH. Winds will continue from the East at 10 to 15
knots with occasional gusts and sea breeze variations, becoming
calm to light and vrb aft 02/23Z.
&&
.MARINE...Tranquil marine conditions expected to continues through
Wednesday with seas generally expected to remain below 5 feet.
Choppy seas are then expected by the second half of the work week
as winds increase. There is a moderate risk of rip currents for
some of the northern beaches of Puerto Rico as well as the eastern
most beaches of Culebra, Vieques, and Saint Croix.
&&
.FIRE WEATHER...Latest surface observations continue to indicate
very dry soils across the southern coastal plains of Puerto Rico
with KBDI values at Camp Santiago and Cabo Rojo at 733 and 594,
respectively, along with ten-hour fuel moisture at around 9%. For
today, expect a drier air mass to move across the area. This
should allow relative humidity values to dip into the mid 40s to
lower 50s. Sustained winds are also expected to peak around 15
mph with frequent higher gusts. Therefore, an elevated fire danger
risk once again is expected for the southern coastal plains and a
Fire Danger Statement (RFDSJU) has been issued accordingly.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 90 78 / 20 10 20 20
STT 89 79 88 79 / 30 20 20 20