Tropical Discussion - International Desks
NWS Weather Prediction Center College Park MD
246 PM EST Mon Feb 09 2026

Forecast Bulletin 09 February 2026 at 1950 UTC:

On Monday, an upper level trough is propagating over northwest
Mexico, as it extends from the southwest United States. Centered
over the Baja California Peninsula, the divergent side of the
trough is located over Sonora, Chihuahua, and north Sinaloa. A
trough axis extending further south, is favoring moisture
transport from the Pacific into the western regions of Mexico
throughout the atmospheric column. In the lower levels, troughing
is favored over the Baja California Peninsula in response to the
presence of the upper level conditions, advecting moisture into
the Sierra Madre Occidental, where this moist onshore flow will
interact with the terrain and favor light to moderate maxima
precipitation of 20-35mm in the northern Sierra Madre Occidental.
Maxima of 15-20mm are expected in Chihuahua and west Sonora and
north Sinaloa. These regions can expect a slight risk of severe
weather on Monday into early Tuesday. The central and southern
regions of Mexico can expect generally dry conditions, as the
region is primarily governed by a mid to upper level ridge that
extends from Central America into Mexico, favoring subsidence and
strong trade wind inversions, as well as low amounts of
precipitable water on Monday and Tuesday. On Tuesday, the mid to
upper level trough reaches Chihuahua by the evening hours, and
with it, the divergence extends over northern Mexico and portions
of southern United States. As the trough enters land, it will
disconnect from the moisture that was once feeding into the
northern regions of Mexico, thus decreasing the amount of
available moisture in the region. This will favor a decrease in
precipitation totals on Tuesday. Portions of west Chihuahua into
Sonora can expect maxima of 15-30mm, while the northern Mexican
Plateau into north Sonora, extending along the coasts of Sonora
and north Sinaloa, can expect maxima of 15-20mm. The risk of
severe weather is expected to decrease on this day as the mid to
upper level trough also begins to weaken as it continues over
land. On Wednesday, the mid to upper level ridge centered over
Central America has extended further north with the weakening of
the upper level trough over the southern United States. Expect
drier conditions throughout the country of Mexico, as the
strengthening of the mid to upper level ridge enhances the trade
wind inversions and subsidence in the region.

In the Caribbean and the Bahamas, frontal passages will be
affecting the presence of precipitation over the next three days.
A broad upper level trough extends into the central Atlantic and
portions of the Greater Antilles on Monday, interacting with the
strengthening mid to upper level ridge over Central America and
western Caribbean. A cold front extending from the central
Atlantic extends over portions of the south Bahamas/Turks and
Caicos and just north of Cuba by Monday evening. A weakening
frontal boundary extends from the Atlantic over the Leeward
Islands, favoring the presence of a prefrontal trough over the
Windward Islands, which will favor light to moderate precipitation
maxima of 15-20mm. On Tuesday, these front over the Lesser
Antilles continues to weaken, but a shear line over the central
Lesser Antilles will favor enhanced moisture convergence over the
regions, where expect maxima of 20-45mm. maxima of 20-35mm are
expected in the Leeward Islands on Tuesday. The advancing cold
front over the Central Atlantic enters north Hispaniola by Tuesday
evening, favoring maxima of 10mm, as less moisture is expected
over the region. On Wednesday, the mid-levels will favor a
weakening of the trough over portions of the east Caribbean,
favoring a decrease in precipitations on Wednesday. However,
remnants of the frontal boundary and shear line will remain over
the Leeward Islands and favor maxima of 20-35mm.

In Central America, the low level northeasterly trade winds will
be at play for favoring precipitation over the next three days.
Throughout the forecast period, a mid to upper level ridge will
dominate the region, favoring subsident conditions and trade wind
inversions capping deep convection. In addition, the lack of
moisture throughout the region will not provide for precipitation
throughout. However, most of the enhanced levels of moisture are
located over the west Caribbean Sea, due to moist plume remnants,
and advected into the Caribbean coasts of Costa Rica and Panama,
as the primary driver of that advection are the northeasterly
winds entering the region and favoring moisture convergence along
the coasts. The presence of Caribbean Low Level Jet is enhancing
this moisture convergence, peaking on Tuesday as long fetch moist
onshore flow is expected as the elevated moisture enters the
continent that day. By Wednesday, the remnants of the moist plumes
exits into the Pacific Ocean, decreasing the amount of moisture in
the region. In terms of precipitation, expect maxima of 20-45mm on
Monday in Costa Rica and northwest Panama. On Tuesday, expect
maxima of 30-60mm with localized higher amounts possible along the
Caribbean coasts of Costa Rica and Panama. On Wednesday, localized
maxima of 20-45mm are expected in northeast Costa Rica, with
maxima of 15-25mm in east Nicaragua and northwest Panama.

In tropical South America, the east and western coasts of the
regions are expected to see the highest amounts of precipitation
as moist onshore flow enters each respective region. In the west,
the Panama Low Level Jet is favoring cyclonic circulation over the
western coasts of Colombia and Ecuador, favoring moist onshore
flow interaction with the mountainous regions and enhanced
moisture convergence and orographic lift. Monday is expected to be
the day with the heaviest influence from the Panama LLJ, as by
Tuesday, the LLJ will weaken, and it will disappear by Wednesday
evening. To the east, moisture associated with propagating troughs
in the lower levels will enter the Amazon Delta and contribute to
the precipitation totals, primarily in the coasts of Amapa-Brasil,
increasing the totals on Tuesday and Wednesday. In terms of
precipitation totals, on Monday expect maxima of 20-45mm from west
Colombia into west Ecuador, as well as in the Amazon Delta. On
Tuesday, a decrease in west Colombia/Ecuador with maxima of
20-35mm, while an increase in Amapa-Brasil with maxima of 30-60mm.
On Wednesday, Amapa can expect maxima of 25-50mm, while Colombia
can expect maxima of 15-25mm, while west Ecuador can expect maxima
of 20-35mm.

Castellanos...(WPC)