TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
238 PM EST FRI JAN 17 2025

NOTE: THE NEXT FORECAST BULLETIN WILL BE AVAILABLE ON TUESDAY 21
JANUARY 2024

FORECAST BULLETIN 17 JANUARY 2025 AT 20 UTC

MEDIUM RANGE DISCUSSION: THE APPROACH OF THE UPPER CONVERGENT
PHASE OF THE MJO WILL LIKELY YIELD INTO DRIER CONDITIONS
DEVELOPING THROUGH EARLY NEXT WEEK AND PERSISTING AT LEAST INTO
THE FIRST WEEK OF FEBRUARY.

NORTHWEST BAHAMAS: A SHORT WAVE TROUGH IN THE MID-TROPOSPHERE IS
INTERACTING WITH A MOIST PLUME LOCATED IN THE SOUTHEAST GULF OF
MEXICO...RESULTING IN SCATTERED THUNDERSTORMS IN THE FLORIDA
STRAIT. AS THE SYSTEM MEANDERS EASTWARD...EXPECT A FEW CELLS TO
IMPACT THE NORTHWEST BAHAMAS THROUGH LATE HOURS OF FRIDAY...TO
FAVOR 05 - 10MM/DAY AND ISOLATED MAXIMA OF 15MM THROUGH SATURDAY
MORNING.

NORTHEAST CARIBBEAN: AN EXTENSIVE FRONT EXTENDS FROM THE CENTRAL
NORTH ATLANTIC INTO THE GREATER ANTILLES. BY FRIDAY EVENING EXPECT
IT TO EXTEND AS A STATIONARY BOUNDARY ALONG 19N 65W OR JUST NORTH
OF PUERTO RICO...INTO CENTRAL HISPANIOLA. IT IS FORECAST TO REMAIN
IN THIS LOCATION THROUGH SATURDAY TO THEN LOSE DEFINITION. BY
SUNDAY EVENING THE BOUNDARY IS ANALYZED AS A SHEAR LINE LOCATED TO
THE NORTH OF THE LEEWARD ISLANDS. ANOTHER SHEAR LINE IS CURRENTLY
PRESENT ACROSS THE LEEWARD ISLANDS...AND IS FORECAST TO MEANDER
NORTH WHILE LOSING DEFINITION. BY FRIDAY EVENING IT IS ANALYZED
ALONG THE NORTHERN LEEWARD ISLANDS INTO SOUTHEAST PUERTO RICO...TO
THEN DISSIPATE. BOTH FRONT AND THE CURRENT SHEAR LINE ARE
ASSOCIATED WITH MOIST PLUMES THAT WILL HIGHLIGHT CLOUD COVER AND
PRECIPITATION IN EASTERN HISPANIOLA AND PUERTO RICO THROUGH THE
CYCLE. HOWEVER...THE INFLUENCE OF A STABLE LAYER ASSOCIATED WITH A
MID-LEVEL RIDGE...AS WELL AS LOW VALUES OF AVAILABLE MOISTURE IN
THE MID TROPOSPHERE...WILL LIMIT POTENTIAL RAINFALL AMOUNTS.
THROUGH EARLY SUNDAY EXPECT 05 - 10MM/DAY AND ISOLATED MAXIMA OF
15 - 20MM PRIMARILY IN EASTERN SLOPES. THIS DECREASES TO MAXIMA OF
15MM IN PUERTO RICO ON SUNDAY THROUGH MONDAY MORNING...AND LESSER
AMOUNTS IN HISPANIOLA.

EASTERN CARIBBEAN: A TRADE WIND SURGE IS FORECAST TO PROPAGATE
RAPIDLY FROM 55W IN THE TROPICAL ATLANTIC ON FRIDAY EVENING TO
REACH THE CENTRAL CARIBBEAN NEAR 72W BY SUNDAY EVENING...WHEN IT
IS FORECAST TO DISSIPATE. THIS WILL SET UP A PERIOD OF FASTER WIND
SPEEDS IN THE EASTERN CARIBBEAN AS THE WEEKEND PROGRESSES...TO
PERSIST INTO NEXT WEEK. IN TERMS OF PRECIPITATION...THE SURGE IS
EXPECTED TO STIMULATE CONVECTION IN THE LESSER ANTILLES ON
SATURDAY WHERE IT WILL FAVOR 05 - 10MM/DAY AND ISOLATED MAXIMA OF
15 - 20MM BETWEEN GUADELOUPE AND TRINIDAD. IN BARBADOS EXPECT
MAXIMA GENERALLY UNDER 15MM. ON SUNDAY...THE CYCLONIC EXIT OF A
LOW-LEVEL JET WILL CONTINUE TO STIMULATE ASCENT IN THE WINDWARD
ISLANDS TO FAVOR SCATTERED SHOWERS AND ISOLATED MAXIMA UNDER
15MM/DAY.

CENTRAL AMERICA: ENHANCED TRADE WIND CONVERGENCE CONTINUES
STIMULATING PRECIPITATION IN THE CARIBBEAN BASINS OF SOUTHERN
CENTRAL AMERICA. A MOIST PLUME IS ENTERING SOUTHERN
NICARAGUA/NORTHERN COSTA RICA ON FRIDAY...WHERE IT WILL FAVOR 10 -
15MM/DAY AND MAXIMA OF 20 - 45MM...WHILE IN NORTHWEST PANAMA
EXPECT MAXIMA OF 15 - 20MM. THIS PATTERN IS EXPECTED TO HOLD ON
SATURDAY. ON SUNDAY...HOWEVER...AN ACCELERATION OF THE MID-LEVEL
FLOW WILL FAVOR AN INCREASE IN VERTICAL WIND SHEAR....TO RESULT IN
A DECREASE IN ACCUMULATION.

NORTHERN SOUTH AMERICA: DRY CONTITIONS CONTINUE IN THE REGION DUE
TO THE PRESENCE OF AN ANOMALOUSLY DRY AIR MASS IN THE LOWER AND
MID-TROPOSPHERE PARTICULARLY EAST OF THE ANDES AND NORTH OF 02S.
THIS PATTERN IS EXPECTED TO HOLD THROUGH THE FORECAST
CYCLE...WHILE MOISTURE GRADUALLY RETURNS NORTHWESTWARD ACROSS
EQUATORIAL PORTIONS OF THE AMAZON IN BRASIL. THIS WILL FAVOR
SCATTERED DIURNAL CONVECTION EXPANDING INTO THE COLOMBIA-BRASIL
AND PERU-BRASIL BORDER BY SUNDAY EVENING. NOTE THAT AN INCREASE IN
THE STRUCTURE OF THE BOLIVIAN HIGH AND ITS WESTWARD MIGRATION
THROUGH THE WEEKEND...WILL LIKELY FAVOR A GRADUAL RETURN OF
MOISTURE AND CONVECTION INTO THE WESTERN AMAZON BY EARLY NEXT
WEEK. IN THE PACIFIC BASIN...DIURNAL CONVECTION IS CLUSTERING IN
ECUADOR AND SOUTHERN COLOMBIA...TO PRODUCE GENERALLY 05 - 10MM/DAY
AND ISOLATED MAXIMA OF 15 - 20MM ON FRIDAY. A PEAK IN
PRECIPITATION IS EXPECTED IN NORTHWEST ECUADOR/SOUTHWEST COLOMBIA
ON SATURDAY EVENING...WHEN EXPECT MAXIMA OF 25 - 50MM ALONG THE
WEST SLOPES OF THE ANDES...DECREASING THEREAFTER.

NEW ARCTIC FRONT: A POTENT ARCTIC FRONT IS EXPECTED TO MOVE
RAPIDLY INTO THE GULF OF MEXICO ON SATURDAY. BY SATURDAY EVENING
IT IS FORECAST ACROSS NEW ORLEANS-LOUISIANA INTO CENTRAL
TAMAULIPAS. BY SUNDAY EVENING IT IS FORECAST ACROSS GRAND
BAHAMA...SOUTH FLORIDA/FLORIDA KEYS...FAR NORTHWEST
CUBA...NORTHERN YUCATAN PENINSULA...INTO SOUTHERN VERACRUZ AND
CENTRAL OAXACA. THE FRONT AND ASSOCIATED NORTHERLIES WILL START
IMPACTING PRECIPITATION ON SUNDAY...GIVEN VERY LIMITED MOISTURE
AMOUNTS AVAILABLE WHILE IT PROPAGATES ACROSS THE CENTRAL AND
NORTHERN GULF ON MEXICO. ON SUNDAY THROUGH MONDAY MORNING...EXPECT
10 - 15MM/DAY AND MAXIMA OF 20 - 35MM DEVELOPING IN NORTHERN AND
NORTHEAST SLOPES OF CENTRAL AND SOUTHERN VERACRUZ...CHIAPAS AND
TABASCO IN MEXICO. ALSO ON SUNDAY...INTERACTIONS WITH THE
DIVERGENT SECTION OF AN UPPER TROUGH WILL FAVOR THE DEVELOPMENT OF
THUNDERSTORMS IN THE NORTHEAST YUCATAN PENINSULA AND WEST
CUBA...WITH POTENTIAL MAXIMA OF 15 - 25MM.

GALVEZ...(WPC)