TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1128 AM EST MON NOV 27 2023

FORECAST BULLETIN 27 NOV 2023 AT 1630 UTC: AN UPPER TROUGH IS
PROPAGATING EASTWARD WHILE EXTENDING ACROSS SONORA/SOUTHERN BAJA
CALIFORNIA ON MONDAY MORNING. WHILE PRESSING ONTO THE SUBTROPICAL
UPPER RIDGE THAT CENTERS OVER HONDURAS...THE UPPER TROUGH IS
STIMULATING THE DEVELOPMENT OF AN UPPER JET THAT EXTENDS FROM
SOUTHERN BAJA CALIFORNIA INTO THE CENTRAL MISSISSIPPI VALLEY.
UPPER JET DYNAMICS ARE STIMULATING ASCENT OVER MOST OF CENTRAL AND
SOUTHERN MEXICO...WHICH IS RESULTING IN WIDESPREAD MID-UPPER
CLOUDS AND SCATTERED LIGHT PRECIPITATION FROM ELEVATED CONVECTION
ON MONDAY. TO THE EAST...A MID-LEVEL RIDGE CENTERING OVER
SOUTHEAST CUBA EXTENDS OVER THE GREATER ANTILLES AND THE CENTRAL
AND EASTERN CARIBBEAN. IN CONTRAST TO THE SCENE IN MEXICO...THE
MID-LEVEL RIDGE WILL LIMIT RAINFALL ACCUMULATIONS IN MOST OF THE
CARIBBEAN THROUGH THE CYCLE.

IN THE LOW-LEVELS...A SURFACE FRONT IS PROPAGATING ACROSS THE
BAHAMAS...NORTH CUBA AND SOUTHERN MEXICO. THE FRONT WILL BE A
SOURCE OF LOW-LEVEL MOISTURE CONVERGENCE TO TRIGGER MODERATE
PRECIPITATION AS IT INTERACTS WITH THE UPPER TROUGH IN MEXICO ON
MONDAY. AFTER THIS PERIOD...THE UPPER TROUGH IS FORECAST TO
RAPIDLY LIFT EASTWARD YIELDING TO DRY WESTERLY FLOW IN THE MID-AND
UPPER TROPOSPHERE AND ASSOCIATED FAIR WEATHER IN MOST OF MEXICO.
IN TERMS OF FRONTAL POSITIONS...ON MONDAY EVENING EXPECT THE
BOUNDARY ACROSS THE NORTHWEST BAHAMAS...NORTHWEST CUBA...NORTHERN
YUCATAN PENINSULA...CAMPECHE...CHIVELA PASS...INTO THE CENTRAL
MEXICAN PLATEAU. BY TUESDAY EVENING EXPECT THE FRONT ACROSS THE
CENTRAL BAHAMAS...CENTRAL CUBA...NORTH BELIZE...CHIVELA
PASS...INTO A DISSIPATING BOUNDARY ACROSS CENTRAL MEXICO. BY
WEDNESDAY EVENING THE FRONT IS FORECAST AS A STATIONARY BOUNDARY
ACROSS THE CENTRAL BAHAMAS...CENTRAL CUBA...CENTRAL YUCATAN
PENINSULA...NORTHWEST GULF OF MEXICO. A SHEAR LINE IS ALSO
EXPECTED. BY MONDAY EVENING IT IS FORECAST ACROSS THE CENTRAL
BAHAMAS...SOUTHEAST CUBA...NORTHEAST HONDURAS. BY TUESDAY EVENING
IT IS EXPECTED ACROSS THE SOUTHEAST BAHAMAS...SOUTHEAST
CUBA...WEST JAMAICA...FAR EASTERN HONDURAS. BY WEDNESDAY
EVENING...A WEAKENING SHEAR LINE IS EXPECTED ACROSS THE TURKS AND
CAICOS...FAR SOUTHEAST CUBA...ISLAS DE LA BAHIA IN NORTHERN
HONDURAS.

REGARDING PRECIPITATION WITH THE FRONT...SHEAR LINE AND UPPER
TROUGH IN MEXICO...ON MONDAY EXPECT 15-20MM/DAY AND MAXIMA OF
25-50MM IN SOUTHERN VERACRUZ/CHIAPAS/TABASCO DUE TO ENHANCED MOIST
ONSHORE FLOW FROM THE GULF. ACROSS MOST OF CENTRAL AND EASTERN
MEXICO...ASCENT BY THE UPPER TROUGH WILL FAVOR SCATTERED AMOUNTS
OF 05-10MM/DAY AND ISOLATED MAXIMA OF 15MM...ALTHOUGH LIGHTER
SHOWERS CAN BE EXPECTED IN SOUTHWEST MEXICO AS WELL. IN THE
YUCATAN PENINSULA EXPECT 05-10MM/DAY AND MAXIMA OF 15-25MM...WHILE
ONSHORE FLOW IN NORTHWEST HONDURAS/CENTRAL GUATEMALA/SOUTH BELIZE
WILL FAVOR MAXIMA OF 20-40MM. SHEAR LINE CONVECTION WILL FAVOR
MAXIMA OF 15-20MM IN EASTERN HONDURAS/NORTHEAST NICARAGUA. ON
TUESDAY...EXPECT FRONTAL CONVECTION AND UPSLOPE TO FAVOR
10-15MM/DAY AND MAXIMA OF 20-40MM FROM SOUTHERN VERACRUZ/CHIAPAS
INTO SOUTH BELIZE/CENTRAL GUATEMALA. SIMILAR AMOUNTS ARE EXPECTED
IN NORTHEAST HONDURAS WITH THE SHEAR LINE. IN THE YUCATAN
PENINSULA EXPECT MAXIMA OF 15-30MM. IN SOUTHEAST CUBA AND THE
SOUTHEAST/CENTRAL BAHAMAS EXPECT 05-10MM/DAY AND MAXIMA OF 15-20MM
PRIMARILY WITH THE SHEAR LINE. IN JAMAICA EXPECT SIMILAR AMOUNTS
WITH THE SHEAR LINE. ON WEDNESDAY...FRONTAL CONVECTION IN THE
SOUTHEAST YUCATAN PENINSULA AND BELIZE WILL FAVOR 05-10MM/DAY AND
MAXIMA OF 15-25MM. SIMILAR AMOUNTS ARE EXPECTED IN NORTH HONDURAS
WITH THE SHEAR LINE. IN SOUTHEAST CUBA AND THE CENTRAL/SOUTHEAST
BAHAMAS EXPECT MAXIMA OF 15MM PRIMARILY WITH THE FRONT.

THE WET-TO-DRY SEASONAL TRANSITION CONTINUES IN SOUTHERN PORTIONS
OF THE BASIN. THE FORECAST SHOWS THE PERSISTENT PRESENCE OF THE
CARIBBEAN AND PAPAGAYO LOW-LEVEL JETS. THIS WILL FAVOR DRYING IN
THE CENTRAL CARIBBEAN/NORTHERN SOUTH AMERICA...YET WILL LIKELY
ENHANCE CONVECTION IN THE CARIBBEAN BASIN OF COSTA RICA AND
WESTERN PANAMA. ON MONDAY AND TUESDAY EXPECT MAXIMA OF 25-50MM IN
BOCAS DEL TORO/EAST COSTA RICA. ON WEDNESDAY...THE FOCUS SHIFTS TO
SOUTHEAST NICARAGUA AND NORTH AND EASTERN COSTA RICA...WHERE
EXPECT MAXIMA OF 30-60MM...WHILE IN SOUTHERN COSTA RICA AND
WESTERN PANAMA EXPECT MAXIMA OF 20-35MM.

THE ITCZ IS RAPIDLY MEANDERING SOUTHWARD. IN THE ATLANTIC...IT IS
NOW FORECAST TO ENTER THE CONTINENT NEAR AMAPA IN NORTH
BRASIL...EXTENDING INTO SOUTH COLOMBIA/NORTH PERU WHILE IN THE
PACIFIC IT IS FORECAST TO THE SOUTH OF PANAMA INTO CENTRAL WESTERN
COLOMBIA. GIVEN AN UPPER CONVERGENT LARGE SCALE PATTERN
ESTABLISHING AND LIMITED AVAILABLE MOISTURE IN THE TROPICAL
ATLANTIC...EXPECT DIURNAL CONVECTION TO REMAIN ISOLATED AND
PRODUCE CONSERVATIVE AMOUNTS IN THE 05-10MM/DAY AND ISOLATED
MAXIMA OF 15-25MM. WETTER CONDITIONS ARE EXPECTED IN WESTERN SOUTH
AMERICA...PARTICULARLY ON SOUTHWEST COLOMBIA...WHERE MOIST ONSHORE
FLOW IS EXPECTED TO PERSIST THROUGH THE FORECAST CYCLE. THIS PEAKS
ON TUESDAY THROUGH EARLY WEDNESDAY WHEN EXPECT 15-20MM/DAY AND
MAXIMA OF 35-70MM. OTHERWISE EXPECT MAXIMA GENERALLY IN THE
20-35MM/DAY RANGE.

POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT 28/00 28/12 29/00 29/12 30/00 30/12 01/00 01/12
NONE

GALVEZ...WPC (USA)