TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
310 PM EDT WED APR 24 2024

FORECAST BULLETIN 24 APR 2024 AT 1900 UTC: AN EXTENSIVE SURFACE
FRONT EXTENDS FROM THE NORTH ATLANTIC ACROSS THE SOUTHEAST
BAHAMAS/CENTRAL CUBA AND IS BECOMING STATIONARY. BY WEDNESDAY
EVENING EXPECT THE SYSTEM ACROSS THE SOUTHEAST BAHAMAS INTO
CENTRAL CUBA...WHERE IT IS FORECAST TO REMAIN THROUGH FRIDAY
MORNING. BY THEN...THE FRONT IS FORECAST TO START ADVANCING AS A
COLD FRONT AGAIN...IN RESPONSE TO A POTENT UPPER TROUGH EXITING
THE EAST COAST OF THE US. A SHEAR LINE IS ALSO ASSOCIATED WITH
THIS SYSTEM...BUT IS FORECAST TO RAPIDLY WEAKEN AS IT MEANDERS
FROM THE TURKS AND CAICOS/WINDWARD PASSAGE INTO REGIONS TO THE
NORTHWEST...TO POTENTIALLY REFORM BY FRIDAY AS THE FRONT RESTARTS
PROPAGATION. THE FRONT ITSELF WILL FAVOR LIMITED RAINFALL AMOUNTS.
HOWEVER...LOCALLY HEAVY PRECIPITATION IS EXPECTED IN AREAS EAST OF
THE SHEAR LINE...GIVEN THE PRESENCE OF A MOIST AIR MASS LOCATED IN
PUERTO RICO AND HISPANIOLA. A PREFRONTAL TROUGH IS ORGANIZING
INSIDE THIS AIR MASS...AND WILL PLAY A ROLE IN HIGHLIGHTING
CONVECTION IN HISPANIOLA DURING THE NEXT THREE DAYS. THE MOST
SIGNIFICANT PRECIPITATION THROUGH THE FORECAST CYCLE IS EXPECTED
TO CLUSTER IN HISPANIOLA IN THE FORM OF AFTERNOON/EVENING
THUNDERSTORMS...AS THE MOIST AND UNSTABLE AIR MASS INTERACT WITH
UPPER TROUGH DYNAMICS. BY WEDNESDAY EXPECT 15-20MM/DAY AND
ISOLATED MAXIMA OF 30-60MM. EXPECT A PEAK ON THURSDAY...WHEN
AMOUNTS ARE FORECAST IN THE 25-50MM/DAY RANGE WITH POTENTIAL
ISOLATED MAXIMA OF 75-125MM. ON FRIDAY...THE ARRIVAL OF ANOTHER
MOIST PLUME FROM THE EAST WILL FAVOR MAXIMA OF40-80MM.

THE FRONT/FRONTAL SHEAR LINE IN THE TROPICAL ATLANTIC IS FORECAST
TO MOVE INTO THE LEEWARD ISLANDS LATER ON WEDNESDAY...TO THEN MOVE
INTO THE WINDWARD ISLANDS WHILE LOSING DEFINITION DURING THURSDAY.
REGARDLESS...LIMITED AMOUNTS OF AVAILABLE MOISTURE WILL LIMIT
ACCUMULATION WITH THIS SYSTEM...LEADING TO VERY ISOLATED MAXIMA
GENERALLY UNDER THE 15MM/DAY RANGE.

ANOTHER REGION OF INTEREST IS PANAMA AND COSTA RICA. A TROUGH IS
ORGANIZING IN/WESTERN COLOMBIA AND IS FORECAST TO GRADUALLY
MEANDER WESTWARD ACCOMPANIED BY A MOIST PLUME. THIS WILL CONTONUE
TO YIELD TO AN INCREASE IN THE COVERAGE AND INTENSITY OF
PRECIPITATION IN SOUTHERN CENTRAL AMERICA. ON WEDNESDAY EXPECT
15-20MM/DAY AND MAXIMA OF 35-70MM FROM NORTHWEST COLOMBIA/EJE
CAFETERO INTO CENTRAL PANAMA. ON THURSDAY...EXPECT MAXIMA OF
40-40MM MOSTLY IN CENTRAL PANAMA. ON FRIDAY...EXPECT THE FOCUS OF
THE HEAVIEST PRECIPITATION IN COSTA RICA AND WEST PANAMA...WHERE
EXPECT MAXIMA OF 20-45MM. ALSO IN THE REGION...FAVORABLE UPPER
DIVERGENCE AND LOW-LEVEL ONSHORE FLOW IN NORTHERN ECUADOR/SOUTHERN
COLOMBIA WILL FAVOR AN INCREASE IN THE AMOUNTS PRODUCED BY DIURNAL
CONVECTION. EXPECT AN INCREASE ON THURSDAY...TO 15-20MM/DAY AND
MAXIMA OF 40-80MM. ON FRIDAY EXPECT MAXIMA OF 30-60MM.

AN EASTERLY WAVE IS PROPAGATING ACROSS EQUATORIAL PORTIONS OF
SOUTH AMERICA. AS THIS WAVE ARRIVES INTO COLOMBIA...IT WILL FAVOR
ONSHORE FLOW IN PORTIONS OF NORTHERN COLOMBIA. AS PRECIPITABLE
WATER VALUES ARE EXPECTED TO REMAIN WELL ABOVE 60MM...EXPECT
STRONG THUNDERSTORMS ON FRIDAY EVENING...WITH THE POTENTIAL OF
PRODUCING MAXIMA OF 75-125MM AND WITH A RISK OF MCS FORMATION.

GALVEZ/CLARKE/LEDESMA...WPC (USA)