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FXCA20 KWBC 142006
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
305 PM EST TUE JAN 14 2025
FORECAST BULLETIN 14 JANUARY 2025 AT 20 UTC
A ROBUST AND EXTENSIVE MID-LEVEL RIDGE CENTERS OVER CUBA AND
COVERS THE ENTIRE NORTHERN CARIBBEAN. THIS IS LIMITING THE
VERTICAL DEVELOPMENT OF CONVECTION ASSOCIATED WITH ACTIVE FRONTS
PROPAGATING IN AREAS NORTH OF 20N. THE RIDGE IS EXPECTED TO WEAKEN
FROM WEDNESDAY THROUGH FRIDAY...TO REESTABLISH NORTHEAST OF THE
LEEWARD ISLANDS. THE DECREASE IN STABILITY IN THE
CENTRAL...NORTHWEST CARIBBEAN AND CENTRAL AMERICA WILL ALLOW FOR
AN INCREASE IN THE VERTICAL DEVELOPMENT OF CONVECTION... WHEREVER
SYSTEMS TRIGGER IT.
IN THE LOWER LEVELS... A SERIES OF BOUNDARIES WILL CONTINUE TO
PROPAGATE THROUGH THE BASIN...IN RESPONSE TO ACTIVE POLAR TROUGHS
IN THE WESTERLIES ACROSS THE UNITED STATES. THE FIRST BOUNDARY OF
INTEREST IS COLD FRONT DRAPING ACROSS THE NORTHWEST BAHAMAS INTO
THE GULF OF MEXICO. THE FRONT HAS MADE IT INTO TABASCO AND
NORTHERN CHIAPAS AND IS HIGHLIGHTING PRECIPITATION IN THE REGION.
THROUGH WEDNESDAY MORNING...CONTINUED ONSHORE FLOW AND
INTERACTIONS WITH TERRAIN WILL FAVOR MAXIMA OF 15-30MM. A SHORT
WAVE TROUGH PROPAGATING ACROSS CENTRAL MEXICO WILL FAVOR
CYCLOGENESIS ON WEDNESDAY OVER THE NORTHWEST GULF OF MEXICO...TO
DEVELOP A NEW COLD FRONT. THE FRONT IS FORECAST TO PROPAGATE
SOUTHWARD TO REACH CENTRAL VERACRUZ BY WEDNESDAY EVENING...AND
TABASCO/CHIAPAS BY THURSDAY EVENING WHEN IT WILL START TO LOSE
DEFINITION. THIS WILL FAVOR MAXIMA OF 15 - 25MM ON WEDNESDAY
THROUGH EARLY THURSDAY...AND MAXIMA OF 20 - 35MM BY THURSDAY
THROUGH EARLY FRIDAY. YET NOTE THAT VERY ISOLATED HIGHER AMOUNTS
ARE POSSIBLE DUE TO TERRAIN INTERACTIONS.
THE EASTERN PORTION OF THE AFOREMENTIONED FRONT IS FORECAST TO
PROPAGATE SOUTHWARD RAPIDLY... IN RESPONSE TO ACCELERATING
LOW-LEVEL WINDS ACROSS THE NORTHWEST ATLANTIC. BY WEDNESDAY
EVENING EXPECT THE BOUNDARY ACROSS THE FAR SOUTHERN
BAHAMAS...CENTRAL CUBA. IT IS THEN EXPECTED TO BECOME STATIONARY
IN THESE LOCATIONS. EXPECT VERY CONSERVATIVE AMOUNTS THROUGH
THURSDAY MORNING. HOWEVER...A SHORT WAVE UPPER TROUGH DEEPENING
ACROSS THE GULF OF MEXICO ON THURSDAY WILL FAVOR THE DEVELOPMENT
OF SHOWERS AND THUNDERSTORMS IN WEST CUBA AND RAINFALL MAXIMA OF
20 - 35MM FROM THURSDAY INTO FRIDAY MORNING. ANOTHER AREA WITH
LOCALLY MODERATE AMOUNTS IN FAR SOUTHEAST CUBA...WHERE OROGRAPHIC
INTERACTIONS WILL FAVOR MAXIMA OF 15-20MM DURING THE SAME PERIOD.
IN THE EASTERN CARIBBEAN...TWO SHEAR LINES ARE PRESENT...AND ARE
EXPECTED TO MOVE VERY LITTLE WHILE ENHANCING PRECIPITATION IN
PORTIONS OF THE LESSER ANTILLLES... ABC ISLANDS...AND NORTHWEST
VENEZUELA. EXPECT VERY CONSERVATIVE RAINFALL AMOUNTS WITH THE
NORTHERN SHEAR LINE... FORECAST TO PERSIST ACROSS THE CENTRAL
LEEWARD ISLANDS. THE SOUTHERN SHEAR LINE...HOWEVER...WILL HAVE
STRONGER IMPACTS ON RAINFALL GIVEN HIGHER AMOUNTS OF PRECIPITABLE
WATER AVAILABLE. EXPECT ACCUMULATION OF 05 - 10MM/DAY AND MAXIMA
OF 15 - 25MM THROUGH EARLY WEDNESDAY IN THE CENTRAL LESSER
ANTILLES... DECREASING GENERALLY TO MAXIMA OF 15 - 20MM. IN THE
ABC ISLANDS AND NORTHWEST VENEZUELA... ABOVE NORMAL PRECIPITABLE
WATER VALUES WILL FAVOR MAXIMA GENERALLY IN THE 15 - 25MM RANGE
THROUGH THURSDAY MORNING... DECREASING THEREAFTER. HIGHER AMOUNTS
ARE LIKELY IN THE LAKE MARACAIBO REGION DUE TO LOCAL ENHANCEMENT.
SEASONALLY QUIET CONDITIONS ARE EXPECTED IN CENTRAL AMERICA DUE TO
INFLUENCE OF THE MID-LEVEL RIDGE AND LIMITED AMOUNTS OF AVAILABLE
MOISTURE. THE LARGEST ACCUMULATIONS ARE EXPECTED IN THE CARIBBEAN
BASINS OF COSTA RICA/SOUTHEAST NICARAGUA AND WEST PANAMA DUE TO
TRADE WIND CONVERGENCE...WHERE EXPECT MAXIMA GENERALLY OF 15 -
25MM ON A DAILY BASIS. ISOLATED HIGHER AMOUNTS ARE POSSIBLE IN
WEST PANAMA ON THURSDAY.
A NOTICEABLE DRYING TREND IS ESTABLISHING IN NORTHERN SOUTH
AMERICA...PARTLY DUE TO INCREASE LOW-LEVEL NORTHWESTERLIES THAT
ARE ADVECTING A DRIER AIR MASS FROM THE CARIBBEAN AND TROPICAL
NORTH ATLANTIC INTO THE SOUTH HEMISPHERE. THIS IS TRANSPORTING
AREAS OF HEAVY RAINFALL INTO CENTRAL AND EASTERN BRASIL. IN THE
TROPICAL DESK DOMAIN... THE HIGHEST ACCUMULATIONS ARE EXPECTED
WITH ITCZ CONVERGENCE IN SOUTHWEST COLOMBIA AND DUE TO ONSHORE
FLOW IN COASTAL ECUADOR. NOTE THAT CONDITIONS IN ECUADOR BECOME
THE MOST FAVORABLE ON WEDNESDAY THROUGH EARLY THURSDAY... WHEN A
DECREASE IN VERTICAL SHEAR AND AN INCREASE IN ONSHORE FLOW AND
AVAILABLE MOISTURE WILL FAVOR MAXIMA OF 25 - 50MM IN THE PACIFIC
BASIN.
GALVEZ...(WPC)
TINOCO...(WPC)
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