350
FXCA20 KWBC 171759
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
159 PM EDT TUE MAR 17 2026
FORECAST BULLETIN 17 MARCH 2026 AT 1800 UTC:
IN MEXICO, NORTHERN CARIBBEAN, AND THE BAHAMAS/TURKS AND CAICOS...
A POTENT MID TO UPPER LEVEL TROUGH EXTENDS FROM THE UNITED STATES
SOUTHWARD, INTO SOUTHERN MEXICO, AND THE WEST CARIBBEAN IN THE
MORNING HOURS OF TUESDAY. IN THE LOWER LEVELS, A FRONTAL BOUNDARY
IS LOCATED OVER THE NORTH BAHAMAS, WESTERN CUBA, AND ENTERS THE
YUCATAN PENINSULA, WEAKENING OVER THE SOUTHERN SIERRA MADRE
ORIENTAL REGION. THIS COOLER AIR MASS IS EXPECTED TO INTERACT WITH
THE WARM, MOIST TROPICAL AIR MASS IN THE REGION, FAVORING
CONVECTION ALONG THE FRONT OVER THE DAY ON TUESDAY AND INTO
WEDNESDAY. BY THE EVENING HOURS OF TUESDAY THE COLD FRONT REACHES
THE CENTRAL BAHAMAS, CENTRAL CUBA, AND ENTERS THE EASTERN YUCATAN,
WHERE SHORTWAVE TROUGHS EMBEDDED ALONG THE PERIPHERY OF THE
GREATER TROUGH VENTILATES CONVECTION OVER CUBA AND THE BAHAMAS,
GIVING WAY FOR A SLIGHT CHANCE OF SEVERE WEATHER. ON WEDNESDAY,
THE MID-UPPER TROUGH SLOWLY MEANDERS EASTWARD, BUT THE FRONTAL
BOUNDARY BECOMES QUASI-STATIONARY OVER THE BAHAMAS, AND CENTRAL
CUBA, BUT ENTERS FURTHER INTO THE GULF OF HONDURAS REGION BY THE
EVENING HOURS. THIS SEMI-STATIONARY POSITION FAVORS THE
DEVELOPMENT OF PRE-FRONTAL TROUGHS AHEAD OF THE FRONT, OVER THE
SOUTHERN BAHAMAS/TURKS AND CAICOS, EAST CUBA, HISPANIOLA, AND INTO
THE WESTERN CARIBBEAN, NEAR THE COASTS OF HONDURAS/NICARAGUA. BY
THURSDAY, A POTENT HIGH PRESSURE SYSTEM ALOFT OVER THE WESTERN
UNITED STATES BEGINS TO PUSH AGAINST THE UPPER TROUGH TO ITS EAST,
ASSISTING WITH THE EASTWARD PROPAGATION OF THE TROUGH. THIS WILL
ALSO RESULT IN A WEAKENING OF THE FRONTAL BOUNDARY OVER THE GULF
OF HONDURAS REGION, HOWEVER MUCH AVAILABLE MOISTURE IS STILL
EXPECTED IN THE REGION THAT WILL PROMOTE MODERATE TO HEAVY
PRECIPITATION. ON TUESDAY, EXPECT MAXIMA OF 30-60MM IN
TABASCO/CHIAPAS, WHILE MAXIMA OF 25-50MM WITH A SLIGHT RISK OF
SEVERE WEATHER IN CENTRAL CUBA. EXPECT MAXIMA OF 20-35MM IN THE
SOUTHERN SIERRA MADRE ORIENTAL, FROM BELIZE THROUGH GUATEMALA, AND
IN THE BAHAMAS, WITH A SLIGHT RISK OF SEVERE WEATHER. ON
WEDNESDAY, EXPECT MAXIMA OF 20-45MM IN CENTRAL CUBA WITH A SLIGHT
RISK OF SEVERE WEATHER, WHILE MAXIMA OF 20-35MM ARE EXPECTED IN
THE BAHAMAS, AND THE GULF OF HONDURAS REGION. ON THURSDAY, EXPECT
MAXIMA 25-50MM OVER THE SOUTH BAHAMAS, TURKS AND CAICOS, EAST
CUBA, AND THE NORTHERN COAST OF HONDURAS. MAXIMA OF 20-45MM ARE
EXPECTED IN JAMAICA AND NORTHERN HAITI, WHILE MAXIMA OF 20-35MM
ARE EXPECTED IN SOUTHERN HAITI, CENTRAL BAHAMAS, AND NORTH-CENTRAL
CUBA. THESE REGIONS SHOULD EXPECT A MARGINAL RISK OF SEVERE
WEATHER ON THURSDAY.
IN THE SOUTHERN PORTION OF CENTRAL AMERICA AND THE EAST CARIBBEAN,
RELATIVELY DRIER CONDITIONS ARE EXPECTED OVER THE NEXT THREE DAYS.
THE FRONTAL BOUNDARY OVER THE NORTHERN CARIBBEAN WILL FAVOR SOME
PREFRONTAL TROUGHING OVER CENTRAL AMERICA, BUT MAXIMA ARE EXPECTED
TO REMAIN LIGHT ON TUESDAY. SIMILARLY, TRACE TO LIGHT
PRECIPITATION TOTALS ARE EXPECTED IN THE LESSER ANTILLES, WITH
POSSIBILITY OF ISOLATED DIURNAL SHOWERS WITH THE PASSING OF MOIST
PLUMES EMBEDDED IN THE EASTERLY TRADE WINDS OVER THE REGION.
SIMILAR CONDITIONS ARE EXPECTED TO REMAIN ON WEDNESDAY FOR BOTH
REGIONS. BY THURSDAY, SOUTHERN CENTRAL AMERICA CAN EXPECT AN
INCREASE IN PRECIPITATION WITH THE ADVECTION OF MOISTURE FROM THE
WEST CARIBBEAN AS THE UPPER LEVEL TROUGH OVER THE NORTHERN
CARIBBEAN BEGINS TO PROPAGATE EASTWARD, ALLOWING FOR NORTHERLY
WINDS IN THE LOW LEVELS TO ADVECT MOISTURE THAT HAS BEEN POOLING
OVER THE NORTHERN CARIBBEAN. WITH THIS SAME ADVECTION FROM THE
NORTH, EXPECT WEAK GAP FLOW THROUGH THE PAPAGAYO REGION, FAVORING
CYCLONIC CIRCULATION ALONG THE PACIFIC COASTS OF COSTA RICA AND
PANAMA, FAVORING SOME MOIST ONSHORE ALONG THE WESTERN COAST. THIS
COULD FAVOR MAXIMA OF 20-45MM IN COSTA RICA AND WESTERN PANAMA.
IN NORTHERN SOUTH AMERICA, ADVECTION OF MOISTURE OVER THE CENTRAL
ATLANTIC AND INTO THE AMAZON DELTA AND NORTHERN BRASIL IS MAKING
ITS WAY OVER NORTHERN BRASIL AND THE EASTERN AMAZON BASIN. AS THIS
MOISTURE POOLS OVER THE REGION, IT ENCOUNTERS DIFFLUENCE ALOFT
FROM THE PERIPHERY OF THE BOLIVIAN HIGH TO ITS SOUTH AND RIDGING
TO THE NORTHEAST, PRIMING THE EASTERN AMAZON BASIN FOR DEEP
CONVECTION. IN ADDITION, TROUGHING IN THE MID LEVELS WILL HELP
ENHANCE THE DEEP CONVECTION OVER THE NEXT THREE DAYS. TO THE WEST,
EXPECT CONDITIONS TO FAVOR RELATIVELY LIGHT TO MODERATE
PRECIPITATION, AS MUCH OF THE AVAILABLE MOISTURE IS EXPECTED TO
THE EAST OF THE REGION. ON TUESDAY, EXPECT GENERALIZED MAXIMA OF
20-50MM IN THE SOUTH-EAST AMAZON BASIN, WHILE GENERALIZED MAXIMA
OF 20-45MM ARE EXPECTED IN CENTRAL COLOMBIA, EASTERN ECUADOR, AND
AMAPA-BRASIL.ON WEDNESDAY, EXPECT MAXIMA OF 30-60MM IN THE CENTRAL
AMAZON BASIN, WHILE THE EASTERN AMAZON BASIN AND AMAZON DELTA
REGION CAN EXPECT MAXIMA OF 20-50MM. ON THURSDAY, EXPECT MAXIMA OF
35-70MM OVER THE EASTERN FRENCH GUIANA, THE AMAZON DELTA, AND THE
AMAZON BASIN
CASTELLANOS...(WPC)
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