424
FXCA20 KWBC 221911
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
210 PM EST THU JAN 22 2026
FORECAST BULLETIN 22 JANUARY 2026 AT 1910 UTC:
ON THURSDAY, THE PATTERN REMAINS SIMILAR IN THAT SCATTERED SHOWERS
ARE SEEN OVER THE CARIBBEAN REGION OVER THE NEXT THREE DAYS. AN
UPPER LEVEL RIDGE EXTENDS OVER THE CARIBBEAN SEA AND INTO THE
BAHAMAS, WHERE IT INTERACTS WITH A WEAK UPPER LEVEL SHORTWAVE
TROUGH. IN THE MID LEVELS A WEAK RIDGE IS PRESENT OVER THE WEST
CARIBBEAN AND INTO CENTRAL AMERICA, FAVORING SUBSIDENCE OVER THE
REGION AND WEAK TRADE WIND CAPS. AS SUCH, MUCH OF THE
PRECIPITATION THAT IS PRESENT IS EXPECTED TO REMAIN SCATTERED AND
LIGHT IN CENTRAL AMERICA AND MOST OF THE CARIBBEAN AND THE
BAHAMAS. IN THE LOWER LEVELS, MOIST PLUMES AND TROUGHS ARE
EMBEDDED IN THE TRADE WINDS, WHICH WILL BE FAVORING THE LIGHT TO
MODERATE PRECIPITATION IN EAST HONDURAS AND NICARAGUA, AS WELL AS
IN THE LESSER ANTILLES, WHERE EXPECT MAXIMA OF 20-40MM ON
THURSDAY. ON FRIDAY, THE UPPER LEVEL RIDGE STRENGTHENS AND EXPANDS
FURTHER, WHILE THE MID LEVEL RIDGE ALSO EXPANDS TO COVER MOST OF
THE GREATER ANTILLES AND CENTRAL AMERICA BY FRIDAY EVENING. THIS
WILL FAVOR SUBSIDENCE AND TRADE WIND CAP INVERSIONS IN THE MID TO
LOWER LEVELS OVER MOST OF THE REGION AND PRECIPITATION IS EXPECTED
TO REMAIN LIGHT AND SCATTERED. THE REGION OF INTEREST IS THE
LESSER ANTILLES, WHICH WILL CONTINUE TO SEE RELATIVELY MOIST
EASTERLY WINDS IMPACT THE REGION, WITH MAXIMA OF 20-35MM EXPECTED
ON FRIDAY. BY SATURDAY, THE UPPER LEVEL RIDGE IS REACTING TO A
RETROGRADING UPPER LEVEL TROUGH OVER THE CENTRAL ATLANTIC THAT
WILL FAVOR THE RIDGE TO MEANDER WEST INTO MEXICO. IN TURN, THE MID
LEVEL RIDGE WILL ALSO SHIFT TO THE NORTH AND WEST, BRINGING DRIER
CONDITIONS WITH IT OVER EASTERN MEXICO, INTO CENTRAL AMERICA, AND
THE CARIBBEAN REGIONS, WHERE EXPECT SCATTERED TO ISOLATED SHOWERS
WITH TRACE TO LIGHT TOTALS.
OF INTEREST, IN NORTHWEST MEXICO, AN INCOMING UPPER LEVEL TROUGH
IS CURRENTLY LOCATED WEST OF CALIFORNIA-UNITED STATES. WITH IT, A
COLD FRONTAL BOUNDARY THAT IS EXPECTED TO PROPAGATE SOUTH OVER THE
NEXT FEW DAYS. ON THURSDAY, THE FRONTAL BOUNDARY REMAINS OUTSIDE
OF THE FORECAST PERIOD, AS THE UPPER LEVEL TROUGH REMAINS TO THE
NORTH AND WEST OF THE BAJA CALIFORNIA PENINSULA. EXPECT TRACE TO
LIGHT PRECIPITATION ON THURSDAY. BY FRIDAY, THE FRONTAL BOUNDARY
ENTERS THE BAJA CALIFORNIA PENINSULA, EXTENDING INTO THE EASTERN
PACIFIC OCEAN, AND WITH IT THE UPPER LEVEL SHORTWAVE TROUGH WITH
AMPLE DIVERGENT CONDITIONS ALOFT. AS MOISTURE FROM THE SOUTH IS
ENTERING THE COASTS OF BAJA CALIFORNIA SUR, SONORA, AND SINALOA,
THIS WILL PROVIDE AMPLE MOISTURE FOR MODERATE TO HEAVY
PRECIPITATION IN THE REGION. THIS MOIST FLOW WILL INTERACT WITH
THE TERRAIN AND FAVOR GENERALIZED MAXIMA OF 20-45MM IN FROM NORTH
SONORA THROUGH THE CENTRAL SIERRA MADRE OCCIDENTAL, AS WELL AS IN
NORTH BAJA CALIFORNIA SUR. ON SATURDAY, THE FRONTAL BOUNDARY
BEGINS TO WEAKEN, BUT IT'S WESTERLY FLOW INTO THE SIERRA MADRE
OCCIDENTAL CONTINUES, NOW EXTENDING FURTHER SOUTH INTO SOUTHERN
SINALOA. WITH THE UPPER LEVEL SHORTWAVE TROUGH ENTERING INTO THE
REST OF NORTHWEST MEXICO, FAVORABLE INSTABILITY IN THE REGION WILL
ENHANCE THE POTENTIAL FOR HEAVY PRECIPITATION ALONG THE SIERRA
MADRE OCCIDENTAL. EXPECT MAXIMA TO RANGE BETWEEN 35-70MM. HIGHER
ELEVATIONS CAN EXPECT THE POTENTIAL FOR MOUNTAIN SNOW/RAIN MIX.
THE BAJA CALIFORNIA PENINSULA CAN EXPECT FURTHER IMPACT FROM THIS
SYSTEM ON SATURDAY WITH MAXIMA OF 20-45MM.
IN NORTHERN SOUTH AMERICA, THE AVAILABLE MOISTURE IS EXPECTED TO
REMAIN FURTHER SOUTH, INTO CENTRAL PORTIONS OF PERU AND BRASIL.
HOWEVER, WITH THE MOISTURE THAT IS AVAILABLE IN THE REGION EXPECT
DIURNAL HEATING TO PROVIDE FUEL FOR AFTERNOON THUNDERSTORMS OVER
THE REGION WITH THE PRESENCE OF TROUGHS IN THE LOWER LEVELS. ON
THURSDAY, WESTERN COLOMBIA CAN EXPECT MOIST ONSHORE FLOW TO
INTERACT WITH THE TERRAIN, AND MAXIMA COULD REACH 30-60MM, WITH A
POTENTIAL FOR LOCALLY HIGHER AMOUNTS. SIMILARLY, AMAPA-BRASIL AND
EASTERN FRENCH GUIANA CAN EXPECT MOISTURE ADVECTION ALONG THE
EASTERLY TRADE WINDS, FAVORING MAXIMA OF 25-50MM. ON FRIDAY, A
DECREASE IN MOIST ONSHORE IN WESTERN COLOMBIA WILL FAVOR MAXIMA OF
20-35MM, WHILE FRENCH GUIANA AND AMAPA REMAIN MOIST WITH THE
EASTERLY ONSHORE FAVORING MAXIMA OF 25-50MM, WITH POTENTIAL FOR
HIGHER AMOUNTS LOCALLY. ON SATURDAY, WESTERN COLOMBIA AND THE
GUIANAS MAY EXPECT A DECREASE IN MOISTURE THROUGHOUT THE DAY, AND
THUS EXPECT A DECREASE IN PRECIPITATION FOR THOSE REGIONS. OVER
THE AMAZON BASIN, MOISTURE WILL CONVERGE WHERE THE PERIPHERY OF
THE BOLIVIAN HIGH HAS ENHANCED DIFFLUENCE OVER THE REGION,
FAVORING DEEP CONVECTION ON SATURDAY, EXPECT HEAVY PRECIPITATION
IN THE CENTRAL AMAZON BASIN.
CASTELLANOS...(WPC)
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