781
FXCA20 KWBC 151928
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
327 PM EDT MON JUN 15 2026
FORECAST BULLETIN 15 JUNE 2026 AT 1930 UTC:
**CORRECTED VERSION ***
MEXICO AND NORTHERN CENTRAL AMERICA...
AN UPPER-LEVEL HIGH-PRESSURE SYSTEM IS FORECAST TO SPLIT INTO TWO
DISTINCT CIRCULATION CENTERS, ALLOWING A LOW-PRESSURE TROUGH TO
DEVELOP OVER NORTHEASTERN MEXICO LATE TODAY INTO TUESDAY. THIS
STRUCTURAL TRANSITION WILL FAVOR DEEP CONVECTION AREAS TO
REORGANIZE AND MIGRATE FROM THE WESTERN PERIPHERY OF THE LEGACY
HIGH-PRESSURE CENTER INTO NORTHEASTERN MEXICO. IN THE LOWER
TROPOSPHERE, STRONG SOUTHEASTERLY WINDS WILL DRIVE HUMID LOW-LEVEL
ADVECTION OVER THE GULF, ENHANCING PRECIPITABLE WATER AMOUNTS
ACROSS NORTHEASTERN AND EASTERN MEXICO. THESE CONDITIONS WILL
INTERACT WITH A LOW-PRESSURE TROUGH OVER NORTHEAST MEXICO AND
LOCAL OROGRAPHY TO PRODUCE SIGNIFICANT RAINFALL TODAY, WITH A
24-HOUR TOTAL PRECIPITATION MAXIMA OF 40 - 80MM LIKELY IN
TAMAULIPAS. ON TUESDAY, THIS TROUGH WILL TRACK INTO NORTHEAST
GULF; DISORGANIZED SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS
THE REGION, EVENTUALLY DIMINISHING BY WEDNESDAY. ADDITIONALLY, A
TROPICAL WAVE WILL BRING SIGNIFICANT RAIN ACCUMULATION TODAY, WITH
A TOTAL PRECIPITATION MAXIMA OF 40 - 60 MM ACROSS PARTS OF EL
SALVADOR, WESTERN HONDURAS AND SOUTHERN GUATEMALA. THIS PATTERN IS
SUPPORTED BY THE SPLIT OF AN UPPER LEVEL RIDGE WHICH WILL FAVOR A
LOW-PRESSURE TROUGH DEVELOPMENT LATE TODAY INTO TUESDAY, WHEN A
PEAK IN PRECIPITABLE WATER (PWAT) VALUES AND RAINFALL ACCUMULATION
IS FORECASTED. HIGHER PRECIPITATION TOTALS WILL BE EXPECTED BOTH
ALONG THE WESTERN COAST AND OFFSHORE.
CARIBBEAN AND THE BAHAMAS...
UPPER-LEVEL WIND CONFLUENCE INTERACTING WITH A SURFACE
HIGH-PRESSURE RIDGE WILL SUPPRESS SIGNIFICANT SHOWER ACTIVITY,
KEEPING THE REGION GENERALLY DRY. THIS STABLE, DRY PATTERN IS
FURTHER REINFORCED BY A SAHARAN AIR LAYER (SAL) DUST PLUME
CURRENTLY MIGRATING WESTWARD ACROSS THE BASIN.
NORTHERN SOUTH AMERICA AND SOUTH CENTRAL AMERICA...
AN UPPER-LEVEL DIFFLUENT PATTERN IS EXPECTED TO ESTABLISH FROM
WESTERN GUYANA TO PANAMA, INTERACTING WITH A SERIES OF TROPICAL
WAVES TODAY AND TUESDAY. THE FIRST TROPICAL WAVE AXIS WILL BE
POSITIONED OVER PANAMA AND WESTERN COLOMBIA; A SECOND WILL SPAN
EASTERN COLOMBIA AND MID-WESTERN VENEZUELA; AND A THIRD WILL SIT
BETWEEN VENEZUELA AND GUYANA TODAY. THESE SYSTEMS WILL TRIGGER
WIDESPREAD, SIGNIFICANT RAINFALL THROUGH THE FORECAST CYCLE. AS
THE FIRST TROPICAL WAVE CONTINUES ITS WESTWARD PROPAGATION, IT
WILL DYNAMICALLY INCREASE RAINFALL ACCUMULATIONS OVER COSTA RICA
ON TUESDAY AND WESTERN NICARAGUA BY WEDNESDAY. DAILY RAIN
ACCUMULATIONS OF 40 - 70MM ARE EXPECTED TO HAVE ACROSS EAST PANAMA
AND WESTERN COLOMBIA FOR TODAY, BEFORE THIS MAXIMUM AREA SHIFTS TO
WESTERN PANAMA AND NORTHERN COLOMBIA ON TUESDAY. BY WEDNESDAY, THE
MAIN CORE OF PRECIPITATION WILL BE LOCATED OFF-SHORE; WEST OF
COSTA RICA AND NICARAGUA; LEAVING A MAXIMUM TOTAL PRECIPITATION
MAXIMA OF 20 - 40MM ACROSS WESTERN NICARAGUA. CONVERSELY,
UPPER-LEVEL CONFLUENCE ALOFT AND SURFACE DRY ADVECTION WILL
MAINTAIN DRIER CONDITIONS OVER NORTHERN BRAZIL AND EASTERN GUYANA.
A BROADER DECREASE IN RAINFALL IS ANTICIPATED ACROSS THE BROADER
REGION BY WEDNESDAY AS A DRIER AIR MASS MOVES IN, ASSOCIATED WITH
A LOWER-LEVEL OF SAL DRY AREA AND AN UPPER-LEVEL HIGH-PRESSURE
SYSTEM MOVING IN FROM THE ATLANTIC BASIN INTO EAST TROPICAL SOUTH
AMERICA. REMAINING AREAS OF SIGNIFICANT PRECIPITATION WILL
PRIMARILY BE DRIVEN BY OROGRAPHIC LIFT IN AREAS BETWEEN COLOMBIA
AND VENEZUELA.
TROPICAL WAVES:
SOF INIT 16/00 16/12 17/00 17/12 18/00 18/12 19/00 19/12
13N 59W 63W 66W 69W 72W 74W 78W 81W 84W
15N 69W 72W 74W 77W 80W 83W 86W 89W 93W
12N 75W 77W 80W 83W 86W 89W 91W 94W DISS
18N 84W 87W 90W 92W 95W 98W DISS --- ---
08N 93W 96W 98W 100W 102W 105W DISS --- ---
SANCHEZ-PEREZ...(WPC)
TINOCO-MORALES...(WPC)
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