705
FXCA20 KWBC 171730
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
130 PM EDT FRI APR 17 2026
FORECAST BULLETIN 17 APRIL 2026 AT 1735 UTC:
NOTE: THE INTERNATIONAL DESK PRODUCTS WILL BE INTERMITTENT FOR THE
PERIOD OF APRIL 20, 2026 THROUGH APRIL 24, 2026. SERVICES WILL
RESUME AT FULL CAPACITY ON APRIL 27, 2026. APOLOGIES FOR THE
INCONVENIENCE.
IN THE UPPER LEVELS...
AN UPPER LEVEL TROUGH THAT HAS BEEN SITUATED OVER THE NORTHERN
CARIBBEAN AND EXTENDING INTO THE CARIBBEAN SEA WILL BEGIN TO LOSE
DEFINITION AT THE END OF THE WEEKEND. DURING THIS PERIOD, ANOTHER
UPPER LEVEL TROUGH WILL BE MOVING INTO NORTHWEST MEXICO AND IT
WILL DISPLACE A RIDGE THAT HAS BEEN PRESENT OVER SOUTHERN MEXICO
AND CENTRAL AMERICA. IN PARTICULAR, THE NORTHERN PERIPHERY OF THE
RIDGE WILL BE MOVING SOUTHWARD AND IT WILL EVENTUALLY BE LOSING
ITS DEFINITION BY EARLY NEXT WEEK. EXPECT A DECREASE IN UPPER
LEVEL SUPPORT WITH PASSING DAYS ACROSS CENTRAL AMERICAN AND THE
EASTERN GREATER ANTILLES WITH THE AFOREMENTIONED UPPER LEVEL
PATTERN.
ACROSS NORTHEAST MEXICO...
TWO JET STREAK MAXES WILL BE TRAVERSING THE REGION ON SATURDAY AND
SUNDAY, WHICH WILL SUPPORT UPPER DIVERGENCE. AT THE SURFACE, A
COLD FRONT WILL ARRIVE IN THE AREA ON SATURDAY AND IT WILL EXTEND
INTO NUEVO LEON AND COAHUILA IN THE EVENING. BY SUNDAY EVENING,
THE FRONTAL BOUNDARY WILL BE OVER NORTHERN TAMAULIPAS AND NUEVO
LEON. WITH THE ARRIVAL OF THE FRONT, THE LOW LEVEL WINDS WILL
CHANGE TO AN EASTERLY DIRECTION, PROMOTING MOISTURE POOLING AND
CONVERGENCE ALONG THE GULF COAST. THUS, THERE WILL BE DAILY
MODERATE TOTAL PRECIPITATION MAXIMA ALONG NORTHEAST MEXICO. ALONG
THE CENTRAL AND SOUTHERN GULF COAST, EASTERLY LOW LEVEL WINDS WILL
INCREASE ON SUNDAY AND IT WILL SUPPORT MOISTURE POOLING AS WELL.
LIGHT TO MODERATE DAILY TOTAL PRECIPITATION MAXIMA IS LIKELY WITH
THE AFOREMENTIONED CONDITIONS FOR SUNDAY.
ACROSS THE GREATER ANTILLES AND THE BAHAMAS....
ANOTHER REGION THAT WILL BE AFFECTED BY THIS FRONTAL BOUNDARY AT
THE START OF THE WEEK WILL BE THE BAHAMAS. THERE IS INDICATION
THAT THE FRONT WILL ENTER THE BAHAMAS DURING THE DAY ON MONDAY AND
IS EXPECTED TO MEANDER ACROSS THE NORTH-CENTRAL BAHAMAS FOR
TUESDAY AND WEDNESDAY.
MEANWHILE ACROSS THE EAST GREATER ANTILLES, A DECAYING INDUCED
TROUGH WILL BE PROPAGATING ACROSS HISPANIOLA ON FRIDAY. AS THE
TROUGH DECAYS, EASTERLY LOW LEVEL WINDS WILL DOMINATE ACROSS
HISPANIOLA, PUERTO RICO, AND THE VIRGIN ISLANDS (VI) FOR THE REST
OF THE FORECAST CYCLE. EXPECT DRY AIR ADVECTION AFTER SATURDAY AS
THE SUBTROPICAL HIGH (BERMUDA HIGH) WILL BE TRANSPORTING DRIER AIR
INTO THE NORTHERN CARIBBEAN. THUS, THE MOST INTENSE TOTAL
PRECIPITATION MAXIMA WILL BE ON FRIDAY AND DECREASING WITH PASSING
DAYS. ALSO, MID-TO-UPPER LEVEL SUBSIDENCE WILL BE PRESENT IN THE
REGION AS THE AFOREMENTIONED UPPER TROUGH WILL BE MOVING EASTWARD
AND LEAVING THE AREA UNDER THE ENTRANCE REGION.
ACROSS TROPICAL SOUTH AMERICA...
ACROSS THE WESTERN AND CENTRAL AMAZON BASIN, ON FRIDAY, THERE WILL
BE LOW LEVEL WIND FLOW CONFLUENCE THAT WILL SUPPORT MOISTURE
CONVERGENCE. WHILE AT THE MID-LEVELS, EASTERLY WINDS WILL BE
PRESENT IN THE REGION. STARTING SATURDAY, A WESTERLY WIND WILL
BEGIN TO DOMINATE ACROSS THE WEST AND NORTHWEST AMAZON BASIN,
WHICH WILL LEAD TO SUBSIDENCE IN THE REGION. THE EASTERLY AND
WESTERLY LOW-TO-MID LEVEL WINDS ARE EXPECTED TO CONVERGE ACROSS
THE WEST-CENTRAL AMAZON BASIN, LEADING TO AN ENHANCEMENT IN
MOISTURE CONVERGENCE. STILL, LOW LEVEL MOISTURE WILL STILL BE
PRESENT IN THE WEST AND NORTHWEST AMAZON ON SATURDAY AND
PRECIPITATION WILL BE LOCALIZED. BY SUNDAY, THERE WILL BE A
SIGNIFICANT DECREASE IN PRECIPITABLE WATER ACROSS THIS REGION AS
NORTHEASTERLY WINDS WILL BEGIN TO DOMINATE AND WILL TRANSPORT DRY
AIR FROM THE CARIBBEAN.
ACROSS THE AMAZON DELTA AND THE GUIANAS, A MID-LEVEL RIDGE IS
CURRENTLY PRESENT IN THE REGION AND WILL BEGIN TO LOSE DEFINITION
ON SUNDAY. AS THE RIDGE WEAKENS, EXPECT THE RETURN OF LONG FETCH
LOW-TO-MID LEVEL EASTERLY WINDS INTO THE GUIANAS. ALSO, THE
MOISTURE PLUME ASSOCIATED WITH THE INTERTROPICAL CONVERGENCE ZONE
(ITCZ) WILL SHIFT NORTHWARD INTO THE GUIANAS, LEADING TO AN
INCREASE IN TOTAL PRECIPITATION MAXIMA FOR SUNDAY. ON FRIDAY AND
SATURDAY, THE MOISTURE PLUME WILL BE CONVERGING INTO THE AMAZON
DELTA. EMBEDDED WITHIN THESE PLUMES, EXPECT THE PRESENCE OF LOW
LEVEL TROUGHS THAT ARE ANTICIPATED TO MOVE INTO THE CONTINENT FOR
THE NEXT THREE DAYS.
TINOCO-MORALES...(WPC)
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