507
FXCA20 KWBC 111837
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
236 PM EDT MON MAY 11 2026
FORECAST BULLETIN 11 MAY 2026 AT 1900 UTC:
MEXICO AND CENTRAL AMERICA:
LOW-LEVEL MOISTURE CONVERGENCE IS EXPECTED TO INCREASE OVER
VERACRUZ AND TAMAULIPAS AS A FRONTAL BOUNDARY APPROACHES THE
REGION TODAY THROUGH TUESDAY MORNING. THIS, COMBINED WITH A
WESTWARD PROPAGATING A LOW-LEVEL TROUGH, WILL FURTHER INCREASE
INSTABILITY IN THE AREA. REMNANTS OF THE FRONTAL BOUNDARY AND
LOW-LEVEL TROUGHING WILL BRING ADDITIONAL PRECIPITATION ALONG THE
SIERRA MADRE ORIENTAL FROM TUESDAY THROUGH WEDNESDAY.
IN CENTRAL MEXICO, AN APPROACHING TROUGH WILL SUPPORT CONVECTIVE
ACTIVITY THROUGH EARLY TUESDAY AS IT WILL INCREASE UPPER-LEVEL
DIVERGENCE IN THE REGION. LESS SUPPORT IS EXPECTED FROM
UPPER-LEVELS FROM TUESDAY THROUGH WEDNESDAY AS THE FLOW BECOMES
MORE ZONAL. BY THURSDAY, AN UPPER-LEVEL HIGH DEVELOPING OVER
WESTERN MEXICO WILL BRING MORE STABLE CONDITIONS.
OVER GUERRERO AND PORTIONS OF OAXACA, PRECIPITATION IS ALSO
EXPECTED TODAY THROUGH TUESDAY WITH A LOW-LEVEL TROUGH PROPAGATING
OVER THE PACIFIC COAST. THEN ON TUESDAY, THE DEVELOPMENT OF THE
TEHUANTEPECER LOW-LEVEL JET WILL DECREASE PRECIPITATION OVER THE
OAXACA AND CHIAPAS REGION, BUT LIGHT RAINFALL WILL CONTINUE OVER
GUERRERO AND MICHOACAN THROUGH THURSDAY DUE TO MOISTURE ADVECTION
DRIVEN BY A LOW-LEVEL TROUGH. DAILY TOTALS WILL REACH 20-35MM FROM
TUESDAY THROUGH THURSDAY.
MOSTLY STABLE CONDITIONS ARE EXPECTED OVER CENTRAL AMERICA, WITH
DRY AIR PRESENT OVER BELIZE, GUATEMALA, EL SALVADOR, HONDURAS AND
NICARAGUA THROUGHOUT THE FORECAST PERIOD. STABILITY WILL BE
FURTHER ENHANCED WITH THE PRESENCE OF THE PAPAGAYO LOW-LEVEL JET.
OVER COSTA RICA AND PANAMA, EXPECT LIGHT DAILY PRECIPITATION DUE
TO MOISTURE ADVECTION AND THE PRESENCE OF THE MONSOON TROUGH
INCREASE LOW-LEVEL CONVERGENCE IN THE REGION. A PROPAGATING
LOW-LEVEL TROUGH SHOULD INCREASE PRECIPITATION FROM TUESDAY
THROUGH WEDNESDAY OVER NORTHERN COSTA RICA AND PORTIONS OF
NICARAGUA.
TROPICAL SOUTH AMERICA:
HEAVY PRECIPITATION IS EXPECTED TODAY OVER THE NORTHWEST, CENTRAL
AND EASTERN AMAZON REGION, IMPACTING ECUADOR, COLOMBIA, PORTIONS
OF PERU AND BRAZIL. THIS HEAVY PRECIPITATION COMES AS A RESULT OF
AN INCREASE IN THE CONVERGENCE OF LOW-LEVEL WINDS PROMOTED BY A
DISSIPATING FRONTAL BOUNDARY AND THE PRESENCE OF DEEP MOISTURE IN
THE REGION. FURTHER SUPPORT FROM UPPER-LEVELS IS EXPECTED,
PARTICULARLY TODAY THROUGH TUESDAY WITH THE ENHANCEMENT OF
UPPER-LEVEL DIFFLUENCE DUE TO THE PRESENCE OF AN UPPER-LEVEL
TROUGH FURTHER SOUTH IN THE CONTINENT AND UPPER-LEVEL RIDGING OVER
THE NORTHERN PORTION OF THE CONTINENT. THE HEAVY PRECIPITATION AND
THUNDERSTORMS ACTIVITY WILL SHIFT FURTHER NORTHEAST IMPACTING
MOSTLY VENEZUELA AND BRAZIL AS LOW-LEVEL MOISTURE CONVERGENCE
INCREASES IN THAT REGION AND THE PRESENCE OF LOW-LEVEL TROUGHS
CONTINUE SUPPORTING INSTABILITY. AT MID- AND UPPER-LEVELS
CONDITIONS WILL ENHANCE DEEP CONVECTION AND THUNDERSTORM ACTIVITY.
HEAVY PRECIPITATION CAN ALSO BE EXPECTED OVER THE GUIANAS
THROUGHOUT THE FORECAST PERIOD WITH THE PRESENCE OF THE ITCZ
INCREASING LOW-LEVEL CONVERGENCE AND LOW-LEVEL TROUGHS
PROPAGATING WESTWARD INCREASING THE ADVECTION OF DEEP MOISTURE
FROM THE ATLANTIC THROUGHOUT THE CONTINENT.
DAILY RAINFALL IS FORECAST FOR THE WESTERN PACIFIC COAST OF
ECUADOR AND COLOMBIA, WITH THE PRESENCE OF DEEP MOISTURE IN THE
REGION, AND LOW-LEVEL WINDS ADVECTION MOISTURE INTO THE COAST.
FURTHER ENHANCEMENT IN THE PRECIPITATION DUE TO DIURNAL HEATING
AND LOCAL EFFECTS IS LIKELY, PRODUCING DAILY ACCUMULATIONS THAT
WILL RANGE BETWEEN 20-45MM.
THE BAHAMAS AND CARIBBEAN:
STABLE CONDITIONS ARE EXPECTED TO CONTINUE TODAY THROUGH TUESDAY
MORNING OVER THE REGION, AS A HIGH AT MID- AND UPPER-LEVELS
PREVAIL IN THE AREA. LIGHT ISOLATED RAINFALL IS FORECAST OVER THE
ISLANDS DUE MOISTURE ADVECTION, LOW-LEVEL TROUGHS, DIURNAL HEATING
AND LOCAL EFFECTS. TOTALS ARE LIKELY TO REMAIN UNDER 15MM OVER
MOST OF THE REGION. AS A FRONTAL BOUNDARY APPROACHES THE BAHAMAS
ON TUESDAY, AN INCREASE IN RAINFALL IS EXPECTED, WITH THE INCREASE
IN THE PRECIPITABLE WATER AVAILABILITY AND ENHANCEMENT OF
LOW-LEVEL CONVERGENCE. A MARGINAL RISK OF SEVERE WEATHER EXISTS
FOR THE NORTHERN BAHAMAS, WITH ACCUMULATIONS OF RAINFALL BETWEEN
20-35MM. THE PRESENCE OF LOW-LEVEL TROUGHS OVER CUBA, IN
COMBINATION WITH THE INCREASE IN PRECIPITABLE WATER AVAILABILITY
IN THE AREA WILL ALSO BRING PRECIPITATION TO THE ISLAND, STARTING
ON TUESDAY THROUGH THURSDAY MORNING, WITH RAINFALL TOTALS BETWEEN
20-35MM EACH DAY. ELSEWHERE ACROSS THE CARIBBEAN, A SEASONABLE
PATTERN IS EXPECTED TO CONTINUE THROUGHOUT THE END OF THE FORECAST
PERIOD.
RIVERA-TORRES...(WPC)
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