877
FXCA20 KWBC 131959
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
358 PM EDT FRI OCT 13 2023
FORECAST BULLETIN 13 OCT 2023 AT 1930 UTC: THE MODEL GUIDANCE ONCE
AGAIN DISAGREE SIGNIFICANTLY IN THE COVERAGE AND AMOUNT OF
RAIN...AND IT SEEMS TO ONCE AGAIN HAVE A BIAS TOWARDS MORE PRECIP
ON THE THIRD DAY OF THE FORECAST PERIOD. THAT BEING SAID...THERE
MAY BE A LEGITIMATE REASON FOR THE INCREASE IN RAIN FOR SUNDAY
INTO MONDAY...ESPECIALLY ACROSS SOUTHERN MEXICO. THE GFS MODEL
SEEMS TO BE MORE AGGRESSIVE...BUT WITH THE ISOLATED HIGHER
AMOUNTS...THE ECMWF MODEL KEEPS SUGGESTING A MORE MODERATE MAX
PRECIP BUT IS MORE GENEROUS WITH THE COVERAGE AND LOW PRECIP AREAL
COVERAGE. CONSIDERING THE RECENT MODEL PERFORMANCE...WE DECIDED TO
ONCE AGAIN CAP THE VERY HIGH ISOLATED RAINFALL AMOUNTS...BUT SHOW
A GENERAL TREND OVER AREAS THAT WOULD BE RECEIVING SIGNIFICANT
RAINFALL. PLEASE BE AWARE THAT AMOUNTS COULD BE HIGHER THAN THE
RANGE IN THE FORECAST OVER VERY ISOLATED AREAS...WITH PARTICULAR
ATTENTION OVER PORTIONS OF SOUTHERN MEXICO...ACROSS
VERACRUZ...TABASCO AND CHIAPAS ON SUNDAY INTO MONDAY.
A SFC HIGH PRESSURE IS EXTENDING FROM THE EAST TROPICAL ATLANTIC
INTO THE CENTRAL TROPICAL ATLANTIC. A SFC LOW PRESSURE IS MOVING
EAST FROM THE WEST TROPICAL ATLANTIC TO THE CENTRAL
ATLANTIC...JUST NORTH OF THE HIGH PRESSURE RIDGE...THIS LOW
PRESSURE HAS AN ASSOCIATED COLD FRONT AND STATIONARY FRONT THAT
WILL REMAIN NORTH OF THE CARIBBEAN ISLANDS AS IT WEAKENS. ANOTHER
SURFACE LOW WILL BE LOCATED OVER SOUTHEAST GEORGIA BY SATURDAY AND
THEN FURTHER NORTHEAST ACROSS THE MID-ATLANTIC STATES OF THE U.S.
BY SUNDAY...WHICH WILL BRING A STRONG COLD FRONT THAT WILL MOVE
SOUTH THROUGH THE SOUTHEAST U.S. INTO THE GULF OF MEXICO AND
REACHING SOUTHERN MEXICO BY LATE SUNDAY. IN THE MID LEVELS THERE
IS A BROAD HIGH PRESSURE CENTERED OVER THE SOUTHWEST
ATLANTIC...CAUSING SOME STABILITY OVER THE GENERAL AREA TODAY AND
SATURDAY...AS THE HIGH PRESSURE DRIFTS SLOWLY TO THE WEST.
HOWEVER...BY LATE SUNDAY INTO MONDAY...THE HIGH PRESSURE WEAKENS
AND A MID LEVEL TROUGH WILL AMPLIFY SOUTH WITH ITS AXIS SLOWLY
DIGGING OVER THE WEST CENTRAL GULF OF MEXICO...THIS WILL CAUSE
SOME INSTABILITY IN AREAS AHEAD OF THE COLD FRONT THAT IS ALSO
MOVING THROUGH THE GULF OF MEXICO. ANOTHER BROAD AREA OF HIGH
PRESSURE IS PRESENT IN THE UPPER LEVELS AND IS CENTERED OVER
CUBA...THIS WILL ALSO HELP PROMOTE SOME STABILITY AND IT IS NEARLY
STATIONARY...BUT IT IS WEAK OVER THE WEST GULF OF MEXICO BY LATE
SUNDAY INTO MONDAY.
CONSIDERING THE BROAD MID AND UPPER LEVEL HIGH PRESSURES OVER THE
CARIBBEAN...MODEST AMOUNTS OF RAIN WOULD BE EXPECTED TODAY ACROSS
THE CARIBBEAN...CENTRAL AMERICA AND MEXICO...WITH MOST OF THE
EXPECTED RAINFALL TODAY DUE TO WIND FLOW AND OROGRAPHIC LIFTING.
MOST AREAS IN THE BASIN THAT EXPECT SOME RAIN TODAY WOULD BE IN
THE ORDER OF 01-10MM WITH MAX VALUES BETWEEN 15-25MM.
HOWEVER...PORTIONS OF COSTA RICA AND WESTERN PANAMA COULD OBSERVE
UP TO 45MM IN ISOLATED AREAS. THUNDERSTORMS ARE EXPECTED TODAY
ACROSS MANY SECTORS OF COLOMBIA AND NORTHWESTERN ECUADOR...WITH
MAX VALUES OF AROUND 40-80MM...BUT EASTERN COLOMBIA AND WESTERN
VENEZUELA WOULD HAVE MAX TOTALS OF AROUND 25-50MM. THE CARIBBEAN
IS EXPECTED TO SEE LITTLE TO NO RAIN INTO THE WEEKEND...THAT
IS...WITH THE EXCEPTION OF VERY ISOLATED AMOUNTS OF 25MM OR HIGHER
ACROSS CENTRAL TO WESTERN PR AND CENTRAL HISPANIOLA...MOST OTHER
AREAS IN THE CARIBBEAN WOULD OBSERVE 15MM OR LESS THROUGH THE
WEEKEND.
FOR SATURDAY INTO SUNDAY...ACROSS THE SOUTHERN HALF OF
MEXICO...ESPECIALLY ACROSS PORTIONS OF SOUTHERN VERACRUZ...TABASCO
AND CHIAPAS...AS WELL AS WESTERN COLOMBIA...AND PORTIONS OF
NORTHWESTERN ECUADOR...SHOWERS AND THUNDERSTORMS ARE
FORECAST...WITH MAX VALUES UP TO 30-80MM WITH THE STRONGEST
STORMS. PORTIONS OF NORTHERN PERU COULD HAVE SOME STORMS AS
WELL...THOUGH AMOUNTS UP TO 50MM OR SO WOULD BE EXPECTED.
ELSEWHERE IN THE TROPICAL REGION...RAINFALL AMOUNTS UP TO 15-25MM
COULD BE EXPECTED...THOUGH ONCE AGAIN THE CARIBBEAN SEEMS TO BE
FAIRLY DRY WITH LITTLE IN THE WAY OF SIGNIFICANT RAINFALL
COVERAGE. SUNDAY INTO MONDAY LOOKS PARTICULARLY RAINY WITH
THUNDERSTORMS ACROSS THE SAME PORTIONS OF SOUTHERN MEXICO...NAMELY
SOUTHERN VERACRUZ...TABASCO AND CHIAPAS. THIS IS BECAUSE OF
PERSISTENT NORTHERLY WIND FLOW...WHICH BY SUNDAY WILL COMBINE WITH
LIFTING OF A COLD FRONT MOVING IN AND A STRENGTHENING MID LEVEL
TROUGH THAT WOULD AFFECT THE AREA. WESTERN PANAMA AND COSTA RICA
WOULD HAVE WIND FLOW CONVERGENCE AND THUNDERSTORMS ARE ALSO
FORECAST ON SUNDAY INTO MONDAY...CAUSING MAX VALUES BETWEEN
40-80MM. IN ADDITION...THE LATEST GUIDANCE HAS AN AREA OF WIDELY
SCATTERED THUNDERSTORMS ACROSS PORTIONS OF WESTERN
BRAZIL...SOUTHERN VENEZUELA AND SOUTHEAST COLOMBIA...WHICH COULD
CAUSE STRONG STORMS WITH MAX RAINFALL OF 40-80MM...A SMALL PORTION
OF SOUTHWEST COLOMBIA AND NORTHERN ECUADOR COULD SEE STRONG
THUNDERSTORMS AS WELL.
ALAMO...WPC (USA)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page