TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
302 PM EDT THU JUL 25 2024

FORECAST BULLETIN 25 JUL 2024 AT 1900 UTC: ANOTHER PLUME OF
RELATIVELY DENSE SAHARAN DUST IS MAKING ITS WAY INTO THE CARIBBEAN
TODAY. THIS PLUME OF SAHARAN DUST WILL MOVE THROUGH THE CARIBBEAN
OVER THE NEXT FEW DAYS...MOST NOTABLY AFFECTING THE GREATER
ANTILLES AND THE BAHAMAS THIS WEEKEND. LOWER CONCENTRATIONS OF
SAHARAN DUST  COULD MOVE INTO THE YUCATAN PENINSULA AND PORTIONS
OF NORTHERN CENTRAL AMERICA BY SUNDAY AFTERNOON. CURRENTLY...THERE
IS HIGHER THAN NORMAL MOISTURE ACROSS THE CARIBBEAN
WATERS...SOUTHERN CENTRAL AMERICA AND NORTHERN SOUTH AMERICA.
THERE IS ALSO A NARROW BAND OF MOISTURE MOVING THROUGH
HISPANIOLA...ASSOCIATED WITH A TROPICAL WAVE MOVING THROUGH.
CENTRAL TO NORTHEASTERN MEXICO ALSO HAS ABOVE NORMAL MOISTURE.
THAT BEING SAID...THE DENSE SAL MOVING INTO THE CARIBBEAN WILL
CAUSE DRIER AIR TO MOVE IN...AND BY SUNDAY...MOST OF THE EASTERN
TO CENTRAL CARIBBEAN WILL HAVE BELOW NORMAL MOISTURE.

ACCORDING TO THE NATIONAL HURRICANE CENTER...THERE IS NO CYCLONE
ACTIVITY EXPECTED OVER THE NEXT 7 DAYS ACROSS THE ATLANTIC BASIN.
HOWEVER...THERE IS A TROPICAL STORM IN THE EASTERN PACIFIC...NAMED
BUD...WHICH IS EXPECTED TO CONTINUE MOVING WEST OVER THE OPEN
WATERS. 

AT THE SURFACE...A STRONG HIGH PRESSURE CONTINUES TO DOMINATE THE
ATLANTIC...CAUSING EASTERLY TO SOUTHEASTERLY WINDS ACROSS THE
ATLANTIC...CARIBBEAN AND THE GULF OF MEXICO. A SFC LOW OVER THE
SOUTHERN CARIBBEAN...COMMONLY KNOWN AS THE PANAMANIAN LOW...IS
CAUSING A TIGHTENING OF THE PRESSURE GRADIENT ACROSS THE CARIBBEAN
SEA AND THEREFORE LOCALLY STRONGER WINDS OVER THE CARIBBEAN
WATERS. THIS SFC LOW WILL MEANDER OVER THE SOUTHERN CARIBBEAN FOR
THE NEXT FEW DAYS...CAUSING PERSISTENT LOCALLY STRONGER WINDS OVER
THE CARIBBEAN...BUT ALSO CAUSING MOISTURE CONVERGENCE OVER COSTA
RICA AND PANAMA...ESPECIALLY ON FRIDAY INTO SATURDAY WHEN ANOTHER
SFC LOW MOVES ACROSS THE EASTERN PACIFIC AND CAUSES PLENTY OF
MOISTURE CONVERGENCE OVER COSTA RICA AND WESTERN PANAMA. THIS SFC
LOW AND INCREASE IN MOISTURE WILL MOVE WEST AND CAUSE SIGNIFICANT
RAIN ACROSS NICARAGUA AND NORTHERN HONDURAS ON SATURDAY INTO
SUNDAY.

THE UPPER LEVELS ARE PROVIDING SOME SUPPORT FOR CONVECTION ACROSS
THE WESTERN GULF OF MEXICO AND INTO PORTIONS OF CENTRAL MEXICO.
THIS IS DUE TO AN UPPER TROUGH OVER CENTRAL US INTO NORTHERN
MEXICO COMBINING WITH DEEP MOISTURE OVER THE AREA. THERE IS
ANOTHER UPPER LOW...THIS ONE ACROSS THE WESTERN TROPICAL ATLANTIC
JUST EAST OF THE BAHAMAS...WHICH WILL CAUSE ENOUGH INSTABILITY TO
PROMOTE THE DEVELOPMENT OF SQUALLY WEATHER ACROSS THE SOUTHERN
BAHAMAS...TURKS AND CAICOS AND INTO CUBA. HOWEVER...THE AVAILABLE
MOISTURE IS LIMITED OVER THE AREA...THOUGH AN INCREASE IN MOISTURE
OVER CUBA ON FRIDAY WILL ALLOW FOR HEAVIER RAIN SHOWERS OVER
CUBA...WITH ISOLATED MAX AMOUNTS OF RAIN OF OVER 50MM ON FRIDAY
INTO SATURDAY.

ABOVE NORMAL MOISTURE OVER MEXICO WILL COMBINE WITH THE
AFOREMENTIONED UPPER TROUGH ACROSS NORTHERN MEXICO TO CAUSE
PERSISTENT SHOWER ACTIVITY OVER CENTRAL AND NORTHEASTERN MEXICO
FOR THE NEXT FEW DAYS. EVEN THOUGH THE SIERRA MADRE OCCIDENTAL IN
MEXICO IS ON THE CONVERGENT SIDE OF THE UPPER TROUGH...THE LOW
LEVEL WIND FLOW WILL BE FROM THE EASTERN PACIFIC INTO THE SIERRA
MADRE OCCIDENTAL...WHICH WILL PROVIDE MOISTURE TO MOVE INLAND AND
SHOWER ACTIVITY IS EXPECTED TO DEVELOP DUE TO OROGRAPHIC
LIFTING...ESPECIALLY ON FRIDAY AND SATURDAY.

ACROSS CENTRAL AMERICA...THE LOCATIONS WITH MOST PRECIPITATION ARE
EXPECTED TO BE AREAS IN AND AROUND COSTA RICA AND PANAMA...DUE TO
THE AFOREMENTIONED SFC LOW PRESSURE AND PERSISTENT DEEP MOISTURE
OVER THE AREA. ONE DAY TO PAY ATTENTION TO IS FRIDAY INTO
SATURDAY...THE GFS MODEL IS STILL VERY BULLISH WITH ITS RAINFALL
FORECAST...SUGGESTING UP TO 100MM AND A RISK OF MCS OVER WESTERN
PANAMA INTO COSTA RICA. THE ECMWF IS NOT AS BULLISH WITH THE
AMOUNTS...BUT CONSIDERING THE DEEP MOISTURE CONVERGENCE AND THE
LOCAL TOPOGRAPHY AND THE DIVERGENCE IN THE UPPER LEVELS...HAVING
ISOLATED AREAS OF OVER 100MM SEEMS VERY POSSIBLE. THE CARIBBEAN
COAST OF NICARAGUA AND HONDURAS WILL HAVE SIGNIFICANT AMOUNTS OF
RAIN OVER THE NEXT FEW DAYS AS WELLY...WITH MAX VALUES NEAR
20-45MM AS THE SFC LOW MOVES CLOSER TO NICARAGUA. THEN EVEN HIGHER
AMOUNTS ON FRIDAY INTO EARLY SATURDAY ACROSS NICARAGUA...THOUGH
SATURDAY INTO SUNDAY MAY BE THE RAINIEST DAY OVER NICARAGUA...AND
THE GFS MODEL IS SUGGESTING MAX VALUES OF OVER 100MM OVER
NICARAGUA AND POSSIBLY INTO NORTHERN COASTAL HONDURAS. OVERALL
ACROSS CENTRAL AMERICA...THE LATEST GFS MODEL IS SUGGESTING
ISOLATED 3-DAY TOTAL AMOUNTS OF OVER 150MM ACROSS PORTIONS OF
WESTERN PANAMA...THROUGH COSTA RICA...INTO EASTERN NICARAGUA AND
NORTHERN HONDURAS.

NORTH CENTRAL TO NORTHWESTERN COLOMBIA WILL HAVE LOCALIZED AMOUNTS
OF RAIN NEAR 50MM TODAY. FRIDAY INTO SATURDAY...A PASSING TROPICAL
WAVE AND A SFC TROUGH WILL COMBINE TO CAUSE POSSIBLE MAX RAINFALL
VALUES OF 40-75MM OVER COLOMBIA. ACROSS VENEZUELA...EVEN THOUGH
THE MID TO UPPER LEVELS ARE NOT CONDUCIVE FOR ENHANCED CONVECTIVE
SUPPORT...THE LOW LEVEL WINDS AND DEEP MOISTURE WILL COMBINE WITH
THE OROGRAPHIC LIFTING OVER THE MOUNTAINOUS TERRAIN TO CAUSE DAILY
SHOWERS AND THUNDERSTORMS. ACROSS THE CARIBBEAN ISLANDS AND INTO
THE BAHAMAS...MODEST AMOUNTS OF RAIN ARE EXPECTED OVER THE NEXT
FEW DAYS GIVEN THE RELATIVELY DRY AIR. THE GLOBAL MODEL GUIDANCE
CONTINUES TO SUGGEST MAX VALUES OF ABOUT 50MM OVER ISOLATED AREAS
FOR A 3-DAY TOTAL PRECIPITATION. HOWEVER...THE MODELS HAVE
ADJUSTED OVER CUBA AND HAVE HIGHER VALUES OF RAIN...TO AROUND
60-75MM FOR A 3-DAY TOTAL...GIVEN THE INCREASE IN MOISTURE AND
POSSIBLE STRONG STORMS OVER THE AREA.


ALAMO...(WPC)
FERNANDER...(BDM)
CLARKE...(CINWS)