TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
310 PM EDT TUE SEP 10 2024

FORECAST BULLETIN 10 SEPT 2024 AT 1900 UTC:

THE NATIONAL HURRICANE CENTER CONTINUES TO ISSUE  ADVISORIES ON
TROPICAL STORM FRANCINE...WHICH IS FORECAST TO BECOME A HURRICANE
BY THIS EVENING. FRANCINE IS CURRENTLY LOCATED ON THE WESTERN GULF
OF MEXICO...AT AROUND 210 KM ESE OF THE MOUTH OF THE RIO GRANDE.
FRANCINE IS FORECAST TO MOVE NORTH NORTHEAST OVER THE NEXT DAY OR
SO BEFORE MAKING LANDFALL IN THE STATE OF LOUISIANA ON WEDNESDAY
EVENING. EVEN THOUGH FRANCINE IS FORECAST TO REMAIN OFFSHORE
NORTHEASTERN MEXICO TODAY...THERE IS THE POTENTIAL OF SIGNIFICANT
RAINFALL OVER NORTHEASTERN TIP OF TAMAULIPAS...CAUSING RAINFALL
TOTALS RANGING FROM 25 TO 100MM. PLEASE SEE THE LATEST OFFICIAL
ADVISORY BY THE NATIONAL HURRICANE CENTER.

ACROSS THE ATLANTIC BASIN...THERE ARE A FEW LOW PRESSURES THAT
HAVE DEVELOPED ALONG THE MONSOON TROUGH. ONE OF THE LOW PRESSURES
IS LOCATED NEAR 13N/53W...15N/42W...AND 13N/34W. THE MODEL
GUIDANCE IS CONSISTENT TO WHAT IT SUGGESTED YESTERDAY WITH REGARDS
TO THESE LOW PRESSURES ALONG THE MONSOON TROUGH. THE LOW PRESSURES
AT 53W AND 43W ARE NEARLY STATIONARY BUT WILL EVENTUALLY MOVE
SLOWLY WEST. THE LATEST MODEL GUIDANCE HAS CHANGED FROM THE
SOLUTION IT PRESENTED YESTERDAY. IT NOW SUGGESTS THAT THE LOW
PRESSURES WILL MOVE WEST...REMAINING SEPARATE SYSTEMS  AS THEY
MOVE TO THE WEST TO WEST NORTHWEST...WEAKENING AS THEY APPROACH
THE LESSER ANTILLES. THE LOW PRESSURE FURTHER EAST...NEAR 34W
COULD MERGE WITH A SPEEDING AND DEVELOPING TROPICAL WAVE CURRENTLY
NEAR THE CABO VERDE ISLANDS...THEN MOVE NORTH INTO THE OPEN
ATLANTIC AS IT STRENGTHENS.

A TROPICAL WAVE CURRENTLY NEAR 74W WILL CONTINUE TO MOVE WEST OVER
THE NEXT FEW DAYS. THIS TROPICAL WAVE WILL  MOVE INTO CENTRAL
AMERICA BY WEDNESDAY EVENING. AS IT MOVES WEST...IT WILL INTERACT
WITH THE PANAMANIAN LOW...ENHANCING THE AVAILABLE MOISTURE AND
INCREASING THE CHANCES OF SHOWERS ACROSS PORTIONS OF SOUTHERN
CENTRAL AMERICA...ESPECIALLY EASTERN NICARAGUA AND PORTIONS OF
COSTA RICA AND PANAMA. ANOTHER TROPICAL WAVE...NEAR 99W IS
EXPECTED TO MOVE WEST FOR THE NEXT FEW DAYS. AS THIS WAVE MOVES
WEST IT WILL EVENTUALLY INTERACT WITH A BROADER AREA OF LOW
PRESSURE LOCATED OFFSHORE OF WESTERN MEXICO. THIS WAVE AND LOW
PRESSURE WILL CAUSE DEEP MOISTURE TO MOVE INTO THE WEST COAST OF
MEXICO...CAUSING SIGNIFICANT RAIN OVER THE WEST COAST OF MEXICO
OVER THE NEXT FEW DAYS. THE LATEST GFS MODEL GUIDANCE DOES DEVELOP
A TROPICAL CYCLONE AND MOVES IT INTO THE BAJA PENINSULA.
HOWEVER...THE GFS ENSEMBLES AS WELL AS THE ECMWF MODELS ARE MUCH
LESS BULLISH WITH THE SYSTEM...DEVELOPING A WEAK LOW AND KEEPING
IT OFFSHORE THE BAJA PENINSULA...THAT BEING SAID...PLEASE FOLLOW
THE OFFICIAL TROPICAL CYCLONE FORECASTS AND OUTLOOKS ISSUED BY THE
NATIONAL HURRICANE CENTER.

IN THE MID LEVELS...THERE IS A LOW PRESSURE OVER THE CENTRAL
ATLANTIC...THEN A WEAKER LOW PRESSURE OVER THE WEST TROPICAL
ATLANTIC...JUST NORTH OF PUERTO RICO/USVI. A BROAD HIGH PRESSURE
IS LOCATED OVER THE BAHAMAS INTO THE EASTERN GULF OF MEXICO. THE
MID LEVEL HIGH PRESSURE WILL MOVE SOUTHWEST AND CENTER OVER
WESTERN CUBA...MEANDERING THROUGH THE END OF THE WORKWEEK. THE MID
LEVEL LOW NORTH OF PR/USVI WILL WEAKEN INTO AN OPEN TROUGH BY
WEDNESDAY...WITH ITS AXIS OVER PUERTO RICO...THEN LIFT ON
THURSDAY. THE MID LEVEL LOW OVER THE CENTRAL ATLANTIC  WILL STAY
MEANDERING OVER THE AREA FOR THE NEXT FEW DAYS...BUT WILL MOVE
EAST BY THE END OF THE WORKWEEK.

IN THE UPPER LEVELS... A TUTT OVER THE WESTERN TROPICAL
ATLANTIC...NORTH OF PUERTO RICO/USVI IS CAUSING CONVECTIVE
DEVELOPMENT ACROSS PORTIONS OF THE NORTHERN LEEWARDS AND THE
EASTERN CARIBBEAN. THERE IS ALSO A HIGH PRESSURE TO THE EAST OF
THE LESSER ANTILLES AND AN ELONGATED HIGH PRESSURE FROM THE GULF
OF MEXICO ACROSS THE BAHAMAS...WHILE ANTHER HIGH PRESSURE IS
LOCATED NORTHEAST OF BERMUDA. THERE IS ALSO AN UPPER TROUGH OVER
NORTHERN MEXICO...WHICH IS EXPECTED TO REMAIN OVER THE COUNTRY FOR
THE NEXT FEW DAYS...PROVIDING SOME DIVERGENCE ALOFT OVER CENTRAL
TO EASTERN MEXICO. BY WEDNESDAY...THE TUTT OVER THE WESTERN
TROPICAL ATLANTIC WILL WEAKEN INTO AN OPEN TROUGH WITH ITS AXIS
NEAR PUERTO RICO...AND THE HIGH PRESSURE EAST OF THE LESSER
ANTILLES WILL MOVE FURTHER EAST...INTO THE CENTRAL TROPICAL
ATLANTIC.

THE TROPICAL REGION OVERALL IS EXPECTED TO HAVE NEAR TO HIGHER
THAN NORMAL MOISTURE FOR THE NEXT SEVERAL DAYS. WITH THE EXCEPTION
OF A SMALL AREA OF BELOW NORMAL MOISTURE OVER THE CENTRAL
CARIBBEAN...WHICH WILL REMAIN MOSTLY OVER THE WATERS...BUT THE DRY
SLOT COULD APPROACH NICARAGUA ON FRIDAY. THE REST OF THE
CARIBBEAN...CENTRAL MEXICO...CENTRAL AMERICA AND NORTHWEST SOUTH
AMERICA WILL HAVE NEAR TO HIGHER THAN NORMAL MOISTURE.

FOR TODAY INTO EARLY WEDNESDAY MORNING...THE AREAS WITH MOST
SIGNIFICANT RAINFALL ARE EXPECTED TO BE ACROSS NORTHEASTERN
TAMAULIPAS...WITH THE RAIN POSSIBLE ASSOCIATED WITH TS FRANCINE AS
IT MOVES NNE AND AWAY FROM MEXICO. A SFC TROUGH WEST OF THE LESSER
ANTILLES MAY CAUSE SOME RAINFALL OVER THE ISLANDS...OBSERVING NEAR
25MM OR MORE ACROSS ISOLATED AREAS OVER THE LESSER
ANTILLES...PUERTO RICO/USVI AND HISPANIOLA. THE INTERACTION OF AN
APPROACHING TROPICAL WAVE AND THE PANAMANIAN LOW...COMBINED WITH
THE LOCAL TERRAIN EFFECTS OVER SOUTHERN CENTRAL AMERICA...WILL
CAUSE SIGNIFICANT RAIN OVER THE AREA FROM NICARAGUA SOUTH INTO
PANAMA.  THE REST OF CENTRAL AMERICA AND SOUTHERN MEXICO ARE
FORECAST TO OBSERVE 10-20MM WITH ISOLATED AMOUNTS OF OVER 30MM.
NORTHERN SOUTH AMERICA WILL HAVE 05-15 MM OF RAIN...WITH ISOLATED
HIGHER AMOUNTS...ESPECIALLY IN AREAS OF MOUNTAINOUS TERRAIN.

FOR WEDNESDAY AND THURSDAY...PORTIONS OF WESTERN AND CENTRAL
MEXICO WILL OBSERVE ISOLATED AMOUNTS OF RAIN SURPASSING 30MM...AS
THE MOISTURE INTERACTS WITH THE LOCAL TERRAIN AND THE UPPER
TROUGH. HOWEVER...THE LATEST GUIDANCE IS NOW SUGGESTING MAX TOTALS
UP TO AROUND 100MM OVER THE NORTHWEST COAST OF SINALOA...AS A LOW
PRESSURE IS PRESENT OFFSHORE AND SOUTHWESTERLY WINDS BRINGS
MOISTURE TO THE COAST OF SINALOA. OTHER AREAS OF THE SOUTHERN HALF
OF MEXICO CAN EXPECT AMOUNTS OF 05-20MM...ISOLATED TO 30MM.
PORTIONS OF CHIAPAS COULD OBSERVE UP TO 20MM ACROSS ISOLATED
AREAS. CENTRAL AMERICA WILL OBSERVE AMOUNTS OF 05-15MM WITH
ISOLATED AMOUNTS UP TO AROUND 30MM...MAINLY ACROSS PANAMA...COSTA
RICA...AND THE PACIFIC SECTIONS OF
HONDURAS...NICARAGUA...GUATEMALA AND OVER EL SALVADOR. THE
CARIBBEAN ISLANDS WILL OBSERVE SCATTERED SHOWER ACTIVITY WITH
ISOLATED THUNDERSTORMS...WITH RAIN TOTALS UP TO 10 MM IN MANY
AREAS BUT ISOLATED TO 25-35 OVER THE HIGHER ELEVATIONS OF
HISPANIOLA. THE BAHAMAS WILL BE SPLIT...NORTHERN BAHAMAS COULD
OBSERVE AS MUCH AS 50MM OF RAIN ON WEDNESDAY AND UP TO 30MM ON
THURSDAY. THE SOUTHERN BAHAMAS AND THE TURKS AND CAICOS WILL
OBSERVE LITTLE TO NO RAIN ON WEDNESDAY AND THURSDAY.  NORTHERN
SOUTH AMERICA IS FORECAST NEAR 10-20MM WITH ISOLATED AMOUNTS NEAR
50MM ON WEDNESDAY...WHILE 05-10MM ISOLATED TO 20 MM ARE EXPECTED
FOR THURSDAY.





ALAMO...(WPC)