236
FXCA20 KWBC 021827
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
226 PM EDT MON OCT 02 2023
FORECAST BULLETIN 02 OCT 2023 AT 1830 UTC: THE MAIN STORY IS THAT
THE NATIONAL HURRICANE CENTER IS STILL ISSUING ADVISORIES ON
TROPICAL STORM PHILIPPE...WHICH IS CURRENTLY ABOUT 80 MILES TO THE
EAST SOUTHEAST OF BARBUDA. TROPICAL STORM PHILIPPE IS EXPECTED TO
CONTINUE MOVING SLOWLY TO THE WEST NORTHWEST AND THEN TO THE
NORTHWEST OVER THE NEXT FEW DAYS. IT IS ALSO EXPECTED TO CAUSE
HEAVY RAINFALL ACROSS THE LEEWARD ISLANDS...POSSIBLY REACHING TWO
TO FOUR INCHES ACROSS MANY OF THE LEEWARD ISLANDS BUT UP TO FOUR
TO SIX INCHES FOR BARBUDA AND ANTIGUA OVER THE NEXT COUPLE OF
DAYS. PUERTO RICO AND THE US VIRGIN ISLANDS AS WELL AS HISPANIOLA
COULD OBSERVE BRIEF PERIODS OF HEAVY RAIN...BUT MOST OF THE
RAINFALL ACTIVITY OVER THE NEXT FEW DAYS IS EXPECTED TO BE DUE TO
BANDS OF RAIN AND BRIEF SHOWERS. A COLD FRONT AND STATIONARY FRONT
ACROSS THE SOUTHWESTERN ATLANTIC COULD BRING SOME SIGNIFICANT
RAINFALL OVER THE BAHAMAS THROUGH THE FIRST HALF OF THE WORKWEEK.
WITH MAX TOTALS THAT COULD BE UP TO 20-45MM EACH DAY THROUGH
THURSDAY MORNING. THE REST OF THE CARIBBEAN ISLANDS ARE FORECAST
TO OBSERVE RAINFALL EACH DAY THROUGH THURSDAY...WITH MAX TOTALS
THAT COULD BE FROM 10 TO 45MM...WHILE A SMALL PORTIONS OF SOUTHERN
DOMINICAN REPUBLIC COULD OBSERVE UPWARDS OF 70MM ON TUESDAY INTO
WEDNESDAY. THE RANGE IN RAINFALL IS WIDE BECAUSE SOME OF THE
EXPECTED RAINFALL WILL BE DEPENDENT ON THE INTERACTION THAT AN
UPPER TROUGH AND A MID LEVEL LOW HAS WITH THE AVAILABLE MOISTURE
AND THE LOCAL EFFECTS OF THE ISLANDS.THIS UPPER TROUGH WILL
PREVAIL THROUGH THURSDAY WITH ITS AXIS OVER THE WESTERN CARIBBEAN.
GENERALLY SPEAKING...MOST OF THE TROPICS HAVE ABOVE NORMAL
MOISTURE AND ARE EXPECTED TO CONTINUE WITH NEAR TO ABOVE THAN
NORMAL MOISTURE THROUGH MIDWEEK. THEREFORE BRIEF RAINFALL SHOWERS
COULD ALSO BE EXPECTED EACH DAY ACROSS MOST OF THE COASTAL AREAS
OF NORTHERN SOUTH AMERICA...CENTRAL AMERICA AND MEXICO. THAT BEING
SAID...ANY OTHER FEATURE THAT WOULD INCREASE INSTABILITY OR CAUSE
CONVERGENCE WILL INCREASE THE POTENTIAL FOR SIGNIFICANT RAINFALL.
ACROSS NORTHERN SOUTH AMERICA...THE NORTHERN AND WESTERN SECTIONS
OF COLOMBIA INTO NORTHWESTERN ECUADOR...AS WELL AS A SMALL PORTION
OF NORTHWESTERN VENEZUELA WILL HAVE THE POTENTIAL OF SIGNIFICANT
RAINFALL EACH DAY. ONSHORE WIND FLOW FROM THE WEST AS THE UPPER
TROUGH DIGGING SOUTH ACROSS THE WESTERN CARIBBEAN...WILL CAUSE
GOOD INSTABILITY AND THEREFORE A GOOD POTENTIAL FOR THUNDERSTORMS
ACROSS THOSE AREAS. BASED ON THE LATEST GUIDANCE...MAX TOTALS
THAT COULD RANGE BETWEEN 30MM AND 80MM COULD BE OBSERVED OVER
ISOLATED AREAS. OTHER SECTIONS OF NORTHERN SOUTH AMERICA WILL NOT
OBSERVE QUITE AS MUCH RAIN SINCE THE UPPER TROUGH IS RELATIVELY
NARROW AND THE IMPACT OF IT WILL BE LIMITED TO AREAS CLOSE TO IT.
A SFC LOW JUST SOUTH OF CENTRAL AMERICA WILL PROVIDE PERSISTENT
ONSHORE WIND FLOW ACROSS WESTERN PANAMA AND COSTA RICA...WHICH
WILL THEN CAUSE PERSISTENT SHOWER ACTIVITY OVER THE AREA. THE
AFOREMENTIONED SECTORS ARE FORECAST TO OBSERVE DAILY MAX VALUES
BETWEEN 30MM AND 80MM THROUGH THURSDAY. FURTHER NORTH IN CENTRAL
AMERICA... THE RAINFALL AMOUNTS ARE MORE MODEST...THOUGH STILL
SIGNIFICANT. MAX DAILY VALUES OF 30MM TO 40MM IS FORECAST ACROSS
THE PACIFIC COASTAL SIDE OF NICARAGUA TO GUATEMALA...WITH LESSER
AMOUNTS FORECAST FOR THE ATLANTIC SIDE.
THE YUCATAN PENINSULA IN MEXICO AS WELL AS THE SOUTHERN STATES ARE
ALSO FORECAST TO OBSERVE SOME RAINFALL EACH DAY. THE AMOUNTS ARE
ALSO ON THE MODEST SIDE...WITH MAX RAINFALL EXPECTED BETWEEN 10MM
AND 25MM FOR THE MOST PART. THE WESTERN COAST OF MEXICO WILL HAVE
SOME RAINFALL AND THE AMOUNTS COULD INCREASE EACH DAY...WITH
WEDNESDAY INTO THURSDAY HAVING THE HIGHEST AMOUNTS...POSSIBLY DUE
TO A DEVELOPING LOW PRESSURE THAT COULD BE PASSING WEST OF
MEXICO...BRINGING ONSHORE FLOW TO THE WEST COAST...AT THE SAME
TIME AS A SURFACE LOW MOVES INTO NORTHERN MEXICO...ADDING
ADDITIONAL SUPPORT FOR MOIST AIR TO MOVE IN AND INCREASE
INSTABILITY.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT 03/00 03/12 04/00 04/12 05/00 05/12 06/00
06/12
TW 19N 40W 42W 43W 45W 48W 51W 54W 57W
60W
TW 13N 103W 106W 108W 109W 109W 110W 110W 110W
110W
A TROPICAL WAVE IS INITIALIZED AT 40W AND TO THE SOUTH OF 19N. THE
TROPICAL WAVE IS NOT EXPECTED TO HAVE AN IMPACT IN THE LOCAL
ISLANDS WITHIN THE NEXT 3 DAYS...AS IT IS A BIT TOO FAR OUT THE
EAST. ADDITIONALLY...AT THIS TIME THE NATIONAL HURRICANE CENTER
DOES SUGGEST IT HAS A CHANCE OF FORMATION INTO A TROPICAL CYCLONE.
A TROPICAL WAVE AND ITS ASSOCIATED LOW PRESSURE INITIALIZED AT 103
AND SOUTH OF 13N HAS A HIGH CHANCE OF DEVELOPING INTO A TROPICAL
CYCLONE...ACCORDING TO THE NATIONAL HURRICANE CENTER. THE LOW
PRESSURE AND TROPICAL WAVE WILL MOVE WEST AND SLOW DOWN
CONSIDERABLY BY TUESDAY AS IT IS EXPECTED TO DEVELOP INTO A
TROPICAL CYCLONE AND TAKE A NORTHWARD TRAJECTORY.
ALAMO...WPC (USA)
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