793
FXCA20 KWBC 121718
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
118 PM EDT FRI MAY 12 2023
NOTE: THE RISK FOR HEAVY RAINFALL IN EXTREME NORTHEAST MEXICO
CONTINUES. UNDER THE INFLUENCE OF A NEGATIVELY TILTED UPPER
TROUGH...A MOIST LOW-LEVEL JET AND AN APPROACHING KELVIN
WAVE...EXPECT ROUNDS OF HEAVY RAIN PRODUCING THUNDERSTORMS ON
FRIDAY AND ESPECIALLY SATURDAY AFTERNOON. THROUGH MONDAY
MORNING...THERE IS A RISK FOR TOTAL ACCUMULATION OF 150-250MM IN 3
DAYS.
FORECAST BULLETIN FROM 12 MAY 2023 AT 1720 UTC: A BROAD MID-UPPER
TROUGH IN THE WESTERN US IS DEVELOPING SHORT WAVE VORTICES THAT
ARE ROTATING ALONG ITS PERIPHERY. ONE OF THESE VORTICES EXTENDS
INTO CHIHUAHUA/DURANGO ON FRIDAY. AS IT PROPAGATES TOWARDS THE RIO
BRAVO REGION...IT WILL FAVOR ENHANCED UPPER DIVERGENCE IN A REGION
OF PRECIPITABLE WATER OVER 45MM AND MOISTURE CONVERGENCE IN THE
CYCLONIC TIER OF A LOW-LEVEL JET. THIS WILL FAVOR 15-20MM/DAY AND
MAXIMA OF 40-80MM WITH A RISK FOR SEVERITY. ON SATURDAY...EXPECT A
PEAK IN THE EVENT...WHEN ACCUMULATIONS ARE LIKELY TO REACH 25-50MM
AND MAXIMA 75-125MM WITH A RISK FOR SEVERITY AND HEAVY RAIN RATES.
THE EVENT IS EXPECTED TO WIND DOWN AFTER.
ELSEWHERE IN MEXICO...THE ARRIVAL OF A KELVIN WAVE AND THE
AFOREMENTIONED UPPER TROUGH ARE FAVORING A RAPID MOISTENING AND
DESTABILIZATION. MOISTURE INFLOW FROM THE GULF OF MEXICO IS
EXPECTED TO GRADUALLY ACTIVATE DIURNAL CONVECTION IN PORTIONS OF
NORTHWEST AND CENTRAL/SOUTHWEST MEXICO. STILL...THE LARGEST
AMOUNTS ARE EXPECTED ALONG/NEAR THE SIERRA MADRE ORIENTAL WHERE
THE LARGEST AMOUNTS OF PRECIPITABLE WATER ARE EXPECTED. ON
FRIDAY...EXPECT 10-15MM/DAY AND MAXIMA OF 20-35MM ALONG THE SIERRA
MADRE ORIENTAL AND EJLE VOLCANICO CENTRAL. ON SATURDAY...EXPECT
15-20MM/DAY AND AMXIMA OF 30-60MM FROM NORTHERN VERACRUZ INTO SAN
LUIS POTOSI/CENTRLA TAMAULIPAS/NUEVO LEON. FROM OAXACA INTO
CENTRAL MEXICO EXPECT 05-10MM/DAY AND MAXIMA OF 15-25MM. ON
SUNDAY...EXPECT MODERATE AMOUNTS DEVELOPING IN
CHIHUAHUA/DURANGO/WESTERN COAHUILA AS A NEGATIVELY TILTED UPPER
TROUGH INTERACTS WITH A MOIST PLUME. THIS WILL FAVOR 10-15MM/DAY
AND MAXIMA OF 20-45MM. TO THE EAST...EXPECT 10-15MM/DAY AND MAXIMA
OF 20-35MM FROM THE RIO BRAVO INTO NORTHERN PUEBLA/HIDALGO. HIGHER
AMOUNTS ARE EXPECTED IN SOUTHERN MEXICO FROM CHIAPAS INTO
VERACRUZ/CENTRLA PUEBLA AS THE FIRST TROPICAL WAVES ENTERS THE
REGION. EXPECT 15-20MM/DAY AND MAXIMA OF 35-70MM.
AN CLOSED UPPER LOW IS ORGANIZING OVER THE EASTERN GULF OF
MEXICO...AND IS FORECAST TO MEANDER VERY SLOWLY TOWARDS THE
FLORIDA STRAIT THROUGH THE FORECAST CYCLE. COLD TEMPERATURES IN
THE MID-UPPER TROPOSPHERE WILL FAVOR ROUNDS OF SEVERE CONVECTION
IN CUBA AND SQUALLY WEATHER IN THE BAHAMAS...ESPECIALLY ON FRIDAY
AND SATURDAY. ON FRIDAY EXPECT 05-10MM/DAY AND MAXIMA OF 15-30MM
IN CENTRAL AND WESTERN CUBA...WITH A RISK FOR SEVERITY. IN THE
BAHAMAS EXPECT 05-10MM/DAY AND MAXIMA OF 15-25MM STIMULATED AS
WELL BY A FRONTAL BOUNDARY ACROSS THE CENTRAL BAHAMAS. ON
SATURDAY...EXPECT ONCE AGAIN RISK FOR SEVERE CONVECTION IN CENTRAL
CUBA...WHERE AMOUNTS WILL REACH 10-15MM/DAY AND MAXIMA OF 20-45MM.
IN EASTERN CUBA AND THE CENTRAL BAHAMAS...EXPECT 10-15MM/DAY AND
MAXIMA OF 20-35MM WITH A RISK FOR SQUALLY WEATHER. ON
SUNDAY...EXPECT 10-15MM/DAY AND MAXIMA OF 20-35MM IN CENTRAL CUBA
AND IN MOST OF THE CENTRAL AND SOUTHEAST BAHAMAS.
ALSO IN THE CARIBBEAN...A MOIST PLUME IS PROPAGATING ACROSS THE
LEEWARD ISLANDS INTO PUERTO RICO ON FRIDAY. SHORT WAVE
PERTURBATIONS EMBEDDED IN THE MID/UPPER TROPOSPHERIC WESTERLIES
WILL AID WITH THE STIMULATION OF DIURNAL CONVECTION IN SOUTHEAST
CUBA...HISPANIOLA AND PUERTO RICO...ESPECIALLY WHEN INTERACTING
WITH THE MOIST PLUME. ON FRIDAY...EXPECT 10-15MM/DAY AND MAXIMA OF
20-45MM IN SOUTHEAST CUBA AND HISPANIOLA...WHILE IN PUERTO RICO
AND THE VI EXPECT 10-15MM/DAY AND MAXIMA OF 20-35MM. ON SATURDAY
EXPECT ISOLATED MAXIMA OF 25-50MM IN NORTHWEST PUERTO RICO AND THE
NORTHERN DOMINICAN REPUBLIC...WHILE IN JAMAICA AND THE REST OF
HISPANIOLA EXPECT ISOLATED MAXIMA OF 15-20MM. ON SUNDAY EXPECT
ISOLATED MAXIMA OF 25-50MM IN NORTHERN HISPANIOLA AND IN SOUTHEAST
CUBA...WHILE IN JAMAICA EXPECT ISOLATED MAXIMA OF 15-20MM.
IN CENTRAL AMERICA AND NORTHERN SOUTH AMERICA...ACTIVITY IS
ORGANIZING PRIMARILY WITH WAVES IN TRADES. IN CENTRAL
AMERICA...EXPECT GENERALLY HIGHER AMOUNTS IN NORTHERN PORTIONS AS
THE REGION HAS LARGER AMOUNTS ON INSTABILITY AND ASCENT STIMULATED
BY MID-UPPER TROUGHS. IN SOUTH AMERICA...THE NET WILL ALSO BE A
SYSTEM THAT WILL ENHANCE CONVECTION LOCALLY. WESTERLY FLOW IN THE
UPPPER LEVELS OF NORTHERN SOUTH AMERICA WILL ALSO PLAY A ROLE IN
STIMULATING CONVECTION. SHORT WAVE PERTURBATIONS ARE EXPECTED TO
PROVIDE LOCAL ENHANCEMENT IN NORTHERN COLOMBIA AND NORTHWEST
VENEZUELA. THE MOST PROMINENT PERTURBATION IS FORECAST TO AMPLIFY
ON SATURDAY AND SUNDAY...TO FAVOR HEAVY RAIN PRODUCING
THUNDERSTORMS. SEE BELOW FOR WAVE POSITIONS AND ASSOCIATED
ACCUMULATIONS IN CENTRAL AMERICA AND NORTHERN SOUTH AMERICA.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT 13/00 13/12 14/00 14/12 15/00 15/12 16/00
TW 10N 39W 42W 44W 46W 48W 50W 52W 55W
EW 13N 59W 62W 66W 69W 72W 76W 79W 83W
TW 19N 82W 85W 88W 91W 93W 96W 98W 102W
EW 21N 89W 91W DISS --- --- --- --- ---
A TROPICAL WAVE IS INITIALIZED AT 39W AND SOUTH OF 10N. THIS WAVE
WILL ARRIVE IN FRENCH GUIANA/AMAPA LATE ON SATURDAY. FOR
SUNDAY...AMOUNTS ARE EXPECTED IN THE 20-35MM RANGE FOR MAXIMA IN
AMAPA AND THE GUIANAS.
AN EASTERLY WAVE IS INITIALIZED AT 59W AND SOUTH OF 13N AND IS
PROPOGATING WEST OVER THE GUIANAS AND INTO CENTRAL VENEZUELA BY
FRIDAY EVENING. ON FRIDAY...GUYANA AND INTO CENTRAL VENEZUELA AND
RORAIMA ARE FORECAST FOR MAXIMAS OF 30-60MM...WHILE NORTHERN
GUYANA AND VENEZUELA MAY SEE MAXIMA OF 15-25MM. ON SATURDAY...THE
WAVE CONTINUES TO PROPAGATE INTO WESTERN PORTIONS OF VENEZUELA AND
EASTERN COLOMBIA TO FAVOR MAXIMA OF 35-70MM IN WESTERN
VENEZUELA...AND 20-45MM IN EASTERN COLOMBIA. ON SUNDAY...EXPECT
15-20MNM/DAY AND MAXIMA OF 30-60MM IN THE EJE CAFETERO...NORTHWEST
COLOMBIA...EXTENDING INTO FAR NORTHWEST VENEZUELA.
A TROPICAL WAVE IS INITIALIZED AT 82W AND TO THE SOUTH OF 19N AND
IS FORECAST TO CONTINUE WEST INTO COSTA RICA...NICARAGUA...AND
EASTERN HONDURAS BY FRIDAY EVENING. ON FRIDAY...IT WILL FAVOR
MAXIMA OF 25-50MM IN EASTERN HONDURAS AND NORTHERN EL
SALVADOR...WHILE FROM EASTERN NICARAGUA INTO COSTA RICA AND PANAMA
EXPECT MAXIMA OF 20-35MM. ON SATURDAY...AS THE WAVE PROPAGATES
OVER THE YUCATAN PENINSULA/GUATEMALA/EL SALVADOR...IT WILL FAVOR
MAXIMA OF 20-40MM FROM CHIAPAS INTO EL SALVADOR/WESTERN
HONDURAS...AND MAXIMA OF 15-25MM IN AREAS NORTH. ON SUNDAY...IT
WILL FAVOR 15-20MM/DAY AND MAXIMA OF 35-70MM SOUTHERN
MEXICO...EXTENDING INTO GUATEMALA IN ASSOCIATION WITH THE TRAILING
MOIST PLUME.
AN EASTERLY WAVE IS INITIALIZED AT 89W SOUTH OF 21N AND
DISSIPATING BY FRIDAY EVENING. ON FRIDAY...IT WILL FAVOR MAXIMA OF
20-40MM FROM EASTERN CHIAPAS INTO WEST-CENTRAL GUATEMALA...AND
CENTRAL BELIZE...WHILE IN THE YUCATAN PENINSULA EXPECT MAXIMA OF
15-20MM.
GALVEZ/ACOSTA...WPC (USA)
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