796
FXCA20 KWBC 281814
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
214 PM EDT THU MAY 28 2020
TROPICAL DISCUSSION FROM MAY 28/18 UTC: A SYSTEM OF CONCERN
CONTINUES BEING THE CENTRAL AMERICAN GYRE...FORECAST TO FORM TO
THE WEST-SOUTHWEST OF EL SALVADOR DURING THE WEEKEND. UNDER THE
INFLUENCE OF AN UPPER DIVERGENT PULSE OF THE MADDEN JULIAN
OSCILLATION AND A ROBUST KELVIN WAVE...EXPECTING THE DEVELOPMENT
OF HEAVY RAINFALL TO AFFECT CENTRAL AND NORTHERN PORTIONS OF
CENTRAL AMERICA DURING THE WEEKEND AND POSSIBLY INTO MID-NEXT
WEEK. THE EXPECTED EVOLUTION OF THE GYRE...WILL FAVOR THE HEAVIEST
PRECIPITATION TO DEVELOP FROM WESTERN NICARAGUA ACROSS SOUTHERN
HONDURAS INTO EL SALVADOR AND SOUTHERN GUATEMALA. LARGEST
ACCUMULATIONS ARE EXPECTED IN EL SALVADOR...ESPECIALLY FROM
SATURDAY THROUGH MONDAY...WHEN THREE-DAY TOTALS COULD REACH
200-300MM AND VERY ISOLATED MAXIMA OF 400-500MM IN REGIONS OF
ENHANCED OROGRAPHIC FORCING. THE AMOUNTS OF RAIN WILL BE LARGELY
DEPENDENT ON THE EVOLUTION OF THE GYRE AND THE ASSOCIATED ONSHORE
SOUTHWEST FLOW INTO EL SALVADOR/SOUTHEAST GUATEMALA AND THE GULF
OF FONSECA REGION FROM SATURDAY THROUGH MONDAY.
NORTH IN THE DOMAIN...A LARGE UPPER TROUGH CENTERS OVER THE
MISSISSIPPI VALLEY AND IS FORECAST TO BE RAPIDLY DRAWN
NORTHEASTWARD BY A TROUGH IN THE WESTERLIES ON FRIDAY. AS THE
TROUGH EXITS...IT WILL SUSTAIN THE BUILDING OF A POLAR RIDGE OVER
THE PLAINS OF THE USA. THIS IS PUSHING A SURFACE COLD FRONT
SOUTHWARD...BUT THE FRONT IS FORECAST TO LOOSE BAROCLINICITY AND
FRONTOLIZE ACROSS EXTREME NORTHEAST MEXICO ON THURSDAY EVENING.
REGARDLESS OF FRONTOLISIS...THE POLAR RIDGE IS ESTABLISH
NORTHEASTERLY WINDS IN THE GULF OF MEXICO. THESE WILL STIMULATE
MOISTURE CONVERGENCE ALONG THE SIERRA MADRE ORIENTAL AND GULF
COAST OF MEXICO TO SUSTAIN HEAVIEST PRECIPITATION ON FRIDAY. IN
THE MEANTIME...THE NORTHERLIES WILL START TO STIMULATE MOISTURE
CONVERGENCE IN NORTHEAST MEXICO TO SUSTAIN 10-15MM/DAY AND MAXIMA
OF 20-45MM WITH A RISK FOR SEVERITY ON THURSDAY. IN CENTRAL
PORTIONS OF THE SIERRA MADRE ORIENTAL EXPECTING 05-10MM/DAY AND
MAXIMA OF 15-30MM. THIS PEAKS ON FRIDAY TO SUSTAIN 15-30MM/DAY AND
MAXIMA OF 40-80MM IN NORTHERN VERACRUZ...WHILE IN NORTHEAST MEXICO
EXPECTING 05-10MM/DAY AND MAXIMA OF 15-30MM. IN SOUTHERN VERACRUZ
EXPECING 15-20MM/DAY AND MAXIMA OF 25-50MM. REMNANT MOISTURE
CONVERGENCE...AND THE REMNANTS OF A TROPICAL WAVE WILL SUSTAIN
ENHANCED CONVECTION ON SATURDAY AS WELL WHEN EXPECTING 15-20MM/DAY
AND MAXIMA OF 25-50MM FROM NORTHERN VERACRUZ INTO
CHIAPAS/TABASCO/CAMPECHE.
TO THE EAST IN CUBA AND THE BAHAMAS...EXPECTING GENERALLY FAIR
WEATHER CONDITIONS AND ISOLATED CONVECTION INITIALLY. HOWEVER...A
MOIST PLUME IS BUILDING IN THE CENTRAL NORTHERN CARIBBEAN IN
ASSOCIATION WITH TUTT LOW TO THE NORTHEAST OF PUERTO RICO. THIS
WILL SUSTAIN ENHANCED CONVECTION IN PUERTO RICO AND HISPANIOLA ON
THURSDAY AND FRIDAY...BUT THE FOCUS SHIFTS TO CENTRAL CUBA
AFTERWARDS. ON THURSDAY...EXPECTING 15-20MM/DAY AND ISOLATED
MAXIMA OF 35-70MM IN PUERTO RICO AND HISPANIOLA...WHILE IN THE
VIRGIN AND LEEWARD ISLANDS EXPECTING 05-10MM/DAY AND MAXIMA OF
15-20MM. BY FRIDAY...EXPECTING STILL ACTIVE CONVECTION TO SUSTAIN
15-20MM/DAY AND MAXIMA OF 30-60MM IN HISPANIOLA AND PUERTO RICO.
IN THE VIRGIN ISLANDS EXPECTING 05-10MM/DAY AND MAXIMA OF 15-20MM.
CONVECTION WILL INCREASE IN SOUTHEAST CUBA ON FRIDAY TO SUSTAIN
10-15MM/DAY AND MAXIMA OF 20-35MM...WHILE IN JAMAICA EXPECTING
05-10MM/DAY AND MAXIMA OF 15-20MM. MOIST PLUME IN THE BAHAMAS AND
TURKS AND CAICOS WILL ALSO SUSTAIN CONVECTION ON FRIDAY TO PRODUCE
05-10MM/DAY AND MAXIMA OF 15MM. BY SATURDAY...LARGEST
ACCUMULATIONS ARE EXPECTED IN CENTRAL AND SOUTHEAST CUBA...WHERE
THE TROPICAL WAVE WILL SUSTAIN 10-15MM/DAY AND MAXIMA OF 20-35MM.
TRAILING MOISTURE IN JAMAICA AND HISPANIOLA WILL SUSTAIN
05-10MM/DAY AND MAXIMA OF 15-25MM. IN PUERTO RICO...A SHARP
DECREASE IN MOISTURE WILL SUSTAIN MAXIMA OF 20-35MM. SIMILAR
AMOUNTS ARE EXPECTED IN THE CENTRAL AND SOUTHEAST BAHAMAS...AS
WELL AS IN THE CAYMAN ISLANDS AND WESTERN CUBA. ELSEWHERE IN THE
EASTERN CARIBBEAN...UNDER THE INFLUENCE OF A STRONG MID-LEVEL
RIDGE CENTERING IN THE WESTERN TROPICAL ATLANTIC...EXPECTING
LITTLE ACCUMULATIONS IN TRADE WIND SHOWER CONVECTION...GENERALLY
UNDER 10MM/DAY.
IN CENTRAL AMERICA...MOIST WEATHER PATTERN CONTINUES UNRAVELING.
MODELS HAVE BEEN RESOLVING THE CENTRAL AMERICAN GYRE FORMING OVER
THE EASTERN PACIFIC...BUT CONFIDENCE HAS BEEN LOW. AS THE MODELS
START TO BECOME IN BETTER AGREEMENT ON THE EVOLUTION THROUGH THE
WEEKEND...IT IS BECOMING MORE EVIDENT THAT THE AREA EXPECTING THE
LARGEST PRECIPITATION AMOUNTS EXTENDS FROM WESTERN
NICARAGUA/EXTREME NORTHWEST COSTA RICA INTO SOUTHERN
GUATEMALA...SOUTHERN HONDURAS AND EL SALVADOR...DURING SATURDAY
THROUGH MONDAY. IN THE MEAN TIME...ACTIVITY WILL ME MODULATED BY
TROPICAL WAVES AND INTERACTIONS WITH THE ITCZ. SEE BELOW FOR
PRECIPITATION AMOUNTS IN ASSOCIATION WITH THE WAVES.
IN NORTHERN SOUTH AMERICA...ACTIVITY WILL BE ORGANIZED MOSTLY WITH
WAVES IN THE TRADES. SEE BELOW.
TROPICAL/EASTERLY WAVES INITIALIZED AT 00UTC ON MAY 28:
========================================
TYPE OF WAVE AND FORECAST LONGITUDE
========================================
TYPE - F12 F24 F36 F48 F60 F72 F84
TW - 40W 44W 48W 52W 56W 60W 63W
TW - 65W 68W 71W 75W 78W 82W 85W
TW - 81W 84W 87W 90W LOW
TW - 94W 96W 98W 100W 102W 104W 107W
========================================
A TROPICAL WAVE IS INITIALISED AT 40W AND TO THE SOUTH OF 10N.
THIS WAVE CROSSES FRENCH GUIANA AND SURINAME ON FRIDAY...WHERE IT
WILL ENHANCE CONVECTION TO SUSTAIN 10-15MM/DAY AND MAXIMA OF
20-40MM IN NORTHERN SURINAME AND NORTHERN GUYANA...WHILE IN FRENCH
GUIANA AND SOUTHERN SURINAME IT WILL SUSTAIN 05-10MM/DAY AND
MAXIMA OF 15-30MM. ON SATURDAY...THE WAVE CROSSES GUYANA AND
EASTERN VENEZUELA. IT WILL SUSTAIN 15-20MM/DAY AND MAXIMA OF
25-50MM IN NORTHERN GUYANA AND THE RINICI DELTA...WHILE TRAILING
MOISTURE WILL SUSTAIN 05-10MM/DAY AND MAXIMA OF 15-20MM IN
NORTHERN SURINAME AND NORTHERN FRENCH GUIANA. ALSO...IT WILL
SUSTAIN SIMILAR ACCUMULATIONS IN THE CANAIMA REGION IN SOUTHEAST
VENEZUELA.
A TROPICAL WAVE IS INITIALIZED AT 65W AND TO THE SOUTH OF 14N.
THIS WAVE WILL SUSTAIN SCATTERED CONVECTION IN SOUTHERN VENEZUELA
AND EASTERN COLOMBIA ON THURSDAY TO SUSTAIN 15-20MM/DAY AND MAXIMA
OF 25-50MM. IN CENTRAL VENEZUELA IT WILL SUSTAIN 05-10MM/DAY AND
MAXIMA OF 15-20MM. ON FRIDAY...THE WAVE WILL CROSS COLOMBIA WHERE
IT WILL SUSTAIN 10-15MM/DAY AND MAXIMA OF 20-40MM EAST OF THE
ANDES ACROSS THE ORINOQUIA AND AMAZON...AND 15-20MM/DAY AND MAXIMA
OF 25-50MM IN NORTHERN...CENTRA.L AND NORTHWEST COLOMBIA INTO THE
DARIEN. IN SOUTHWEST COLOMBIA IT WILL SUSTAIN 05-10MM/DAY AND
MAXIMA OF 15-20MM. BY SUNDAY...THE WAVE WILL PROPAGATE ACROSS THE
CAYMAN ISLANDS...CENTRAL CUBA AND PANAMA. LARGEST ACUMULATIONS ARE
EXPECTED IN SOUTHERN PANAMA WHERE ENHANCED CONVECTION WILL SUSTAIN
15-20MM/DAY AND MAXIMA OF 35-70MM. IN CENTRAL CUBA...EXPECTING
10-15MM/DAY AND MAXIMA OF 20-35MM. IN THE CAYMAN ISLANDS EXPECTING
MAXIMA OF 15MM. TRAILING MOISTURE IN JAMAICA WILL SUSTAIN
ACCUMULATION OF 05-10MM/DAY AND MAXIMA OF 15-25MM. IN SAN
ANDRES/PROVIDENCIA AND NORTHEAST NICARAGUA THE WAVE WILL SUSTAIN
05-10MM/DAY AND MAXIMA OF 15-25MM.
A TROPICAL WAVE IS INITIALIZED AT 81W AND TO THE SOUTH OF 15N.
THIS WAVE WILL INTERACT WITH THE ITCZ TO SUSTAIN HEAVY RAINFALL IN
COSTA RICA AND EASTERN NICARAGUA ON THURSDAY...WHERE EXPECTING
15-20MM/DAY AND MAXIMA OF 40-80MM. IN PANAMA...TRAILING MOISTURE
WILL SUSTAIN 05-10MM/DAY AND MAXIMA OF 15-25MM. BY FRIDAY...THE
WAVE WILL PROPAGATE ACROSS WESTERN NICARAGUA...EL
SALVADOR...HONDURAS AND GUATEMALA. IN INTERACTION WITH THE ITCZ
AND THE FORMING CENTRAL AMERICAN GYRE...IT WILL SUSTAIN HEAVY
RAINFALL FROM NORTHWEST COSTA RICA INTO EL SALVADOR AND SOUTHERN
HONDURAS TO SUSTAIN 25-50MM/DAY AND MAXIMA OF 75-125MM. IT WILL
THEN BECOME ABSORBED BY THE CENTRAL AMERICAN GYRE LOW IN THE
EASTERN PACIFIC. HOWEVER...REMNANT MOISTURE WILL PROPAGATE INTO
NORTHERN CENTRAL AMERICA AND SOUTHERN MEXICO. HERE...IT WILL
SUSTAIN 15-20MM/DAY AND MAXIMA OF 25-50MM IN
VERACRUZ/TABASCO/CAMPECHE AND NORTHERN CHIAPAS...WHILE IN
BELIZE...GUATEMALA...WESTERN HONDURAS AND SOUTHERN CHIAPAS
EXPECTING 10-15MM/DAY AND MAXIMA OF 20-35MM.
A TROPICAL WAVE IS INITIALIZED AT 94W AND TO THE SOUTH OF 18N. THE
WAVE WILL ENHANCE CONVECTION IN VERACRUZ/CHIAPAS/OAXACA WHERE IT
WILL SUSTAIN 05-10MM/DAY AND MAXIMA OF 15-30MM. IT WILL THEN EXERT
LIMITED EFFECTS IN CONTINENTAL AREAS.
GALVEZ/DAVISON...WPC (USA)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page