819
FXCA20 KWBC 061840
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
139 PM EST MON MAR 06 2023
FORECAST BULLETIN FROM 06 MAR 2023 AT 1840 UTC: THE MJO AND
EQUATORIAL WAVE ANALYSIS SHOWS A ROBUST UPPER DIVERGENT PULSE OF
THE MJO CROSSING THE BASIN THROUGH MARCH 15TH. THIS UNUSUALLY
STRONG PULSE WILL LIKELY FAVOR AN INCREASE IN THE COVERAGE AND
INTENSITY OF PRECIPITATING CONVECTION DURING THE NEXT TEN
DAYS...IN PARTICULAR IN REGIONS WHERE THE SYNOPTIC ENVIRONMENT
SETUP IS FAVORABLE FOR HEAVY RAINFALL. OF SPECIAL CONCERN ARE THE
COASTS AND WESTERN SLOPES OF ECUADOR AND NORTHERN PERU...WHERE
WARMER-THAN-AVERAGE SEA SURFACE TEMPERATURES AND AN ACTIVE
SOUTHERN BRANCH OF THE ITCZ ARE PRESENT.
NORTH IN THE DOMAIN...AN UPPER TROUGH OVER THE NORTHERN NORTH
ATLANTIC IS SUSTAINING A SURFACE FRONT THAT EXTENDS ZONALLY ALONG
27N FROM 50W INTO NORTHEAST FLORIDA. THIS FRONT IS FORECAST TO
MEANDER SOUTHWARD THROUGH THE FORECAST CYCLE WHILE WEAKENING...TO
FAVOR 00-05MM/DAY AND MAXIMA OF 10MM IN THE NORTHWEST BAHAMAS ON
MONDAY. THE FRONT LOOSES DEFINITION EAST OF THE BAHAMAS ON
TUESDAY...WHEN EXPECT AN ADDITIONAL 00-05MM/DAY AND MAXIMA OF 10MM
IN ELEUTHERA AND GRAND ABACO IN ASSOCIATION WITH THE REMAINING
MOIST PLUME. ON WEDNESDAY...A POTENT UPPER TROUGH IN THE NORTH
ATLANTIC WILL FAVOR AN INCREASE IN THE SURFACE PRESSURES ALONG THE
EAST COAST OF THE USA. THIS WILL FAVOR AN INCREASE IN NORTHERLY
LOW-LEVEL WINDS...WHICH WILL PUSH A COLD FRONT SOUTHWARD VERY
RAPIDLY. THE NEW FRONT IS EXPECTED TO RAPIDLY CROSS THE BAHAMAS
FROM NORTH TO SOUTH ON WEDNESDAY...AND BY WEDNESDAY EVENING IT IS
FORECAST ACROSS THE TURKS AND CAICOS...SOUTHERN BAHAMAS...INTO THE
FLORIDA STRAIT. LITTLE AVAILABLE MOISTURE AND THE RAPID
PROGRESSION OF THE SYSTEM WILL FAVOR VERY LIMITED PRECIPITATION
ACROSS THE BAHAMAS WITH THIS SYSTEM. NOTE THAT THIS FRONT WILL
ARRIVE INTO PUERTO RICO AND NORTHERN HISPANIOLA ON
THURSDAY...WHERE HIGHER ACCUMULATIONS ARE EXPECTED.
FURTHER SOUTH AND ON MONDAY MORNING...THE MID-LEVEL RIDGE EXTENDS
FROM A HIGH IN CENTRAL MEXICO ACROSS THE NORTHERN YUCATAN
PENINSULA...CUBA INTO ANOTHER HIGH OVER HISPANIOLA. THE RIDGE IS
FORECAST TO WEAKEN IN LOCATIONS OVER AND TO THE EAST OF
HISPANIOLA...AS A BROAD UPPER TROUGH PATTERN ESTABLISHES OVER THE
NORTH ATLANTIC. YET...THE RIDGE OVER MEXICO AND NORTHERN CENTRAL
AMERICA IS ALSO FORECAST TO WEAKEN TO A LESSER EXTENT...AIDED BY
THE INFLUENCE OF THE UPPER DIVERGENT MJO. ALTHOUGH THIS EVOLUTION
WILL FAVOR SOME DESTABILIZATION OF THE TRADE WIND CAP ACROSS THE
CARIBBEAN AND CENTRAL AMERICA...THE PRESENCE OF DRY AIR ABOVE THE
BOUNDARY LAYER WILL LIMIT ANY PRECIPITATION IN TERMS OF COVERAGE
AND ACCUMULATION. THIS WILL LEAD TO MAXIMA GENERALLY UNDER
15MM/DAY THROUGH THE CYCLE...CLUSTERING IN JAMAICA ON MONDAY AND
IN SOUTHERN HISPANIOLA ON TUESDAY. ON WEDNESDAY EXPECT ISOLATED
MAXIMA NEAR 15MM/DAY IN SOUTHERN HISPANIOLA AND NORTHEAST
NICARAGUA/EASTERN HONDURAS. ALSO ON WEDNESDAY...EXPECT ISOLATED
MAXIMA OF 15-25MM IN SOUTHERN GUATEMALA AND SOUTHERN CHIAPAS...AS
DIURNAL INSTABILITY FAVORS ISOLATED LATE AFTERNOON THUNDERSTORMS.
AN EXCEPTION TO THESE SEASONALLY DRY CONDITIONS WILL BE COSTA RICA
AND WESTERN PANAMA. WARM SEA SURFACE TEMPERATURES BETWEEN SOUTHERN
COSTA RICA AND THE ISLA DEL COCO WILL FAVOR DEEP CONVECTION ON A
DAILY BASIS OVER THE PACIFIC. THIS WILL LIKELY EXTEND INTO THE OSA
PENINSULA REGION TO FAVOR 05-10MM/DAY AND MAXIMA OF 15-20MM ON
MONDAY...INCREASING TO 10-15MM/DAY AND MAXIMA OF 20-35MM ON
TUESDAY...AND INCREASING TO 10-15MM/DAY AND MAXIMA OF 20-40MM ON
WEDNESDAY.
OF INTEREST AND CONCERN THROUGH THE FORECAST CYCLE IS NORTHWEST
SOUTH AMERICA...ESPECIALLY WESTERN ECUADOR AND NORTHERN PERU. IN
THE UPPER LEVELS...THE BOLIVIAN HIGH IS FORECAST TO STRENGTHEN
OVER SOUTHERN PERU...TO SUSTAIN A GRADUAL INCREASE IN VENTILATION
ACROSS PERU...ECUADOR AND WESTERN COLOMBIA THROUGH THE CYCLE. THIS
WILL BE ALSO FAVORED BY INCREASINGLY UPPER DIVERGENT CONDITIONS AS
THE MJO PULSE ENTERS THE REGION IN THE NEXT THREE DAYS. IN THE
LOWER LEVELS...ENHANCED ONSHORE FLOW AND AN ACTIVE DOUBLE ITCZ
WILL CONTINUE TO STIMULATE LOW-LEVEL MOISTURE CONVERGENCE OVER
WATERS...COASTAL AREAS AND THE WESTERN SLOPES...WHICH WILL FAVOR
HEAVY RAIN GIVEN THE CURRENT WARM SST ANOMALIES. ON
MONDAY...EXPECT 20-40MM/DAY AND MAXIMA OF 75-125MM IN SOUTHERN
ECUADOR/GULF OF GUAYAQUIL INTO TUMBES AND THE INTERIOR OF PIURA IN
NORTHERN PERU...INCLUDING A RISK FOR MCS FORMATION. ENHANCED
INSTABILITY AND FAVORABLE VENTILATION WILL FAVOR 15-20MM/DAY AND
MAXIMA OF 30-60MM IN THE EJE CAFETERO AND CHOCO REGIONS IN WESTERN
COLOMBIA. IN SOUTHWEST COLOMBIA...CENTRAL COLOMBIA AND THE
NORTHWEST AMAZON BASIN IN SOUTHERN COLOMBIA/SOUTHERN VENEZUELA
EXPECT 10-15MM/DAY AND SCATTERED MAXIMA OF 20-40MM. IN
NORTHERN/CENTRAL ECUADOR AND MOST OF THE AMAZON BASIN OF NORTHERN
PERU EXPECT 05-10MM/DAY AND SCATTERED MAXIMA OF 15-30MM. ON
TUESDAY...EXPECT THE HEAVIEST PRECIPITATION BETWEEN INTERIOR
PORTIONS OF SOUTHERN ECUADOR INTO NORTHERN PERU...TO PRODUCE
15-30MM/DAY AND MAXIMA OF 50-100MM...INCLUDING A RISK FOR MCS. IN
NORTHERN ECUADOR/SOUTHWEST COLOMBIA EXPECT 15-20MM/DAY AND MAXIMA
OF 35-70MM. ACROSS MOST OF CENTRAL...WESTERN AND INTERIOR PORTIONS
OF NORTHERN COLOMBIA EXPECT 10-15MM/DAY AND MAXIMA OF 20-45MM. ON
WEDNESDAY...WIDESPREAD ONSHORE FLOW FROM THE CHOCO/EJE CAFETERO IN
COLOMBIA SOUTH INTO LAMBAYEQUE/PIURA IN PERU WILL FAVOR SCATTERED
HEAVY RAIN-PRODUCING THUNDERSTORMS...WITH FORECAST AMOUNTS OF
15-20MM/DAY AND MAXIMA OF 35-70MM. ELSEWHERE IN COLOMBIA...EXPECT
AN INCREASE IN THE COVERAGE OF CONVECTION WHICH WILL FAVOR
10-15MM/DAY AND MAXIMA OF 20-35MM..EXTENDING AS FAR NORTH AS THE
LAKE MARACAIBO REGION IN WESTERN VENEZUELA.
TO THE EAST...SEASONALLY ACTIVE CONVECTION IS EXPECTED IN NORTHERN
BRASIL/AMAZON BASIN ON A DAILY BASIS. IN THESE LOCATIONS...THE NET
WILL FAVOR 10-15MM/DAY AND MAXIMA OF 20-40MM ON MONDAY...AND
HIGHER AMOUNTS IN INTERIOR PORTIONS OF PARA/SOUTHERN
AMAZONAS-BRASIL. A SIMILAR DISTRIBUTION IS EXPECTED ON
TUESDAY...ALTHOUGH A MOIST PULSE ACROSS THE AMAZON DELTA/AMAPA
WILL FAVOR 15-20MM/DAY AND MAXIMA OF 25-50MM. ON
WEDNESDAY...EXPECT 10-15MM/DAY AND MAXIMA OF 20-45MM IN AMAPA AND
IN AMAZONAS/WESTERN PARA. OVER THE GUIANAS...EXPECT LIGHTER
ACCUMULATIONS GIVEN THE SEASONAL PRESENCE OF A DRIER AIR MASS
ABOVE THE BOUNDARY LAYER ENTERING FROM THE NORTH ATLANTIC. THIS
WILL GENERALLY FAVOR SHALLOW CONVECTION AND MAXIMA UNDER 15MM.
YET...INCREASINGLY UPPER DIVERGENT CONDITIONS WITH THE MJO WILL
STIMULATE VERTICAL DEVELOPMENT ON WEDNESDAY...WHEN EXPECT MAXIMA
OF 15-25MM IN SURINAME AND HIGHER AMOUNTS IN SOUTHWESTERN GUYANA.
GALVEZ/ACOSTA...WPC (USA)
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