499
FXCA20 KWBC 221644
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1144 AM EST FRI DEC 22 2023
FORECAST BULLETIN 22 DEC 2023 AT 1645 UTC: A POTENT UPPER TROUGH
AND ASSOCIATED SURFACE FEATURES IS ENTERING THE SOUTHWEST USA ON
FRIDAY. AS THE UPPER TROUGH INTERACTS WITH A POLAR TROUGH TO ITS
NORTH...IT IS FORECAST TO PROGRESS INTO THE PLAINS OF THE USA BY
SUNDAY ACCOMPANIED BY ITS ASSOCIATED SURFACE FEATURES. BY FRIDAY
EVENING...A FRONT IS EXPECTED ALONG NORTH SONORA...CENTRAL BAJA
CALIFORNIA. BY SATURDAY EVENING EXPECT THE FRONT ALONG WEST
TEXAS...SOUTHEAST CHIHUAHUA...CENTRAL SINALOA...LOS CABOS. BY
SUNDAY EVENING EXPECT A WEAKENING COLD FRONT ACROSS CENTRAL
DURANGO...SOUTHERN SINALOA INTO ISLAS REVILLAGIGEDO. ON
FRIDAY...EXPECT 10-15MM/DAY AND MAXIMA OF 20-40MM IN NORTHERN
SONORA...INCLUDING A MARGINAL RISK FOR SEVERE CONVECTION. ONSHORE
FLOW ALONG THE WESTERN SLOPES OF THE SIERRA SAN PEDRO MARTIR WILL
FAVOR 05-10MM/DAY AND MAXIMA OF 15-30MM. ON SATURDAY EXPECT MAXIMA
OF 15MM DEVELOPING IN NORTHERN COAHUILA AND ALONG WESTERN SLOPES
OF THE SIERRA MADRE OCCIDENTAL FROM NORTHERN CHIHUAHUA INTO
NORTHERN SINALOA. THE PASSAGE OF THE FRONT WILL ALSO FAVOR 15-30KT
DOWNSLOPING WINDS EAST OF THE SIERRA TARAHUMARA IN MOST OF CENTRAL
CHIHUAHUA. BY SUNDAY EXPECT LITTLE PRECIPITATION WITH THE
DISSIPATING FRONT.
A FRONT EXTENDS FROM THE NORTH ATLANTIC INTO THE GREATERNA
ANTILLES AND NORTHERN CENTRAL AMERICA. BY FRIDAY EVENING EXPECT A
STATIONARY BOUNDARY ACROSS SOUTHERN HISPANIOLA...JAMAICA INTO
NORTHEAST HONDURAS WHILE A DISSIPATING PREFRONTAL SHEAR LINE
EXTENDS JUST TO ITS SOUTH INTO EASTERN NICARAGUA. BY SATURDAY
EVENING EXPECT A WEAKENING STATIONARY FRONT ALONG SOUTHERN
HISPANIOLA...JAMAICA...NORTHEAST HONDURAS. ON FRIDAY THIS WILL
FAVOR 10-15MM/DAY AND MAXIMA OF 20-45MM IN EASTERN HONDURAS AND
EASTERN NICARAGUA. IN NORTHERN COSTA RICA EXPECT 05-10MM/DAY AND
MAXIMA OF 15-20MM. IN NORTHERN HISPANIOLA...ONSHORE FLOW WILL
FAVOR 05-10MM/DAY AND MAXIMA OF 15-25MM. ON SATURDAY...EXPECT
MAXIMA OF 15-30MM/DAY IN EASTERN HONDURAS AND NORTHEAST
NICARAGUA...WHILE IN JAMAICA EXPECT MAXIMA OF 10MM. A NOTICEABLE
DECREASE IN ACCUMULATION IS EXPECTED ON SUNDAY IN MOST OF THE
NORTHERN CARIBBEAN...GREATER ANTILLES AND THE CARIBBEAN BASIN OF
CENTRAL AMERICA.
ELSEWHERE IN THE CARIBBEAN EXPECT GENERALLY FAIR WEATHER
CONDITIONS. AVAILABLE MOISTURE REMAINS ENHANCED ACROSS THE LESSER
ANTILLES...WHICH WILL FAVOR LIGHT PRECIPITATION ON A DAILY BASIS.
ON FRIDAY EXPECT MAXIMA UNDER 15MM FROM NORTHERN GUYANA/EAST
VENEZUELA INTO GUADELOUPE. ON SATURDAY EXPECT SIMILAR AMOUNTS FROM
GRENADA...BARBADOS NORTH INTO ANTIGUA AND MONSERRATE. ON
SUNDAY...EXPECT SIMILAR AMOUNTS BETWEEN MARTINIQUE AND ANTIGUA.
IN NORTHERN SOUTH AMERICA...THE SUBTROPICAL UPPER RIDGE/BOLIVIAN
HIGH IS FORECAST TO REMAIN WELL CONFIGURATED THROUGH THE FORECAST
CYCLE. THIS WILL CONTINUE TO SUSTAIN AN ENHANCED UPPER DIVERGENT
TIER ACROSS MOST OF EQUATORIAL PORTIONS OF THE AMAZON
BASIN...ESPECIALLY IN WESTERN PORTIONS OF THE CONTINENT. ITCZ/NET
CONVERGENCE WILL STIMULATE ACCUMULATION PARTICULARLY IN NORTHWEST
ECUADOR AND SOUTHWEST COLOMBIA WHERE EXPECT 15-30MM/DAY AND MAXIMA
OF 40-80MM WITH A RISK FOR MCS FORMATION ON FRIDAY
EVENING...DECREASING GRADUALLY TO 15-20MM/DAY AND MAXIMA OF
30-60MM BY SUNDAY EVENING. IN THE AMAZON BASIN...ON FRIDAY EXPECT
MAXIMA OF 20-45MM IN EASTERN ECUADOR/NORTHERN PERU DUE TO
WEAKENING DEEP CONVECTION FROM OVERNIGHT. EXPECT SIMILAR AMOUNTS
IN MOST OF NORTHERN BRASIL AND THE GUIANAS...ALTHOUGH IN FRENCH
GUIANA EXPECT MAXIMA OF 25-50MM DUE TO ITCS MOISTURE CONVERGENCE.
ON SATURDAY...EXPECT A FLARE UP OF DEEP CONVECTION IN THE WESTERN
AMAZON WHERE EXPECT 15-20MM/DAY AND MAXIMA OF 35-70MM WITH A RISK
FOR MCS FORMATION. ON SUNDAY EXPECT MAXIMA OF 25-50MM IN WESTERN
BRASIL IN MOST OF WESTERN BRASIL AND NORTHERN PERU/SOUTHEAST
COLOMBIA...ALTHOUGH ISOLATED HIGHER AMOUNTS ARE POSSIBLE.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
NONE
GALVEZ...WPC (USA)
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