134
FXCA20 KWBC 162003
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
303 PM EST THU JAN 16 2025
FORECAST BULLETIN 16 JANUARY 2025 AT 20 UTC
A POTENT UPPER TROUGH LOCATED TO THE EAST OF NEW FOUNDLAND
CONTINUES TO EXTEND AN ELONGATED FRONT THAT HAS REACHED THE
GREATER ANTILLES AND IS PROPAGATING ACROSS NORTH-CENTRAL PORTIONS
OF HISPANIOLA ON THURSDAY AFTERNOON. NOTE THAT THE MODELS ARE
STRUGGLING RESOLVING THE SOUTHWARD PROGRESSION OF THIS
SYSTEM...BUT SATELLITE DATA SHOWS THAT THE FRONT IS ABOUT 2 TO 3
DEGREES SOUTH OF FRONTAL SOLUTIONS IN NUMERICAL MODEL DATA. THE
FRONT IS FORECAST TO BECOME STATIONARY NORTH OF PUERTO RICO NEAR
19-20N AND ACROSS SOUTHERN PORTIONS OF HISPANIOLA LATER TODAY...TO
START LOSING DEFINITION DURING THE DAY ON SATURDAY. TO THE NORTH
OF THIS FRONT...OTHER WEAKER BOUNDARIES ARE PROPAGATING
SOUTHWARD...BUT THEY ARE HAVING VERY LIMITED IMPACTS ON
PRECIPITATION. THE FRONT IN HISPANIOLA IS EXPECTED TO ENHANCE
TRADE WIND SHOWERS IN THE REGION...BUT EXPECT CONSERVATIVE
RAINFALL ACCUMULATION THROUGH THE FORECAST CYCLE GIVEN THE
STABILIZING INFLUENCE OF THE CARIBBEAN MID-LEVEL RIDGE...BUT MORE
SO THE PRESENCE OF VERY DRY AIR IN THE MID TROPOSPHERE. THROUGH
EARLY FRIDAY EXPECT MAXIMA OF 15MM PARTICULARLY IN NORTHEAST
SLOPES OF NORTHERN AND CENTRAL HISPANIOLA. THIS INCREASES TO
MAXIMA OF 15 - 20MM ON FRIDAY THROUGH EARLY SUNDAY. TO THE EAST OF
THIS FRONT...A SHEAR LINE CURRENTLY EXTENDING ACROSS THE NORTHERN
LEEWARD ISLANDS IS FORECAST TO MEANDER NORTHWESTWARD TO REACH THE
VI AND PUERTO RICO BY FRIDAY AFTERNOON/EVENING. ALTHOUGH THE SHEAR
LINE IS THEN FORECAST TO DISSIPATE... THE REMAINING MOIST PLUME
WILL LIKELY ENHANCE TRADE WIND SHOWERS AND RAINFALL AMOUNTS IN
PUERTO RICO AND THE VI ON FRIDAY LASTING THROUGH SUNDAY. EXPECT 05
- 10MM/DAY AND ISOLATED MAXIMA OF 15 - 20MM WITH THIS EVOLUTION.
IN MEXICO... A FRONTOLIZING BOUNDARY EXTENDS CROSS THE CENTRAL
GULF INTO WESTERN TABASCO AND ASSOCIATES WITH A WEAKENING NORTES
EVENT IN SOUTHERN VERACRUZ. THIS IS EXPECTED TO CONTINUE FAVORING
ENHANCED LOW-LEVEL MOISTURE CONVERGENCE AS THE NORTES INTERACT
WITH TERRAIN IN NORTHERN CHIAPAS/TABASCO AND SOUTHERN VERACRUZ...
TO FAVOR 05 - 10MM/DAY AND ISOLATED MAXIMA OF 15 - 30MM THROUGH
EARLY FRIDAY. THE RAPID CHANGE IN THE LOW-LEVEL FLOW AND
INCREASING STABILIZING INFLUENCE OF THE MID-LEVEL RIDGE OVER THE
REGION WILL LEAD TO A RAPID DECREASE IN ACCUMULATIONS THEREAFTER.
ANOTHER SYSTEM OF INTEREST IS A POTENT ARCTIC FRONT THAT IS
FORECAST TO ENTER THE NORTHWEST GULF OF MEXICO EARLY ON SATURDAY.
BY SATURDAY EVENING IT IS FORECAST ACROSS SOUTHERN MISSISSIPPI
INTO SOUTHERN TAMAULIPAS. NOTE THAT BY EARLY MONDAY MORNING THE
FRONT IS LIKELY TO EXTEND ACROSS THE NORTHWEST BAHAMAS... WEST
CUBA...CENTRAL YUCATAN PENINSULA INTO TABASCO AND SOUTHERN
VERACRUZ...TO FAVOR ANOTHER NORTES EVENT IN WESTERN PORTIONS OF
THE GULF OF MEXICO. AS THIS FRONT MOVES SOUTHWARD EXPECT GENERALLY
CONSERVATIVE AMOUNTS IN EASTERN SLOPES OF THE SIERRA MADRE
ORIENTAL. HOWEVER...HIGHER AMOUNTS ARE EXPECTED IN TABASCO AND FAR
SOUTHEAST VERACRUZ/CHIAPAS ON MONDAY...AS ENHANCED CYCLONIC
VORTICITY ASSOCIATED WITH THE FRONT COUPLES WITH HIGH VALUES OF
LOW-LEVEL MOISTURE FLUX CONVERGENCE...TO FAVOR MAXIMA LIKELY ABOVE
THE 30 - 60MM/DAY RANGE.
THE EASTERN CARIBBEAN WILL CONTINUE TO BE INFLUENCED BY THE
STABILIZING EFFECTS OF A MID-LEVEL RIDGE... WHICH WILL CONTINUE TO
FAVOR SEASONALLY CONSERVATIVE PRECIPITATION AMOUNTS. OF INTEREST
IS A TRADE WIND SURGE FORECAST TO RAPIDLY PROPAGATE ACROSS THE
ISLANDS DURING SATURDAY AFTERNOON INTO EARLY HOURS OF SUNDAY. THE
RAPID PASSAGE OF THE SURGE WILL LIKELY LIMIT RAINFALL AMOUNTS.
HOWEVER...HIGH VALUES OF LOW-LEVEL MOISTURE CONVERGENCE AND
INTERACTIONS WITH TERRAIN WILL FAVOR MAXIMA OF 15-25MM FROM SAINT
VINCENT NORTH INTO GUADELOUPE...WHILE IN
BARBADOS...GRENADA...TRINIDAD AND TOBAGO AND NORTHEAST VENEZUELA
EXOECT MAXIMA GENERALLY UNDER 15MM.
IN CENTRAL AMERICA...WET LOCATIONS ARE LIMITING TO THE CARIBBEAN
BASINS OF SOUTHEAST NICARAGUA...COSTA RICA AND WEST PANAMA. NOTE
THAT HIGH DAILY TOTALS ARE CLUSTERING TO ELEVATED TERRAIN IN COSTA
RICA. THROUGH EARLY FRIDAY EXPECT MAXIMA OF 20 - 35MM IN THESE
REGIONS WHILE IN SOUTHEAST NICARAGUA...TORTUGUERO AND PANAMA
EXPECT MAXIMA OF 15 - 25MM. THIS INCREASES ON FRIDAY TO MAXIMA OF
20 - 45MM IN ELEVATED TERRAIN OF COSTA RICA AND 20 - 35MM IN
COASTAL LOCATIONS. ON SATURDAY...A WEAK TROUGH IN THE EASTERLY
TRADES IS EXPECTED TO FAVOR MAXIMA OF 20 - 40MM IN MOST OF
NORTHERN COSTA RICA AND SOUTHEAST NICARAGUA. NOTE THAT ISOLATED
HIGHER AMOUNTS ARE ALWAYS POSSIBLE DUE TO LOCAL TERRAIN
ENHANCEMENT.
FAIR WEATHER CONDITIONS ARE OCCURRING IN MOST OF NORTHERN SOUTH
AMERICA DUE TO THE PRESENCE OF A VERY DRY AIR MASS IN THE
MID-TROPOSPHERE. FURTHERMORE...LOW PRESSURES IN SOUTHEAST AND
EASTERN BRASIL COUPLED WITH HIGHER PRESSURES IN THE SOUTHERN
ATALNTIC/CARIBBEAN BASIN HAVE FAVORED PERSUISTENT LOW-LEVEL
NORTHERLY FLOW ACROSS THE WESTERN AMAZON...TRANSPORING THE DRY AIR
INTO NORTHERN PERU AND FAR WESTERN BRASIL...AREAS THAT SHOULD
EXPECT VERY ISOLATED PRECIPITATION AND CONSERVATIVE RAINFALL
TOTALS THROUGH THE FORECAST CYCLE. WETTER CONDITIONS ARE EXPECTED
IN THE PACIFIC BASIN OF ECUADOR AND WESTERN COLOMBIA WHERE ITCZ
CONVERGENCE AND WEAK ONSHORE FLOW WILL ALLOW FOR DIURNAL
CONVECTION ON A DAILY BASIS. FURTHERMORE...WEAK VERTICAL WIND
SHEAR WILL ALLOW THE DEVELOPMENT OF MODERATE AMOUNT IN A LOCAL
SCALE. EXPECT MAXIMA OF 20 - 35MM ON THURSDAY. THIS DECREASES TO
MAXIMA OF 15 - 25MM ON FRIDAY...AND INCREASES TO MAXIMA OF 20 -
40MM IN NORTHERN ECUADOR AND SOUTHWEST COLOMBIA ON SATURDAY. NOTE
AN EXPECTED INCREASE IN NORTHWEST COLOMBIA/EJE CAFETERO ON
SATURDAY AS WELL...WHEN EXPECT ISOLATED MAXIMA OF 15 - 30MM.
GALVEZ...(WPC)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page