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FXCA20 KWBC 061903
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
202 PM EST TUE JAN 06 2026
FORECAST BULLETIN 06 JANUARY 2026 AT 1905 UTC:
A POTENT MID-TO-UPPER LEVEL TROUGH, THAT CURRENTLY HAS A CENTER
NEAR 31S 124W WILL CONTINUE TO MOVE SOUTHEASTWARD INTO NORTHWEST
MEXICO. THE AXIS OF THIS TROUGH WILL BE OVER BAJA CALIFORNIA BY
WEDNESDAY AFTERNOON AND WILL BE ACCOMPANIED BY A SURFACE OCCLUDED
FRONT AND COLD FRONT. THESE FRONTS WILL EXTEND ACROSS BAJA
CALIFORNIA AND WILL QUICKLY LOSE THEIR DEFINITION AS THEY CONTINUE
TREKKING SOUTHWARD, TRANSITIONING INTO A SURFACE-TO-LOW LEVEL
TROUGH BY THURSDAY. ALSO EXPECT AN INCREASE IN DEEP TROPICAL
MOISTURE INTO THE BAJA CALIFORNIA PENINSULA, SONORA, AND CHIHUAHUA
WHERE PRECIPITABLE WATER VALUES WILL EXCEED 31MM ON WEDNESDAY. THE
INCREASE IN UPPER LEVEL DIVERGENCE, VORTICITY ADVECTION, MOISTURE
CONVERGENCE, AND SURFACE LIFT WILL HELP IN THE DEVELOPMENT AND
SUSTENANCE OF SHOWERS ACROSS THE AFOREMENTIONED REGIONS. A TOTAL
PRECIPITATION MAXIMA OF 15 - 30MM IS POSSIBLE ACROSS THE PACIFIC
COAST OF THE CENTRAL REGIONS OF THE BAJA CALIFORNIA PENINSULA,
NORTHERN SONORA, AND NORTHWEST CHIHUAHUA. DRIER CONDITIONS WILL
RETURN FOR THURSDAY.
ANOTHER REGION OF INTEREST IN MEXICO IS THE CARIBBEAN COAST OF THE
YUCATAN PENINSULA. A LOW LEVEL TROUGH WILL BE ARRIVING FROM THE
CARIBBEAN SEA ON WEDNESDAY AFTERNOON AND ANY SHOWERS AND
CONVECTION THAT DEVELOP WILL BE REINFORCED BY THE DIURNAL CYCLE.
THUS, EXPECT A TOTAL PRECIPITATION MAXIMA OF UP TO 15MM FROM
WEDNESDAY MORNING THROUGH THURSDAY MORNING. NOTE THAT THERE IS A
MID-LEVEL RIDGE PRESENT IN THE REGION THAT WILL HINDER THE
DEVELOPMENT OF DEEP CONVECTION ON WEDNESDAY. THIS RIDGE WILL
CONTINUE TO MOVE EASTWARD WITH PASSING DAYS INTO THE BAHAMAS AND
NORTHERN CARIBBEAN AND WILL PROMOTE A DRYING TREND ACROSS THE
REGION.
ALONG THE PACIFIC COASTS OF COLOMBIA AND ECUADOR, A LOW LEVEL
TROUGH WILL CONTINUE MEANDERING IN THE REGION THAT WILL ALSO BE
ACCOMPANIED BY PRECIPITABLE WATER VALUES EXCEEDING 57MM. THOUGH
THE LOW LEVEL WIND SPEED WILL BE WEAK, RANGING BETWEEN 5 TO 10
KNOTS FOR THE NEXT THREE DAYS, STILL ANTICIPATE FOR THE DIURNAL
CYCLE AND LOCAL EFFECTS TO ENHANCE TOTAL PRECIPITATION MAXIMA. A
DAILY MAXIMA OF 25 - 50MM IS LIKELY ACROSS THE SOUTHERN PACIFIC
COLOMBIAN COAST, WHERE THE LOW LEVEL WIND FLOW WILL BE ORTHOGONAL
TO THE LOCAL TOPOGRAPHY. THERE WILL ALSO BE A MOISTENING TREND
ACROSS THE NORTHERN PACIFIC COLOMBIAN COAST AND CENTRAL COLOMBIA
THAT WILL YIELD TOTAL PRECIPITATION MAXIMA IN EXCESS OF 35MM FOR
THE NEXT THREE DAYS.
ELSEWHERE IN TROPICAL SOUTH AMERICA, EXPECT THE PRESENCE OF UPPER
LEVEL DIVERGENCE THAT IS BEING SUSTAINED BY AN UPPER LEVEL
DIFFLUENT PATTERN ACROSS THE CENTRAL AMAZON BASIN FOR TUESDAY AND
WEDNESDAY. THERE WILL ALSO BE LOW LEVEL TROUGHING PRESENT IN THE
REGION THAT WILL ENABLE THE INCREASE IN MOISTURE CONVERGENCE AND
SURFACE-TO-LOW LEVEL VERTICAL ASCENT. THESE CONDITIONS WILL FAVOR
DAILY TOTAL PRECIPITATION MAXIMA IN EXCESS OF 45MM. ANOTHER TROUGH
WILL BE MOVING INTO THE AMAZON DELTA ON WEDNESDAY AND WILL BE
PROPAGATING ACROSS THE EASTERN AMAZON BASIN ON THURSDAY. THIS
TROUGH WILL PROMOTE THE INCREASE IN PRECIPITATION ACCUMULATIONS
WITH ITS PASSAGE. OTHERWISE, EXPECT SEASONAL CONDITIONS FOR THE
REST OF THE REGION.
IN THE NORTHERN CARIBBEAN, AN EASTWARD MOVING UPPER LEVEL TROUGH
WILL BE EXITING THE REGION BY WEDNESDAY MORNING. THIS TROUGH WILL
HELP IN THE DEVELOPMENT OF LOW LEVEL TROUGHS ACROSS THE REGION
THAT WILL PROMOTE THE INCREASE IN MOISTURE CONVERGENCE. WEAK
MOISTURE PLUMES WILL ALSO BE MOVING INTO PUERTO RICO, HISPANIOLA,
JAMAICA, AND CUBA FOR THE NEXT THREE DAYS, THOUGH THE MAGNITUDE OF
THE MOISTURE ADVECTION WILL BE WEAK. THUS IF ANY SHOWERS DO
DEVELOP, THEY WILL BE ISOLATED. WITH THE EXIT OF THE UPPER LEVEL
TROUGH, EXPECT THE RETURN OF THE EASTERLY TRADE WIND PATTERN
ACROSS THE CARIBBEAN.
TINOCO-MORALES...(WPC)
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