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FXCA20 KWBC 081802
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
101 PM EST THU JAN 08 2026
FORECAST BULLETIN 08 JANUARY 2026 AT 1805 UTC:
A MID-TO-UPPER LEVEL TROUGH THAT IS CURRENTLY MOVING ACROSS THE
SOUTHWEST UNITED STATES WILL BE SUSTAINING THE DEVELOPMENT OF TWO
COLD FRONTS ACROSS THE CENTRAL AND SOUTHERN PLAINS OF THE UNITED
STATES. THESE COLD FRONTS ARE EXPECTED TO COMBINE INTO ONE SYSTEM
AS THE MID-TO-UPPER LEVEL TROUGH MOVES INTO THE PLAINS REGION ON
FRIDAY. THIS COLD FRONT SYSTEM WILL START MOVING INTO NORTHEAST
MEXICO ON FRIDAY NIGHT. BY LATE SATURDAY AFTERNOON, IT SHOULD BE
LOCATED ACROSS SOUTHERN VERACRUZ AND WILL REMAIN STATIONARY IN
THIS REGION THEREAFTER. THIS FRONTAL SYSTEM WILL FAVOR THE
INCREASE IN VERTICAL ASCENT AT THE SURFACE. AT THE LOW LEVELS,
EXPECT INCREASING NORTHERLY AND NORTHEASTERLY LOW LEVEL WINDS
AFTER EARLY SATURDAY MORNING ALONG THE GULF STATES OF MEXICO. THIS
LOW LEVEL WIND FLOW PATTERN WILL CONTINUE THROUGH SUNDAY. BY LATE
SATURDAY NIGHT, EXPECT INCREASING LOW LEVEL WIND FLOW CONFLUENCE
ACROSS SOUTHERN VERACRUZ, WHICH WILL FURTHER MOISTURE POOLING AND
OROGRAPHIC ENHANCEMENT. FURTHERMORE, THE REGION WILL BE INFLUENCED
BY THE PERIPHERY OF A MID-LEVEL RIDGE, WHICH WILL FURTHER ENHANCE
MID-LEVEL DIVERGENCE. THESE FACTORS WILL FAVOR TOTAL PRECIPITATION
MAXIMA OF 20 - 35MM FOR SOUTHERN VERACRUZ FROM SATURDAY MORNING
THROUGH SUNDAY MORNING, THOUGH PRECIPITATION IS EXPECTED TO BEGIN
LATE FRIDAY EVENING. MEANWHILE, NORTHERLY LOW LEVEL WINDS WILL
INTERACT WITH THE LOCAL TOPOGRAPHY OF SOUTHERN TAMAULIPAS AND
NORTHERN VERACRUZ, WHICH WILL FAVOR VERTICAL ASCENT AND MOISTURE
POOLING. THESE CONDITIONS WILL FAVOR A TOTAL PRECIPITATION MAXIMA
OF 20 - 45MM FROM SATURDAY MORNING THROUGH SUNDAY MORNING. NOTE
THAT THERE IS MODEL DISAGREEMENT IN HOW FAR SOUTH THE COLD FRONT
WILL EXTEND INTO VERACRUZ AND THIS WILL OVERALL DETERMINE THE
MAGNITUDE OF THE DAILY ACCUMULATIONS FROM SATURDAY INTO SUNDAY.
REGARDLESS, THERE IS HIGH CONFIDENCE THAT THE AFOREMENTIONED TWO
REGIONS WILL HAVE THE MOST SIGNIFICANT PRECIPITATION IMPACT FROM
THIS FRONTAL SYSTEM.
ACROSS CENTRAL AMERICA, EXPECT THE INTENSIFICATION OF THE
CARIBBEAN LOW LEVEL JET (CLLJ). THE CLLJ WILL REINFORCE LOW LEVEL
CYCLONIC CIRCULATION ALONG ITS SOUTHERN PERIPHERY. AT THE SAME
TIME, A SERIES OF LOW LEVEL TROUGHS THAT WILL BE EMBEDDED WITHIN
THE EASTERLY TRADE WINDS WILL CONTINUE TO MOVE INTO THE CARIBBEAN
COASTS OF NICARAGUA, COSTA RICA, AND PANAMA. ANOTHER DRIVING FORCE
FOR PRECIPITATION PROCESSES WILL BE THE PRESENCE OF THE MONSOON
TROUGH AND THE SURFACE-TO-LOW LEVEL WIND AND MOISTURE REGIME.
DAILY PRECIPITATION MAXIMA OF 15 - 20MM ARE POSSIBLE ACROSS THE
REGION FOR THE NEXT THREE DAYS.
MEANWHILE, A LOW LEVEL TROUGH OFF THE PACIFIC COAST OF COLOMBIA
AND ECUADOR WILL CONTINUE TO INFLUENCE PRECIPITATION PATTERNS IN
THIS REGION FOR THE NEXT THREE DAYS. LOW LEVEL WIND SPEEDS WILL BE
WEAK FOR THURSDAY AND INCREASING SLIGHTLY IN MAGNITUDE BY SUNDAY
MORNING. THESE CONDITIONS WILL FAVOR AN INCREASE IN MOISTURE
CONVERGENCE ALONG THE SOUTHERN COAST OF COLOMBIA AND NEARBY
REGIONS. NOTE THAT THE DIURNAL CYCLE, LOCAL EFFECTS, AND THE
PRESENCE OF INSTABILITY WILL HELP ENHANCE PRECIPITATION PROCESSES
AS WELL. THUS, DAILY TOTAL PRECIPITATION MAXIMA WILL REACH 50MM
FOR THE NEXT THREE DAYS.
ANOTHER REGION OF INTEREST IN TROPICAL SOUTH AMERICA IS THE
WESTERN AND NORTHWESTERN AMAZON BASIN. THE LOW LEVEL WINDS WILL
CONVERGE IN THIS REGION FOR THE NEXT THREE DAYS AND THIS WILL
FAVOR THE INCREASE IN MOISTURE POOLING. AT THE SAME TIME, A WEAK
UPPER LEVEL DIFFLUENT WIND PATTERN WILL DEVELOP AFTER FRIDAY
AFTERNOON IN THIS REGION AND THIS WILL HELP AMPLIFY UPPER
DIVERGENCE THROUGH EARLY SUNDAY MORNING. THE MID-LEVEL WINDS WILL
ALSO WEAKEN DURING THE FORECAST CYCLE WHICH WILL REDUCE SPEED
SHEAR. THESE CONDITIONS WILL FAVOR DAILY TOTAL PRECIPITATION
MAXIMA REACHING 35MM.
ELSEWHERE IN TROPICAL SOUTH AMERICA, A SERIES OF LOW LEVEL TROUGHS
WILL BE MOVING ACROSS THE BASIN FOR THE NEXT THREE DAYS, WHICH
WILL ENHANCE MOISTURE CONVERGENCE AND LOW LEVEL CYCLONIC ROTATION.
THUS, EXPECT HIGHER PRECIPITATION ACCUMULATIONS IN THE VICINITY OF
THESE TROUGHS. ACROSS THE GUIANAS, THE PRESENCE OF THE
INTERTROPICAL CONVERGENCE ZONE AND ACCOMPANYING LONG FETCH
MOISTURE PLUME WILL CONTINUE TO DRIVE THE PRECIPITATION PROCESSES
IN THIS REGION. DAILY TOTAL PRECIPITATION MAXIMA OF 20 - 35MM IS
EXPECTED. OTHERWISE, EXPECT SEASONAL CONDITIONS ELSEWHERE.
IN THE CARIBBEAN, LOW LEVEL TROUGHS WILL CONTINUE TO PROPAGATE
ACROSS THE REGION AND THE COMBINATION OF THE LOCAL EFFECTS, THE
DIURNAL CYCLE, AND OROGRAPHIC LIFT WILL HELP SUPPORT THE
DEVELOPMENT FOR ISOLATED SHOWERS. A LOW LEVEL TROUGH WILL BE
DEVELOPING TO THE NORTHEAST OF HISPANIOLA AND PUERTO RICO EARLY
FRIDAY MORNING WITH THE PASSAGE OF A MID-TO-UPPER LEVEL TROUGH.
THE INDUCED WEAK TROUGH WILL GAIN DEFINITION EARLY FRIDAY MORNING
AND WILL BE MOVING ACROSS HISPANIOLA THROUGH THE DAY ON FRIDAY.
THUS, A TOTAL PRECIPITATION MAXIMA OF 15MM IS EXPECTED FROM FRIDAY
MORNING THROUGH SATURDAY MORNING IN THIS REGION. OTHERWISE,
SEASONAL CONDITIONS WILL PREVAIL THROUGHOUT THE REST OF THE
REGION.
TINOCO-MORALES...(WPC)
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