TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
736 AM EST WED JAN 26 2022

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM JAN
25/12UTC: A ROBUST MID-LEVEL RIDGE CENTERS OVER THE CAYMAN ISLANDS
AND JAMAICA ON WEDNESDAY MORNING...WHILE EXTENDING AN AXIS INTO
THE NORTHEAST CARIBBEAN. THE ASSOCIATED SUBSIDENCE INVERSION HAS
STRENGTHENED OVER THE EASTERN CARIBBEAN...AND ITS BASE LIES UNDER
800 HPA...AS SUGGESTED BY WPC'S TWIN ALGORITHM. THE SATELLITE
PRESENTATION CONFIRMS A LOW-LYING AND STRONG INVERSION...AS
POCKETS SHALLOW CONVECTION WITH STRATIFORM SIGNATURES PROPAGATE
ACROSS THE VI AND AREAS TO THE SOUTH ON WEDNESDAY MORNING.

THE RIDGE IS FORECAST TO MOVE VERY LITTLE THROUGH THE FORECAST
CYCLE...TO START WEAKENING LATE ON FRIDAY UNDER THE PRESSURE OF A
LONG WAVE TROUGH ARRIVING FROM THE SOUTHERN USA. THE STABILIZING
INFLUENCE OF THE RIDGE WILL CONTINUE TO FAVOR FAIR WEATHER
CONDITIONS AND VERY LIGHT PRECIPITATION WHEREVER IT DEVELOPS. SOME
VARIABILITY WILL BE PROVIDED BY SHALLOW MOIST PLUMES PROPAGATING
IN THE TRADES. A PLUME IS FORECAST TO ARRIVE EARLY ON
THURSDAY...TO SUSTAIN A PEAK IN PRECIPITATION ON THURSDAY
AFTERNOON. AS THE PLUME ARRIVES...EXPECT AN INCREASE IN EARLY
MORNING CONVECTION IN NORTHEAST PUERTO RICO/WESTERN VI TO FAVOR
MAXIMA OF 0.1-0.15 INCHES EARLY ON THURSDAY MORNING. IN THE
AFTERNOON...EXPECT MAXIMA OF 0.3-0.5 INCHES IN THE SOUTHWEST
CORDILLERA.

THE EAST-NORTHEASTERLY TRADES WILL FAVOR LIGHT NOCTURNAL SHOWERS
ONCE AGAIN IN NORTHEASTERN PUERTO RICO AND PARTS OF THE NORTHERN
COAST ON THURSDAY EVENING INTO FRIDAY. FRIDAY AFTERNOON CONVECTION
WILL CLUSTER AGAIN IN THE SOUTHWEST CORDILLERA BUT GIVEN LIMITED
AVAILABLE MOISTURE EXPECT MAXIMA UNDER 0.2 IN. THE TRADES ARE THEN
FORECAST TO VEER TO EASTERLIES...AND TO SOUTH EASTERLIES BY
SATURDAY. THIS WILL CLUSTER SATURDAY AFTERNOON CONVECTION IN
NORTHWEST AND NORTH-CENTRAL PUERTO RICO...WHERE EXPECT MAXIMA OF
0.2-0.3 INCHES.

GALVEZ...WPC (USA)