484
FXCA20 KWBC 251220
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
720 AM EST WED JAN 25 2023
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM JAN
25/12UTC: ON WEDNESDAY MORNING...AN EXTENSIVE MID-LEVEL RIDGE
CENTERS ON A HIGH NEAR 21N 70W OR NORTH OF HISPANIOLA. THE RIDGE
EXTENDS ACROSS THE ENTIRE NORTHERN AND EASTERN CARIBBEAN...AND
ASSOCIATES WITH A STRONG TRADE WIND CAP. THE WPC MACRO SHOWS THE
CAP LOWERING BELOW 800 HPA THIS MORNING. THIS IS CONSISTENT WITH
THE SATELLITE PRESENTATION OF TRADE WIND CONVECTION...WHICH
SUGGESTS SHALLOW DEVELOPMENT AND STRATIFORM
STRUCTURES...CONSISTENT WITH THE STRONG AND SHALLOW CAP. OF
RELEVANCE...A FRONT EXTENDS ALONG 28N...THIS SYSTEM IS EXPECTED TO
ACCELERATE SOUTHWARD AND CROSS THE ISLANDS ON FRIDAY AFTERNOON
FROM NORTHEAST TO SOUTHWEST AS A FRONTAL SHEAR LINE.
THE MID-LEVEL RIDGE IS FORECAST TO CONTINUE BEING THE DOMINANT
FEATURE THROUGH THE FORECAST CYCLE. MODELS AGREE ON THE CENTER OF
THE RIDGE MEANDERING WESTWARD SLOWLY...TO CENTER OVER CUBA BY
SUNDAY. THIS SHOULD RESULT IN SOME WEAKENING AND LOFTING OF THE
TRADE WIND CAP INTO EARLY NEXT WEEK...BUT NOT SUFFICIENTLY TO
ALLOW FOR THE DEVELOPMENT OF DEEP CONVECTION. SEASONABLY LOW
VALUES OF THE GDI AND AVAILABLE MOISTURE WILL SUPPORT VERY LOW
RAINFALL ACCUMULATIONS THROUGH THE CYCLE. THE SYSTEM OF INTEREST
IS THE FRONTAL SHEAR LINE EXPECTED TO ARRIVE FROM THE NORTHEAST ON
FRIDAY AFTERNOON. THIS WILL FAVOR A TRANSIENT INCREASE IN
PRECIPITATION...BUT ACCUMULATIONS WILL BE LIMITED DUE TO THE RAPID
PASSAGE OF THE BOUNDARY AND LIMITED AMOUNTS OF MOISTURE.
YET...FAST 20-25KT NORTHEASTERLY TRADES WILL ESTABLISH THE
CLASSICAL COLD-ADVECTIVE PATTERN CHARACTERIZED BY SCATTERED
INTERMITTENT LIGHT RAIN SHOWERS...TO FAVOR PERIODS OF SHORT LIVED
LIGHT PRECIPITATION IN NORTHERN AND EASTERN PUERTO RICO DURING
LATE NIGHT AND EARLY MORNING HOURS.
GALVEZ/ACOSTA/ALAMO...WPC (USA)
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page