FXCA20 KWBC 191146
PMDCA

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
746 AM EDT TUE JUL 19 2022

PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM JUL
19/12UTC: ON TUESDAY MORNING...A TUTT CENTERS NEAR 23N 64W AND
EXTENDS AN AXIS INTO NORTHWEST PUERTO RICO. IN THE LOWER
LEVELS...A PERTURBATION IS PROPAGATING WESTWARD WHILE EXTENDING
OVER THE EASTERN VI INTO THE CENTRAL EASTERN CARIBBEAN. CIRA'S
PROXY VISIBLE IMAGERY SHOWS STRATIFORM CLOUD STRUCTURES IN THE
CONVECTION ASSOCIATED WITH THIS PERTURBATION...WHICH IS CONSISTENT
WITH THE STABLE LAYER UNDER 600 HPA EVIDENT IN THE SAN JUAN
SOUNDING. FURTHERMORE...PLENTY OF DRY AIR BETWEEN 600 AND 850 HPA
ARE LIMITING THE COVERAGE OF CONVECTION...WHICH WILL RESULT IN
ISOLATED PRECIPITATION ONCE THE PERTURBATION CROSSES PUERTO RICO
DURING THE DAY ON TUESDAY. THE TRADES CONTINUE ACCELERATED...WITH
SPEEDS IN THE ORDER OF 15-20KT BETWEEN 925 AND 850 HPA...PRIMARILY
WITH AN EASTERLY COMPONENT. OF RELEVANCE...A TROPICAL WAVE IS
PROPAGATING ALONG 54W...FORECAST TO ENTER THE REGION ON WEDNESDAY.

THE TUTT IS FORECAST TO SLOWLY MEANDER WESTWARD WHILE AN UPPER
RIDGE ENTERS THE REGION FROM THE TROPICAL ATLANTIC...STARTING TO
SET FOOTHOLD ON WEDNESDAY MORNING. DESTABILIZATION BY THE TUTT
WILL FAVOR ISOLATED MAXIMA OF 1 INCH ON TUESDAY AFTERNOON IN
EXTREME WESTERN PUERTO RICO...BUT EXPECT THE CONVECTION TO BE
RAPIDLY SHEARED OFFSHORE BY THE STRONG SOUTHEASTERLY TRADES
TRAILING TUESDAY'S PERTURBATION. AS THE RIDGE SETS FOOTHOLD ON
WEDNESDAY AND ON...IT WILL ESTABLISH AN ENHANCED UPPER DIVERGENT
PATTERN ALONG ITS SOUTHWESTERN PERIPHERY...WHICH WILL LIKELY
ENHANCE DEEP CONVECTION ASSOCIATED WITH THE TROPICAL WAVE. THIS
WILL FAVOR WET CONDITIONS DEVELOPING EARLY ON THURSDAY
MORNING...WHERE EXPECT THE HEAVIEST PRECIPITATION TO CLUSTER IN
THE WESTERN VI AND EASTERN PUERTO RICO. EXPECT SCATTERED MAXIMA IN
THE ORDER OF 1 INCH...ALTHOUGH ISOLATED HIGHER AMOUNTS ARE
EXPECTED IN PORTIONS OF EASTERN PUERTO RICO. THE TROPICAL WAVE IS
EXPECTED TO RAPIDLY CROSS INTO THE DOMINICAN REPUBLIC DURING THE
DAY ON THURSDAY ACCOMPANIED BY PLENTIFUL CLOUD COVER. THIS WILL
LIMIT AFTERNOON MAXIMA IN NORTHWEST PUERTO RICO TO 0.5 INCHES. A
MUCH DRIER AIR MASS TRAILS THIS WAVE...WHICH WILL FAVOR FAIR
WEATHER AND VERY LITTLE PRECIPITATION FROM LATE THURSDAY EVENING
INTO THE WEEKEND.

GALVEZ...WPC (USA)
$$