208
FXCA20 KWBC 111525
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1124 AM EDT FRI AUG 11 2023
FORECAST BULLETIN FROM 11 AUG 2023 AT 1530 UTC: A QUASI-STATIONARY
UPPER PATTERN NORTH OF 24N IN MEXICO WILL FAVOR VENTILATION ALONG
THE SIERRA MADRE OCCIDENTAL...GIVEN TAHT THE REGION WILL LIE UNDER
UPPER DIFFLUENT/DIVERGENT FLOW BETWEEN A RIDGE CENTERING IN THE
NORTHERN GULF OF MEXICO AND A TROUGH WEST OF THE BAJA CALIFORNIA
PENINSULA. THIS WILL FAVOR MAXIMA GENERALLY IN THE 20-35MM/DAY
RANGE. YET...EXPECT ISOLATED HIGHER AMOUNTS CLUSTERING IN
SINALOA/DURANGO ON FRIDAY...WHERE MAXIMA WILL LIKELY REACH
25-50MM. ON SATURDAY...EXPECT MAXIMA OF 25-50MM FRMO NAYARIT NORTH
INTO SOUTHERN SONORA. THIS DECREASES AFTER. TO THE SOUTH OF
24N...MID-UPPER SYSTEMS ARE FORECAST TO CONTINUE RETROGRADING. A
TUTT LOW IS FORECAST TO MOVE FRMO SOUTHEAST MEXICO INTO THE
SOUTHERN GULF OF CALIFORNIA BY SUNDAY. THIS WILL FAVOR MAXIMA OF
20-45MM IN SOUTH-CENTRAL MEXICO ON FRIDAY...AND MAXIMA OF 20-40MM
FROM OAXACA/PUEBLA WEST INTO JALISCO ON SATURDAY...DECREASING
AFTER.
IN THE CARIBBEAN AND TROPICAL ATLANTIC...A PROGRESSIVE TRAIN OF
MID-UPPER TROUGHS AND RIDGES IS PROPAGATING FROM EAST TO WEST.
TROPICAL WAVE ACTIVITY IS REDUCED IN FREQUENCY...YET A TOBUST WAVE
IS PROPAGATING FROM EAST CUBA/JAMAICA ON FRIDAY INTO
GUATEMALA/SOUTHEAST MEXICO BY SUNDAY...AND WILL FAVOR MODERATE TO
LOCALLY HEAVY PRECIPITATION AS IT MOVES THROUGH (SEE BELOW). OF
INTEREST...AN EASTERLY WAVE IS MOVING IN FROM THE ATLANTIC...AND
IS FORECAST TO IMPROVE ITS STRUCTURE AND IMPACT IN PRECIPITATION
ONCE IT REACHES THE ARC OF THE LESSER ANTILLES ON SATURDAY. THIS
WILL FAVOR MAXIMA OF 15MM THEN. ON SUNDAY...THE WAVE IS FORECAST
ALONG 70W...AND WILL FAVOR MAXIMA OF 15-20MM IN THE DOMINICAN
REPUBLIC AND MAXIMA OF 15-25MM IN WEST VENEZUELA.
AN EVOLUTION OF INTEREST IS THE INTENSIFICATION OF THE PANAMANIAN
LOW. THIS WILL FAVOR PERIODS OF HEAVY RAINFALL FROM WESTERN
COLOMBIA INTO COSTA RICA THROUGH THE CYCLE. ON FRIDAY...EXPECT
MAXIMA OF 25-50MM IN NORTHWEST COLOMBIA AND MAXIMA OF 20-35MM IN
PANAMA. ONSHORE FLOW FROM THE WEST INCREASES IN WESTERN COLOMBIA
ON SATURDAY. GIVEN VALUES OF PRECIPITABLE WATER EXCEEDING 60MM
EXPECT MAXIMA OF 50-100MM. MODERATE AMOUNTS ARE ALSO EXPECTED IN
EAST HONDURAS/EAST NICARAGUA WHERE ENHANCED TRADE WIND CONVERGENCE
WILL TRIGGER MAXIMA OF 30-60MM. FROM NORTHWEST COLOMBIA INTO
SOUTHERN COSTA RICA EXPECT MAXIMA OF 25-50MM. ON SUNDAY...A BROAD
CIRCULATION IS EXPECTED WELL TO THE WEST OF COSTA RICA OR NEAR
90W. HOWEVER...THIS IMPLIES ENHANCED SOUTHERLY/SOUTHWESTERLY
LOW-LEVEL FLOW IN COSTA RICA...WHICH WILL TRIGGER MAXIMA OF
75-125MM ALONG THE PACIFIC BASIN FROM WEST PANAMA INTO SOUTHWEST
NICARAGUA. EAST OF THE CONTINENTAL DIVIDE EXPECT MAXIMA OF 20-45MM.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT 12/00 12/12 13/00 13/12 14/00 14/12 15/00 15/12
TW 18N 75W 79W 82W 85W 88W 92W 96W 100W 104W
TW 21N 78W 80W ABSORBED
TW 23N 108W 111W 113W EXITS
A TROPICAL WAVE IS INITIALIZED AT 75W AND SOUTH OF 18N. IT IS
MOVING RAPIDLY WHILE ACCOMPANIED BY STRONG EASTERLY TRADES. ON
FRIDAY...IT WILL FAVOR MAXIMA OF 25-50MM IN EAST AND CENTRAL CUBA.
IN WESTERN AND NORTHWEST COLOMBIA EXPECT SIMILAR AMOUNTS...WHILE
IN PANAMA EXPECT MAXIMA OF 20-35MM. ON SATURDAY...THE WAVE IS
EXPECTED TO MERGE WITH A WEAKENING TROPICAL WAVE LOCATED JUST TO
ITS WEST. GIVEN PARTICULARLY HIGH LEVELS OF PRECIPITABLE WATER
THIS WILL FAVOR MAXIMA OF 30-50MM IN WEST CUBA AND IN EASTERN
HONDURAS/EAST NICARAGUA AND NORTHERN COSTA RICA. IN SOUTHERN COSTA
RICA AND WEST PANAMA THIS WILL FAVOR MAXIMA OF 25-50MM. ON
SUNDAY...THIS WILL FAVOR MAXIMA OF 30-60MM IN THE GULF COAST OF
SOUTHEAST MEXICO AND MAXIMA OF 20-45MM FROM EL SALVADOR...WEST
HONDURAS AND BELIZE INTO CHIAPAS.
A TROPICAL WAVE IS INITIALIZED AT 78W AND SOUTH OF 21N AND IS
FORECAST TO BE ABSORBED BY TRAILING TROPICAL WAVE THAT IS
PROPAGATING FASTER.
A TROPICAL WAVE IS INTIALIZED NEAR 108W AND SOUTH OF 23N AND WILL
HAVE LIMITED EFFECTS ON CONTINENTAL PRECIPITATION AS IT IS EXITING
THE FORECAST AREA.
GALVEZ/ACOSTA...WPC (USA)
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