677
FXCA20 KWBC 251829
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
228 PM EDT TUE JUL 25 2023
FORECAST BULLETIN FROM 25 JUL 2023 AT 1830 UTC: THE SUBTROPICAL
UPPER RIDGE CENTERS OVER THE SOUTHWEST US. THIS IS ALLOWING
EASTERLY FLOR ACROSS MOST OF MEXICO...ESPECIALLY IN THE LOW AND
MID-TROPOSPHERE. THIS IS ADVECTING MOISTURE FROM THE GULF OF
MEXICO INTO CENTRAL AND SOUTHWEST MEXICO...TO FAVOR SEASONAL
CONVECTION ON A DAILY BASIS. EXPECT THE HEAVIEST PRECIPITATION IN
WESTERN MEXICO...PRIMARILY BETWEEN JALISCO/NAYARIT/SOUTHERN
SINALOA. THE INFLUENCE OF HIGH SEA SURFACE TEMPERATURES AND
OROGRAPHIC ENHANCEMENT OF CIRCULATIONS WILL FAVOR STRONG
AFTERNOON/EVENING THUNDERSTORMS ON A DAILY BASIS. EXPECT MAXIMA OF
30-60MM ON TUESDAY AND WEDNESDAY...DECREASING TO MAXIMA OF 20-45MM
ON THURSDAY INTO EARLY FRIDAY. ELSEWHERE IN CENTRAL AND SOUTHWEST
MEXICO EXPECT GENERALLY MAXIMA OF 15-35MM IN DIURNAL CONVECTION.
NOTE THAT...AS A TROPICAL WAVE EXITS WEST OF BAJA CALIFORNIA ON
WEDNESDAY AND THURSDAY...NORTHWARD MOISTURE TRANSPORT ALONG THE
GULF OF CALIFORNIA WILL FAVOR AN INCREASE IN DEEP CONVECTION IN
SONORA BY THURSDAY.
A TUTT LOW CENTERS OVER THE GULF OF HONDURAS AND IS RETROGRADING
NORTHWESTWARD. THIS SYSTEM WILL CONTINUE TO DESTABILIZE THE
NORTHWEST CARIBBEAN...WHICH IS RECOVERING FROM A DRY AIR MASS
ASSOCIATED FROM A SAHARAN AIR LAYER EVENT IN THE LAST FEW DAYS.
THIS WILL STIMULATE AFTERNOON/EVENING THUNDERSTORMS IN WEST CUBA
WHERE EXPECT MAXIMA OF 20-35MM ON TUESDAY. ON WEDNESDAY THIS WILL
FAVOR MAXIMA OF 15-30MM IN WEST CUBA AND THE NORTHWEST BAHAMAS. IN
THE YUCATAN PENINSULA EXPECT AN INCREASE IN CONVECTION TO FAVOR
MAXIMA OF 15MM...ALTHOUGH ISOLATED LARGER AMOUNTS ARE POSIBLE IN
WESTERN AREAS. ON THURSDAY...THE TUTT WILL REACH NORTHEAST MEXICO.
THIS WILL FAVOR A DECREASE TO MAXIMA OF 15-25MM IN WEST CUBA...AND
A DECREASE IN COVERAGE IN THE YUCATAN PENINSULA.
IN THE CARIBBEAN...AN UUUPER RIDGE EXTENDS FROM NORTHERN COLOMBIA
INTO HISPANIOLA/PUERTO RICO. THIS IS FAVORING THE BULK OF MOISTURE
ASSOCIATED WITH THE CURRENT TROPICAL WAVE TO REMAIN SOUTH OF 17N.
THIS WILL LIMIT MAXIMA GENERALLY TO 20-35MM IN PUERTO RICO ON
TUESDAY AND TO 15-20MM IN HISPANIOLA. ON WEDNESDAY...HOWEVER...A
WEAKNESS IN THE RIDGE WILL ALLOW THE MOIST PLUME TO ENTER SOUTHERN
HISPANIOLA...TO FAVOR A PEAK IN PRECIPITATION IN THE DOMININCAN
REPUBLIC...WHERE AMOUNTS ARE FORECAST TO REACH MAXIMA OF 35-70MM.
IN HAITI ENHANCED WIND SHEAR WILL GENERALLY LIMIT MAXIMA TO
15-30MM. ON THURSDAY THE LARGEST AMOUNTS ARE EXPECTED IN JAMAICA
ACCOMPANIED BY SQUALLS DUE TO THE STRONG 30-35KT TRADES. EXPECT
ISOLATED MAXIMA OF 20-45MM.
LIMITED MOISTURE AND ENHANCED LOW-LEVEL WIND SHEAR WILL CONTINUE
TO LIMIT ACCUMULATIONS IN NORTHERN CENTRAL AMERICA...CONSISTENT
WITH THE CANICULA/MID-SUMMER DROUGHT...AND THE EFFECTS OF A
WEAKENING SAHARAN AIR LAYER OVER THE REGION. WETTER CONDITIONS ARE
EXPECTED IN SOUTHERN CENTRAL AMERICA AND NORTHERN SOUTH
AMERICA...WHERE ACTIVITY WILL BE LARGELY SENSITIVE TO WAVES IN THE
TRADES AND THE ITCZ. THE LARGEST AMOUNTS ARE EXPECTED IN NORTHERN
COLOMBIA ON TUESDAY...AIDED BY ENHANCED VENTILATION IN THE
SOUTHERN PERIPHERY OF AN UPPER RIDGE. FOR MORE DETAILS REFER TO
THE TROPICAL WAVE SECTION AND FORECAST CHARTS.
POSITIONS OF TROPICAL/EASTERLY WAVES INITIALIZED AT 12 UTC
TYPE SOF INIT 26/00 26/12 27/00 27/12 28/00 28/12 29/00 29/12
TW 10N 38W 42W 45W 49W 52W 54W 56W 60W 64W
TW 20N 61W 64W 67W 71W 73W 76W 79W 82W 84W
TW 23N 100W 104W 106W 108W 110W 112W 114W EXITS
A TROPICAL WAVE IS INITIALIZED AT 38W AND SOUTH OF 10N. IT IS
FORECAST TO ARRIVE INTO THE GUIANAS ON THURSDAY...TO FAVOR MAXIMA
OF 15-25MM.
A TROPICAL WAVE IS INITIALIZED AT 61W AND SOUTH OF 20N. ON TUESDAY
IT WILL FAVOR MAXIMA OF 25-50MM IN NORTHEAST VENEZUELA AND MAXIMA
OF 20-35MM IN PUERTO RICO. TRAILING MOISTURE WILL FAVOR MAXIMA OF
25-50MM IN THE FRENCH LESSER ANTILLES. ON WEDNESDAY IT WILL FAVOR
MAXIMA OF 35-70MM IN THE DOMINICAN REPIUBLIC...MAXIMA OF 15-30MM
IN HAITI AND MAXIMA OF 20-45MM IN WESTERN VENEZUELA AND NORTHERN
COLOMBIA. ON THURSDAY IT WILL FAVOR MAXIMA OF 20-35MM IN NORTHWEST
COLOMBIA...MAXIMA OF 20-45MM IN EASTERN JAMAICA AND MAXIMA OF
15-25MM IN WESTERN JAMAICA. IN EAST CUBA EXPECT MAXIMA OF 15-25MM.
A TROPICAL WAVE INITIALIZED AT 100W WILL FAVOR MAXIMA OF 30-60MM
IN JALISCO/NAYARIT ON TUESDAY...AND MAXIMA OF 20-35MM ELSEWHERE IN
SOUTHWEST MEXICO. ON WEDNESDAY IT WILL FAVOR MAXIMA OF 15-25MM IN
SINALOA/SOUTHERN SONORA...WHILE TRAILING MOISTURE FAVORS MAXIMA OF
30-60MM IN JALISCO...NAYARIT AND SOUTHERN SINALOA.
GALVEZ/ACOSTA...WPC (USA)
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