236
FXCA20 KWBC 111806
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
205 PM EDT TUE AUG 11 2026
FORECAST BULLETIN 11 AUGUST 2026 AT 1950 UTC:
SIGNIFICANT RAINFALL ACCUMULATION IS EXPECTED ACROSS SOUTHERN
MEXICO TO NORTHERN HONDURAS, SOUTHERN CARIBBEAN TO WESTERN
COLOMBIA, AND FROM WESTERN AMAZON BASIN TO ORINOQUIA IN NORTHERN
SOUTH AMERICA.
MEXICO AND CENTRAL AMERICA . . .
AN UPPER LEVEL LOW CENTERED OVER THE SOUTHERN GULF FAVORS ASCENT
AND UPPER LEVEL DYNAMICS HELPING TO DEEPEN A MID LEVEL TROUGH
ALONG THE WESTERN GULF TODAY. THIS LOW IS ASSOCIATED WITH TWO
UPPER LEVEL TROUGHS ONE EXTENDED OVER YUCATAN PENINSULA AND
ANOTHER TO THE SOUTH ALONG NORTHERN CENTRAL AMERICA. IN THE MID
LEVELS, THE REFLECTED TROUGH ENHANCES MOISTURE ASCENT AND
INCREASES PRECIPITABLE WATER (PWAT) ACROSS THE REGION AROUND THE
GULF OF HONDURAS.
A TROPICAL WAVE EXTENDS OVER THE SOUTHERN CARIBBEAN SEA ENHANCING
VALUES OF PWAT AROUND THE REGION AND INDUCING INSTABILITY ALONG
THE EASTERN CENTRAL AMERICAN COAST. AS THIS SETUP CONTINUES
PROPAGATING WESTWARD, IT WILL SUPPORT THE MOST SIGNIFICANT
RAINFALL ACCUMULATIONS IN THE REGION FROM SOUTHERN MEXICO TO
NORTHERN CENTRAL AMERICA AND MODERATE SHOWERS ALONG THE EASTERN
CENTRAL AMERICA COAST TODAY AND WEDNESDAY. BY THURSDAY, THE UPPER
LEVEL DISTURBANCE WILL BE CENTERED OVER NORTHERN CENTRAL MEXICO
WITH AN UPPER LEVEL TROUGH EXTENDED SOUTHWEST TO PROMOTE ISOLATED
CONVECTIVE SHOWERS ACROSS SOUTHERN CENTRAL MEXICO.
ISOLATED CONVECTIVE SHOWERS ARE EXPECTED TODAY ACROSS NORTHWESTERN
MEXICO, SUPPORTED BY A SERIES OF MID LEVEL TROUGHS. ON WEDNESDAY,
THE UPPER LEVEL HIGH PRESSURE CENTERED OVER SOUTHWESTERN US WILL
SHIFT EASTWARD. THIS CONDITION WILL HELP TO BUILD AN UPPER LEVEL
RIDGE OVER NORTHWESTERN MEXICO THAT WILL RESTRAIN MODERATE TO
SIGNIFICANT RAINFALL TO ISOLATED REGIONS OVER SONORA TO NAYARIT
FROM THURSDAY TO FRIDAY.
THE BAHAMAS AND CARIBBEAN . . .
THE REGION IS CURRENTLY DOMINATED BY A POTENT HIGH PRESSURE RIDGE.
IT EXTENDS FROM THE NORTHERN GULF INTO THE ATLANTIC AND FAVORS
DOWNWARD MOTION ALOFT AND THE ENTRANCE OF A DENSE PLUME OF SAHARAN
DUST ALL OVER ANTILLES. AN UPPER LEVEL LOW PRESSURE SYSTEM
ORGANIZES EAST OF THE BAHAMAS AND TURKS AND CAICOS AND ITâ€S WELL
REFLECTED IN THE MID LEVELS PROMOTING THE INCREASE OF PWAT TO THE
EAST OF HISPANIOLA. A SECOND WELL DEVELOPED MID- TO LOW-LEVEL
TROUGH EXTENDS ACROSS THE LESSER ANTILLES ASSOCIATED WITH A
TROPICAL WAVE THAT WILL TRIGGER SOME SHOWERS AROUND THE REGION BUT
WILL BE LIMITED BY A DENSE PLUME OF SAHARAN DUST. THROUGHOUT THE
NEXT FEW DAYS, THE UPPER LEVEL LOW WILL LINGER AND SUPPORT DYNAMIC
CONVECTION FROM HISPANIOLA TO PUERTO RICO TO FAVOR MODERATE
SHOWERS AND LOCALLY SIGNIFICANT ONES SUPPORTED BY TOPOGRAPHY. BY
THURSDAY ANOTHER TROPICAL WAVE WILL MOVE IN THE REGION INCREASING
THE CHANCE OF MODERATE TO SIGNIFICANT SHOWERS OVER SOUTHERN LESSER
ANTILLES.
NORTHERN SOUTH AMERICA . . .
AN UPPER LEVEL HIGH PRESSURE SYSTEM IS LOCATED OVER THE CENTRAL
AMAZON BASIN AND EXTENDS NORTH TO THE ORINOQUIA REGION FAVORING
DIFFLUENCE IN THE UPPER LEVELS AND SUPPORTING ASCENDING MOTION.
ALL ALONG THE ECUADORIAN AND COLOMBIAN PACIFIC COAST, PWAT IS
ENHANCED DUE TO THE TROPICAL WAVE CENTERED OVER SOUTHERN CENTRAL
AMERICA. THESE CONDITIONS WILL LEAVE MORE SIGNIFICANT RAINFALL
ACCUMULATION OVER WESTERN COLOMBIA AND WESTERN AMAZON BASIN. ON
WEDNESDAY, THE UPPER LEVEL HIGH SYSTEM WILL MOVE NORTHWESTWARD
SUPPRESSING ASCENT OVER MOST OF COLOMBIA AND FAVORING DIFFLUENCE
ALOFT OVER VENEZUELA. AN ENHANCEMENT IN PWAT IS EXPECTED OVER
VENEZUELA AND WILL LAST INTO THURSDAY. A TROPICAL WAVE WILL MOVE
INTO NORTHEASTERN VENEZUELA BY THURSDAY, INTERACTING WITH THE
PRIOR ENHANCED PWAT AND UPPER LEVEL DYNAMICAL FORCING TO LEAVE
RAINFALL MAXIMA OF 15-25 MM MAINLY LOCATED OVER CENTRAL AND
NORTHERN VENEZUELA AND NORTHWESTERN GUIANAS REGION.
TROPICAL WAVES INITIALIZED AT 12 UTC:
TYP SOF INIT 11/00 11/12 12/00 12/12 13/00 13/12 14/00 14/12
TW 13N 40W 43W 46W 48W 51W 55W 58W 63W 67W
TW 18N 56W 60W 64W 67W 72W 74W 78W 82W 85W
TW 19N 73W 76W 80W 84W 86W 90W 93W 96W 98W
TW 08N 95W 99W 103W 107W 111W 115W EXIT
SANCHEZ-PEREZ...(WPC)
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