[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 190554
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON AUG 19 2013

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE EXTENDS FROM 08N24W TO 19N25W MOVING W AT 10-15
KT. THE WAVE IS EMBEDDED WITHIN A BROAD 700 MB TROUGH S OF 17N
BETWEEN 15W-32W AND IS LOCATED IN AN AREA OF MAXIMUM DEEP LAYER
MOISTURE WITHIN 210 NM EITHER SIDE OF A LINE FROM 13N17W TO
06N24W AS NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. NO
SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE AT THIS TIME.

A TROPICAL WAVE EXTENDS FROM 11N64W TO 20N63W MOVING W AT 10-15
KT. THE WAVE REMAINS EMBEDDED WITHIN A MOISTURE MAXIMUM
ACCORDING TO TOTAL PRECIPITABLE WATER IMAGERY FROM 10N-21N
BETWEEN 58W-64W. THE WAVE ALSO COINCIDES WITH A WEAK 700 MB
TROUGH MOVING ACROSS THE NE CARIBBEAN AND PORTIONS OF THE SW
NORTH ATLC IN THE VICINITY OF THE NORTHERN EXTENSION OF THE WAVE
AXIS. ISOLATED MODERATE CONVECTION IS FROM 19N-21N BETWEEN 61W-
63W.

TROPICAL WAVE EXTENDS FROM 12N84W TO 22N82W MOVING W AT 10-15
KT. THE WAVE COINCIDES WITH A WEAK 700 MB TROUGH AXIS EXTENDING
FROM CENTRAL CUBA TO EASTERN HONDURAS WITH THE STRONGEST
RELATIVELY VORTICITY LOCATED OVER THE OPEN WATERS OF THE NW
CARIBBEAN WEST OF THE CAYMAN ISLANDS. ISOLATED MODERATE
CONVECTION IS OCCURRING MOSTLY NEAR THE NORTHERN EXTENT OF THE
WAVE AXIS FROM 20N-24N BETWEEN 83W-87W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 18N16W TO
08N20W TO 06N26W TO 07N38W. THE INTERTROPICAL CONVERGENCE ZONE
AXIS EXTENDS FROM 07N38W TO 10N47W TO 13N51W TO 14N58W.
SCATTERED MODERATE CONVECTION IS FROM 03N-08N BETWEEN 27W-32W. A
SURFACE TROUGH IS ANALYZED ON THE WESTERN EXTENT OF THE ITCZ
AXIS FROM 09N60W TO 13N60W. ISOLATED MODERATE CONVECTION ALONG
WITH ISOLATED SHOWERS ARE OCCURRING FROM 08N-14N BETWEEN 52W-
63W. MOST OF THE STRONGEST CONVECTION IS OCCURRING INLAND OVER
PORTIONS OF NE VENEZUELA.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY
WITH AXIS EXTENDING FROM NORTH TEXAS NEAR 32N95W TO A BASE OVER
EAST-CENTRAL MEXICO NEAR 20N100W. TO THE EAST OF THIS TROUGH
AXIS AN UPPER LEVEL RIDGE EXTENDS WESTWARD FROM OVER THE SW
NORTH ATLC INTO THE EASTERN GULF RESULTING IN PRIMARILY
SOUTHERLY UPPER LEVEL DIFFLUENT FLOW BETWEEN 88W-95W. A SURFACE
TROUGH REFLECTS THE INFLUENCE OF THE MIDDLE TO UPPER LEVELS
ANALYZED FROM THE MISSISSIPPI RIVER DELTA NEAR 30N89W SW TO
27N94W THEN S TO THE SOUTHERN MEXICO COAST NEAR 19N94W. WHILE
MIDDLE TO UPPER LEVEL MOISTURE IS PREVALENT...ONLY A FEW
ISOLATED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE
SURFACE TROUGH. A FEW ISOLATED SHOWERS WITH EMBEDDED TSTMS ARE
HOWEVER OCCURRING S OF 21N IN THE BAY OF CAMPECHE. THE REMAINDER
OF THE GULF IS UNDER THE INFLUENCE OF THE NORTHERN EXTENT OF A
TROPICAL WAVE MOVING ACROSS THE WESTERN CARIBBEAN SEA ALONG 84W.
MID-LEVEL ENERGY CONTINUES TO FRACTURE NORTHWARD DUE TO THE
WEAKNESS IN THE MID-LEVEL RIDGING OVER THE GULF THAT IS
GENERATING WIDELY SCATTERED SHOWERS AND TSTMS E OF 86W...
INCLUDING PORTIONS OF WESTERN FLORIDA PENINSULA. OTHERWISE...E-
SE WINDS PREVAIL AND ARE FORECAST TO REMAIN GENERALLY BELOW 20
KT FOR MOST OF THE WEEK AHEAD. THE SURFACE TROUGH OVER THE
WESTERN GULF IS EXPECTED TO DRIFT SLOWLY WESTWARD AND DISSIPATE
INLAND OVER SOUTHERN TEXAS AND EASTERN MEXICO LATE MONDAY INTO
TUESDAY.

CARIBBEAN SEA...
AN UPPER LEVEL LOW IS CENTERED OVER THE NW CARIBBEAN NEAR 17N85W
AND ALONG WITH A TROPICAL WAVE ALONG 84W IS GENERATING WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS N OF 20N BETWEEN 83W-87W...
INCLUDING THE YUCATAN CHANNEL. THE ENERGY AND MOISTURE
ASSOCIATED WITH THE TROPICAL WAVE IS EXPECTED TO MOVE WESTWARD
OVER THE NEXT 24 TO 36 HOURS AND INFLUENCE THE YUCATAN PENINSULA
AS WELL AS AREAS ACROSS THE SOUTHERN GULF OF MEXICO. FARTHER
EAST...AN UPPER LEVEL RIDGE AXIS EXTENDS FROM THE TROPICAL ATLC
OVER THE CENTRAL AND EASTERN CARIBBEAN ALONG 15N. WATER VAPOR
IMAGERY INDICATES MOSTLY DRY AIR ACCOMPANIES THIS RIDGE AND
PRIMARILY LOW-LEVEL MOISTURE AND MARGINAL MIDDLE TO UPPER LEVEL
DIFFLUENCE ARE GENERATING ISOLATED LOW-TOPPED ISOLATED SHOWERS
AND TSTMS E OF 80W. A TROPICAL WAVE ALONG 64W REMAINS A FOCAL
POINT FOR MOST OF THIS SHOWER ACTIVITY BRINGING INCREASE
PRECIPITATION CHANCES TO THE LESSER ANTILLES...PUERTO RICO...AND
HISPANIOLA OVER THE NEXT 24 TO 48 HOURS.

HISPANIOLA...
CURRENTLY AFTERNOON AND LATE EVENING CONVECTION HAS DIMINISHED
WITH ONLY A FEW REMAINING ISOLATED SHOWERS OCCURRING THE ACROSS
THE ISLAND. WITH AN UPPER LEVEL DIFFLUENT ENVIRONMENT REMAINING
OVER THE ISLAND DUE TO SOUTHWEST TO WESTERLY FLOW ALOFT...AND AN
APPROACHING TROPICAL WAVE ANALYZED ACROSS THE EASTERN CARIBBEAN
SEA...ISOLATED SHOWERS ARE EXPECTED TO PERSIST OVER THE NEXT FEW
DAYS WITH STRONGER SCATTERED CONVECTION EXPECTED TO INIATATE
DURING THE AFTERNOON HOURS DUE TO PEAK DAYTIME HEATING AND
INSTABILITY. ANY ACTIVITY THAT FORMS WILL LIKELY LAST INTO THE
EVENING HOURS AND DIMINISH THEREAFTER.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED
OVER THE SW NORTH ATLC NEAR 34N69W THAT IS PROVIDING OVERALL
STABLE CONDITIONS FOR THE SW NORTH ATLC W OF 70W. WATER VAPOR
IMAGERY INDICATES THIS AREA REMAINS DRY ALOFT WITH SATELLITE
IMAGERY INDICATING ISOLATED LOW-TOPPED SHOWERS ARE OCCURRING
PRIMARILY W OF 50W...AND MORE CONCENTRATED OVER THE BAHAMAS AND
AREAS IMMEDIATELY OFFSHORE OF THE FLORIDA PENINSULA THIS
EVENING. OTHERWISE...A 1023 MB HIGH CENTERED NEAR 33N65W IS
FURTHER PROVIDING OVERALL FAIR CONDITIONS FOR MUCH OF THE
WESTERN ATLC. FARTHER EAST...A MIDDLE TO UPPER LEVEL LOW IS
CENTERED NEAR 27N51W THAT IS GENERATING A FEW ISOLATED SHOWERS
FROM 25N-28N BETWEEN 45W-52W...AND CONTAINS THE REMNANT SURFACE
LOW PRESSURE AREA OF ERIN...ANALYZED AS A 1010 MB LOW CENTERED
NEAR 20N40W. NO SIGNIFICANT DEEP CONVECTION IS NOTED WITH THIS
LOW HOWEVER.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
HUFFMAN


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