Tropical Weather Discussion
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000
AXNT20 KNHC 011754
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI AUG 01 2014

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...
TROPICAL STORM BERTHA IS CENTERED NEAR 14.5N 60.3W AT 01/1800
UTC OR ABOUT 39 NM E OF MARTINIQUE AND ABOUT 100 NM NNW OF
BARBADOS MOVING WNW AT 19 KT. ESTIMATED MINIMUM CENTRAL PRESSURE
IS 1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO
50 KT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS
WITHIN 120-240 NM OF THE CENTER IN THE NE SEMICIRCLE. SEE LATEST
NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT3/WTNT33 KNHC AND THE FULL FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 1013 MB LOW PRES NEAR 10.5N24W TO
20N24W MOVING W AT 10-15 KT. THE WAVE COINCIDES WITH A FAIRLY
AMPLIFIED 700 MB TROUGH ALONG 22W WITH A MAXIMUM IN 850 MB
RELATIVE VORTICITY CENTERED NEAR THE LOW. THE LOW REMAINS A
CIRCULATION EMBEDDED WITHIN THE MONSOON TROUGH AXIS. CONVECTION
HAS DIMINISHED WITH MAINLY SCATTERED SHOWERS ACCOMPANYING THE
WAVE AXIS AND LOW.

TROPICAL WAVE EXTENDS FROM 1012 MB LOW PRES NEAR 09.5N35W TILTED
TO THE NW TO 17N39W MOVING W AT 10-15 KT. 700 MB TROUGHING
EXTENDS N-NW FROM THE SOUTHERN EXTENT OF THE WAVE WITH AN 850 MB
RELATIVE VORTICITY MAXIMUM NOTED TO THE SE OF THE WAVE. THE LOW
REMAINS EMBEDDED WITHIN THE MONSOON TROUGH AXIS. CONVECTION IS
LIMITED WITH ISOLATED TO SCATTERED SHOWERS NEAR THE WAVE AXIS
AND LOW.

TROPICAL WAVE EXTENDS FROM 12N63W TILTED SLIGHTLY NW TO 19.5N65W
APPROACHING THE E COAST OF PUERTO RICO AND MOVING W AT 15 KT.
THE WAVE REMAINS TO THE W OF TROPICAL STORM BERTHA AND IS
LARGELY SURROUNDED BY THE SAHARAN AIR LAYER TO THE NE OF THE
AXIS. NO SIGNIFICANT DEEP CONVECTION IS NOTED WITH THE WAVE AT
THIS TIME...HOWEVER ISOLATED SHOWERS ARE OCCURRING ACROSS THE
US/UK VIRGIN ISLANDS AND MOVING ONSHORE INTO EASTERN PUERTO RICO.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W
TO A 1013 MB LOW PRES NEAR 10.5N24W TO A 1012 MB LOW PRES NEAR
09.5N35W TO 05N40W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 05N40W TO 04N50W. NO SIGNIFICANT CONVECTION IS
NOTED.

...DISCUSSION...

GULF OF MEXICO...
BROAD LONGWAVE UPPER LEVEL TROUGHING IS OVER THE EASTERN HALF OF
THE CONUS THAT SUPPORTS A SERIES OF MID-LEVEL IMPULSES MOVING
OVER THE SE CONUS. A DISSIPATING STATIONARY FRONT IS ANALYZED
OVER FLORIDA FROM NEAR 30N83W TO OFFSHORE OF PUNTA GORDA TO
26N84W CONTINUING WESTWARD TO 25N90W AS A TROUGH. THE FRONT IS
TRANSITIONING INTO A REMNANT TROUGH WITH THE DEWPOINT SPREAD ON
EITHER SIDE OF IT BECOME LESS WITH TIME. ISOLATED TO SCATTERED
SHOWERS AND TSTMS ARE OCCURRING WITHIN 30-45 NM EITHER SIDE OF
THE FRONT/TROUGH AXIS OVER THE EASTERN GULF WATERS WITH ACTIVITY
OVER FLORIDA ITSELF LIMITED AS OF EARLY THIS AFTERNOON. ANOTHER
MID-LEVEL IMPULSE OF ENERGY IS NOTED OVER THE ARKLATEX REGION
THAT IS SUPPORTIVE OF A 1014 MB LOW CENTERED ACROSS INLAND
EASTERN TEXAS NEAR 31N94W. A STATIONARY FRONT EXTENDS SE OF THE
LOW TO THE SE TIP OF LOUISIANA...AND ALSO SW OF THE LOW INTO
MEXICO NEAR 28N100W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE
ACROSS THE NW AND N CENTRAL GULF WATERS MAINLY N OF 26N W OF
90W. OTHERWISE...THE REMAINDER OF THE GULF IS UNDER THE
INFLUENCE OF VERY WEAK SURFACE RIDGING ANCHORED BY A 1016 MB
HIGH CENTERED IN THE NE GULF NEAR 27.5N86W. THIS RIDGING IS
FORECAST TO REMAIN ANCHORED IN THE NORTH-CENTRAL TO NE GULF WITH
A RIDGE AXIS EXTENDING ACROSS THE WESTERN GULF WITH A WEAK
PRESSURE PATTERN IN PLACE SUPPORTING MAINLY LIGHT/GENTLE WINDS
AND 0-2 FT SEAS ACROSS THE GULF THROUGH THE WEEKEND...EXCEPT
MODERATE WINDS AND 2-3 FT SEAS IN THE SW GULF.

CARIBBEAN SEA...
RELATIVELY DRY AND STABLE CONDITIONS ALOFT ARE NOTED OVER MUCH
OF THE CARIBBEAN EARLY THIS AFTERNOON. AN ELONGATED UPPER LEVEL
LOW IS POSITIONED OVER THE NW CARIBBEAN WITH A CENTER NEAR
18N83W. AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS TO THE SE
CENTERED NEAR 11N75W WITH A RIDGE AXIS EXTENDING TO THE N TO
ACROSS EASTERN CUBA. AN UPPER LEVEL LOW PROVIDING NW FLOW ALOFT
FOR THE NE CARIBBEAN IS CENTERED IN THE SW NORTH ATLC NEAR
21N64W WITH A TROUGH AXIS EXTENDING TO THE S ACROSS THE FAR
EASTERN CARIBBEAN. SKIES ACROSS THE BASIN REMAIN MOSTLY CLEAR
WITH ONLY A FEW ISOLATED SHOWERS OCCURRING ON THE NORTHERN
PERIPHERY OF THE UPPER LEVEL LOW N OF 17N TO THE COAST OF THE
DOMINICAN REPUBLIC AND ACROSS THE WINDWARD PASSAGE APPROACHES.
SCATTERED SHOWERS AND TSTMS ARE ALSO OCCURRING IN THE SW
CARIBBEAN W OF 80W NEAR THE COASTS OF NICARAGUA...COSTA RICA...
AND WESTERN PANAMA SUPPORTED BY THE ELONGATED UPPER LOW AND
TROUGHING IN THE NW CARIBBEAN. OTHERWISE...UPPER LEVEL NW TO W
FLOW IS PROVIDING MOSTLY STABLE CONDITIONS FOR MOST OF THE
EASTERN CARIBBEAN EVEN AS A TROPICAL WAVE IS ANALYZED ALONG
64W/65W. A FEW ISOLATED SHOWERS ARE OCCURRING ACROSS THE US/UK
VIRGIN ISLANDS AND MOVING ONSHORE INTO EASTERN PUERTO RICO EARLY
THIS AFTERNOON. LIGHT/GENTLE WINDS AND 1-3 FT SEAS ARE FORECAST
IN THE NW CARIBBEAN...WITH MODERATE TO FRESH TRADE WINDS AND 3-6
FT SEAS ELSEWHERE...EXCEPT FRESH TO STRONG WINDS AND 7-10 FT
SEAS IN THE S CENTRAL CARIBBEAN NEAR THE COAST OF COLOMBIA WHERE
THE PRESSURE GRADIENT WILL BE TIGHT.

...HISPANIOLA...
CURRENTLY...ISOLATED TO SCATTERED SHOWERS AND TSTMS CONTINUE
ACROSS THE ADJACENT COASTAL WATERS INCLUDING THE WINDWARD
PASSAGE DUE TO THE PRESENCE OF AN UPPER LEVEL LOW CENTERED IN
THE SW NORTH ATLC NEAR 21N64W AND AN APPROACHING TROPICAL WAVE
ALONG 64W/65W. WITH THE UPPER LEVEL LOW AND ASSOCIATED TROUGHING
EXPECTED TO MOVE LITTLE DURING THE NEXT 24 HOURS...AN OVERALL
UNSTABLE ENVIRONMENT WILL REMAIN IN PLACE ACROSS HISPANIOLA WITH
SCATTERED SHOWERS AND TSTMS FORECAST THROUGH THIS EVENING DURING
PEAK DAYTIME HEATING AND INSTABILITY.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS OVER THE EASTERN CONUS REMAINING
LARGELY N OF 30N THAT SUPPORTS A 1014 MB LOW CENTERED NEAR
SAVANNAH GEORGIA. A STATIONARY FRONT EXTENDS TO THE NE AWAY FROM
THE LOW ALONG THE SOUTH CAROLINA COAST...WHILE A NOW
DISCONNECTED DISSIPATING STATIONARY FRONT LINGERS ACROSS CENTRAL
FLORIDA...CURRENTLY TRANSITIONING TO A REMNANT TROUGH. NUMEROUS
SHOWERS AND SCATTERED TSTMS ARE OCCURRING WITHIN 120 NM OF SHORE
N OF 29.5N ALONG THE FRONT AND BEING FUELED BY THE UPPER LEVEL
TROUGHING. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR
21N64W WITH TROUGHING EXTENDING NW TO 31N71W AND TO THE S ACROSS
THE FAR EASTERN CARIBBEAN SEA. THESE UPPER FEATURES ARE
SUPPORTING A LARGE AREA OF WIDELY SCATTERED SHOWERS AND ISOLATED
TSTMS FROM 20N-28N BETWEEN 64W-75W. OTHERWISE...THE REMAINDER OF
THE CENTRAL ATLC IS UNDER THE INFLUENCE OF A BROAD MIDDLE TO
UPPER LEVEL RETROGRADING LOW CENTERED NEAR 31N52W THAT IS
SUPPORTING A BROAD AREA OF LOWER SURFACE PRESSURE FOCUSED ON A
1016 MB LOW CENTERED NEAR 29N46W. THE PRIMARY SURFACE TROUGH
EXTENDS SW FROM THE LOW TO 25N50W THEN W-NW TO 27N60W WITH
ISOLATED SHOWERS AND TSTMS OCCURRING WITHIN 30 NM EITHER SIDE OF
THE BOUNDARY. TO THE NORTH OF THE PRIMARY BOUNDARY...ANOTHER
WAVE OF ENERGY MANIFESTS ITSELF AS A SURFACE TROUGH EXTENDING
FROM 28N48W SW TO 27N52W THEN W-NW TO 31N60W WITH SCATTERED
SHOWERS AND ISOLATED TSTMS OCCURRING WITHIN 30-60 NM EITHER SIDE
OF THIS BOUNDARY. FINALLY...THE EASTERN ATLC IS UNDER THE
INFLUENCE OF A SURFACE RIDGE PROVIDING MOSTLY FAIR WEATHER
CONDITIONS N OF 20N E OF 40W. MAINLY LIGHT TO MODERATE SE WINDS
AND 3-5 FT SEAS ARE EXPECTED ACROSS THE NE HALF OF THE SW NORTH
ATLC OFFSHORE WATERS...WITH MODERATE TO LOCALLY FRESH E-SE WINDS
AND 4-7 FT SEAS ELSEWHERE OUTSIDE OF THE INFLUENCE OF BERTHA...
EXCEPT 1-3 FT SEAS AND LIGHT TO MODERATE WINDS INSIDE THE
BAHAMAS.

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

$$
LEWITSKY



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