Tropical Weather Discussion
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000
AXNT20 KNHC 310549
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI JUL 31 2015

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...
TROPICAL WAVE EXTENDS FROM 10N42W TO 20N43W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 40W-48W AND
LIES TO THE WEST OF A LOW-LEVEL MONSOONAL GYRE FOCUSED ON A 1009
MB LOW CENTERED ALONG THE MONSOON TROUGH NEAR 12N30W. NO
SIGNIFICANT CONVECTION IS ASSOCIATED WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 10N74W TO 20N73W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 68W-
80W. ISOLATED MODERATE CONVECTION IS FROM 18N-20N BETWEEN 73W-
76W...AND FROM 08N-11N BETWEEN 70W-75W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
19N16W TO A 1009 MB LOW NEAR 12N30W TO 08N47W. SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION IS FROM 09N-17N BETWEEN
18W-24W. ISOLATED MODERATE CONVECTION IS FROM 07N-14N BETWEEN
26W-34W...AND FROM 05N-09N BETWEEN 35W-45W.

...DISCUSSION...

GULF OF MEXICO...
NORTHEASTERLY FLOW ALOFT PREVAILS OVER THE GULF THIS EVENING ON
THE SOUTHEASTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONIC
CIRCULATION CENTERED OVER THE ARKLATEX REGION. WHILE THE RIDGING
IS THE MAIN SYNOPTIC FEATURE PROVIDING AN OVERALL DIFFLUENT
ENVIRONMENT OVER THE GULF...AN UPPER LEVEL SHORTWAVE TROUGH AXIS
REMAINS EMBEDDED WITHIN THE RIDGING EXTENDING FROM OVER THE
DELMARVA REGION SW TO OVER THE LOWER MISSISSIPPI RIVER VALLEY.
THE TROUGHING SUPPORTS A STATIONARY FRONT EXTENDING FROM THE
CENTRAL CAROLINAS SW TO SOUTHERN ALABAMA AND MISSISSIPPI THEN
WESTWARD INTO NORTHERN LOUISIANA AND NORTH TEXAS. WEAK LOW-LEVEL
MOISTURE CONVERGENCE ALONG AND MOSTLY SOUTH OF THE FRONT
CONTINUES TO GENERATE SCATTERED SHOWERS AND TSTMS ACROSS
PORTIONS OF THE CENTRAL GULF N OF 26N BETWEEN 85W-95W...WITH
ISOLATED SHOWERS AND TSTMS OCCURRING ELSEWHERE N OF 22N E OF
93W. THE MAJORITY OF THIS ACTIVITY IS OCCURRING ON THE NORTHERN
PERIPHERY OF A WEAK SURFACE RIDGE AXIS ANCHORED BY A 1016 MB
HIGH CENTERED IN THE WESTERN GULF NEAR 25N95W. THE RIDGE AXIS
EXTENDS FROM THE HIGH EASTWARD TO THE FLORIDA STRAITS NEAR
24N80W. THE WEAK AREA OF LOWER PRESSURE AND FRONTAL TROUGHING IS
EXPECTED TO LINGER ACROSS THE NORTHERN GULF WATERS THROUGH
SUNDAY NIGHT LATE AS IT FINALLY LIFTS NORTH OF THE COASTAL PLAIN
BY MONDAY. SURFACING RIDGING IS EXPECTED TO RE-ESTABLISH ITSELF
ACROSS THE GULF BASIN EARLY NEXT WEEK.

CARIBBEAN SEA...
MOST OF THE CARIBBEAN BASIN REMAINS FAIRLY TRANQUIL THIS EVENING
WITH WATER VAPOR IMAGERY INDICATING RELATIVELY DRY CONDITIONS
ALOFT FOCUSED ON VERY BROAD TROUGHING EXTENDING OVER THE NORTH-
CENTRAL CARIBBEAN FROM AN UPPER LEVEL LOW NORTH OF HISPANIOLA
NEAR 23N73W. THE TROUGHING EXTENDS WESTWARD INTO ANOTHER UPPER
LEVEL LOW WITH SMALLER AREAL INFLUENCE CENTERED OVER THE GULF OF
HONDURAS NEAR 16N86W. SHORTWAVE INFRARED SATELLITE IMAGERY
INDICATES GENERALLY CLEAR SKIES WITH ONLY A FEW ISOLATED SHOWERS
AND TSTMS OCCURRING IN ASSOCIATION WITH A TROPICAL WAVE
EXTENDING ALONG 74W. THE CONVECTION IS OCCURRING IN CLOSE
PROXIMITY TO THE WINDWARD PASSAGE REGION BETWEEN HISPANIOLA AND
CUBA. LOW-LEVEL MOISTURE AND CLOUDINESS EXTENDS FARTHER
EAST...WITH POSSIBLE ISOLATED SHOWERS OCCURRING E OF 70W.
FINALLY...THE PRIMARY IMPACT FOR THE BASIN REMAINS FRESH TO
STRONG BREEZE CONDITIONS GENERALLY S OF 16N BETWEEN 68W-79W. AS
SURFACE RIDGING TO THE NORTH RE-ESTABLISHES HOLD ACROSS THE SW
NORTH ATLC DURING THE WEEKEND...THESE TRADES ARE FORECAST TO
GRADUALLY INCREASE SUNDAY INTO MONDAY ACROSS THE CENTRAL
CARIBBEAN.

...HISPANIOLA...
CURRENTLY...MOSTLY CLEAR SKIES AND FAIR CONDITIONS PREVAIL
ACROSS THE ISLAND FOR THE OVERNIGHT HOURS. A FEW ISOLATED
SHOWERS REMAIN EMBEDDED WITHIN THE TRADEWINDS TO THE
EAST...HOWEVER NO SIGNIFICANT DEEP CONVECTION IS EXPECTED ACROSS
THE ISLAND FRIDAY.

ATLANTIC OCEAN...
NORTHEASTERLY FLOW ALOFT PREVAILS OVER MUCH OF THE SW NORTH ATLC
BETWEEN A BROAD UPPER LEVEL RIDGE COVERING MUCH OF THE SE AND
SOUTH-CENTRAL CONUS AND AN ELONGATED UPPER LEVEL LOW CENTERED
NORTH OF HISPANIOLA NEAR 23N73W. GLOBAL MODEL GUIDANCE INDICATES
PLENTY OF MID-LEVEL ENERGY N OF 26N W OF 75W AND THIS ENERGY
SUPPORTS A 1010 MB LOW CENTERED NEAR 32N77W AND ASSOCIATED
SURFACE TROUGH EXTENDING SW TO 29N80W. SCATTERED SHOWERS AND
ISOLATED TSTMS ARE OCCURRING N OF 25N BETWEEN 74W-80W. THE
REMAINDER OF THE SW NORTH ATLC BETWEEN 55W-75W REMAINS FAIRLY
TRANQUIL UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A
1023 MB HIGH CENTERED NEAR 28N58W. FINALLY...THE CENTRAL AND
EASTERN ATLC IS ALSO UNDER THE INFLUENCE OF A SURFACE RIDGE
ANCHORED BY A 1026 MB HIGH CENTERED SW OF THE AZORES NEAR
33N36W.

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

$$
HUFFMAN


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