Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 300548
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU JUL 30 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.

...SPECIAL FEATURES...
A STRENGTHENED PRESSURE GRADIENT IS NOTED ACROSS THE CENTRAL
CARIBBEAN SEA WITH NEAR GALE TO GALE FORCE WINDS OCCURRING FROM
11N-13N BETWEEN 74W-78W. THESE CONDITIONS ARE FORECAST TO
DIMINISH BELOW GALE FORCE WARNING CRITERIA BY 30/1800 UTC. SEE
LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/
FZNT02 KNHC FOR MORE DETAILS.

A 1011 MB LOW CENTERED NEAR 30N78W AND IS EXPECTED TO INCREASE
THE PRESSURE GRADIENT BETWEEN IT AND THE SURFACE RIDGE TO THE
EAST. NEAR GALE TO GALE FORCE WINDS ARE EXPECTED TO MATERIALIZE
WITHIN THE EASTERN SEMICIRCLE OF THE LOW BY 30/1200 UTC. SEE
LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/
FZNT02 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 08N31W TO 18N33W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 30W-41W AND
LIES ON THE WESTERN PERIPHERY OF A LOW-LEVEL MONSOONAL GYRE
EMBEDDED WITHIN THE MONSOON TROUGH AXIS THAT HAS SPUN UP A 1010
MB LOW CENTERED NEAR 12N24W. NO SIGNIFICANT CONVECTION IS
ASSOCIATED WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 10N46W TO 16N46W MOVING W AT 15 KT.
THE WAVE REMAINS EMBEDDED WITHIN VERY SUBTLE 700 MB TROUGHING
BETWEEN 44W-50W. NO SIGNIFICANT DEEP CONVECTION IS OCCURRING
WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 10N63W TO 18N63W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 60W-67W.
NO SIGNIFICANT CONVECTION IS OCCURRING WITH THE WAVE AT THIS
TIME.

TROPICAL WAVE EXTENDS FROM 10N85W TO 19N85W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 82W-90W.
SCATTERED MODERATE CONVECTION IS FROM 07N-11N BETWEEN 81W-86W.
ISOLATED MODERATE CONVECTION IS FROM 14N-20N BETWEEN 83W-87W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
20N16W TO 16N19W TO A 1010 MB LOW NEAR 12N24W TO 09N40W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N40W TO
12N54W TO 11N62W. WIDELY SCATTERED MODERATE CONVECTION IS FROM
07N-14N BETWEEN 22W-31W IN ASSOCIATION WITH THE 1010 MB LOW
SOUTH OF THE CAPE VERDE ISLANDS.

...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 EASTERN TEXAS. WATER VAPOR IMAGERY
INDICATES MOST ATMOSPHERIC MOISTURE IS NOTED N OF 22N PRIMARILY
AS CONVECTIVE DEBRIS MOISTURE ATTRIBUTED TO CONVECTION OCCURRING
ACROSS THE NE GULF WATERS AND SE LOUISIANA. AN AREA OF LOWER
PRESSURE IS ANALYZED ACROSS THE NE GULF AND FLORIDA PENINSULA
FOCUSED ON A 1011 MB LOW CENTERED IN THE SW NORTH ATLC WATERS
NEAR 30N78W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING FROM 26N-
31N BETWEEN 83W-89W. OTHERWISE...A SURFACE RIDGE ANCHORED BY A
1017 MB HIGH CENTERED NEAR 26N91W IS PROVIDING THE BASIN WITH
GENTLE TO MODERATE ANTICYCLONIC BREEZE CONDITIONS. THE HIGH IS
FORECAST TO DRIFT SLOWLY W-NW THROUGH LATE FRIDAY NIGHT.
THEREAFTER...WEAK FRONTAL TROUGHING IS EXPECTED TO EXTEND ALONG
THE COASTAL PLAIN AND NORTHERN GULF WATERS THROUGH LATE
SATURDAY.

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 CENTRAL
CARIBBEAN FROM AN UPPER LEVEL LOW NORTH OF HISPANIOLA NEAR
21N69W. THE TROUGHING EXTENDS WESTWARD TO ANOTHER UPPER LEVEL
LOW WITH SMALLER AREAL INFLUENCE CENTERED OVER THE NW CARIBBEAN
NEAR 17N86W. SHORTWAVE INFRARED SATELLITE IMAGERY INDICATES
GENERALLY CLEAR SKIES WITH ONLY A FEW ISOLATED SHOWERS AND TSTMS
OCCURRING IN ASSOCIATED WITH THE UPPER LEVEL LOW OVER THE NW
CARIBBEAN AND A TROPICAL WAVE EXTENDING ALONG 86W. SCATTERED
SHOWERS AND ISOLATED TSTMS ARE OCCURRING FROM 14N-18N BETWEEN
83W-87W. ANOTHER TROPICAL WAVE IS ALONG 63W HOWEVER IS ONLY
GENERATING POSSIBLE ISOLATED SHOWERS ACROSS THE LESSER ANTILLES
THIS EVENING. FINALLY...THE PRIMARY IMPACT FOR THE BASIN REMAINS
NEAR GALE TO GALE FORCE WINDS OCCURRING WITHIN CLOSE PROXIMITY
TO THE COAST OF COLOMBIA AND FRESH TO STRONG TRADES ELSEWHERE
ACROSS THE CENTRAL CARIBBEAN S OF 16N BETWEEN 70W-80W.

...HISPANIOLA...
CURRENTLY...MOSTLY CLEAR SKIES AND FAIR CONDITIONS PREVAIL
ACROSS THE ISLAND FOR THE OVERNIGHT HOURS. GIVEN DRY AND STABLE
AIR ALOFT ALONG WITH RELATIVELY CLEAR SKIES NOTED ON SATELLITE
IMAGERY TO THE EAST...NO SIGNIFICANT DEEP CONVECTION IS EXPECTED
ACROSS THE ISLAND THROUGH THURSDAY INTO FRIDAY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY
OVER THE WESTERN NORTH ATLC WITH AXIS EXTENDING FROM 39N58W TO
32N70W TO 29N76W. THIS TROUGHING SUPPORTS A 1011 MB LOW CENTERED
NEAR 34N75W WITH THE ASSOCIATED STATIONARY FRONT EXTENDING SW
INTO A 1011 MB LOW NEAR 30N78W THEN SURFACE TROUGHING TO THE
FLORIDA COAST NEAR 28N81W. WIDELY SCATTERED SHOWERS AND TSTMS
ARE OCCURRING N OF 24N BETWEEN 73W-81W...AND ISOLATED SHOWERS N
OF 29N BETWEEN 65W-73W. THE REMAINDER OF THE SW NORTH ATLC IS
UNDER THE INFLUENCE OF A SURFACE RIDGE WITH AXIS EXTENDING FROM
28N57W TO THE FLORIDA STRAITS NEAR 24N80W. FARTHER EAST...THE
CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1028 MB HIGH CENTERED SW OF THE AZORES NEAR
34N33W.

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

$$
HUFFMAN



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