[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 172352
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUL 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS EAST OF THE CAPE VERDE ISLANDS WITH AXIS
EXTENDING FROM 16N20W TO 7N19W MOVING W AT 10 KT. THE WAVE IS
EMBEDDED IN THE MOIST ENVIRONMENT OF THE MONSOON TROUGH WHICH IS
SUPPORTING SCATTERED MODERATE CONVECTION AHEAD OF THE WAVE FROM
7N-13N BETWEEN 18W-28W.

TROPICAL WAVE IS OVER THE CENTRAL ATLC EMBEDDED IN THE ITCZ WITH
AXIS EXTENDING FROM 12N40W TO 4N40W MOVING W AT 15-20 KT.
ISOLATED SHOWERS ARE FROM 5N-10N BETWEEN 38W-45W.

TROPICAL WAVE IS 350 NM SE OF THE WINDWARD ISLANDS WITH AXIS
EXTENDING FROM 13N54W TO 5N57W MOVING W AT 20 KT. SSMI TPW SHOW
THE WAVE IS EMBEDDED IN A VERY MOIST ENVIRONMENT THAT SUPPORTS
SCATTERED MODERATE CONVECTION FROM 4N-12N BETWEEN 53W-58W.

TROPICAL WAVE IS JUST N OF THE ITCZ WITH AXIS EXTENDING FROM
13N46W TO 6N48W MOVING W AT 15 KT. THE WAVE IS EMBEDDED IN THE
DRY ENVIRONMENT OF THE SAHARAN AIR LAYER WHICH IS HINDERING
CONVECTION AT THE TIME.

TROPICAL WAVE FORMERLY ANALYZED E-NE OF THE LESSER ANTILLES HAS
VANISHED. SURFACE HIGH PRESSURE AND A DRY ENVIRONMENT AT THE
LOWER-LEVELS CONTRIBUTED TO THE WEAKENING OF THE WAVE.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO GUINEA-BISSAU NEAR
13N16W AND THEN INTO THE E ATLC ALONG 11N22W TO 8N33W. THE ITCZ
BEGINS NEAR 8N34W TO 7N40W...IT THEN RESUMES NEAR 6N42W AND
CONTINUES ALONG 7N55W. IN ADDITION TO THE CONVECTION ASSOCIATED
WITH THE WAVES...SCATTERED MODERATE CONVECTION IS FROM 7N-11N
BETWEEN 29W-38W AND FROM 6N-8N BETWEEN 44W-50W.

...DISCUSSION...

GULF OF MEXICO...

AN UPPER LEVEL TROUGH EXTENDS ALONG THE EASTERN CONUS TO A BASE
OVER CENTRAL FLORIDA. OVER THE GULF...AN ANTICYCLONE IS CENTERED
NEAR 26N91W. THE FLOW IN THE EASTERN PERIPHERY OF THE UPPER HIGH
IS GENERATING A DIFFLUENT ENVIRONMENT OVER THE CENTRAL-SOUTHERN
FLORIDA WHICH IS SUPPORTING SCATTERED SHOWERS S OF
28N...INCLUDING THE FLORIDA STRAITS. A DIFFLUENT ENVIRONMENT IS
ALSO OVER THE NW GULF BEING GENERATED BY THE FLOW IN THE WESTERN
PERIPHERY OF THE UPPER HIGH AND AN UPPER LOW CENTERED OVER THE
COASTLINE OF NE MEXICO. THIS IS SUPPORTING SCATTERED MODERATE
CONVECTION AND ISOLATED TSTMS N OF 27N W OF 91W. THE ANTICYCLONE
ALOFT ALSO SUPPORTS A 1016 MB HIGH ANCHORED NEAR 25N86W WHICH IS
PROVIDING VARIABLE WINDS OF 5-15 KT ACROSS THE GULF.
OTHERWISE...MID-LEVEL WESTERLY WIND FLOW E OF 90W SUPPORT A WEAK
STATIONARY FRONT ALONG 29N83W TO 28N89W TO 29N94W. THE FRONT IS
EXPECTED TO DISSIPATE BY FRIDAY MORNING. SURFACE RIDGING AND
RETURN FLOW WILL DOMINATE ACROSS THE REGION FOR THE NEXT TWO
DAYS.

CARIBBEAN SEA...

A MID-LEVEL ANTICYCLONE IS OVER THE NW CARIBBEAN WHICH ALONG A
SHORT-WAVE TROUGH OVER THE SW N ATLC IS CAUSING A DIFFLUENT
ENVIRONMENT OVER CUBA TO SUPPORT HEAVY SHOWERS AND TSTMS ISLAND-
WIDE. FARTHER EAST...JUST N OF PUERTO RICO...A MID-LEVEL
ANTICYCLONE IS GENERATING DIFFLUENT FLOW NW OF HISPANIOLA THAT
IS SUPPORTING SCATTERED MODERATE CONVECTION OVER CENTRAL HAITI
AND ISOLATED SHOWERS ACROSS THE REMAINDER ISLAND. SCATTERED
MODERATE CONVECTION IS INLAND FROM HONDURAS TO PANAMA WHICH
EXTENDS WITHIN 20 NM OF THE COASTLINE. OTHERWISE...FAIR WEATHER
DOMINATES ELSEWHERE INFLUENCED BY DRY AIR SUBSIDENCE FROM ALOFT.
HIGH PRESSURE ACROSS THE NORTHERN CARIBBEAN CONTINUE TO SUPPORT
A TIGHTER PRESSURE GRADIENT OVER THE SOUTHERN-CENTRAL CARIBBEAN.
THIS IS GENERATING A MODERATE TO FRESH BREEZE S OF 17N BETWEEN
66W-80W. TROPICAL WAVE CURRENTLY NEAR 350 NM SE OF THE WINDWARD
ISLANDS IS FORECAST TO ENTER THE E CARIBBEAN FRIDAY MORNING.

...HISPANIOLA...

A MID-LEVEL ANTICYCLONE N OF PUERTO RICO IS GENERATING
DIFFLUENT FLOW NW OF HISPANIOLA THAT IS SUPPORTING SCATTERED
MODERATE CONVECTION OVER CENTRAL HAITI AND ISOLATED SHOWERS
ACROSS THE REMAINDER ISLAND. SHOWER ACTIVITY IS EXPECTED TO
CONTINUE THROUGH SAT NIGHT.

ATLANTIC OCEAN...

A MID-LEVEL SHORT-WAVE TROUGH IS OVER THE SW N ATLC AS WELL AS
UPPER-LEVEL DIFFLUENCE. THIS ENVIRONMENT ALONG WITH ABUNDANT
MOISTURE IN THE REGION CONTINUE TO SUPPORT HEAVY SHOWERS AND
TSTMS N OF 21N W OF 68W. OTHERWISE...THE CENTRAL AND EASTERN
ATLC ARE UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A
1031 MB HIGH CENTERED NEAR 36N51W. BESIDES SURFACE HIGH
PRESSURE...MOSTLY DRY AIR ACROSS THE REMAINDER BASIN SUPPORTS
FAIR WEATHER.

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

$$
NR

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