[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170606
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON AUG 17 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
0545 UTC.

...SPECIAL FEATURES...

A TROPICAL WAVE SEVERAL HUNDRED MILES SW OF THE CAPE VERDE
ISLANDS IS ASSOCIATED WITH A 1011 MB LOW PRESSURE CENTER
EMBEDDED IN THE MONSOON TROUGH NEAR 10N29W. THE SYSTEM IS MOVING
W AT 15-20 KT OVER A PERIOD OF 24 HOURS. CIRA LAYER PRECIPITABLE
WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW THE WAVE IS
ASSOCIATED WITH A BROAD AREA OF MODERATE MOISTURE THAT ALONG
WITH A DIVERGENT WIND ENVIRONMENT ALOFT SUPPORT A CLUSTER OF
MODERATE CONVECTION FROM 06N TO 09N BETWEEN 28W AND 32W. SAHARAN
DRY AIR AND DUST ENGULF THE SYSTEM...THUS HINDERING CONVECTION
ELSEWHERE. THERE IS A MEDIUM CHANCE THIS SYSTEM WILL DEVELOP
INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

...TROPICAL WAVES...

A TROPICAL WAVE IS IN THE CENTRAL ATLC WITH AXIS NEAR 46W
...MOVING W AT 10 KT OVER THE PAST 24 HOURS. CIRA LAYER
PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW THE
WAVE IS WITHIN A MODERATE MOIST ENVIRONMENT. UPPER-LEVEL
DIFFLUENCE W OF THE WAVE AXIS SUPPORT ISOLATED SHOWERS AND TSTMS
FROM 08N TO 10N BETWEEN 46W AND 49W. SAHARAN DRY AIR AND DUST IN
THE WAVE ENVIRONMENT HINDER CONVECTION ELSEWHERE.

A TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN WITH AXIS NEAR 76W
...MOVING W AT 15-20 KT OVER THE PAST 24 HOURS. THE WAVE IS
ASSOCIATED WITH A MODERATE MOIST ENVIRONMENT FROM THE SURFACE TO
850 MB ACCORDING TO CIRA LAYER PRECIPITABLE WATER IMAGERY.
HOWEVER...THE WAVE IS DEVOID OF CONVECTION DUE TO DRY AIR
SUBSIDENCE FROM ALOFT AND STRONG DEEP LAYER WIND SHEAR ACROSS
THE CENTRAL AND EASTERN CARIBBEAN.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM A 1011 MB LOW OVER THE WEST
AFRICAN COAST NEAR 19N16W AND CONTINUES SW TO THE SPECIAL
FEATURES 1011 MB LOW NEAR 10N29W THEN TO 07N38W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N38W TO
05N46W TO 04N51W. ASIDE FROM CONVECTION ASSOCIATED WITH THE
SPECIAL FEATURES LOW AND TROPICAL WAVE ALONG 46W...A CLUSTER OF
MODERATE TO ISOLATED STRONG CONVECTION IS FROM 08N TO 12N
BETWEEN 19W AND 22W. SCATTERED MODERATE CONVECTION IS FROM 04N
TO 10N BETWEEN 34W AND 39W.

...DISCUSSION...

GULF OF MEXICO...

AN UPPER LOW OVER SOUTHERN ILLINOIS EXTENDS A TROUGH SW TO
SOUTHERN TEXAS TO A BASE OVER SOUTHERN MEXICO SUPPORTING A
SURFACE TROUGH ALONG THE MISSISSIPPI COAST...ACROSS SOUTHERN
LOUISIANA TO 28N94W...WHICH IS ENHANCING SCATTERED TO ISOLATED
SHOWERS N OF 27N BETWEEN 90W AND 92W. AN ELONGATED UPPER RIDGE
EXTENDS FROM THE SE CONUS...ACROSS THE FLORIDA PENINSULA AND THE
NE GULF TO A HIGH CENTER OVER HONDURAS. DIFFLUENCE ALOFT BETWEEN
THE UPPER TROUGH AND RIDGE ALONG WITH MOISTURE INFLOW ACROSS THE
BASIN FROM THE CARIBBEAN SEA SUPPORT SCATTERED MODERATE
CONVECTION ACROSS CENTRAL FLORIDA AND S OF 23N BETWEEN 88W AND
92W...INCLUDING THE NW YUCATAN PENINSULA AND EASTERN GULF OF
CAMPECHE. OTHERWISE...BROAD SURFACE HIGH PRESSURE OVER THE ATLC
CONTINUES TO EXTEND A RIDGE AXIS SW ACROSS FLORIDA AND THE
EASTERN BASIN...THUS PROVIDING MAINLY SE WIND FLOW OF LESS THAN
15 KT ACROSS THE GULF. SURFACE RIDGING WILL BE THE DOMINANT
FEATURE ACROSS THE BASIN THE NEXT TWO DAYS.

CARIBBEAN SEA...

AN UPPER LEVEL ANTICYCLONE CENTERED OVER HONDURAS EXTENDS A
RIDGE AXIS E-SE ACROSS THE CARIBBEAN...EXCEPT THE N-NE BASIN
WHERE A DIFFLUENT ENVIRONMENT PREVAILS BEING GENERATED BY A
SMALL UPPER LOW BETWEEN HISPANIOLA AND SOUTHERN BAHAMAS.
DIFFLUENCE ALOFT ALONG WITH SHALLOW MOISTURE SUPPORT SCATTERED
TO ISOLATED SHOWERS OVER WESTERN PUERTO RICO...THE MONA
PASSAGE...DOMINICAN REPUBLIC AND ADJACENT WATERS. SHOWERS AND
TSTMS ARE BETWEEN JAMAICA AND EASTERN CUBA. A TROPICAL WAVE IS
MOVING ACROSS THE CENTRAL BASIN...HOWEVER DRY AIR SUBSIDENCE
FROM ALOFT AND STRONG DEEP LAYER WIND SHEAR ACROSS THE CENTRAL
AND EASTERN CARIBBEAN HINDER CONVECTION. EAST WINDS OF 20 TO 25
KT ARE FROM 11N TO 14N BETWEEN 69W AND 75W WITH SEAS TO 9 FT.
THESE CONDITIONS ARE EXPECTED TO PREVAIL IN THIS REGION FOR THE
NEXT TWO DAYS. THE WAVE WILL MOVE ACROSS THE WESTERN BASIN
MONDAY AND OVER THE EPAC WATERS TUESDAY EVENING.

...HISPANIOLA...

A DIFFLUENT ENVIRONMENT ALOFT PREVAILS OVER THE N-NE CARIBBEAN
BEING GENERATED BY AN UPPER LEVEL ANTICYCLONE CENTERED OVER
HONDURAS EXTENDING A RIDGE AXIS E-SE TO THE WINDWARD ISLANDS AND
A SMALL UPPER LOW BETWEEN HISPANIOLA AND SOUTHERN BAHAMAS.
DIFFLUENCE ALOFT ALONG WITH SHALLOW MOISTURE SUPPORT SCATTERED
TO ISOLATED SHOWERS OVER THE MONA PASSAGE...DOMINICAN REPUBLIC
AND ADJACENT N AND S WATERS. SHOWERS ARE EXPECTED TO CONTINUE
THROUGH MONDAY NIGHT.

ATLANTIC OCEAN...

A FRACTURED PORTION OF A TROPICAL WAVE MOVING ACROSS THE CENTRAL
CARIBBEAN SEA EXTENDS FROM 24N69W TO 20N71W AND IS PROVIDING
FOCUS FOR ISOLATED SHOWERS S OF 24N BETWEEN 66W-74W. FATHER
EAST...AN UPPER LEVEL LOW SUPPORTS A TROUGH FROM 26N53W TO
19N56W WITH NO CONVECTION ASSOCIATED WITH IT. OTHERWISE...THE
REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A
SURFACE RIDGE ANCHORED BY A 1029 MB HIGH CENTERED NW OF THE
AZORES NEAR 40N29W. FOR TROPICAL WAVES SEE SECTION ABOVE. THERE
IS A MEDIUM CHANCE OF TROPICAL CYCLONE DEVELOPMENT ASSOCIATED
WITH THE EASTERMOST TROPICAL WAVE. SEE SPECIAL FEATURES FOR DETAILS.

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

$$
NR
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