[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170003
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUL 16 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE CENTRAL ATLC ASSOCIATED WITH A 1012
MB LOW PRESSURE CENTER NEAR 10N36W...MOVING W AT NEARLY 15-20
KT. SSMI TPW IMAGERY DEPICT THE WAVE IS EMBEDDED IN A BROAD AREA
OF HIGH MOISTURE CONTENT THAT ALONG WITH MIDDLE-LEVEL DIVERGENT
WIND FLOW SUPPORT A CLUSTER OF MODERATE CONVECTION FROM 05N TO
14N BETWEEN 30W AND 42W.

A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN WITH AXIS
APPROXIMATELY ALONG 73W...MOVING W AT 20-25 KT DURING THE LAST
24 HOURS. SSMI TPW IMAGERY DEPICT A MODERATE MOIST AIRMASS
ASSOCIATED WITH THE TROPICAL WAVE ACROSS THE NORTH-CENTRAL AND
PORTIONS OF THE E CARIBBEAN. AN ELONGATED UPPER LOW EXTENDING
FROM NE OF THE LEEWARD ISLANDS TO CENTRAL CUBA SUPPORT SCATTERED
SHOWERS AND TSTMS ACROSS PUERTO RICO...THE MONA PASSAGE AND
HISPANIOLA.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N16W TO
10N30W TO THE 1012 MB LOW NEAR 10N36W TO 08N41W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N44W TO
05N53W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL
WAVE...SCATTERED MODERATE CONVECTION IS FROM 08N-11N E OF 18W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD RIDGE COVERING GREAT PORTIONS OF THE ATLC BASIN EXTENDS
AN AXIS SW ACROSS THE CENTRAL AND SOUTHERN FLORIDA PENINSULA AND
THE CENTRAL AND SE GULF OF MEXICO WHERE IS ANCHORED BY A 1018 MB
HIGH NEAR 27N88W. ALOFT...AN UPPER LOW IS OBSERVED CENTERED OVER
SOUTHERN MEXICO AND EXTENDING EASTWARD ACROSS THE BAY OF
CAMPECHE WHERE MOISTURE INFLOW FROM THE CARIBBEAN SUPPORT
SCATTERED MODERATE CONVECTION FROM 18N TO 21N E OF 92W. MIDDLE
TO UPPER LEVEL RIDGING DOMINATES ACROSS THE REMAINDER BASIN.
SSMI TPW IMAGERY SHOW MOISTURE INFLOW FROM THE SE CONUS AND THE
NW CARIBBEAN TO THE NE GULF...WHICH CONVERGENCE SUPPORTS
SCATTERED SHOWERS AND TSTMS ALONG NORTHERN FLORIDA. A MIDDLE
LEVEL TROUGH IS OVER THE E CONUS SEABOARD WITH BASE EXTENDING SW
ACROSS CENTRAL-SOUTHERN FLORIDA...THUS SUPPORTING SCATTERED
SHOWERS AND TSTMS FROM 25N TO 29N E OF 85W. VARIABLE WINDS OF 5
TO 10 KT DOMINATE ACROSS THE BASIN. THE RIDGE IS FORECAST TO
REMAIN NEARLY STATIONARY THROUGH SATURDAY.

CARIBBEAN SEA...

A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN ASSOCIATED
WITH A MODERATE MOIST AIRMASS OVER THE NORTH-CENTRAL AND
PORTIONS OF THE E CARIBBEAN. THIS MOISTURE ALONG WITH A BROAD
AND ELONGATED UPPER LEVEL LOW EXTENDING FROM NE OF THE LEEWARD
ISLANDS TO CENTRAL CUBA SUPPORT SCATTERED SHOWERS AND TSTMS
ACROSS PUERTO RICO...THE MONA PASSAGE AND HISPANIOLA. ANOTHER
MODERATE MOIST AIRMASS IS OVER THE NW CARIBBEAN ASSOCIATED WITH
A TROPICAL WAVE THAT MOVED ACROSS CENTRAL AMERICA EARLY TODAY. A
MIDDLE-LEVEL DIFFLUENT WIND FLOW OVER THIS REGION ALONG THE
MOISTURE SUPPORT SCATTERED MODERATE CONVECTION N OF 18N W OF
80W...INCLUDING WESTERN CUBA. OVER THE SW CARIBBEAN...LOW
PRESSURE ASSOCIATED WITH A LOW CENTER OVER N COLOMBIA AND THE
EPAC MONSOON TROUGH SUPPORT SCATTERED MODERATE CONVECTION S OF
12N W OF 79W. STRONG DEEP LAYER WIND SHEAR AND DRY AIR INHIBIT
CONVECTION ELSEWHERE. A GENERALLY TIGHT PRESSURE GRADIENT
BETWEEN A RIDGE OVER THE ATLC EXTENDING ACROSS THE NORTHERN
BASIN AND LOWER PRESSURE OVER COLOMBIA SUPPORT WINDS OF 20 KT TO
25 KT FROM 11N TO 14N BETWEEN 74W AND 77W. TRADES OF 15 KT
DOMINATE ELSEWHERE. FRESH TO OCCASIONAL STRONG E-NE WINDS ARE
EXPECTED TO PERSIST THROUGH THE UPCOMING WEEKEND.

...HISPANIOLA...

MOISTURE ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE WITH
AXIS CURRENTLY NEAR 73W ALONG WITH MIDDLE-LEVEL DIFFLUENT WIND
FLOW SUPPORT SCATTERED MODERATE CONVECTION AND TSTMS ACROSS THE
ISLAND AND MONA PASSAGE. SHOWERS ACTIVITY IS FORECAST THROUGH
FRIDAY NIGHT.

ATLANTIC OCEAN...

AN MIDDLE-LEVEL TROUGH IS OVER THE E CONUS SEABOARD AND W ATLC W
OF 66W SUPPORTING A 1008 MB LOW CENTERED NEAR 39N65W WITH
STATIONARY FRONT EXTENDING SW TO 32N80W. TO THE SOUTH OF THE
FRONT...LOW-LEVEL MOISTURE CONVERGENCE COUPLED WITH MIDDLE-LEVEL
DIFFLUENCE IS GENERATING ISOLATED SHOWERS AND TSTMS ACROSS MUCH
OF THE SW NORTH ATLC W OF 70W. FARTHER EAST...THE REMAINDER OF
THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1024 MB HIGH CENTERED NEAR 31N53W AND A 1023
MB HIGH CENTERED NEAR 31N32W. A WEAKNESS BETWEEN THESE TWO HIGHS
IS ANALYZED AS A SURFACE TROUGH FROM 30N44W TO 26N51W. HIGH
PRESSURE AND RIDGING WILL CONTINUE TO BE THE MAIN FEATURE ACROSS
THE BASIN DURING THE NEXT TWO DAYS.

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

$$
NR
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