[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 242341
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI JUL 24 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
2330 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AXIS EXTENDING
FROM 14N39W TO 07N40W...MOVING W AT 10-15 KT OVER THE PAST 24
HOURS. THE WAVE COINCIDES WITH A SUBTLE 700 MB TROUGHING ALONG
40W AND THE WAVE AXIS IS AHEAD OF A 700 MB WIND MAXIMA
PREVAILING E OF 40W. NO SIGNIFICANT CONVECTION IS OCCURRING IN
ASSOCIATION WITH THIS WAVE DUE TO A STRONG SAHARAN AIR LAYER
WHICH CONTINUES TO PROVIDE STABLE CONDITIONS OVER THE TROPICAL
EASTERN ATLANTIC.

A TROPICAL WAVE IS APPROACHING THE WINDWARD ISLANDS WITH AXIS
EXTENDING 14N53W TO 06N56W...MOVING W AT 15-20 KT. TPW IMAGERY
DEPICTS HIGH MOISTURE CONTENT SURROUNDING THIS WAVE WHICH WILL
MOVE OVER THE LESSER ANTILLES AND NORTHERN PORTION SOUTH AMERICA
SUPPORTING CONVECTION. CURRENTLY...ISOLATED CONVECTION PREVAILS
ACROSS THE SOUTHERN PORTION OF THE WAVE AFFECTING SURINAME AND
GUYANA.

A TROPICAL WAVE IS OVER THE CENTRAL AMERICA WITH AXIS EXTENDING
FROM 16N83W TO 07N82W...MOVING W AT 15-20 KT. THE WAVE REMAINS
EMBEDDED WITHIN A MAXIMUM OF TOTAL PRECIPITABLE WATER ACROSS THE
WESTERN CARIBBEAN SUPPORTING CONVECTION ACROSS NICARAGUA AND
HONDURAS AS WELL AS THE CARIBBEAN WATERS S OF 12N.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
13N17W TO 08N39W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 07N41W TO 07N53W. SCATTERED MODERATE CONVECTION IS
FROM 06N-13N BETWEEN 17W-29W.

...DISCUSSION...

GULF OF MEXICO...

FAIR WEATHER AND CLEAR SKIES CONTINUE ACROSS THE W AND CENTRAL
GULF AS A 1020 MB SURFACE HIGH PREVAILS NEAR 25N90W. TO THE
E...A SURFACE TROUGH EXTENDS ACROSS THE E GULF AND FLORIDA
PENINSULA AHEAD OF A FRONTAL BOUNDARY CURRENTLY N OF OUR AREA.
THE TROUGH EXTENDS FROM 28N85W TO 31N78W AND COMBINED WITH UPPER-
LEVEL DIFFLUENCE ACROSS THE FLORIDA PENINSULA SUPPORT SCATTERED
MODERATE CONVECTION E OF 85W. SCATTEROMETER DATA DEPICTS A LIGHT
ANTICYCLONIC FLOW ACROSS MOST OF THE BASIN EXCEPT A LIGHT TO
GENTLE FLOW ACROSS THE NE GULF MAINLY NEAR THE SURFACE TROUGH
AND AHEAD OF THE FRONTAL BOUNDARY N OF 28N AND E OF 89W. EXPECT
SIMILAR CONDITIONS OVER THE NEXT 24 HOURS.

CARIBBEAN SEA...

AN ELONGATED UPPER-LEVEL LOW CONTINUES OVER THE W CARIBBEAN
DOMINATING THE AREA W OF 71W WHILE AN UPPER-LEVEL HIGH CENTERED
OVER THE ATLANTIC WATERS E OF THE LESSER ANTILLES EXTENDS W
REACHING THE EASTERN HALF OF THE CARIBBEAN BASIN. WITH THESE
FEATURES...A DIFFLUENT FLOW PREVAILS ACROSS THE CENTRAL
CARIBBEAN SUPPORTING UPPER-LEVEL CLOUDINESS BETWEEN 70W-80W.
ASIDE FROM THE CONVECTION GENERATED BY THE TROPICAL WAVE
CURRENTLY OVER CENTRAL AMERICA...A MODERATE TO STRONG DEEP-LAYER
WIND SHEAR PREVAILS ACROSS THE BASIN SUPPORTING FAIR WEATHER.
SCATTEROMETER DATA DEPICTS LIGHT TO GENTLE TRADES ACROSS MOST OF
THE CARIBBEAN EXCEPT GENTLE TO MODERATE WINDS S OF 18N BETWEEN
71W-81W. OVER THE NEXT 24 HOURS...EXPECT FOR THE NEXT TROPICAL
WAVE TO APPROACH THE LESSER ANTILLES INCREASING MOISTURE AND
SUPPORTING CONVECTION ACROSS THE E CARIBBEAN.

...HISPANIOLA...

FAIR WEATHER PREVAILS ACROSS THE ISLAND AS A DRY AND STABLE
AIRMASS CONTINUES ACROSS THE CARIBBEAN. NO SIGNIFICANT CHANGE IS
EXPECTED OVER THE NEXT 24 HOURS.

ATLANTIC OCEAN...

A LONGWAVE MIDDLE TO UPPER-LEVEL TROUGH IS EVIDENT ON WATER
VAPOR IMAGERY OVER THE WESTERN ATLANTIC THAT SUPPORTS A
STATIONARY FRONT EXTENDING FROM 37N52W INTO A 1011 MB LOW
CENTERED NEAR 34N75W THEN EXTENDS W INTO THE SE CONUS. SCATTERED
LIGHT TO MODERATE CONVECTION IS OCCURRING IN THE VICINITY OF THE
FRONT WITHIN 120 NM EITHER SIDE. TWO SURFACE TROUGHS PRECEDE
THIS FRONT SUPPORTING CONVECTION ACROSS THE FLORIDA PENINSULA
AND THE W ATLANTIC MAINLY N OF 26N AND W OF 72W. TO THE E...A
SURFACE RIDGE AXIS EXTENDING ACROSS THE REMAINDER OF THE BASIN
WITH ONLY A FEW ISOLATED SHOWERS OCCURRING FROM 26N-30N BETWEEN
56W-63W. AN UPPER-LEVEL LOW IS REFLECTED AT THE SURFACE AS A
TROUGH THAT EXTENDS FROM 30N49W TO 23N52W. ISOLATED SHOWERS
ARE WITHIN 120 NM EITHER SIDE OF THIS BOUNDARY.

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

$$

ERA
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