[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261019
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT JUL 26 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS OVER THE EASTERN ATLC WITH AXIS EXTENDING FROM
18N28W TO 9N30W MOVING W AT 15-20 KT DURING THE PAST 24 HOURS.
METEOSAT SAL TRACKING IMAGERY INDICATE THE WAVE CONTINUES
EMBEDDED IN THE DRY SAHARAN AIRMASS WHICH IS INHIBITING
CONVECTION AT THE TIME.

TROPICAL WAVE IS OVER THE WINDWARD ISLANDS AND SE CARIBBEAN WITH
AXIS EXTENDING FROM 13N60W TO 8N61W MOVING W AT 20-25 KT IN THE
PAST 24 HOURS. DEEP LAYER MOISTURE IN THE WAVE ENVIRONMENT IS
SUPPORTING SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS FROM
9N-16N BETWEEN 55W-65W.

TROPICAL WAVE IS ON THE WESTERN CARIBBEAN WITH AXIS EXTENDING
FROM 21N78W TO 10N78W MOVING W AT 20 KT DURING THE PAST 24
HOURS. MODERATE LOW-LEVEL MOISTURE IS NOTED IN THE WAVE
ENVIRONMENT...HOWEVER DRY AIR SUBSIDENCE FROM ALOFT AND STRONG
DEEP LAYER ENVIRONMENTAL SHEAR HINDER THE DEVELOPMENT OF
CONVECTION.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF WEST AFRICA NEAR
12N16W AND THEN CONTINUES ALONG 9N27W TO 9N35W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 9N35W TO 7N48W
TO 9N55W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVES...SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE
FROM 6N-9N E OF 16W...FROM 8N-10N BETWEEN 20W-35W AND FROM 6N-
10N BETWEEN 43W-52W.

...DISCUSSION...

GULF OF MEXICO...

LOW-LEVEL MOISTURE ACROSS THE GULF HAS SLIGHTLY REDUCED IN THE
LAST COUPLE OF HOURS WHICH ALONG MIDDLE-LEVEL AND SURFACE
RIDGING CONTINUE TO SUPPORT STABILITY AND MAINLY CLEAR SKIES
BASIN-WIDE. THE SURFACE RIDGE IS BEING ANCHORED BY A 1017 MB
HIGH NEAR 26N87W WHICH IS PROVIDING VARIABLE WINDS OF 5-15 KT
ACROSS THE BASIN. AN UPPER-LEVEL CYCLONIC CIRCULATION OVER THE
EASTERN GULF AND AN ANTICYCLONE CENTERED OVER THE SW N ATLC ARE
GENERATING DIVERGENT WIND FLOW ALOFT OVER PORTIONS OF THE
FLORIDA PENINSULA. THIS ALONG WITH MODERATE DEEP LAYER MOISTURE
IS SUPPORTING ISOLATED SHOWERS AND TSTMS OVER THE SOUTH FLORIDA
PENINSULA AND ADJACENT WATERS. SURFACE RIDGING AND FAIR WEATHER
IS FORECAST ACROSS MUCH OF THE BASIN FOR THE NEXT TWO DAYS.
SHOWERS ARE EXPECTED FOR THE SW GULF MONDAY MORNING AS A
TROPICAL WAVE MOVES TOWARDS THE BAY OF CAMPECHE.

CARIBBEAN SEA...

AN ANTICYCLONE CENTERED OVER THE SW N ATLC ALONG WITH AN
INVERTED TROUGH OVER THE CENTRAL CARIBBEAN ARE GENERATING
DIFFLUENT FLOW ALOFT WHICH ALONG LOW-LEVEL MOISTURE SUPPORT
ISOLATED SHOWERS AND TSTMS OVER THE WINDWARD PASSAGE AS WELL AS
WESTERN AND EASTERN CUBA. A TROPICAL WAVE IS MOVING OVER THE
WESTERN CARIBBEAN WATERS WHILE ANOTHER WAVE ENTERS THE WINDWARD
ISLANDS THIS MORNING. SEE TROPICAL WAVE SECTION FOR DETAILS. THE
PASSAGE OF THE TROPICAL WAVE ACROSS THE CENTRAL CARIBBEAN ALONG
WITH THE CONTINUATION OF A TIGHT PRESSURE GRADIENT IN THE REGION
SUPPORT TRADES OF 20-30 KT S OF 17N E OF 79W WITH GALE FORCE
WINDS ALONG THE COAST OF COLOMBIA. STRONG DEEP LAYER
ENVIRONMENTAL WIND SHEAR AND DRY AIR SUBSIDENCE FROM ALOFT
SUPPORT CLEAR SKIES ACROSS THE REMAINDER BASIN. THE WESTERNMOST
TROPICAL WAVE IS FORECAST TO MOVE ACROSS THE YUCATAN PENINSULA
BY MON MORNING WHILE THE SECOND WAVE MOVES S OF PUERTO RICO.

...HISPANIOLA...

AN ANTICYCLONE CENTERED OVER THE SW N ATLC ALONG WITH AN
INVERTED TROUGH OVER THE CENTRAL CARIBBEAN IS GENERATING
DIFFLUENCE ALOFT WHICH ALONG LOW-LEVEL MOISTURE IS SUPPORTING
SCATTERED SHOWERS AND TSTMS OVER THE WINDWARD PASSAGE. THIS
PATTERN ALOFT ALSO SUPPORT CLOUDINESS ACROSS THE ISLAND. EXCEPT
FOR AFTERNOON/EARLY EVENING SHOWERS...FAIR WEATHER IS FORECAST
FOR THE ISLAND SAT AND SUN.

ATLANTIC OCEAN...

A DIFFLUENT ENVIRONMENT ALOFT BEING GENERATED BY AN UPPER-LEVEL
CYCLONIC CIRCULATION OVER THE EASTERN GULF AND AN ANTICYCLONE
CENTERED OVER THE SW N ATLC SUPPORT ISOLATED SHOWERS AND TSTMS N
OF 25N W OF 77W. FARTHER EAST...A MID-UPPER LEVEL LOW CENTERED
NEAR 27N62W ENHANCES SCATTERED SHOWERS AND ISOLATED TSTMS FROM
23N-29N BETWEEN 59W-67W. OVER THE E ATLC...A MID-UPPER LEVEL LOW
N OF THE AREA EXTENDS A TROUGH SW WITH A BASE NEAR 24N. THIS
CYCLONIC CIRCULATION AND ASSOCIATED TROUGH SUPPORT A FRONTAL
BOUNDARY ANALYZED AS A STATIONARY FRONT FROM 30N31W SW TO 26N36W
TO 24N43W WITH NO CONVECTION ASSOCIATED WITH IT. THE REMAINDER
BASIN IS FAIRLY DRY AND UNDER THE INFLUENCE OF A SURFACE RIDGE
ANCHORED BY A 1022 MB HIGH NEAR 38N43W. THESE TWO FACTORS
SUPPORTS FAIR WEATHER ELSEWHERE IN THE BASIN. OTHERWISE...SEE
ABOVE THE TROPICAL WAVES SECTION. SURFACE RIDGING WILL DOMINATE
ACROSS THE CENTRAL AND WESTERN ATLC. THE FRONT IS FORECAST TO
DISSIPATE TONIGHT.

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

$$
NR

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