[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261051
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SAT OCT 26 2013

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
1015 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 05N44W TO 13N40W MOVING W AT 15-20
KT. THE WAVE REMAINS EMBEDDED WITHIN LOW-LEVEL TROUGHING AND A
DEEP MOISTURE MAXIMUM FROM 06N-14N BETWEEN 38W-44W AS NOTED ON
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION
FROM 05N-12N BETWEEN 34W-45W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 16N17W TO
07N21W TO 05N30W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 05N30W TO 04N34W TO 07N41W TO 03N51W. SCATTERED
MODERATE CONVECTION IS FROM 03N-13N BETWEEN 19W-34W.

...DISCUSSION...

GULF OF MEXICO...
WEST-SOUTHWESTERLY UPPER LEVEL FLOW DOMINATES ACROSS THE GULF
THIS MORNING AS WATER VAPOR IMAGERY SHOWS A BROAD MIDDLE TO
UPPER LEVEL TROUGH EXITING EASTWARD OFF THE EASTERN U.S.
SEABOARD. THE TROUGHING SUPPORTED A STATIONARY FRONT WHICH HAS
DISSIPATING IN THE PAST 6 HOURS ACROSS PORTIONS OF THE GULF.
WHILE OVERALL SURFACE RIDGING ANCHORED OVER THE SE CONUS IS
PROVIDING BRISK E-NE WINDS...MIDDLE TO UPPER LEVEL MOISTURE AND
CLOUDINESS WITH POSSIBLE EMBEDDED ISOLATED SHOWERS IS NOTED S OF
25N...AND IN THE VICINITY OF A SURFACE TROUGH ANALYZED FROM
17N92W TO 22N97W. THE RIDGING IS FORECAST TO DRIFT SOUTH-
SOUTHEASTWARD THROUGH EARLY SUNDAY WITH THE CURRENT PRESSURE
GRADIENT RELAXING SOMEWHAT WHICH WILL IN TURN DIMINISH E-NE
WINDS TO 20 KT OR LESS BY LATE SUNDAY. BY EARLY NEXT WEEK AS THE
RIDGING SLIDES INTO THE SW NORTH ATLC...E-SE WINDS ARE EXPECTED
TO PREVAIL WITH SOUTHERLY RETURN FLOW NOTED N OF 25N W OF 90W AS
AN AREA OF LOW PRESSURE DEVELOPS ACROSS THE CENTRAL PLAINS.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE
GULF OF HONDURAS NEAR 16N86W WHICH IS PROVIDING MUCH OF THE
WESTERN CARIBBEAN W OF 75W WITH AN UPPER LEVEL DIFFLUENT
ENVIRONMENT THIS MORNING. AT THE SURFACE...CONVERGENT TRADES AND
THE PRESENCE OF A SHEAR LINE DRAPED FROM CENTRAL CUBA NEAR
22N79W TO THE COAST OF BELIZE NEAR 17N88W IS GENERATING
SCATTERED SHOWERS AND TSTMS N OF 16N W OF 81W. ANOTHER AREA OF
STRONGER TSTMS IS FOCUSED IN THE VICINITY OF AND ALONG A SURFACE
TROUGH ANALYZED FROM 11N80W TO 16N85W WITH CONVECTION MAINLY
OCCURRING WITHIN 120 NM EITHER SIDE OF THE TROUGH AXIS...
INCLUDING INLAND PORTIONS OF NICARAGUA AND EASTERN HONDURAS.
FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 15N70W AND
ALONG WITH BROAD FRONTAL TROUGHING TO THE NORTH ACROSS THE SW
NORTH ATLC IS PROVIDING FOR ISOLATED SHOWERS AND TSTMS N OF 15N
BETWEEN 70W-78W. FINALLY...MOIST SOUTHWESTERLY UPPER LEVEL FLOW
IS NOTED ON WATER VAPOR IMAGERY E OF 70W WITH STRONG DIFFLUENCE
NOTED OVER THE WINDWARD ISLANDS AND SE CARIBBEAN. A SURFACE
TROUGH IS ANALYZED ALONG 63W WEST OF THE WINDWARD ISLANDS AND IS
PROVIDING FOCUS FOR SCATTERED SHOWERS AND ISOLATED TSTMS FROM
10N-16N BETWEEN 59W-66W.

HISPANIOLA...
CURRENTLY AN UPPER LEVEL LOW IS CENTERED SOUTH OF THE ISLAND
NEAR 15N70W THAT CONTINUES TO ADVECT MOISTURE NORTHWARD WITH
ENHANCED CLOUDINESS AND ISOLATED SHOWERS NOTED IN THE ADJACENT
COASTAL WATERS N OF 15N BETWEEN 70W-76W. MOST OF THE DYNAMIC
LIFT IS GENERATED BY THE UPPER LEVEL LOW...HOWEVER TO THE
NORTH...A FRONTAL TROUGH REMAINS NEARLY STATIONARY ACROSS THE SW
NORTH ATLC WITH SHOWER AND TSTM ACTIVITY REMAINING MOSTLY N OF
20N AT THIS TIME. WHILE THE MORNING PERIOD REMAINS RELATIVELY
QUIET...WITH PEAK DAYTIME HEATING AND INSTABILITY...SCATTERED
SHOWERS AND TSTMS ARE EXPECTED ACROSS HISPANIOLA SUNDAY
AFTERNOON AND EVENING.

ATLANTIC OCEAN...
A BROAD MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR
IMAGERY OFFSHORE OF THE EASTERN U.S. SEABOARD WITH AXIS
EXTENDING FROM 42N61W TO 34N70W. THE TROUGH SUPPORTS A
STATIONARY FRONT ANALYZED FROM 32N60W SW TO 26N70W TO CENTRAL
CUBA NEAR 22N78W. A PRE-FRONTAL TROUGH IS ALSO NOTED FROM
WESTERN HISPANIOLA NEAR 19N73W TO 26N67W. WITH LOW-LEVEL
MOISTURE CONVERGENCE OCCURRING IN CLOSE PROXIMITY OF THE
FRONT...AND MIDDLE TO UPPER LEVEL DIFFLUENCE MAXIMIZED EAST AND
SOUTH OF THE TROUGH AXIS...SCATTERED SHOWERS AND ISOLATED TSTMS
ARE OCCURRING ACROSS A LARGE AREA OF THE SW NORTH ATLC THIS
MORNING. THIS CONVECTION LIES WITHIN 210 NM EITHER SIDE OF A
LINE FROM 32N62W TO 26N67W TO 22N77W. OTHERWISE...THE NORTHWEST
PORTION CONTINUES TO DRY OUT DUE TO SURFACE RIDGING BUILDING IN
ACROSS THE SE CONUS. FARTHER EAST...AN UPPER LEVEL LOW IS
CENTERED NEAR 24N57W AND CONTINUES TO PRODUCE LITTLE SENSIBLE
WEATHER AT THE SURFACE. GENERALLY THE REMAINDER OF THE CENTRAL
AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE
ANCHORED BY A 1026 MB HIGH CENTERED NEAR 33N34W. THE ONLY
WEAKNESS NOTED IN THE RIDGING IS A 1019 MB LOW CENTERED NEAR
33N44W AND A SURFACE TROUGH AXIS ANALYZED FROM THE LOW CENTER S-
SW TO 30N46W. ISOLATED SHOWERS ARE OCCURRING WITHIN 90 NM EITHER
SIDE OF THE TROUGH AXIS.

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

$$
HUFFMAN


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