[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 260555
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 05N41W TO 14N38W MOVING W AT 15-20
KT. THE WAVE REMAINS EMBEDDED WITHIN LOW-LEVEL TROUGHING AND A
DEEP MOISTURE MAXIMUM FROM 05N-12N BETWEEN 34W-43W AS NOTED ON
TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION
FROM 04N-11N BETWEEN 36W-44W.

TROPICAL WAVE EXTENDS FROM 12N70W TO 20N72W MOVING W AT 5-10 KT.
THE WAVE REMAINS DIFFICULT TO TRACK AND MOST OF THE ENERGY HAS
LIKELY BEEN ABSORBED BY BY A MIDDLE TO UPPER LEVEL LOW CENTERED
OVER THE CENTRAL CARIBBEAN SEA NEAR 16N72W. TO THE WEST...A VERY
UNFAVORABLE ENVIRONMENT FOR THE WAVE EXISTS AS NORTHERLY WINDS
ALOFT ARE RELATIVELY DRY AND STABLE. ISOLATED MODERATE
CONVECTION IS FROM 16N-17N BETWEEN 71W-73W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO
08N21W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
08N21W TO 05N31W TO 06N36W. WIDELY SCATTERED MODERATE CONVECTION
IS FROM 03N-12N BETWEEN 22W-36W.

...DISCUSSION...

GULF OF MEXICO...
WEST-SOUTHWESTERLY UPPER LEVEL FLOW DOMINATE ACROSS THE GULF
THIS EVENING AS WATER VAPOR IMAGERY SHOWS A BROAD MIDDLE TO
UPPER LEVEL TROUGH EXITING EASTWARD OFF THE EASTERN SEABOARD.
THE TROUGHING SUPPORTS A DISSIPATING STATIONARY FRONT ANALYZED
ACROSS THE SW NORTH ATLC...ACROSS THE NW CARIBBEAN SEA...AND
INTO THE SW GULF NEAR 19N92W. 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 20N94W TO 24N97W. 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 17N88W WHICH IS PROVIDING MUCH OF THE
WESTERN CARIBBEAN W OF 74W WITH AN UPPER LEVEL DIFFLUENT
ENVIRONMENT THIS EVENING. AT THE SURFACE...CONVERGENT TRADES AND
THE PRESENCE OF A DISSIPATING STATIONARY FRONT DRAPED FROM
CENTRAL CUBA NEAR 22N79W TO THE YUCATAN PENINSULA NEAR 20N87W IS
GENERATING SCATTERED SHOWERS AND TSTMS N OF 15N W OF 75W.
ANOTHER AREA OF STRONGER TSTMS IS FOCUSED IN THE VICINITY OF A
SURFACE TROUGH ANALYZED FROM 11N81W TO 15N82W WITH CONVECTION
MAINLY WEST OF A LINE FROM 10N77W TO 16N83W...INCLUDING INLAND
PORTIONS OF NICARAGUA AND EASTERN HONDURAS. IN ADDITION...THE
CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ALONG 10N IS
ENHANCING THIS CONVECTION WHICH STRETCHES ACROSS PORTIONS OF
WESTERN PANAMA AND COSTA RICA. FARTHER EAST...A WEAK TROPICAL
WAVE IS ALONG 71W...YET IS LIKELY INFLUENCED BY AN UPPER LEVEL
LOW CENTERED NEAR 16N71W INHIBITING ANY SIGNIFICANT DEEP
CONVECTION AND CONTINUING TO DISSIPATE ENERGY NORTHWARD INTO THE
FRONTAL TROUGHING PRESENT ACROSS THE SW NORTH ATLC. FINALLY...
MOIST SOUTHWESTERLY UPPER LEVEL FLOW IS NOTED ON WATER VAPOR
IMAGERY E OF 70W WITH STRONG DIFFLUENCE NOTED OVER THE WINDWARD
ISLANDS. A SURFACE TROUGH IS ANALYZED ALONG 60W EAST OF THE
WINDWARD ISLANDS AND IS PROVIDING FOCUS FOR SCATTERED SHOWERS
AND ISOLATED TSTMS FROM 11N-15N BETWEEN 58W-63W.

HISPANIOLA...
CURRENTLY AN UPPER LEVEL LOW IS CENTERED SOUTH OF THE ISLAND
NEAR 16N71W THAT CONTINUES TO ADVECT MOISTURE NORTHWARD ACROSS
EASTERN PORTIONS WITH ENHANCED CLOUDINESS AND ISOLATED SHOWERS
NOTED IN THE ADJACENT COASTAL WATERS IN THE VICINITY OF 17N72W.
WHILE MOST OF THIS DYNAMIC LIFT IS GENERATED BY THE UPPER LEVEL
LOW...THE PRESENCE OF A TROPICAL WAVE ALONG 71W IS ALSO
PROVIDING FOR LOW-LEVEL CONVERGENCE. TO THE NORTH...A FRONTAL
TROUGH REMAINS NEARLY STATIONARY ACROSS THE SW NORTH ATLC WITH
SHOWER AND TSTM ACTIVITY REMAINING MOSTLY N OF 21N AT THIS TIME.
WHILE THE OVERNIGHT 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 41N66W TO 33N74W. 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 THE SE
BAHAMAS NEAR 21N73W TO 27N67W. 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 EVENING. THIS
CONVECTION LIES WITHIN 210 NM EITHER SIDE OF A LINE FROM 32N63W
TO 26N70W TO 23N78W. 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 23N57W
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 1022 MB HIGH
CENTERED NEAR 28N52W AND A 1027 MB HIGH CENTERED NEAR 33N33W.
THE ONLY WEAKNESS NOTED IN THE RIDGING IS A 1019 MB LOW CENTERED
NEAR 32N45W AND A SURFACE TROUGH AXIS ANALYZED FROM THE LOW
CENTER S-SW TO 28N47W. ISOLATED SHOWERS ARE OCCURRING WITHIN 90
NM EAST OF THE LOW AND TROUGH AXIS.

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

$$
HUFFMAN


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