[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281027
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE OCT 28 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...

A TROPICAL WAVE IS OVER THE EASTERN ATLC WITH AXIS EXTENDING
FROM 16N23W TO 8N24W...MOVING W AT 15-20 KT. THE HOVMOLLER OF
METEOSAT SATELLITE IMAGERY SHOW A VERY WEAK SIGNAL OF THIS WAVE.
SSMI TPW AND GOES-R AIRMASS IMAGERY DEPICT THE WAVE IS IN A DRY
MIDDLE TO LOWER LEVEL ENVIRONMENT THAT ALONG DEEP LAYER
ENVIRONMENTAL SHEAR HINDER THE DEVELOPMENT OF CONVECTION. MODEL
GUIDANCE INDICATES THE WAVE WILL CONTINUE IN A SIMILAR
ENVIRONMENT FOR THE NEXT DAY OR SO...THUS ACTING TO VANISH THE
WAVE.

A TROPICAL WAVE IS MOVING ACROSS THE LESSER ANTILLES WITH AXIS
EXTENDING FROM 20N59W TO 10N62W...MOVING W AT 15-20 KT. SSMI TPW
AND WATER VAPOR IMAGERY INDICATE THE WAVE IS EMBEDDED IN A
MODERATE TO HIGH DEEP LAYER MOIST ENVIRONMENT THAT ALONG A
DIFFLUENT ENVIRONMENT ALOFT SUSTAIN SCATTERED MODERATE
CONVECTION FROM 12N-20N BETWEEN 52W-62W.

A THIRD TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN WITH AXIS
EXTENDING FROM 17N66W TO 10N67W...MOVING W AT 15 KT. SSMI TPW
AND WATER VAPOR IMAGERY INDICATE THE WAVE IS IN A ZONE OF DEEP
LAYER DRY AIR THAT IS KEEPING THE WAVE DEVOID OF CONVECTION.
MODEL GUIDANCE INDICATE THE WAVE WILL VANISH IN THE NEXT DAY OR
SO.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 9N13W AND CONTINUES TO 7N16W. THE ITCZ BEGINS NEAR
7N16W AND CONTINUES ALONG 7N33W TO 5N47W. BESIDES THE CONVECTION
MENTIONED IN THE TROPICAL WAVES SECTION...SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-10N BETWEEN 22W-
42W. SCATTERED MODERATE CONVECTION IS FROM 3N-10N E OF 21W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD UPPER-LEVEL RIDGE CONTINUES OVER THE BASIN EXTENDING AN
AXIS NORTHWARD ACROSS THE EASTERN CONUS...THUS SUPPORTING
SURFACE RIDGING IN THE GULF BEING ANCHORED BY A 1022 MB HIGH
OVER THE WESTERN ATLC NEAR 31N72W AND A 1020 MB HIGH OVER THE NE
GULF NEAR 29N83W. DEEP LAYER DRY AIR REMAINS ACROSS THE ENTIRE
BASIN...WHICH SUSTAINS FAIR WEATHER. WINDS ARE FROM THE S-SE IN
THE RANGE OF 5-15 KT. SURFACE RIDGING WILL DOMINATE OVER THE
GULF THROUGH WED NIGHT WHEN A COLD FRONT WILL ENTER AND EXTEND
ACROSS THE NORTHERN BASIN.

CARIBBEAN SEA...

THE REMNANTS OF FORMER TROPICAL DEPRESSION HANNA CONTINUE TO
SUPPORT HEAVY SHOWERS AND ISOLATED TSTMS OVER
HONDURAS...NORTHERN NICARAGUA AS WELL AS THE YUCATAN BASIN S OF
20N W OF 80W. FARTHER EAST...A PRE-FRONTAL SURFACE TROUGH
EXTENDS FROM THE SW N ATLC WATERS SW TO CENTRAL DOMINICAN
REPUBLIC NEAR 18N70W. LOW-LEVEL MOISTURE CONVERGENCE ALONG THE
TROUGH AS WELL AS A DIFFLUENT ENVIRONMENT AT THE UPPER-LEVELS
SUPPORT SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 100 NM
EITHER SIDE OF THE TROUGH AXIS. A TROPICAL WAVE IS MOVING OVER
THE EASTERN CARIBBEAN WATERS JUST S OF PUERTO RICO. THIS WAVE IS
BEING SUPPORTED BY AN INVERTED MIDDLE-LEVEL TROUGH...HOWEVER
DEEP LAYER DRY AIR IN THIS REGION OF THE BASIN IS HINDERING THE
DEVELOPMENT OF CONVECTION. A SECOND TROPICAL WAVE IS MOVING OVER
THE LESSER ANTILLES. THIS WAVE IS EMBEDDED IN A DEEP MOIST
ENVIRONMENT AS WELL AS IN A REGION OF DIFFLUENT FLOW ALOFT THAT
ENHANCES SCATTERED SHOWERS AND TSTMS OVER THE FAR EASTERN BASIN
E OF 62W...INCLUDING PORTIONS OF THE LEEWARD AND WINDWARD
ISLANDS. SEE TROPICAL WAVES SECTIONS ABOVE FOR MORE DETAILS.
OTHERWISE...THE WESTERNMOST TROPICAL WAVE IS EXPECTED TO
DISSIPATE WEDNESDAY NIGHT. THE NORTHERN PORTION OF THE TRAILING
TROPICAL WAVE IS FORECAST TO TRANSITION INTO A TROUGH OF LOW
PRESSURE TO MOVE ACROSS PUERTO RICO WED NIGHT INTO THU MORNING.

HISPANIOLA...

A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM THE SW N ATLC WATERS
SW TO CENTRAL DOMINICAN REPUBLIC NEAR 18N70W. LOW-LEVEL MOISTURE
CONVERGENCE ALONG THE TROUGH AXIS AS WELL AS A DIFFLUENT
ENVIRONMENT AT THE UPPER-LEVELS SUPPORT SCATTERED SHOWERS AND
ISOLATED TSTMS WITHIN 100 NM EITHER SIDE OF THE AXIS. ISOLATED
SHOWERS ARE POSSIBLE ACROSS THE REMAINDER ISLAND AS THE TROUGH
SLOWLY DRIFT EASTWARD AND DISSIPATE LATER TODAY. SHOWER ACTIVITY
ASSOCIATED WITH THE REMNANTS OF THE TROUGH IS EXPECTED THROUGH
WED NIGHT/THU MORNING.

ATLANTIC OCEAN...

AN UPPER LEVEL TROUGH IS OVER THE WESTERN ATLC WITH A BASE
EXTENDING TO NORTHERN HISPANIOLA. THIS TROUGH ALOFT SUPPORTS A
FRONTAL SYSTEM ANALYZED AS A STATIONARY FRONT FROM 30N56W SW TO
27N65W TO 26N75W AND A PRE-FRONTAL SURFACE TROUGH ALONG 27N61W
TO CENTRAL DOMINICAN REPUBLIC NEAR 18N70W. SCATTERED SHOWERS ARE
WITHIN 100 NM EITHER SIDE OF THE TROUGH AXIS. SURFACE HIGH
PRESSURE DOMINATES ELSEWHERE IN THE ATLC N OF 20N BEING ANCHORED
BY A 1022 MB HIGH IN THE SW N ATLC NEAR  31N72W AND A 1021 MB
HIGH OVER THE CENTRAL ATLC NEAR 28N40W. OTHERWISE...SEE THE
TROPICAL WAVES SECTION.

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

$$
NR


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