[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271154
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON OCT 27 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
1015 UTC.

...SPECIAL FEATURE...

A 1008 MB SURFACE LOW ASSOCIATED WITH THE REMNANTS OF TROPICAL
DEPRESSION NINE IS LOCATED NEAR 15N83W DRIFTING SOUTHWESTWARD. A
CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION IS FROM 13N-16N
BETWEEN 81W-85W. ISOLATED MODERATE CONVECTION AND TSTMS ARE OVER
DOMINICAN REPUBLIC EXTENDING TO NORTHERN COASTAL WATERS. THIS
SYSTEM IS EXPECTED TO MOVE INLAND OVER NICARAGUA LATER TODAY.
THERE IS A MEDIUM CHANCE OF THIS SYSTEM DEVELOPING INTO A
TROPICAL CYCLONE BEFORE MOVING OVER LAND LATER TODAY.

...TROPICAL WAVES...

A TROPICAL WAVE IS OVER THE FAR EASTERN ATLC WITH AXIS EXTENDING
ALONG 17W. A HOVMOLLER OF METEOSAT SATELLITE IMAGERY AS WELL AS
AN UPPER-AIR TIME SECTION ANALYSIS FROM DAKAR...SENEGAL SUGGEST
THAT THE WAVE CAME OFF THE WESTERN AFRICAN COAST SUNDAY EVENING.
THE 700 MB WIND AND STREAMFUNCTION ANALYSIS FROM THE UNIVERSITY
OF ALBANY ALSO DEPICTS THE PRESENCE OF A TROPICAL WAVE NEARBY THE
AFOREMENTIONED LONGITUDE. THIS LOW AMPLITUDE WAVE IS MAINLY
EMBEDDED IN MODERATE MIDDLE TO LOWER LEVEL MOISTURE THAT
ENHANCES ISOLATED SHOWERS FROM 5N-14N E OF 24W.

A TROPICAL WAVE IS ABOUT 450 NM EAST OF THE LESSER ANTILLES WITH
AXIS EXTENDING FROM 17N51W TO 7N54W...MOVING W AT 15 KT. SSMI
TPW AND WATER VAPOR IMAGERY INDICATE THE WAVE IS EMBEDDED IN
HIGH DEEP LAYER MOISTURE THAT ALONG A DIFFLUENT ENVIRONMENT
ALOFT SUSTAIN SCATTERED MODERATE CONVECTION FROM 13N-18N BETWEEN
49W-56W.

A THIRD TROPICAL WAVE IS JUST MOVING ACROSS THE LESSER ANTILLES
WITH AXIS EXTENDING FROM 17N61W TO 10N62W...DRIFTING W AT 10 KT.
SSMI TPW AND WATER VAPOR IMAGERY INDICATE THE WAVE IS ENTERING A
ZONE OF DEEP LAYER DRY AIR THAT IS KEEPING CONVECTION MINIMAL.
ISOLATED SHOWERS ARE FROM 7N-17N WITHIN 300 NM EAST OF THE WAVE
AXIS.

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

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 11N15W AND CONTINUES TO 9N19W. THE ITCZ BEGINS NEAR
9N19W AND CONTINUES ALONG 7N34W TO 8N51W. BESIDES THE CONVECTION
MENTIONED IN THE TROPICAL WAVES SECTION...SCATTERED MODERATE
CONVECTION IS FROM 5N-8N BETWEEN 29W-52W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD MIDDLE TO UPPER LEVEL RIDGE OVER THE BASIN EXTENDS AN
AXIS NORTHWARD ACROSS THE EASTERN CONUS...THUS SUPPORTING
SURFACE RIDGING IN THE GULF BEING ANCHORED BY A 1017 MB HIGH S
OF PENSACOLA NEAR 29N86W. DEEP LAYER DRY AIR IS ACROSS THE
ENTIRE BASIN...WHICH SUSTAINS CLEAR SKIES AND FAIR WEATHER.
WINDS ARE VARIABLE IN THE RANGE OF 5-10 KT. SURFACE RIDGING WILL
DOMINATE OVER THE GULF THROUGH WED NIGHT.

CARIBBEAN SEA...

AN UPPER LEVEL TROUGH IS OVER THE WESTERN ATLC WITH A BASE
EXTENDING TO THE WINDWARD PASSAGE. SOUTH OF THE TROUGH...A BROAD
RIDGE IS ANCHORED OVER EASTERN HONDURAS AND COVERS THE WESTERN
AND CENTRAL CARIBBEAN SEA. THIS WIND PATTERN ALOFT SUPPORTS A
COLD FRONT ANALYZED OVER THE SW N ATLC AND ACROSS
HISPANIOLA...WHICH THEN TRANSITIONS INTO A STATIONARY FRONT NEAR
17N77W TO 17N81W TO A 1008 MB LOW NEAR 15N83W. SEE THE SPECIAL
FEATURE SECTION REGARDING THE LOW. LOW LEVEL MOISTURE
CONVERGENCE ALONG THE FRONT AS WELL AS A DIFFLUENT ENVIRONMENT
AT THE UPPER LEVELS SUPPORT ISOLATED SHOWERS AND TSTMS WITHIN
120 NM EITHER SIDE OF THE FRONTAL BOUNDARY.  IN THE SW
BASIN...THE MONSOON TROUGH ENHANCES SCATTERED SHOWERS AND TSTMS
S OF 13N BETWEEN 73W-82W. A TROPICAL WAVE MOVED ACROSS THE
LESSER ANTILLES EARLY THIS MORNING...HOWEVER A DEEP LAYER DRY
AIR ENVIRONMENT OVER THE EASTERN BASIN MAINTAINS THE WAVE DEVOID
OF DEEP CONVECTION. SEE TROPICAL WAVES SECTIONS ABOVE.
OTHERWISE...THE STATIONARY PORTION OF THE FRONT IS FORECAST TO
DISSIPATE OVER THE NW BASIN TONIGHT WHILE A SECOND TROPICAL WAVE
ENTERS THE BASIN.

HISPANIOLA...

A COLD FRONT CONTINUES TO MOVE ACROSS THE ISLAND THIS MORNING
...THUS SUPPORTING ISOLATED SHOWERS AND TSTMS OVER THE DOMINICAN
REPUBLIC AND NORTHERN COASTAL WATERS. PRECIPITATION  ACTIVITY IS
EXPECTED THROUGH MONDAY NIGHT.

ATLANTIC OCEAN...

AN UPPER LEVEL TROUGH IS OVER THE WESTERN ATLC WITH A BASE
EXTENDING TO THE WINDWARD PASSAGE. THROUGHINESS ALOFT SUPPORT A
COLD FRONT ANALYZED FROM 30N60W SW TO 22N66W TO NORTHERN
HISPANIOLA NEAR 19N70W THEN INTO NW CARIBBEAN SEA WATERS.
SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE WITHIN 160
NM EITHER SIDE OF THE FRONT. SURFACE HIGH PRESSURE DOMINATES
ELSEWHERE IN THE ATLC N OF 18N BEING ANCHORED BY A 1021 MB HIGH
NEAR 30N36W...WHICH IS EXPECTED STALL THROUGH MONDAY NIGHT.
OTHERWISE...SEE THE TROPICAL WAVES SECTION.

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

$$
NR


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