[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED OCT 29 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1615 UTC.

...SPECIAL FEATURES...

AN AREA OF LOW PRESSURE OF 1010 MB IS NE OF THE LEEWARD ISLANDS
NEAR 20N61W. A SURFACE TROUGH EXTENDS FROM 22N60W IN THE CENTRAL
ATLANTIC THROUGH THE LOW TO NEAR 15N64 IN THE E CARIBBEAN. AN
UPPER TROUGH TO THE WEST OF THIS LOW OVER PUERTO RICO AND
HISPANIOLA IS PRODUCING DIFFLUENCE OVER THE SURFACE TROUGH AND
LOW. THE COMBINATION OF THESE FEATURES WITH A VERY MOIST
ENVIRONMENT IS SUPPORTING CLUSTERS OF MODERATE AND ISOLATED
STRONG CONVECTION FROM 17N TO 23N BETWEEN 56W AND 62W. SCATTERED
MODERATE CONVECTION IS WITHIN 60 NM OF THE SURFACE TROUGH TO THE
SW OF THE LOW...INCLUDING PORTIONS OF THE LEEWARD ISLANDS.
ALTHOUGH UPPER LEVEL WINDS ARE NOT VERY CONDUCIVE FOR
DEVELOPMENT...SOME DEVELOPMENT IS POSSIBLE OVER THE NEXT DAY OR
TWO AS IT MOVES WEST-NORTHWESTWARD TO NORTHWESTWARD AT AROUND 10
KT. TROPICAL   CYCLONE FORMATION CHANCES THROUGH 48 HOURS REMAIN
MEDIUM. SEE   LATEST NHC TROPICAL WEATHER OUTLOOK UNDER
AWIPS/WMO HEADERS   MIATWOAT/ABNT20 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS MOVING ACROSS THE EASTERN CARIBBEAN WITH AXIS
EXTENDING FROM 17N67W TO 11N69W...MOVING W AT 15-20 KT. THE WAVE
IS EMBEDDED IN A SHALLOW MODERATE MOIST ENVIRONMENT. DRY AIR AND
SUBSIDENCE FROM ALOFT IN THIS REGION OF THE BASIN LIMITS THE
CONVECTION TO ISOLATED SHOWERS WITHIN 100 NM OF EITHER SIDE 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 8N20W TO 7N26W. THE ITCZ
BEGINS NEAR 7N26W AND CONTINUES ALONG 7N41W TO 7N58W. NUMEROUS
MODERATE AND ISOLATED STRONG CONVECTION ARE FROM 5N TO 10N
BETWEEN 15W AND 25W. SCATTERED SHOWERS ARE WITHIN 100 NM OF A
SURFACE TROUGH EXTENDING N OF THE ITCZ FROM 12N32W TO 8N35W.
SCATTERED MODERATE CONVECTION IS FROM 4N TO 12N BETWEEN 39W AND
54W. A SURFACE TROUGH IS EMBEDDED IN THE MIDDLE OF THIS AREA OF
CONVECTION FROM 12N46W TO 5N47W.

...DISCUSSION...

GULF OF MEXICO...

A BROAD UPPER TROUGH OVER THE CENTRAL CONUS AND NW GULF IS
SUPPORTING A COLD FRONT NEARING THE NW GULF COAST ACROSS TEXAS
AND LOUISIANA. DUE TO DRY AIR IN THE LOW TO MID LEVELS...THERE
IS NO CONVECTION ASSOCIATED WITH THE COLD FRONT AT THIS TIME. A
SURFACE TROUGH AXIS EXTENDS FROM THE FL PANHANDLE NEAR 31N86W TO
26N86W. SCATTERED THUNDERSTORMS ARE OCCURRING WITHIN 50 NM OF
THE TROUGH AXIS. MOIST AIR FROM FORMER TROPICAL CYCLONE HANNA IS
STREAMING INTO THE SW GULF AND BAY OF CAMPECHE. THIS MOISTURE
IS SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM
19N TO 22N BETWEEN 92W AND 94W. DRY AIR SUPPORTS FAIR WEATHER
ACROSS THE REMAINDER OF THE BASIN. WEAK STEERING FLOW IS
PRODUCING SE TO NE WINDS MAINLY BETWEEN 5 TO 10 KT ACROSS THE
BASIN. OVER THE NEXT 24 HOURS A COLD FRONT WILL ENTER THE
NORTHERN BASIN WITH ISOLATED SHOWERS AND THUNDERSTORMS POSSIBLE.
THE COLD FRONT WILL CONTINUE SE ACROSS FL AND THE EASTERN AND
CENTRAL GULF ON THURSDAY. MOISTURE FROM THE REMNANTS OF HANNA
WILL SUPPORT SHOWERS AND THUNDERSTORMS IN THE SW GULF AND BAY OF
CAMPECHE THROUGH THURSDAY.

CARIBBEAN SEA...

THE REMNANTS OF HANNA ARE CENTERED OVER CENTRAL AMERICA WITH
PART OF THE CIRCULATION ANALYZED AS A SURFACE TROUGH WITH AXIS
FROM 22N87W TO 15N89W. SCATTERED MODERATE CONVECTION IS FROM 17N
TO 21N BETWEEN 81W AND 88W. A CLUSTER OF MODERATE CONVECTION IS
ACROSS THE SW CARIBBEAN S OF 11N BETWEEN 76W AND 81W. THIS
CONVECTION IS ASSOCIATED WITH THE MONSOON TROUGH. MUCH OF THE
CENTRAL BASIN HAS FAIR WEATHER DUE TO DRY AIR IN THE MID TO
UPPER LEVELS AND SUBSIDENCE. A TROPICAL WAVE IS IN THE EASTERN
CARIBBEAN. SEE THE TROPICAL WAVES SECTION. A SURFACE TROUGH WITH
CONVECTION IS IN THE E CARIBBEAN AND ACROSS THE LEEWARD ISLANDS.
SEE THE SPECIAL FEATURES SECTION. OVER THE NEXT 24 HOURS THE
TROPICAL WAVE WILL CROSS THE CENTRAL CARIBBEAN WITH LITTLE TO NO
CONVECTION. REMNANTS OF HANNA WILL CONTINUE TO PRODUCE
CONVECTION IN THE NW CARIBBEAN. CONVECTION ASSOCIATED WITH THE
SURFACE TROUGH IN THE E CARIBBEAN WILL MOVE NW AND AFFECT THE
VIRGIN ISLANDS AND PUERTO RICO.

HISPANIOLA...

A SURFACE TROUGH EXTENDING NE FROM THE COAST OF HAITI IS
PRODUCING CONVERGENT FLOW ACROSS THE NE PORTIONS OF THE ISLAND.
THIS WILL SUPPORT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
ACROSS HAITI THIS AFTERNOON. ADDITIONAL SHOWERS AND
THUNDERSTORMS CAN BE EXPECTED THURSDAY AND FRIDAY AS A
DISTURBANCE MOVES W TO NW JUST NORTH OF PUERTO RICO.

ATLANTIC OCEAN...

A BROAD AREA OF LOW PRESSURE AND ACCOMPANYING SURFACE TROUGH IS
ACROSS AND NE OF THE LEEWARD ISLANDS. SEE THE SPECIAL FEATURES
SECTION. A MID TO UPPER LEVEL TROUGH OVER THE CENTRAL ATLANTIC
CONTINUES TO SUPPORT A COLD FRONT FROM 31N42W TO 27N52W WHERE IT
TRANSITIONS TO A STATIONARY FRONT ALONG 27N60W TO 25N71W.
ISOLATED SHOWERS ARE WITHIN 60 NM OF WITHER SIDE OF THE FRONTAL
BOUNDARY. A SURFACE TROUGH EXTENDS FROM 25N69W TO THE N COAST OF
HAITI NEAR 20N72W. ISOLATED SHOWERS ARE WITHIN 90 NM W OF THIS
TROUGH. A 1017 MB SURFACE HIGH PRESSURE IS CENTERED NEAR 28N34W.
THIS HIGH IS SUPPORTING FAIR WEATHER ACROSS THE CENTRAL AND
EASTERN ATLANTIC E OF THE SPECIAL FEATURE AND COLD FRONT. A
WEAKENING SURFACE LOW IS NEAR 26N20W WITH NO NOTABLE CONVECTION.
OVER THE NEXT 24 HOURS THE STATIONARY FRONT WILL DISSIPATE WHILE
THE SPECIAL FEATURE MOVES W TO NW WITH CONVECTION.

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

$$
LATTO


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