[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181049
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN OCT 18 2015

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
0900 UTC.

...SPECIAL FEATURES...
THE COMBINATION OF STRONG HIGH PRESSURE ACROSS EASTERN MEXICO...
LOW PRESSURE ACROSS CENTRAL AMERICA AND SOUTHERN MEXICO...AND A
SURFACE TROUGH ANALYZED ACROSS THE SW GULF OF MEXICO WATERS IS
SUPPORTING NEAR GALE TO GALE FORCE NW WINDS ALONG THE COAST OF
VERACRUZ...MAINLY S OF 21N W OF 95W. SEE LATEST NWS HIGH SEAS
FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 FOR MORE
DETAILS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR
12N16W TO 11N20W TO LOW PRES 1011 MB NEAR 12N29W TO LOW PRES
1012 MB NEAR 10N37W TO 08N45W. THE ITCZ CONTINUES FROM 08N45W TO
05N53W. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 120 NM N
OF MONSOON TROUGH AXIS BETWEEN 26W AND 29W...AND WITHIN 120 NM N
OF ITCZ BETWEEN 45W AND 48W.

...DISCUSSION...

GULF OF MEXICO...
THE MAIN ENERGY ASSOCIATED WITH A BROAD LONG WAVE TROUGH OVER
THE EASTERN UNITED STATES IS MOVING OFF THE MID ATLANTIC COAST
THIS MORNING...SUPPORTING THE MOVEMENT OF A COLD FRONT THROUGH
THE NORTHERN GULF OF MEXICO. UPPER FLOW IS TURNING MORE ZONAL
ACROSS THE WESTERN GULF...AND SURFACE ARE VEERING EASTERLY
ALLOWING THE FRONT TO SLOW THE S TEXAS COAST. FARTHER SOUTH...A
STATIONARY FRONT PERSISTS OVER THE SE AND S CENTRAL GULF BETWEEN
MORE MOIST TROPICAL AIRMASS TO THE SOUTH...AND SLIGHTLY DRIER
AIRMASS FROM SOUTH FLORIDA TO THE CENTRAL GULF. THE COLD FRONT
WILL EVENTUALLY MERGE WITH THE STATIONARY FRONT LATE
TODAY...WITH NORTHERLY FLOW FUNNELING ALONG THE MEXICAN COAST
AND OVER THE FAR WESTERN GULF AS WELL. 1009 MB LOW PRES IS
ANALYZED ALONG THE COAST IN THE BAY OF CAMPECHE NEAR CIUDAD DEL
CARMEN AND WILL DRIFT NW TODAY...SUPPORTING GALE FORCE WINDS
ALONG THE COAST OF VERACRUZ. THE TIGHT GRADIENT WILL SUPPORT
FRESH TO STRONG NE TO E WINDS ACROSS THE GULF THROUGH EARLY NEXT
WEEK.

CARIBBEAN SEA...
A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION INFLUENCES MUCH OF
THE WESTERN CARIBBEAN AND CENTRAL AMERICA TONIGHT PROVIDING AN
OVERALL DIFFLUENT ENVIRONMENT ALOFT. AN AREA OF LOW PRESSURE
ACROSS CENTRAL AMERICA FOCUSES ON A 1008 MB LOW CENTERED NEAR
19N93W. THE LOW IS ASSOCIATED WITH A LARGE AND BROAD MONSOONAL
GYRE THAT COVERS A LARGE PORTION OF CENTRAL AMERICA AND A
PORTION OF THE EASTERN PACIFIC WATERS N OF 10N BETWEEN 90W-100W.
THE OVERALL CIRCULATION SUPPORTS PERIODIC SHOWERS AND
THUNDERSTORMS MAINLY OVER THE NW CARIBBEAN. AS THE AREA OF LOW
PRESSURE PERSISTS THROUGH THE REMAINDER OF THE WEEKEND...
CONTINUED PRECIPITATION IS EXPECTED ACROSS THE WESTERN CARIBBEAN
AND MORE IMPORTANTLY CENTRAL AMERICA RESULTING IN POSSIBLE FLASH
FLOODING POTENTIAL AND MUD SLIDES. ELSEWHERE ACROSS THE EASTERN
CARIBBEAN...DRIER AIR AND SUBSIDENCE ALOFT ASSOCIATED WITH AN
UPPER TROUGH OVER THE FAR EASTERN CARIBBEAN SUPPORTS GENERALLY
FAIR WEATHER CONDITIONS E OF 80W. MODERATE TO OCCASIONAL FRESH
TRADE WINDS PREVAIL ACROSS THE BASIN WITH LITTLE CHANGE EXPECTED
THROUGH MID WEEK.

...HISPANIOLA...
NW TO N WINDS ALOFT PERSIST ACROSS HISPANIOLA BETWEEN AN UPPER
ANTICYCLONE TO THE WEST AND A AN UPPER TROUGH TO THE EAST. WITH
RELATIVELY HIGH DEEP LAYER MOISTURE IN PLACE...THIS PATTERN
FAVORS LOW TOPPED AND FAST MOVING SHOWERS AND THUNDERSTORMS
FAVORING THE HIGHLAND PORTIONS OF WESTERN DOMINICAN REPUBLIC AND
EASTERN HAITI DURING THE AFTERNOON AND EVENING HOURS OVER THE
NEXT COUPLE OF DAYS.

ATLANTIC OCEAN...

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 16N54W TO 10N48W MOVING W AT 5-10 KT.
PATTERN ON THE NORTHERN END OF THE WAVE AXIS. THE WAVE COINCIDES
WITH A LOW-AMPLITUDE 700 MB TROUGH BETWEEN 47W-55W. IN
ADDITION...A NEARBY UPPER LEVEL LOW CENTERED NEAR 22N57W IS
INTERACTING WITH THE WAVE AND SHEARING THE CONVECTION TO THE
EAST OF THE WAVE AXIS. ISOLATED MODERATE CONVECTION IS FROM 09N
TO 17N BETWEEN 45W AND 53W.

A COLD FRONT IS MOVING SE ACROSS THE GULF STREAM WATERS OFF NE
FLORIDA THIS MORNING AS THE SUPPORTING MAIN MID/UPPER ENERGY
PUSHES OFF THE MID ATLANTIC COAST TO THE NORTH. FARTHER
SOUTH...A STATIONARY FRONT PERSISTS FROM BERMUDA TO THE NW
BAHAMAS. A FEW MODERATE SHOWERS AND THUNDERSTORMS PERSIST SOUTH
OF THE STATIONARY FRONT...MAINLY ACROSS THE SOUTHERN BAHAMAS.
THE COLD FRONT WILL EVENTUALLY MERGE WITH THE STATIONARY
BOUNDARY AND REACH FROM NEAR BERMUDA TO THE NW BAHAMAS AND SOUTH
FLORIDA BY LATE TODAY. STRONG HIGH PRES BUILDING OFF THE
CAROLINAS WILL ALLOW FRESH TO STRONG NE WINDS RESULTING IN VERY
ROUGH AND BUILDING SEAS W OF 65W. FARTHER EAST...AN UPPER LOW
REMAINS IN PLACE OVER 22N57W WITH AN ADJOINING UPPER TROUGH
EXTENDING ACROSS THE EASTERN CARIBBEAN TO N CENTRAL VENEZUELA.
SW FLOW ALOFT ASSOCIATED WITH THIS UPPER TROUGH IS SHEARING
CONVECTION ALONG THE SURFACE TROUGH EAST OF THE WINDWARD
ISLANDS. SCATTERED MODERATE CONVECTION IS ONGOING NEAR THE
CENTER OF THE UPPER LOW AS WELL...FROM 22N TO 25N BETWEEN 52W
AND 57W. A DRIER AIRMASS PREVAILS ACROSS THE SUBTROPICAL ATLC
WATERS EAST OF 45W...BEHIND AN EARLY SEASON COLD FRONT OVER THE
EASTERN ATLC THAT PENETRATED AS FAR SOUTH AS 16N BEFORE
EVENTUALLY DISSIPATING LATE YESTERDAY. A COLLECTION OF VERY WEAK
LOW PRES AREAS ARE PULSING ALONG A DISORGANIZED MONSOON TROUGH
OVER THE DEEP TROPICS OF THE EASTERN ATLC. A QUASI-STATIONARY
1011 MB LOW PRES WAS ANALYZED LOW PRES NEAR 12N29W...AND A 1012
MB LOW NEAR 10N37W. TRADE WINDS ARE EXPECTED TO INCREASE
SLIGHTLY OVER THE CENTRAL AND EASTERN ATLC THROUGH MID WEEK AS
HIGH PRES BUILDS N OF THE AREA.

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

$$
CHRISTENSEN
This weather bulletin was brought to you by:
www.nashvilleweather.net