[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 182326
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE 18 JAN 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 4N1W 5N35W 1N50W 2N80W.  WIDELY
SCATTERED MODERATE CONVECTION IS FROM 4N-7N BETWEEN
23W-28W...AND FROM 2N-7N BETWEEN 32W-38W.

...DISCUSSION...

GULF OF MEXICO...
A STRONG 1044 MB HIGH IS OVER THE OHIO VALLEY NEAR 39N81W
PRODUCING NE/E WINDS OVER THE GULF OF MEXICO.  TEMPERATURES HAVE
MODERATED NICELY OVER THE WARMER WATERS OF THE W GULF NOW THAT
THE STRONGEST COLD ADVECTION EXTENDS FROM THE CAROLINAS SWD TO
FLORIDA AND THE E GULF...SUPPORTING BROKEN STRATOCUMULUS CLOUDS
BEYOND 200 NM SW OF THE FLORIDA COAST. THE E SLOPES OF THE
SIERRA MADRE IN MEXICO REMAIN OVERCAST WITH LOW CLOUDS AND
SHOWERS BUT THIS ACTIVITY ALSO EXTENDS 200 NM E OF THE
COAST ADJACENT TO A LOW-LEVEL COASTAL TROUGH ALONG 26N98W
18N94W.  THE UPPER LEVEL PATTERN IS DOMINATED BY A BROAD RIDGE
WITH A 110-130W KT SUBTROPICAL JET RIDING FROM E TEXAS TO
CENTRAL FLORIDA.  UPPER LEVEL MOISTURE IS MOVING IN WITH THE JET
N OF 24N.  STRONG SUBSIDENCE IS S OF 24N.

CARIBBEAN...
A STATIONARY FRONT EXTENDS FROM HISPANIOLA TO PANAMA ALONG
19N70W 9N80W.  STRONG HIGH PRESSURE CONTINUES TO BUILD IN BEHIND
THE FRONT.  BROKEN STRATUS/STRATOCUMULUS CLOUDS WITH EMBEDDED
SHOWERS EXTEND OVER THE ENTIRE W CARIBBEAN BEHIND THE FRONT AND
IS BANKING UP AGAINST THE CENTRAL AMERICAN MOUNTAINS ESPECIALLY
OVER HONDURAS. E OF THE FRONT...SKIES ARE MUCH CLEARER BUT A FEW
SHOWERS ARE AFFECTING THE WINDWARD/LEEWARD ISLANDS ALONG A SFC
TROUGH WHICH EXTENDS ALONG 23N63W 8N60W. THIS FEATURE IS
WELL-OBSERVED IN SURFACE OBSERVATIONS AND SATELLITE IMAGERY...
MOVING W/NW TOWARDS THE APPROACHING COLD FRONT. THE UPPER LEVELS
CONTINUE TO BE OVERWHELMINGLY DRY DUE TO CONFLUENT WESTERLY FLOW
EXTENDING FROM THE CAYMAN ISLANDS TO THE NORTHERN LEEWARD
ISLANDS.

WEST ATLANTIC...
1007 MB LOW IS OVER THE W ATLANTIC NEAR 39N56W.  A COLD FRONT
EXTENDS S FROM 31N57W TO 23N66W TO HISPANIOLA NEAR 19N70W.
SCATTERED MODERATE CONVECTION EXTENDS SE OF THE FRONT N OF 24N
BETWEEN 56W-62W.  A BROKEN/OVERCAST BAND OF LOW CLOUDS AND
EMBEDDED SHOWERS EXTENDS UP TO 120 NM W OF THE FRONT.  BROKEN
STRATOCUMULUS CLOUDS EXTENDS W TO THE U.S. COAST.  THE FRONT IS
BEING SUPPORTED BY A FLAT UPPER TROUGH WHICH IS MOVING OFF THE
NEW ENGLAND/MID-ATLC COAST...AND ALL THE DEEP CONVECTION IS
ORIENTED WITHIN A ZONE OF DIFFLUENCE E OF A SHORTWAVE ALONG 61W.

CENTRAL AND EAST ATLANTIC...
THE UPPER LEVEL PATTERN OVER THE SUBTROPICAL E ATLC IS DOMINATED
BY A LARGE AND ELONGATED CYCLONIC CIRCULATION CENTERED NEAR
27N30W AND ALIGNED ALONG AN AXIS FROM MADEIRA ISLAND SW TO
24N43W. THE 1008 MB SFC LOW IS CENTERED ABOUT 580 NM WSW OF THE
CANARY ISLANDS NEAR 27N29W WITH A TROUGH ALONG 25N27W 22N35W.
SCATTERED MODERATE CONVECTION IS LOCATED N OF THE LOW FROM
26N-30N BETWEEN 25W-35W. FARTHER S...AN ACTIVE SUBTROPICAL JET
EXTENDS ACROSS THE TROPICAL ATLC FROM 16N50W TO THE CAPE VERDE
ISLANDS AND NE TO MOROCCO WITH CORE SPEEDS NEAR 110 KT AT 250
MB. THE JET IS ADVECTING A LARGE SWATH OF MOISTURE FROM THE ITCZ
NEWD TO W AFRICA...AND IS EXPANDING N/NW AS A STRONG RIDGE
BUILDS ALONG 7W. MOISTURE WILL CONTINUE FEEDING UP TO THE NE
THROUGH THE REST OF THE WEEK UNTIL THE DEEP-LAYERED LOW
DISSOLVES AND THE RIDGE BREAKS DOWN.

$$
FORMOSA


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