[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180505
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SUN JAN 18 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0430 UTC.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 6N10W 1N20W ALONG THE EQUATOR
FROM 22W-42W AND INTO NE BRAZIL NEAR 1S46W. SCATTERED MODERATE
CONVECTION IS WITHIN 150 NM ON EITHER SIDE OF THE AXIS BETWEEN
19W-29W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
3S-2N BETWEEN 32W-39W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE RIDGE EXTENDS FROM A 1029 MB HIGH CENTERED OVER
GEORGIA SW ACROSS THE FLORIDA BIG BEND TO THE BAY OF CAMPECHE.
E TO SE WINDS 10-15 KT IN THE SW GULF WILL SHIFT SOUTHERLY AND
DIMINISH AS THE RIDGE WEAKENS AND DRIFTS SOUTHEAST. N OF
25N...SOUTHERLY RETURN FLOW TO 15 KT IS EXPECTED TO SHIFT SW AND
INCREASE TO 15-20 KT AS A COLD FRONT APPROACHES FROM THE NORTH.
THIS FRONT IS EXPECTED TO ENTER THE NW GULF LATER TODAY.
ISOLATED SHOWERS ARE OBSERVED ON DOPPLER RADAR IN THE FLORIDA
STRAIGHTS. ELSEWHERE...MODERATE TO STRONG SUBSIDENCE ALOFT IS
PREVENTING THE FORMATION OF SIGNIFICANT CONVECTION.

CARIBBEAN SEA...
PATCHY CLOUDS AND ISOLATED SHOWERS...ASSOCIATED WITH A FORMER
FRONTAL BOUNDARY...REMAIN IN THE NW CARIBBEAN. NE WINDS 20-25 KT
IN THE REGION ARE EXPECTED TO WEAKEN TO NE-E 15-20 KT. BROAD
CIRCULATION IS EVIDENT ON SATELLITE IMAGERY SURROUNDING A SFC
TROUGH IN THE E CARIBBEAN. THIS TROUGH ENTERS THE REGION FROM
THE W ATLC THROUGH THE MONA PASSAGE AND EXTENDS TO CURACAO IN
THE NETHERLANDS ANTILLES. SCATTERED SHOWERS MOVING OVER THE MONA
PASSAGE...PUERTO RICO AND ERN HISPANIOLA ARE OBSERVED ON SAN
JUAN DOPPLER RADAR. ADDITIONAL SHOWERS ARE W OF THE TROUGH AXIS
N OF 13N AND E OF 75W. THIS TROUGH IS EXPECTED TO MOVE WESTWARD
AND BECOME DIFFUSE NEAR 76W ON MON. MODERATE TRADE WINDS PERSIST
ACROSS THE CARIBBEAN W OF THE TROUGH. ALOFT...AN UPPER LEVEL
TROUGH IS ACROSS THE NW CARIBBEAN WHILE AN UPPER LEVEL RIDGE IS
ACROSS THE CENTRAL AND ERN CARIBBEAN WITH STRONG SUBSIDENCE AND
DRY AIR OBSERVED E OF 71W.

ATLANTIC OCEAN...
SFC HIGH PRESSURE OVER SOUTHEAST GEORGIA IS MAINTAINING FAIR
CONDITIONS ACROSS THE W ATLC...HOWEVER...A COLD FRONT IS
EXPECTED TO MOVE OFF THE SE US COAST LATE TONIGHT AS THE HIGH
WEAKENS AND SHIFTS TO THE SOUTHEAST. SCATTERED SHOWERS EXTEND 60
NM AHEAD OF A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR
31N57W AND EXTENDS TO 26N63W WHERE IT WEAKENS AND CONTINUES AS A
SFC TROUGH TO THE WINDWARD PASSAGE. FARTHER SOUTH...ANOTHER SFC
TROUGH EXTENDS FROM 21N67W THROUGH THE MONA PASSAGE AND INTO THE
E CARIBBEAN. SCATTERED SHOWERS ASSOCIATED WITH THE TROUGH ARE S
OF 22N BETWEEN 65W-70W. A STRONG SURFACE RIDGE ANCHORED ON A
1036 MB HIGH NEAR 32N33W COVERS THE REMAINDER OF THE ATLC.
ALOFT...A DIFFLUENT PATTERN IN THE TROPICS IS ENHANCING
CONVECTION ALONG THE ITCZ.

$$
WADDINGTON



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