[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191109
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI DEC 19 2008

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...THE ITCZ...
ITCZ IS CENTERED ALONG 9N13W 6N22W 4N34W 4N43W 2N53W. SCATTERED
MODERATE CONVECTION IS FROM 2N-7N BETWEEN 15W-21W. NUMEROUS
MODERATE/SCATTERED STRONG CONVECTION IS FROM 1N-8N BETWEEN
22W-38W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM
5N-11N BETWEEN 39W-45W. SCATTERED MODERATE CONVECTION IS FROM
7N-10N BETWEEN 53W-58W...WHICH IS BEING ENHANCED BY UPPER LEVEL
DIVERGENCE.

...DISCUSSION...

GULF OF MEXICO...
A 1026 MB SURFACE HIGH IS E OF THE FLORIDA PENINSULA NEAR
29N80W...WITH THE ANTICYCLONIC FLOW AROUND THIS HIGH RESULTING
IN SE TO S SURFACE WINDS OF 10 TO 20 KT ACROSS MUCH OF THE GULF
REGION. SUBSIDENCE ASSOCIATED WITH THIS HIGH IS RESULTING IN
ATMOSPHERIC STABILITY AND FAIR WEATHER CONDITIONS ACROSS MUCH OF
THE GULF REGION. THIS STABILITY IS BEING ENHANCED BY THE
PRESENCE OF AN UPPER HIGH OVER THE E GULF CENTERED NEAR
25N84W...WITH RELATIVELY LIGHT AND BROAD ANTICYCLONIC FLOW
ALOFT...AND DEEP LAYER DRY AIR...ACROSS MUCH OF THE GULF REGION.

CARIBBEAN SEA...
CONFLUENCE IN WESTERLY FLOW ALOFT IS GENERATING SUBSIDENCE AND
ATMOSPHERIC STABILITY ACROSS THE CARIBBEAN REGION...WHERE
GENERALLY DEEP LAYER DRY AIR IS PRESENT. THESE FACTORS ARE
RESULTING IN FAIR WEATHER CONDITIONS ACROSS MUCH THE CARIBBEAN
REGION. THE SOUTHERN PERIPHERY OF THE ANTICYCLONIC FLOW AROUND
THE AFOREMENTIONED 1026 MB SURFACE HIGH E OF THE FLORIDA
PENINSULA NEAR 29N80W IS BRINGING NE TO E SURFACE WINDS OF 15 TO
25 KT TO THE CARIBBEAN REGION. UPPER LEVEL MOISTURE IS STREAMING
NORTHWARD FROM SOUTH AMERICA INTO THE SW CARIBBEAN...WITH
ISOLATED SHOWERS ACROSS THE SW CARIBBEAN S OF 15N W OF 79W...
INCLUDING PORTIONS OF PANAMA...COSTA RICA...NICARAGUA...AND
N COLOMBIA.

ATLANTIC OCEAN...
ACROSS THE W ATLC...A 1026 MB SURFACE HIGH IS CENTERED E OF THE
FLORIDA PENINSULA NEAR 29N80W...WHICH IS BRINGING SUBSIDENCE AND
FAIR WEATHER CONDITIONS TO MUCH OF THE W ATLC. NORTHERLY UPPER
LEVEL FLOW TO THE E OF THE UPPER HIGH OVER THE E GULF OF MEXICO
IS ADVECTING UPPER LEVEL MOISTURE ACROSS THE W ATLC. FARTHER TO
THE E...A SURFACE TROUGH OVER THE CENTRAL ATLC EXTENDS FROM
28N58W TO A 1013 MB SURFACE LOW NEAR 24N61W TO 22N63W. LOW LEVEL
CONVERGENCE IS RESULTING IN ISOLATED SHOWERS WITHIN 60 NM EITHER
SIDE OF THIS SURFACE TROUGH. THIS ACTIVITY IS BEING ENHANCED BY
INSTABILITY IN THE VICINITY OF AN UPPER TROUGH WITH AN AXIS
EXTENDING FROM 19N67W TO 26N54W TO 32N49W TO N OF THE DISCUSSION
AREA. ALSO...UPPER LEVEL DIVERGENCE ASSOCIATED WITH A 95-105-KT
UPPER LEVEL JET MAXIMUM E OF THIS UPPER TROUGH AXIS IS
SUPPORTING SCATTERED SHOWERS FROM 25N-29N BETWEEN 45W-51W AND
FROM 12N-19N BETWEEN 47W-52W. ACROSS THE E ATLC...SUBSIDENCE
ASSOCIATED WITH A SURFACE RIDGE EXTENDING SOUTHWESTWARD FROM A
1033 MB SURFACE HIGH NEAR 42N18W IS GENERALLY INHIBITING DEEP
CONVECTION N OF 14N E OF 33W. HOWEVER...ATMOSPHERIC INSTABILITY
ASSOCIATED WITH AN UPPER LOW NEAR 31N19W IS RESULTING IN
SCATTERED SHOWERS N OF 28N BETWEEN 15W-23W. FARTHER TO THE S...A
SURFACE TROUGH EXTENDS FROM 21N56W TO 16N56W TO 12N56W...WITH
CYCLONIC CURVATURE NOTED IN THE LOW LEVEL WIND FIELD IN THE
VICINITY OF THIS SURFACE TROUGH BASED ON A RECENT ASCAT PASS.
LOW LEVEL CONVERGENCE IS RESULTING IN SCATTERED SHOWERS WITHIN
60 NM EITHER SIDE OF THIS SURFACE TROUGH. ACROSS THE TROPICAL
ATLC...AN UPPER RIDGE IS S OF 13N BETWEEN 16W-58W. UPPER LEVEL
DIVERGENCE ASSOCIATED WITH THIS UPPER RIDGE IS ENHANCING THE
CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN




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