[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 061709
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI MAR 06 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 1200 UTC SURFACE ANALYSIS...AND SATELLITE IMAGERY
THROUGH 1645 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N8W 3N17W CROSSING THE EQUATOR
NEAR 26W EXTENDING TO 2S34W INTO NE BRAZIL NEAR 3S45W. SCATTERED
MODERATE CONVECTION IS FROM 3N-7N BETWEEN 9W-17W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE IS PRESENT ACROSS MUCH OF THE GULF
REGION...WHERE STABLE ATMOSPHERIC CONDITIONS...DEEP LAYER DRY
AIR...AND SUBSIDENCE ARE PRESENT. AS A RESULT...GENERALLY FAIR
WEATHER CONDITIONS PERSIST ACROSS THE GULF REGION. THE
SUBSIDENCE IS BEING SUPPORTED BY A SURFACE RIDGE THAT EXTENDS
SOUTHWESTWARD FROM A SURFACE HIGH IN THE W ATLC NEAR 35N69W. THE
FLOW AROUND THIS SURFACE RIDGE IS RESULTING IN E TO SE SURFACE
WINDS ACROSS MUCH OF THE GULF.

CARIBBEAN SEA...
SUBSIDENCE RESULTING FROM CONFLUENCE IN WESTERLY FLOW ALOFT IS
LIMITING DEEP CONVECTION ACROSS MUCH OF THE CARIBBEAN...WHERE
GENERALLY FAIR WEATHER CONDITIONS ARE OCCURRING. DEEP LAYER DRY
AIR IS PRESENT ACROSS MUCH OF THE W AND CENTRAL CARIBBEAN...
WHILE UPPER LEVEL MOISTURE IS BEING DRAWN NORTHEASTWARD ACROSS
THE E CARIBBEAN. ALSO...A DEEP LAYER TROUGH OVER THE W ATLC IS
ASSOCIATED WITH A DISSIPATING SURFACE STATIONARY FRONT IN THE
NE CARIBBEAN THAT EXTENDS FROM 17N66W TO E OF PUERTO RICO NEAR
18N65W INTO THE SW NORTH ATLC. LOW LEVEL CONVERGENCE IS
SUPPORTING SCATTERED SHOWERS ALONG AND WITHIN 60 NM EITHER SIDE
OF THIS FRONT. ADDITIONALLY...PATCHES OF LOW LEVEL MOISTURE ARE
BEING ADVECTED SOUTHWESTWARD ACROSS THE CARIBBEAN...WITH
SCATTERED SHOWERS EMBEDDED WITHIN THESE PATCHES OF LOW LEVEL
MOISTURE. THE GREATEST CONCENTRATION OF THESE SHOWERS IS FROM
15N-18N BETWEEN 73W-79W. ALSO...A GALE WARNING IS IN EFFECT FOR
LOCATIONS WITHIN 90 NM OF THE COLOMBIAN COAST WITH THE INCREASED
SURFACE WINDS RESULTING FROM THE INCREASED SURFACE PRESSURE
GRADIENT ACROSS THE CARIBBEAN.

ATLANTIC OCEAN...
THE AFOREMENTIONED DEEP LAYER TROUGH OVER THE W ATLC IS
ASSOCIATED WITH A SURFACE FRONT THAT EXTENDS FROM THE NE
CARIBBEAN TO E OF PUERTO RICO NEAR 18N65W TO A 1014 MB SURFACE
LOW NEAR 28N54W TO 32N50W TO NE OF THE DISCUSSION AREA. THIS
SURFACE FRONT IS A DISSIPATING SURFACE STATIONARY FRONT S OF
21N...A SURFACE COLD FRONT FROM 21N TO THE SURFACE LOW...AND A
SURFACE STATIONARY FRONT N OF THE SURFACE LOW. THIS SURFACE LOW
IS ASSOCIATED WITH GALE FORCE WINDS. THE DEEP LAYER TROUGH IS
ALSO ASSOCIATED WITH A SURFACE TROUGH THAT EXTENDS FROM 15N54W
TO 24N52W TO 31N49W. LOW LEVEL CONVERGENCE IS SUPPORTING
SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE FRONT S OF
22N...AND NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 90
NM EITHER SIDE OF THE FRONT ALONG AND N OF 22N. ALSO...LOW LEVEL
CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 90 NM EITHER
SIDE OF THE SURFACE TROUGH. THIS ACTIVITY IS BEING SUPPORTED BY
UPPER LEVEL DIVERGENCE ASSOCIATED WITH TWO UPPER LEVEL JET
MAXIMA IN THE VICINITY OF THE SURFACE LOW. THE SURFACE LOW IS
FORECAST TO MOVE NORTHEASTWARD DURING THE NEXT DAY AND BE
LOCATED NEAR 30N51W AT 07/1200 UTC AS A 1010 MB SURFACE LOW. TO
THE W OF THE FRONT...A RELATIVELY COOLER AND DRIER AIRMASS IS
PRESENT...WHERE SUBSIDENCE AND ATMOSPHERIC STABILITY ARE
SUPPORTING GENERALLY FAIR WEATHER CONDITIONS. THIS SUBSIDENCE IS
BEING SUPPORTED BY A SURFACE RIDGE THAT EXTENDS SOUTHWESTWARD
FROM A 1034 MB SURFACE HIGH OVER THE W ATLC NEAR 35N69W. THIS
SURFACE HIGH IS FORECAST TO MOVE SOUTHWARD DURING THE NEXT DAY
AND BE LOCATED NEAR 32N70W AS A 1030 MB SURFACE HIGH AT
07/1200 UTC. ACROSS THE E ATLC...AN UPPER LOW IS LOCATED NEAR
24N29W. ATMOSPHERIC INSTABILITY ASSOCIATED WITH THIS UPPER LOW
IS SUPPORTING SCATTERED SHOWERS FROM 27N-30N BETWEEN 21W-29W.
HOWEVER...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE IS
INHIBITING DEEP CONVECTION ACROSS MUCH OF THE E ATLC. ACROSS THE
TROPICAL ATLC...AN UPPER RIDGE IS S OF 8N E OF 54W WITH AN UPPER
HIGH NEAR 3N33W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THIS
UPPER HIGH AND UPPER RIDGE IS ENHANCING THE CONVECTION
ASSOCIATED WITH THE ITCZ.

$$
COHEN




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