[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211040
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN JUN 21 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE EXTENDS FROM 10N48W TO 2N51W MOVING W AROUND 12
KT. THIS WAVE COINCIDES WITH A RELATIVELY LOW AMPLITUDE MAXIMUM
IN DEEP LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER
PRODUCT FROM CIMSS. SATELLITE-DERIVED WINDS INDICATE CYCLONIC
CURVATURE IN THE LOW FLOW IN THE VICINITY OF THIS WAVE...WHICH
IS CONFIRMED BY THE CIMSS WAVETRAK PRODUCT. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-7N BETWEEN
50W-52W. SCATTERED MODERATE CONVECTION IS FROM 9N-11N BETWEEN
44W-48W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N13W 4N30W 8N48W AND INTO NE
BRAZIL NEAR 7N58W. SCATTERED MODERATE CONVECTION IS FROM 6N-9N
BETWEEN 35W-42W.

...DISCUSSION...

GULF OF MEXICO...
ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER LEVEL LOW
CENTERED OVER THE SOUTHERN BAY OF CAMPECHE NEAR 20N93W IS
SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE
S GULF S OF 22N BETWEEN 87W-95W. ACROSS THE N AND CENTRAL
GULF...DEEP LAYER DRY AIR IS SUPPORTING GENERALLY FAIR
WEATHER...WHERE EASTERLY FLOW ALOFT IS OCCURRING BETWEEN THE
AFOREMENTIONED UPPER LEVEL LOW OVER THE YUCATAN AND AN UPPER
LEVEL HIGH OVER ARKANSAS. THIS UPPER LEVEL HIGH IS REFLECTED AT
THE SURFACE WITH A 1014 MB HIGH CENTER OVER THE N GULF NEAR
27N89W. ANTICYCLONIC FLOW AROUND THE SURFACE HIGH IS AFFECTING
MUCH OF THE GULF...WITH SE WINDS OF 15 TO LOCALLY 20 KT
OCCURRING ACROSS PORTIONS OF THE W GULF IN RESPONSE TO A BROAD
SURFACE TROUGH OVER MEXICO AND THE SOUTHERN PLAINS OF THE UNITED
STATES. THE SURFACE HIGH IS FORECAST TO MOVE W ACROSS THE N GULF
THROUGH NEXT WEEK. A WEAK COLD FRONT WILL THEN MOVE SOUTHWARD
ACROSS PORTIONS OF THE E WATERS MONDAY AND DISSIPATE
TUESDAY...LEAVING BROAD LOW PRESSURE IN NE GULF THROUGH MID TO
LATE WEEK.

CARIBBEAN SEA...
AN UPPER LEVEL LOW HAS MOVED OFF THE YUCATAN PENINSULA INTO THE
BAY OF CAMPECHE AND IS CENTERED NEAR 20N93W. ATMOSPHERIC
INSTABILITY ASSOCIATED WITH THIS UPPER LEVEL LOW IS IS
SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS OVER THE W
CARIBBEAN FROM 16N-20N W OF 85W INCLUDING PORTIONS OF
HONDURAS...BELIZE AND YUCATAN STATE. ACROSS THE CENTRAL
CARIBBEAN...UPPER LEVEL MOISTURE AND HIGH LEVEL CLOUDS ARE
GENERALLY STREAMING EASTWARD. THIS MOISTURE IS INTERACTING WITH
ATMOSPHERIC INSTABILITY AND UPPER LEVEL DIFFLUENCE TO RESULT IN
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER
CUBA...HISPANIOLA...AND THE NEARBY COASTAL WATERS. MODERATE TO
FRESH EASTERLY TRADES ARE FORECAST TO OCCUR ACROSS THE SE
CARIBBEAN THROUGH THURSDAY.

ATLANTIC OCEAN...
SUBSIDENCE IN NORTHERLY FLOW ALOFT IS SUPPORTING GENERALLY FAIR
WEATHER ACROSS THE SW NORTH ATLC. HOWEVER...UPPER LEVEL
DIFFLUENCE AND UPPER LEVEL MOISTURE ARE SUPPORTING SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS FROM 29N-32N BETWEEN 56W-62W.
TO THE E...AN UPPER LEVEL TROUGH OVER THE CENTRAL ATLC IS
ASSOCIATED WITH A STATIONARY FRONT SKIRTING THE FAR NORTHERN
PORTION OF THE AREA ALONG 32N BETWEEN 43W AND 50W. LOW LEVEL
CONVERGENCE NEAR THE FRONT IS RESULTING IN PATCHY SHOWERS N OF
30N BETWEEN 45W-50W. ACROSS MUCH OF THE CENTRAL AND E ATLC...
GENERALLY FAIR WEATHER IS PRESENT WHERE SUBSIDENCE IS OCCURRING
NEAR A BROAD SURFACE RIDGE. ACROSS THE TROPICAL ATLC...A BROAD
UPPER LEVEL RIDGE IS S OF 16N E OF 55W. UPPER LEVEL DIVERGENCE
ASSOCIATED WITH THE UPPER LEVEL RIDGE IS SUPPORTING THE
CONVECTION ASSOCIATED WITH THE ITCZ AND THE TROPICAL WAVE THAT
EXTENDS FROM 10N48W TO 3N51W...AS WELL AS SCATTERED SHOWERS AND
THUNDERSTORMS OFF THE W AFRICA COAST FROM 4N-6N BETWEEN 11W-13W.

$$
COBB





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