[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211707
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1630 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE EXTENDS FROM 10N49W TO 1N51W MOVING W AROUND 10
KT. THIS WAVE COINCIDES WITH A RELATIVELY LOW AMPLITUDE DEEP
MOISTURE MAXIMUM SEEN IN TOTAL PRECIPITABLE WATER IMAGERY.
SATELLITE-DERIVED WINDS INDICATE GOOD CYCLONIC SURFACE FLOW IN
THE VICINITY OF THIS WAVE. SCATTERED MODERATE CONVECTION IS FROM
4N-7N BETWEEN 51W-54W AND FROM 10N-14N BETWEEN 43W-50W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N13W 6N25W 5N38W 7N48W AND INTO
NE S AMERICA NEAR 6N58W. SCATTERED MODERATE CONVECTION IS FROM
4N-8N BETWEEN 23W-27W AND FROM 7N-10N BETWEEN 39W-43W.

...DISCUSSION...

GULF OF MEXICO...
UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN UPPER LEVEL LOW
CENTERED OVER THE S BAY OF CAMPECHE NEAR 21N92W IS SUPPORTING
ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS OVER THE S GULF OF
MEXICO S OF 22N W OF 92W. ACROSS THE N AND CENTRAL GULF...A 1015
MB STATIONARY SURFACE HIGH NEAR 28N87W DOMINATES BRINGING FAIR
WEATHER. THE SURFACE HIGH HAS UPPER LEVEL SUPPORT WITH AN UPPER
LEVEL HIGH OVER ARKANSAS WHICH IS PROVIDING DEEP LAYER DRY AIR
AND SUBSIDENCE. ANTICYCLONIC FLOW AROUND THE SURFACE HIGH IS
AFFECTING MUCH OF THE GULF...WITH SE WINDS OF 10-15 KTS
AFFECTING THE NW GULF W OF 93W. ATMOSPHERIC INSTABILITY BETWEEN
THE UPPER LEVEL HIGH OVER ARKANSAS AND AN UPPER LEVEL LOW OFF
THE NEW ENGLAND COAST IS SUPPORTING CLOUDS AND ISOLATED SHOWERS
ACROSS THE FLORIDA PENINSULA AND THE FAR E GULF. EXPECT...THE
SURFACE HIGH 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 OVER THE S BAY OF CAMPECHE NEAR 21N92W IS
PROVIDING ATMOSPHERIC INSTABILITY AND SUPPORTING SCATTERED
SHOWERS AND THUNDERSTORMS OVER THE W CARIBBEAN FROM 16N-20N W OF
84W INCLUDING PORTIONS OF THE YUCATAN PENINSULA. SURFACE
CONVERGENCE NEAR A STATIONARY 1009 MB SURFACE LOW OVER N
COLUMBIA NEAR 9N74W ALONG WITH UPPER LEVEL DIFFLUENCE ARE
SUPPORTING NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS PORTIONS OF
PANAMA...COLUMBIA...AND THE ADJACENT COASTAL WATERS S OF 11N
BETWEEN 75W-83W. THE REMAINDER OF THE CARIBBEAN IS UNDER MOSTLY
FAIR WEATHER AS NWLY FLOW ALOFT IS DRAWING IN RELATIVELY DRY
AIR. HOWEVER...ATMOSPHERIC INSTABILITY IS RESULTING IN ISOLATED
SHOWERS 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...
UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL HIGH OVER ARKANSAS
AND AN UPPER LEVEL LOW OFF THE NEW ENGLAND COAST IS SUPPORTING
SCATTERED SHOWERS ACROSS THE FAR W ATLC N OF 29N W OF 72W. AN
UPPER LEVEL TROUGH OVER THE W ATLC CONNECTED WITH THE UPPER
LEVEL LOW IS SUPPORTING SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS
N OF 27N BETWEEN 55W-63W. THE UPPER LEVEL TROUGH IS ALSO
SUPPORTING A STATIONARY FRONT THAT CLIPS THE DISCUSSION AREA
ALONG 32N BETWEEN 43W-49W. SURFACE CONVERGENCE AROUND A 1016 MB
SURFACE LOW AHEAD OF THE FRONT N OF THE DISCUSSION AREA NEAR
33N36W IS SUPPORTING ISOLATED SHOWERS FROM 27N-30N BETWEEN
31W-35W. A SECOND UPPER LEVEL TROUGH OVER THE E/CENTRAL ATLC IS
SUPPORTING ISOLATED SHOWERS IN THE FAR E ATLC FROM 23N-28N
BETWEEN 17W-23W. ELSEWHERE...A BROAD SURFACE RIDGE DOMINATES
ANCHORED BY A 1023 MB SURFACE HIGH NEAR 27N28W. FARTHER S...A
BROAD UPPER LEVEL RIDGE IS S OF 20N E OF 55W. UPPER LEVEL
DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL RIDGE IS SUPPORTING
THE CONVECTION ASSOCIATED WITH THE ITCZ AND THE TROPICAL
WAVE...SEE ABOVE.

$$
WALTON






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