[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 311804 AAA
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON JUL 31 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

A DEVELOPING TROPICAL WAVE IS LOCATED IN THE FAR EAST ATLANTIC
JUST SOUTH OF THE CAPE VERDE ISLANDS. THIS WILL BE ADDED AS A
TROPICAL WAVE TO THE 18Z MAP AS VISIBLE SATELLITE IMAGERY FROM
THIS MORNING AND AFTERNOON CLEARLY SHOWS CYCLONIC CURVATURE.
FURTHERMORE...THE DAKAR UPPER AIR TIME SECTION ANALYSIS SHOWS
THE DEVELOPING WAVE MOVED THROUGH EARLY SUNDAY WHEN NE WINDS
VEERED SE.

THE TROPICAL WAVE PREVIOUSLY ALONG 55W/56W HAS BEEN REPOSITIONED
TO 60/61W S OF 14N MOVING W NEAR 15 KT. THE SURFACE LOW
ASSOCIATED WITH THIS FEATURE HAS BEEN REMOVED AND ANALYZED AS A
TROF FROM 13N58W TO 18N56W. THIS CHANGE WAS MADE DUE TO LOW/MID
CLOUD MOTIONS AND WIND OBSERVATIONS NEAR THE SOUTHERN LESSER
ANTILLES SUGGESTING THE SOUTHERN PORTION OF THE WAVE HAS BECOME
DETACHED...AND IS MOVING WESTWARD THROUGH THE SE CARIBBEAN
SEA...WITH THE NORTHERN TROF PORTION MOVING MORE WNW. THIS MAY
BE REANALYZED AS A SINGLE/CURVED WAVE IN THE 18Z ANALYSIS BUT
CURRENT DATA SUGGESTS THERE ARE TWO SEPARATE FEATURES. THE
SOUTHERN PORTION OF THE WAVE SEEMS TO BE ENHANCING CONVECTION
OVER NORTHERN SOUTH AMERICA SOUTH OF THE ITCZ...WHERE ISOLATED
SHOWERS AND THUNDERSTORMS LIE FROM 2N TO 8N BETWEEN 59W AND 64W.
SHIP...BUOY...AND CLOUD MOTIONS ABOUT 250NM EAST OF DOMINICA
FROM 14N TO 18N BETWEEN 55W AND 59W STILL SHOW CLEAR CYCLONIC
TURNING. SCATTERED MODERATE CONVECTION HAS DEVELOPED NEAR THE
TROF AXIS FROM 13N TO 17N BETWEEN 55W AND 58W. ALTHOUGH
ENVIRONMENTAL CONDITIONS ARE ONLY MARGINAL FOR TROPICAL CYCLONE
DEVELOPMENT...AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT WILL
BE AVAILABLE TO INVESTIGATE THE SYSTEM THIS AFTERNOON...IF
NECESSARY.

A TROPICAL WAVE IS ALONG 83W SOUTH OF 21N MOVING WEST 15 TO 20
KT THROUGH THE WESTERN CARIBBEAN SEA. THE WAVE MAY BE ENHANCING
THE ISOLATED MODERATE CONVECTION THAT IS DOTTING THE NW
CARIBBEAN SEA FROM 16N TO 22N BETWEEN 79W AND 88W...WHICH ALSO
REMAINS A REGION OF PRONOUNCED UPPER DIFFLUENCE.

THE EXTREME NORTHERN PORTION OF A MOSTLY E PACIFIC TROPICAL WAVE
IS EXTENDING THROUGH S MEXICO AND INTO THE FAR WESTERN BAY OF
CAMPECHE IN THE GULF OF MEXICO. THIS IS ONLY PRODUCING A FEW
SCATTERED SHOWERS IN THE FAR SW GULF OF MEXICO...AND WILL
CONTINUE MOVING WEST OF THE AREA.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 12N17W 9N30W 11N40W 11N57. OUTSIDE
OF THE TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS ALONG
THE WAVE AXIS AND WITHIN AROUND 100 NM SOUTH OF THE AXIS FROM
25W-40W.

...DISCUSSION...
THE GULF OF MEXICO...
A COUPLE OF UPPER LEVEL LOW CENTERS ARE IN THE AREA...ONE IS
OVER THE NW CORNER OF THE GULF WHILE THE SECOND ONE IS STILL
INLAND OVER NE MEXICO. AN UPPER RIDGE COVERS THE EAST GULF AND
SOUTH FLORIDA WITH ANOTHER UPPER LEVEL LOW IN NE FLORIDA. AN
UPPER TROUGH EXTENDS FROM THIS LOW ACROSS THE FLORIDA PANHANDLE.
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OVER THE NE PORTION OF
THE GULF JUST AHEAD OF THE UPPER TROUGH. A TROPICAL WAVE IS
GENERATING WIDELY SCATTERED SHOWERS OVER THE BAY OF CAMPECHE. A
1018 MB SURFACE HIGH IS ALONG THE GEORGIA/FLORIDA BORDER WITH A
RIDGE EXTENDING WWD TO EASTERN TEXAS. BROAD 10-15 SELY FLOW
DOMINATES THE GULF OF MEXICO. A RIDGE WILL PERSIST ACROSS THE
NORTHERN GULF DURING THE NEXT FEW DAYS.

THE CARIBBEAN SEA...
PATCHES OF MODERATE CONVECTION SPOT THE NW CARIBBEAN SEA THIS
AFTERNOON IN ASSOCIATION WITH UPPER DIFFLUENCE BETWEEN AN UPPER
RIDGE EXTENDING EAST FROM SOUTHERN MEXICO...AN UPPER TROF THAT
EXTENDS INTO THE NORTH CENTRAL CARIBBEAN FROM ITS CENTER JUST NE
OF THE BAHAMAS...AND AN UPPER RIDGE CENTERED OVER THE VIRGIN
ISLANDS. THE MOST INTENSE OF THIS CONVECTION LIES BETWEEN
JAMAICA AND EASTERN CUBA WHICH DEVELOPED AFTER 14Z THIS MORNING
WITH CLOUD TOPS COOLING TO -72C TO -75C. ISOLATED MODERATE
CONVECTION IS ALSO MOVING INTO THE EXTREME SE CARIBBEAN SEA FROM
11N TO 14N BETWEEN 62W AND 67W...LIKELY ENHANCED BY THE TROPICAL
WAVE MOVING INTO THE REGION. MODEST 10-15 KT E/SE SFC WINDS
DOMINATE MUCH OF THE CARIBBEAN SEA THIS AFTERNOON...ROTATING
CLOCKWISE AROUND THE W/SW EXTENSION OF THE ATLANTIC HIGH. GFS
SUGGESTS SURFACE WINDS WILL INCREASE A TOUCH ESPECIALLY. IN THE
CENTRAL CARIBBEAN OVER THE NEXT COUPLE OF DAYS AS THE HIGH TO
THE N/NE INTERACTS WITH LOWER PRESSURE NEAR COLOMBIA...ALONG
WITH OUR NEXT TROPICAL WAVE PROPAGATING WESTWARD THROUGH THE
AREA.

THE ATLANTIC OCEAN...
A LARGE UPPER RIDGE IS CENTERED JUST WEST OF THE AFRICAN COAST
NEAR 20N25W. NORTH OF THIS CENTER LIES EXTENSIVE DRY AIR ALONG
WITH A DENSE LAYER OF SAHARAN DUST. THE WEST PORTION OF THIS
RIDGE MEETS AN UPPER TROF THAT EXTENDS NE FROM NEAR 21N56W TO
NEAR 30N46W. ANOTHER UPPER TROF CONTINUES TO EXTEND NE FROM THE
BAHAMAS AND TURKS AND CAICOS ISLANDS. STRONG UPPER LEVEL N/NE
WINDS ON THE NW PORTION OF THIS UPPER TROF ARE SHEARING THE
CLOUD TOPS ASSOCIATED WITH THE AREA OF LOW PRESSURE LOCATED
ABOUT 150 MILES ESE OF CAPE HATTERAS NORTH CAROLINA. ALTHOUGH
THIS SHOWER ACTIVITY IS NOT WELL ORGANIZED AT THE MOMENT...THE
SYSTEM HAS SOME POTENTIAL FOR DEVELOPMENT OVER THE NEXT DAY OR
SO. CLOUDINESS AND DISORGANIZED SHOWERS ALSO EXTEND
NORTHEASTWARD FROM THE VICINITY OF THE WINDWARD PASSAGE INTO THE
ATLANTIC FOR A FEW HUNDRED MILES.  UPPER-LEVEL WINDS ARE
FORECAST TO REMAIN UNFAVORABLE FOR DEVELOPMENT OF THIS SYSTEM.
HOWEVER...LOCALLY HEAVY RAINS CAN BE EXPECTED OVER PORTIONS OF
EASTERN CUBA AND HISPANIOLA DURING THE NEXT DAY OR SO. A
STATIONARY 1027MB SURFACE HIGH PRESSURE CENTER IS LOCATED NEAR
36N25W WITH ANOTHER HIGH CENTER ANALYZED JUST TO THE SW NEAR
25N49W.



$$
WILLIS/RUBIO


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