[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE JUN 27 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.

...SPECIAL FEATURES...
SATELLITE AND RADAR INFORMATION CONTINUE TO INDICATE THAT A SMALL
LOW PRESSURE SYSTEM COULD BE FORMING ABOUT 140 MILES SOUTH-
SOUTHWEST OF CAPE LOOKOUT NORTH CAROLINA. THIS SYSTEM HAS BECOME
BETTER ORGANIZED THIS MORNING...AND POTENTIAL REMAINS FOR IT TO
DEVELOP INTO A TROPICAL DEPRESSION OR A TROPICAL STORM AT ANY
TIME AS THE SYSTEM MOVES NORTH TO NORTH-NORTHEASTWARD AT ABOUT
20 MPH. AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT IS
INVESTIGATED THE SYSTEM TO DETERMINE IF A CLOSED CIRCULATION
EXISTS AT THE SURFACE. AREA OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION COVERS THE AREA FROM 30.5N-35W BETWEEN
75.5W-78.5W AND ACROSS PORTIONS OF THE OUTER BANKS IN NORTH
CAROLINA. EVEN IF THIS SYSTEM DOES NOT FORM INTO A TROPICAL
CYCLONE...SHOWERS AND THUNDERSTORMS PRODUCING LOCALLY HEAVY
RAINFALL AND STRONG GUSTY WINDS WILL GRADUALLY SPREAD ONSHORE
THE NORTH CAROLINA AND VIRGINIA COASTS TODAY AND TONIGHT.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 37W/38W S OF 12N MOVING W 10 KT.
LOW-AMPLITUDE WAVE IS WELL-DEFINED ON SATELLITE IMAGERY. SHOWER
OR CONVECTION ACTIVITY IS WITHIN THE ITCZ.

A LARGE TROPICAL WAVE ACCOMPANIED BY A WEAK 1013 MB LOW PRESSURE
AREA IS ALONG 50W/51W S OF 15N OR ABOUT 550 MILES EAST OF THE
SOUTHERN WINDWARD ISLANDS. CLUSTERS OF MODERATE TO STRONG
CONVECTION ARE ASSOCIATED WITH THE LOW. A DEVELOPMENT OF THIS
SYSTEM...IF ANY...IS EXPECTED TO BE SLOW TO OCCUR AS THE WAVE
CONTINUES WEST-NORTHWESTWARD AT ABOUT 20 MPH. SHOWERS AND A FEW
TSTMS ACCOMPANIED BY BRIEF HEAVY RAINFALL AND GUSTY WINDS WILL
AFFECT THE LESSER ANTILLES ON WEDNESDAY. THIS WAVE IS EXPECTED
TO REACH THE VIRGIN ISLANDS AND PUERTO RICO ON THURSDAY...
INCREASING THE CHANCES OF RAIN AND THE RISK OF FLASH FLOODING
OVER THAT AREA.

TROPICAL WAVE IS ALONG 85W S OF 22N MOVING W 10-15 KT. WEAK LOW
LEVEL SIGNATURE CURVATURE IS OBSERVED ON SATELLITE IMAGERY DUE
TO THE WAVE IS BENEATH THE W PORTION OF A BROAD UPPER RIDGE THAT
IS OVER THE CARIBBEAN. CLUSTERS OF MODERATE TO STRONG CONVECTION
ARE OVER THE SW CARIBBEAN...THE EASTERN PORTION OF NICARAGUA...
THE GULF OF HONDURAS AND BELIZE. SHOWERS WITH EMBEDDED TSTMS ARE
ALSO AFFECTING THE WESTERN PORTION OF CUBA...INCLUDING THE ISLE
OF YOUTH. THE TROPICAL WAVE AND A DIFFLUENT PATTERN ALOFT ARE
ENHANCING THIS CONVECTIVE ACTIVITY.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N15W 7N25W 7N35W 7N40W 9N49W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120/150
NM S OF THE AXIS BETWEEN 20W-33W. SIMILAR CONVECTION IS WITHIN
120 NM N OF THE AXIS WEST OF 53W AND ALONG THE COAST OF GUYANA
AND NE VENEZUELA.

...DISCUSSION...
GULF OF MEXICO...
BROAD DEEP LAYERED TROUGH EXTENDS FROM THE UPPER MISSISSIPPI
VALLEY INTO THE CENTRAL GULF WHILE A SHORT WAVE TROF IS OVER
WEST FLORIDA...THE SE GULF AND THE YUCATAN CHANNEL. THIS FEATURE
IS SUPPORTING THE DEVELOPMENT OF SCATTERED/NUMEROUS SHOWERS AND
TSTMS OVER NORTH-CENTRAL FLORIDA. AN UPPER RIDGE OVER MEXICO
EXTENDS OVER THE BAY OF CAMPECHE. AT THE SURFACE...WEAK HIGH
PRESSURE IS KEEPING RATHER QUIET CONDITIONS ACROSS THE GULF WITH
LIGHT WINDS. A SURFACE TROUGH RUNS FROM THE FLORIDA PANHANDLE TO
NEAR 27N91W. ISOLATED SHOWERS/THUNDERSTORMS ARE OVER THE NE
QUADRANT OF THE GULF AND NORTHERN FLORIDA ASSOCIATED WITH THE
TROUGH.

CARIBBEAN SEA...
BROAD UPPER RIDGE COVERS THE W CARIBBEAN WITH THE AXIS EXTENDING
NEWD ACROSS EASTERN CUBA...THE BAHAMAS AND THE W ATLC WEST OF
70W. TROPICAL MOISTURE IS BEING ADVECTED OVER CENTRAL AMERICA
AND THE NW CARIBBEAN. AN UPPER TROUGH THAT EXTENDS MAINLY SOUTH
FROM THE W ATLC OVER PUERTO RICO AND THE EASTERN CARIBBEAN IS
GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE
WINDWARD ISLANDS. PRESSURE GRADIENT BETWEEN THE ATLC HIGH AND
THE COLOMBIAN LOW IS PRODUCING MODERATE TO STRONG TRADE WINDS
OFF THE COLOMBIA COAST. EARLIER QUIKSCAT PASS SHOWS WINDS OF
20-25 KT.

ATLANTIC OCEAN...
AN UPPER RIDGE COVERS THE W ATLC WEST OF 70W. A DEEP LAYERED
TROUGH PERSISTS OVER THE CENTRAL ATLC. THIS UPPER TROUGH IS N OF
22N FROM 50W-70W WITH AN UPPER LOW NEAR 31N56W. A SURFACE TROUGH
EXTENDS ALONG 31N50W 25N60W TO 21N68W. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE WITHIN AROUND 100 NM E AND S OF THE
TROUGH FROM 46W-58W AND WITHIN 50N N OF THE TROUGH FROM 58W-62W.
AN LARGE UPPER HIGH IN THE TROPICAL ATLC IS LOCATED NEAR 12N38W
WITH AN UPPER RIDGE COVERING MOST OF THE TROPICS. AT THE
SURFACE...BROAD HIGH PRESSURE COVERS MOST OF THE ATLC ANCHORED
BY 1036 MB HIGH NW OF THE AZORES. TYPICAL STRATOCUMULUS CLOUDS
ARE EAST OF THE AFOREMENTIONED SURFACE TROUGH. ACCORDING TO THE
27/1500 UTC CIMSS SAHARAN AIR LAYER A BROAD AREA OF AFRICAN DUST
COVERS THE E ATLC EAST OF 40W.

$$
GR




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