[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 030528
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI OCT 03 2008

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 44W S OF 18N MOVING W NEAR 10 KT. WAVE
REMAINS EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE AS
INDICATED BY MIMIC TPW ANIMATION WITH A BROAD INVERTED-V
CURVATURE IS OBSERVED AND A LOW LEVEL COUNTERCLOCKWISE
CIRCULATION NEAR WAVE AXIS. HOWEVER...ISOLATED SHOWERS ARE ALL
THAT ARE ACROSS A BROAD AREA FROM 14N-19N BETWEEN 35W-50W.

TROPICAL WAVE IS ALONG 55W S OF 18N MOVING W 10-15 KT. WELL
DEFINED INVERTED-V CURVATURE IS OBSERVED IN THE LOW LEVEL CLOUDS
N OF 13N ON SATELLITE IMAGERY AND COINCIDES WITH A MAXIMUM IN
MIMIC TPW ANIMATION. HOWEVER...CONVECTION IS ASSOCIATED WITH THE
ITCZ MORE THAN THE TROPICAL WAVE.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 10N13W 7N29W 11N50W 8N62W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 120/150 NM N OF
THE ITCZ FROM 56W-59W AND WITHIN 75/90 NM S OF THE ITCZ FROM
56W-60W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN
60 NM OF LINE FROM 13N19W TO 9N25W WITH CLUSTERS OF SIMILAR
CONVECTION WITHIN 150 NM ALONG THE COAST OF SW AFRICA S OF 13N W
OF 10W. SCATTERED CLUSTERS OF SCATTERED MODERATE CONVECTION DOT
THE AREA WITHIN 150 NM OF THE ITCZ E OF 33W AND FROM 4N-9N
BETWEEN 40W-48W.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYERED TROUGH CONTINUES TO DOMINATE THE E US AND GULF
PROVIDING DRY STABLE AIR OVER THE GULF WATERS WITH THE EXCEPTION
OF THE FLORIDA STRAITS. THIS DEEP TROUGH CONTINUES TO SUPPORT A
SURFACE COLD FRONT THAT IS BEGINNING TO BECOME QUASI-STATIONARY
EXTENDING ACROSS S FLORIDA NEAR NAPLES ALONG THE N COAST OF THE
YUCATAN NEAR 90W INTO THE BAY OF CAMPECHE TO NEAR 20N94W. LOW
LEVEL CONVERGENCE IN THE BAY OF CAMPECHE IS SUPPORTING LOW
CLOUDS AND POSSIBLE ISOLATED SHOWERS S OF 20N ACROSS THE BAY.
THE REMAINDER OF THE GULF REMAINS CLEAR AGAIN TONIGHT WITH DEW
POINTS IN THE 50 DEG RANGE ACROSS THE GULF N OF 25N E OF 96W.

CARIBBEAN SEA...
A SURFACE TROUGH EXTENDS FROM A 1010 MB SURFACE LOW NEAR 17N85W
NE ACROSS CENTRAL CUBA NEAR 22N80W INTO THE W ATLC AND S TO
INLAND OVER HONDURAS. AN UPPER RIDGE ANCHORED OVER THE CAYMAN
ISLANDS COVERS THE W CARIBBEAN AND COUPLED WITH THE DEEP LAYERED
TROUGH OVER THE GULF IS BRINGING MOIST SW FLOW ALOFT TO THE NW
CARIBBEAN AND GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS ACROSS THE AREA W OF A LINE FROM THE E
TIP OF CUBA TO CENTRAL NICARAGUA WITH CLEAR SKIES OVER THE
YUCATAN CHANNEL. A WEAK UPPER LOW IS IN THE CENTRAL CARIBBEAN
NEAR 13N76W GIVING THE AREA S OF 17N W OF 73W MULTILAYERED
CLOUDS WITH ISOLATED SHOWERS. THE UPPER RIDGE ANCHORED IN THE W
ATLC COVERS THE FAR NE CARIBBEAN BETWEEN THE VIRGIN ISLANDS AND
HISPANIOLA AND AN UPPER LOW IN THE W TROPICAL ATLC EXTENDS OVER
THE REMAINDER OF THE LESSER ANTILLES BRINGING MODERATE
SUBSIDENCE AND DRIER AIR TO THE E CARIBBEAN E OF 70W LIMITING
DEEP CONVECTION AND CLOUD FORMATION. HOWEVER...ISOLATED LOW
LEVEL SHOWERS ARE BEING USHERED ACROSS THE E CARIBBEAN ON
MODERATE TRADE WINDS.

ATLANTIC OCEAN...
DEEP LAYERED TROUGH OVER THE E US AND GULF OF MEXICO CONTINUES
TO IMPACT PORTIONS OF THE W ATLC WITH A COLD FRONT ENTERING THE
REGION NEAR 31N75W EXTENDING ACROSS FLORIDA NEAR WEST PALM BEACH
INTO THE GULF OF MEXICO. DRY STABLE AIR IS W OF THE FRONTAL
BOUNDARY WITH MOIST SW UPPER FLOW FROM THE CARIBBEAN ACROSS CUBA
AHEAD OF THE FRONT AND W OF A LINE FROM 32N65W ALONG 25N71W TO
HAITI NEAR 20N72W. A SURFACE TROUGH IS BENEATH THIS SW UPPER
FLOW ALONG 30N68W TO THE BAHAMAS NEAR 24N76W ACROSS CENTRAL CUBA
INTO THE W CARIBBEAN NEAR 22N80W. SCATTERED SHOWERS/
THUNDERSTORMS ARE S OF 25N TO THE N COAST OF CUBA BETWEEN
74W-78W AND POSSIBLE ISOLATED SHOWERS BETWEEN THE SURFACE TROUGH
AND THE COLD FRONT ACROSS THE REMAINDER OF THE AREA. AN UPPER
RIDGE COVERS THE REMAINDER OF THE W ATLC ANCHORED NEAR 28N62W
WITH THE AXIS EXTENDING NE TO BEYOND 32N57W AND SW TO
HISPANIOLA. AN UPPER LOW IS UNDERCUTTING THE UPPER RIDGE OVER
THE W ATLC CENTERED IN THE W TROPICAL ATLC NEAR 17N58W MOVING
OVER THE LESSER ANTILLES. A SECOND CUT-OFF UPPER LOW IS TO THE
NE IN THE CENTRAL ATLC CENTERED NEAR 28N43W WITH A SURFACE
TROUGH EXTENDING FROM 30N40W SW TO 24N43W GENERATING ISOLATED
SHOWERS WITHIN 90 NM EITHER SIDE OF THE SURFACE TROUGH.
DIFFLUENCE ALOFT TO THE SW OF THIS UPPER LOW IS GENERATING
SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 21N-25N
BETWEEN 37W-41W. NEAR ZONAL WESTERLY FLOW ALOFT DOMINATES THE NE
ATLC AND THE TYPICAL E/W UPPER RIDGE DOMINATES THE REMAINDER OF
THE TROPICAL ATLC ALONG 15N FROM AFRICA TO 50W. AFRICAN DUST
CONTINUES TO STREAM OFF W AFRICA WITH THE LAST VISIBLE SATELLITE
IMAGES SHOWING DUST TO 33W.

$$
WALLACE




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