[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101804
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN AUG 10 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A TROPICAL WAVE LOCATED
OVER THE CENTRAL ATLANTIC ALONG 42W/43W OR ABOUT 980 NM EAST OF
THE WINDWARD ISLANDS HAVE BECOME A LITTLE BETTER ORGANIZED THIS
MORNING. SAT IMAGERY SHOWS SCATTERED TO ISOLATED STRONG
CONVECTION WITHIN AROUND 150 NM W SEMICIRCLE OF A 1009 MB LOW
EMBEDDED ON THE WAVE AXIS NEAR 10.5N 43.0W. CONDITIONS APPEAR
SOMEWHAT FAVORABLE FOR GRADUAL DEVELOPMENT OF THIS SYSTEM DURING
THE NEXT COUPLE OF DAYS AS IT MOVES WESTWARD AT 15 TO 20 MPH.


...TROPICAL WAVES...
A NEW TROPICAL WAVE HAS BEEN ADDED TO THE 1200 UTC MAP BASED ON
SATELLITE IMAGERY...OBSERVATIONS AND THE DAKAR VERTICAL SOUNDING
WHICH REVEALS THAT THE LOW LEVEL WINDS HAVE VEERED OUT TO THE
SOUTH INDICATING THE PASSAGE OF THE WAVE AXIS OVERNIGHT. THE
WAVE AXIS IS ALONG 18W SOUTH OF 17N MOVING W 10-15 KT. SOME
CYCLONIC TURNING IS SEEN ALON THE WAVE AXIS NEAR 12N WITH
MODERATE TO STRONG CONVECTION WELL AHEAD OF THE WAVE LINE FROM
10N-14N BETWEEN 20W-25W.

A TROPICAL WAVE IS ALONG 62W/63W S OF 18N MOVING W 15-20 KT. THE
WAVE CONTINUES TO SHOW A NARROW NORTH-SOUTH MOISTURE MAXIMUM ON
THE MIMIC-TPW PRODUCT. NO DEEP CONVECTION IS OBSERVED WITH
SCATTERED SHOWERS NEAR THE N END OF THE WAVE AXIS...AND OVER
TRINIDAD AND TOBAGO ISLANDS. A SURGE OF AFRICAN DUST FOLLOWS
THIS WAVE.

A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN ALONG 73W S OF 20N
MOVING W NEAR 15 KT. THE WAVE SHOWS AN INVERTED-V SIGNATURE ON
VIS SATELLITE IMAGERY ACROSS THE CARIBBEAN SEA WATERS. NO DEEP
CONVECTION IS OBSERVED WITH THE WAVE...HOWEVER SCATTERED SHOWERS
ARE OVER HISPANIOLA AND NEAR THE VENEZUELA/COLOMBIA BORDER.

...THE ITCZ...
THE ITCZ IS PRETTY ACTIVE THIS MORNING. ITS AXIS IS CENTERED
ALONG 12N17W 11N25W 12N37W 9N43W 8N59W. OUTSIDE OF THE
CONVECTION ASSOCIATED WITH TWO TROPICAL WAVES...THERE IS AN AREA
OF SCATTERED MODERATE CONVECTION FROM 10N-14N BETWEEN 29W-35W.
THIS DISORGANIZED AREA OF DISTURBED WEATHER HAS SOME POTENTIAL
FOR SLOW DEVELOPMENT DURING THE NEXT COUPLE OF DAYS AS IT MOVES
WESTWARD AT ABOUT 15 MPH. MODERATE CONVECTION IS ALSO NOTED
WITHIN 100 NM N OF AXIS BETWEEN 50W-54W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER-LEVEL HIGH CENTERED OVER WEST TEXAS EXTENDS A RIDGE
OVER THE N GULF WATERS MAINLY N OF 24N. AN UPPER-LEVEL TROUGH
LIES JUST SOUTH OF THE RIDGE AND EXTENDS FROM THE W ATLC THROUGH
SOUTH FLORIDA INTO THE GULF REGION ALONG 22N TO AN UPPER-LEVEL
LOW CENTERED OVER CENTRAL MEXICO. THIS TROUGH SUPPORTS A
WEAKENING STATIONARY FRONT WHICH CROSSES CENTRAL FLORIDA THEN
CONTINUES NW TO SE LOUISIANA. SCATTERED SHOWERS AND TSTMS ARE
AHEAD OF THE FRONTAL BOUNDARY AFFECTING THE EAST GULF E OF 85W
AND SOUTH-CENTRAL FLORIDA. THE FRONT IS FORECAST TO DISSIPATE
LATER TODAY. A RIDGE ANCHORED ON A 1018 MB HIGH OVER WESTERN
CUBA DOMINATES THE REMAINDER OF THE GULF. SURFACE CIRCULATION
AROUND THIS HIGH IS PROVIDING THE WRN AND CENTRAL GULF LIGHT
SOUTHERLY RETURN FLOW...BUT THESE WINDS ARE EXPECTED TO INCREASE
ON TUE AS A LOW PRES SYSTEM DEVELOPS OVER TEXAS AND NE MEXICO.

CARIBBEAN SEA...
AN UPPER-LEVEL LOW HAS BEEN MEANDERING OVER CUBA DURING THE LAST
TWO OR THREE DAYS ENHANCING CONVECTION EVERY AFTERNOON. THE
CYCLONIC FLOW COVERS THE NW CARIBBEAN AND EXTENDS EWD OVER
HISPANIOLA. UPPER DIFFLUENCE BETWEEN THIS LOW AND A RIDGE WHICH
COVERS THE YUCATAN PENINSULA AND N CENTRAL AMERICA IS SUPPORTING
SOME SHOWER/TSTM ACTIVITY S OF THE CAYMAN ISLANDS AND OVER THE
SW CARIBBEAN. THIS UPPER-LEVEL FEATURE IS ALSO AIDING IN
GENERATING SCATTERED MODERATE CONVECTION ACROSS PANAMA...NRN
COLOMBIA AND ADJACENT COASTAL WATERS S OF 10N. MODERATE TO
STRONG SUBSIDENCE AND DRY AIR IS IN CONTROL ACROSS THE THE ERN
AND CENTRAL CARIBBEAN SEA. MODERATE TO STRONG EASTERLY TRADE
WINDS ARE BLOWING ACROSS THE BASIN WITH THE STRONGEST WINDS
OFFSHORE OF THE NRN COLOMBIAN COAST. TWO TROPICAL WAVES ARE
MOVING WWD ACROSS THE BASIN. SEE TROPICAL WAVE SECTION.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS LOCATED OVER THE ERN U.S. INTO THE FAR
W ATLC WITH THE ASSOCIATED STATIONARY FRONTAL BOUNDARY ENTERING
THE AREA NEAR 31N72W EXTENDING ACROSS CENTRAL FLORIDA AND INTO
THE GULF OF MEXICO TO SE LOUISIANA. AN UPPER RIDGE IS TO THE SE
CENTERED NEAR 26N70W. A DIFFLUENT PATTERN ALOFT BETWEEN THIS
HIGH THE UPPER-LEVEL LOW SPINNING OVER E CUBA IS HELPING TO
INDUCE SCATTERED SHOWERS AND TSTMS OVER THE NW BAHAMAS AND
COASTAL WATERS. A SHORT-WAVE TROUGH IS JUST TO THE EAST ALONG
62W AND IS GENERATING A NARROW BAND OF SHOWERS WITH EMBEDDED
TSTMS ALONG 32N62N 27N65W 24N67W. ELSEWHERE AN UPPER LOW IS OVER
THE CENTRAL ATLC NEAR 26N47W WITH ANOTHER WEAK UPPER-LEVEL LOW
OVER THE ERN ATLC NEAR 28N26W WITH TROUGHING EXTENDING SW TO
ANOTHER UPPER LOW CENTERED NEAR 22N35W. AN UPPER-LEVEL HIGH IS
SITUATED NEAR 22N20W EXTENDING A RIDGE ACROSS THE DEEP TROPICS.
THIS UPPER SYSTEM IS ENHANCING CONVECTION ALONG THE ITCZ.
OTHERWISE...THE ATLANTIC FORECAST AREA IS DOMINATED BY A 10125
SFC HIGH CENTERED NEAR 33N46W. THIS HIGH EXTENDS A RIDGE TO THE
NE CARIBBEAN AND WILL REMAIN NEARLY STATIONARY DURING THE NEXT
24 HOURS OR SO.

$$
GR




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