[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 261802
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN AUG 26 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
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...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1730 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS TILTED ALONG 16N33W 3N29W ESTIMATED TO BE
MOVING W NEAR 10-15 KT. HOWEVER...MUCH OF THE CYCLONIC TURNING
AND HIGHEST MOISTURE CONTENT WITH THIS WAVE HAVE HAD A SW MOTION
OVER THE LAST DAY OR SO...AS DENOTED BY TODAYS VIS IMAGERY AND
THE UW-CIMSS TPW PRODUCT. ASSOCIATED SCATTERED MODERATE
CONVECTION REMAINS DISORGANIZED FROM 10N-13N BETWEEN 29W-35W.

TROPICAL WAVE IS ALONG 53/54W S OF 15N MOVING W 10 KT. THIS
SYSTEM HAS GENERALLY CHANGED LITTLE SINCE YESTERDAY WITH A LOW
LEVEL CYCLONIC SWIRL AND A LOW LATITUDE INVERTED V-SHAPE CLEARLY
APPARENT ON VIS IMAGES...THOUGH STILL PARTIALLY EMBEDDED IN THE
ITCZ. WHILE THIS WAVE HAS MAINTAINED FAIR STRUCTURE...SHOWER AND
TSTM ACTIVITY REMAINS MINIMAL.

TROPICAL WAVE IS IN THE W CARIBBEAN AND OVER CENTRAL AMERICA
ALONG 85W S OF 21N MOVING W 10-15 KT. THIS WAVE COULD BE
ENHANCING SOME OF THE SHOWER/TSTM ACTIVITY IN THE SE GULF...AND
THE SCATTERED TSTMS IN THE NW CARIB OFF THE COAST OF WRN CUBA N
OF 20N. LOW CLOUD MOTIONS DO SHOW A LITTLE CYCLONIC TURNING JUST
E OF BELIZE AND THE YUCATAN WHICH WAS CONFIRMED BY THIS MORNINGS
QUIKSCAT PASS...BUT OVERALL SHOWER/TSTM ACTIVITY OVER THE
CARIBBEAN PORTION OF THE WAVE ARE MINIMAL AND DISORGANIZED.

THE TROPICAL WAVE PREVIOUSLY IN THE WRN BAY OF CAMPECHE APPEARS
TO HAVE FRACTURED...AND AS OF 1500 UTC THE NRN PORTION IS BEING
ANALYZED AS A TROUGH EXTENDING NW TO SE FROM NEAR BROWNSVILLE TO
THE CENTRAL BAY OF CAMPECHE NEAR 19N94W. A 1010 MB LOW IS ALONG
THE TROUGH AXIS NEAR 22N96W. FOR MORE DETAILS ON THIS SYSTEM SEE
GULF SECTION BELOW.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 13N16W 12N28W 7N34W 9N51W 9N61W.
BESIDES FOR THE CONVECTION DISCUSSED IN THE TROPICAL WAVES
SECTION ...SCATTERED MODERATE CONVECTION IS MAINLY S OF THE AXIS
FROM 5N-9N E OF 18W. ISOLATED CLUSTERS OF MODERATE CONVECTION
ARE FROM 4N-8N BETWEEN 20W-41W.

DISCUSSION...

GULF OF MEXICO...
THERE IS QUITE A BIT OF SPOTTY CONVECTION OVER THE GULF THIS
AFTERNOON BUT NO REALLY STRONG SFC FEATURES AT THE MOMENT. THE
MOST PRONOUNCED SFC FEATURE IS THE BROAD AREA OF LOW PRESSURE IN
THE SW GULF. AS OF THE 26/1500 UTC MAP...A 1010 MB LOW WAS NEAR
22N96W THAT HAS WITH A TROUGH EXTENDING THROUGH THE LOW BETWEEN
BROWNSVILLE AND THE SOUTH CENTRAL BAY OF CAMPECHE. THE
ASSOCIATED SCATTERED MODERATE CONVECTION IS FROM 19N-25N BETWEEN
92W AND THE COAST OF MEXICO. THIS SYSTEM IS EXPECTED TO CONTINUE
TO
DRIFT WESTWARD OVER MEXICO WITH NO DEVELOPMENT. A WEAK 1015 MB
HIGH IS OVER THE MIDDLE GULF NEAR 27N88W...AND APPEARS TO BE
SLOWLY DISSIPATING. HOWEVER...THE FLOW AROUND THIS HIGH IS
COLLIDING WITH ESE FLOW AROUND ATLC RIDGING TO PRODUCE A SFC
TROUGH IN THE ERN GULF FROM NEAR CEDAR KEY FLORIDA TO 25N87W.
THIS IS SPARKING SCATTERED TO NUMEROUS SHOWERS AND TSTMS
OFFSHORE FLORIDA AND CUBA MAINLY E OF 86W. SCATTERED SHOWERS AND
TSTMS ALSO DOT THE NRN GULF COASTAL REGION GENERALLY WITHIN 90
NM OF THE COAST E OF 95W. THE AFOREMENTIONED CONVECTION IS ALSO
BEING SUPPORTED BY AN ABUNDANCE OF DIFFLUENCE ALOFT...WITH THE
DRIVING UPPER FEATURES BEING THE LOW JUST S OF
LOUISIANA...RIDGING OVER THE FAR NE AND SW PORTIONS...AND AN
INVERTED UPPER TROUGH OVER THE FAR SE PORTION. WEAK RIDGING WILL
MEANDER AROUND 30N OVER THE NEXT COUPLE OF DAYS AS BROAD LOW
PRES TROUGHING DRIFTS W OVER THE SW PORTION.

CARIBBEAN SEA...
THE MOST SIGNIFICANT AREA OF CONVECTION IS OFF THE COAST OF
COLOMBIA AND VENEZUELA...WITH SCATTERED MODERATE CONVECTION S OF
16N BETWEEN 64W-78W. ISOLATED TSTMS ARE ALSO N OF 16N BETWEEN
THE SAME AREA AFFECTING PUERTO RICO...HISPANIOLA..AND ADJACENT
WATERS. THE MORE CONCENTRATED ACTIVITY IN THE SRN CARIBBEAN
APPEARS TO BE TIED TO THE ITCZ. ALL OF THE ACTIVITY IS ALSO
BEING SUPPORTED BY DIFFLUENCE ALOFT BETWEEN THE UPPER TROUGHING
BETWEEN PANAMA AND HAITI...AND ATLC RIDGING EXTENDING INTO THE
ERN CARIBBEAN. THE TRADE WIND FLOW IS ON THE LIGHT TO MODERATE
SIDE...AND IS ONLY EXPECTED TO INCREASE SLIGHTLY OVER THE NEXT
COUPLE OF DAYS.

ATLANTIC OCEAN...
THE SFC PATTERN ACROSS THE ATLC DISCUSSION AREA REMAINS FAIRLY
WEAK THIS AFTERNOON. THIS WEAK PATTERN IS MAINLY DUE TO AN
UNUSUAL (FOR AUGUST) FRONT DEEP INTO THE SUBTROPICS ENTERING THE
AREA NEAR 32N37W TO 26N55W THEN SNAKING WSW THEN NW AS A TROUGH
THROUGH 23N63W 29N69W. SHOWER AND TSTM ACTIVITY IS MAINLY
ISOLATED IN NATURE WITHIN 30NM OF THE BOUNDARY.  THE MOST
CONCENTRATED TSTM ACTIVITY NEAR THE FRONT IS SCATTERED FROM
24N-27N BETWEEN 55W-60W...WHICH ARE OCCURRING AROUND THE
PERIPHERY OF THE UPPER LOW NEAR 25N58W. A WEAK 1018 MB HIGH IS
OVER THE WRN ATLC NEAR 29N72W. A SFC TROUGH IS JUST E OF THE
LEEWARD ISLANDS ALONG 21N58W 15N59W THAT IS GENERATING JUST A
FEW SHOWERS WITHIN 60 NM EITHER SIDE OF THE AXIS. A WEAK RIDGE
AXIS IS OVER THE REMAINDER OF THE CENTRAL AND E ATLC PORTION OF
THE DISCUSSION AREA...WITH THE AXIS ENTERING THE AREA NEAR
32N29W THEN CONTINUING SW THROUGH 25N40W 23N55W. LOOK FOR THE
FRONT TO CONTINUE BECOMING DIFFUSE OVER THE NEXT DAY OR
SO...THOUGH REMNANT TROUGHING WILL BE SLOW TO FADE. WEAK RIDGING
WILL PERSIST ELSEWHERE.

ELSEWHERE ALOFT...AN UPPER HIGH IS JUST OFFSHORE N FLORIDA NEAR
30N79W. ANOTHER UPPER HIGH IS OVER THE CENTRAL ATLC NEAR 22N42W
THAT IS SURROUNDED BY DRY/STABLE AIR. THIS UPPER HIGH...AMONG
OTHER BENIGN UPPER FEATURES...IS EMBEDDED IN THE LARGER SCALE
RIDGING EXTENDING E FROM THE COAST OF AFRICA.

$$
WILLIS


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