[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED OCT 04 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
1745 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 41 S OF 19N WITH AN EXPOSED 1011 MB LOW
ON THE WAVE NEAR 12N MOVING W 10-15 KT. THIS LOW IS FORECAST TO
DISSIPATE OVER THE NEXT 24 HRS. THIS WAVE IS EXPERIENCING FAIRLY
SIGNIFICANT W/SW SHEAR S OF AN UPPER TROUGH. SCATTERED MODERATE
CONVECTION IS FROM 16N-18N BETWEEN 38W-41W...WITH SCATTERED
SHOWERS/TSTMS ALSO NOTED NEAR THE ITCZ AND WAVE AXIS FROM 8N-13N
BETWEEN 37W-45W.

A LOW AMPLITUDE TROPICAL WAVE IS ALONG 51W/52W S OF 15N MOVING W
NEAR 10 KT. SUBTLE CYCLONIC TURNING OF THE LOW TO MID CLOUD
FIELD NOTED FROM 7N-13N BETWEEN 49W-56W. SHOWER/TSTM ACTIVITY IS
MINIMAL WITH THE ONLY ISOLATED ACTIVITY NOTED WITHIN 75NM OF THE
AXIS FROM 8N-12N.

TROPICAL WAVE IS ALONG 70W/71 S OF 20N MOVING W 10 TO 15 KT.
THERE IS A SLIGHT INVERTED V PATTERN NOTED...WITH CONVECTION
MOSTLY LIMITED TO THE FAR N PORTION. THESE SCATTERED SHOWERS
WITH EMBEDDED TSTMS ARE SEEN FROM 15N-19N BETWEEN 66W-75W. SAN
JUAN DOPPLER RADAR SHOWS THESE SHOWERS AFFECTING THE VIRGIN
ISLANDS...PUERTO RICO...AND THE DOMINICAN REPUBLIC.

TROPICAL WAVE IS ALONG 92W/93W S OF 17N MOVING W AT 10-15 KT.
WAVE IS INLAND OVER SE MEXICO AND ENHANCING DISORGANIZED
CONVECTION IN THE EPAC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 10N14W 6N25W 10N37W 9N50W 7N58W.
OUTSIDE OF THE CONVECTION NEAR THE TROPICAL WAVES...PATCHES OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE OVER THE COAST
OF AFRICA AND ADJACENT ATLC WATERS FROM 5N-13N BETWEEN 13W-19W.
SCATTERED SHOWERS/TSTMS FROM 1N-7N BETWEEN 20W-36W WHICH IS
PARTLY BEING INFLUENCED BY SPEED CONFLUENCE S OF THE ITCZ.

...DISCUSSION...
GULF OF MEXICO...
AN UPPER TROUGH EXTENDS DOWN THE COAST OF TEXAS THROUGH NE
MEXICO. UPPER DIFFLUENCE BETWEEN THIS FEATURE AND THE
ANTICYCLONIC FLOW AROUND AN UPPER RIDGE EXTENDING N FROM THE
YUCATAN IS HELPING TO SUPPORT THE SCATTERED MODERATE CONVECTION
IN THE SW GULF/BAY OF CAMPECHE FROM 19N-25N BETWEEN 91W-98W.
THERE IS ALSO A SURFACE TROUGH IN THIS REGION ALONG 19N92W
27N96W. ANOTHER AREA OF SCATTERED MODERATE CONVECTION IS IN THE
SRN GULF FROM 22N-25N BETWEEN 83W-91W. ASSOCIATED MOISTURE AND
HIGH CLOUDS FROM THESE SHOWER/TSTM REGIONS ARE STREAMING TO THE
E AROUND THE RIDGING OVER THE GULF THROUGH 85W. THE FAR ERN GULF
E OF 85W IS UNDER VERY DRY MID TO UPPER AIR WITH TROUGHING
JUST OFF THE EAST COAST. A 1025 MB SURFACE HIGH IS EXTENDING S
FROM ITS CENTER NEAR ASHEVILLE...PRODUCING 15-20 KT E WINDS
ACROSS MUCH OF THE GULF. THIS IS EXPECTED TO PERSIST THE NEXT
COUPLE OF DAYS...SENDING A MODERATE E SWELL THROUGH THE WRN GULF
AFFECTING COASTAL TX AND MEXICO THROUGH THE END OF THE WEEK.

CARIBBEAN SEA...
MID TO UPPER ANTICYCLONIC FLOW IS DOMINATING MUCH OF THE WRN
CARIBBEAN ON THE W SIDE OF AN UPPER RIDGE EXTENDING THROUGH
CENTRAL AMERICA/SE MEXICO. ISOLATED SHOWERS/TSTMS SEEN IN THE NW
CARIBBEAN FROM 17N-22N BETWEEN 82W-88W. AN UPPER TROUGH IS
EXTENDING S/SE THROUGH ERN CUBA AND HISPANIOLA INTO THE CENTRAL
CARIBBEAN. UPPER DIFFLUENCE BETWEEN THIS TROUGH AND A SHORT WAVE
RIDGE OVER THE ERN CARIBBEAN IS HELPING TO SUPPORT THE SCATTERED
SHOWERS/TSTMS IN THE WATERS S OF HISPANIOLA THROUGH PUERTO RICO
FROM 15N-19N BETWEEN 65W-77W. THIS ACTIVITY ALSO BEING ENHANCED
BY THE TROPICAL WAVE MOVING THROUGH THE AREA. 10-20 KT TRADES
PERSIST AT THE SURFACE WITH SLIGHTLY STRONGER WINDS NEAR THE
COLOMBIAN COAST...AS S SIDE OF HIGH PRESSURE INTERACTS WITH
LOWER PRESSURE NEAR COLOMBIA.

ATLANTIC OCEAN...
UPPER LEVEL TROUGH EXTENDS THROUGH THE SW NORTH ATLC WITH VERY
DRY MID TO UPPER AIR JUST OFF THE FLORIDA AND SE US COAST. THIS
REGION ALSO DOMINATED BY THE SRN PORTION OF A 1025MB SURFACE
HIGH CENTERED NEAR ASHEVILLE NORTH CAROLINA. THIS HIGH WILL
REMAIN STATIONARY OVER THE NEXT 24HRS...AND WILL CONTINUE TO
PRODUCE MODERATE NE/E WINDS AND SHORT PERIOD WIND SWELL OFF
FLORIDA. SEE STATEMENTS FROM LOCAL WEATHER SERVICE OFFICES FOR
MORE INFO. NUMEROUS MODERATE CONVECTION EXTENDING NE FROM THE SE
BAHAMAS FROM 21N-30N BETWEEN 68W-75W...ASSOCIATED WITH A SURFACE
TROUGH EXTENDING NE FROM 22N74W THROUGH 31N64W. THE ASSOCIATED
MOISTURE/CLOUDINESS IS BEING STRETCHED NE WITH UPPER SW FLOW
BETWEEN THE TROUGHING OFF THE EAST COAST AND AN UPPER HIGH JUST
N OF THE LEEWARD ISLANDS. ANOTHER UPPER HIGH IS SEEN IN WV
IMAGERY NEAR 27N51W SURROUNDED BY VERY DRY MID TO UPPER AIR. A
DEEP LAYER LOW IS NEAR 31N35W WHERE A WEAK 1016MB SURFACE LOW IS
ALSO ANALYZED. THIS LOW IS EXPECTED TO WEAKEN FURTHER WHILE
DRIFTING N...EVENTUALLY GETTING ABSORBED INTO A FRONTAL SYSTEM
IN THE NORTH ATLANTIC. THERE IS AN ELONGATED UPPER TROUGH
EXTENDING SW FROM THIS REGION ALONG 24N37W 20N43W 20N56W. UPPER
W TO SW FLOW S OF THIS TROUGH IS SHEARING THE TWO TROPICAL WAVES
IN THE AREA. AN UPPER HIGH PERSISTS JUST OFF THE W COAST OF
AFRICA. THE ERN ATLC ALSO DOMINATED BY THE SOUTHERN PORTION OF A
1030MB SURFACE HIGH JUST N OF THE MADEIRA ISLANDS.

$$
WILLIS




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