[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 140002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU SEP 13 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...

TROPICAL DEPRESSION HUMBERTO IS LOCATED NEAR 31.4N 92.6W AT
13/2100 UTC OR ABOUT 10 MILES...15 KM...NORTHWEST OF ALEXANDRIA
LOUISIANA MOVING NORTHEAST AT 10 KT.  ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1003 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH
GUSTS TO 40 KT.  SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS.
RAINFALL AMOUNTS OF 4 TO 6 INCHES ARE EXPECTED THROUGH FRIDAY
NEAR THE TRACK OF HUMBERTO OVER PORTIONS OF MISSISSIPPI...
ALABAMA...AND EASTERN LOUISIANA.  ISOLATED MAXIMUM ACCUMULATIONS
OF 8 INCHES ARE POSSIBLE.  PRESENTLY...A RESIDUAL CONVECTIVE
BAND IS OVER THE N GULF OF MEXICO FROM 27N-30N BETWEEN 88W-92W.

TROPICAL DEPRESSION EIGHT IS LOCATED NEAR 14.2N 48.4W AT 13/2100
UTC OR ABOUT 865 MILES...1395 KM...EAST OF THE LESSER ANTILLES
MOVING WEST-NORTHWEST AT 5 KT.  ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH
GUSTS TO 40 KT.  SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.
ALTHOUGH UPPER-LEVEL CONDITIONS HAVE BECOME LESS FAVORABLE FOR
STRENGTHENING...THE DEPRESSION STILL HAS THE CHANCE TO BECOME A
TROPICAL STORM DURING THE NEXT 12 TO 24 HOURS.  A NOAA HURRICANE
HUNTER PLANE IS SCHEDULED TO INVESTIGATE THE SYSTEM THIS EVENING.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 21W S OF 17N MOVING W 10-15 KT.  A 1010
MB LOW IS ON THE WAVE AXIS NEAR 10N21W.  THIS WAVE SHOWS AN AREA
OF LOW CLOUDS FROM 6N-20N BETWEEN 15W-30W.  SCATTERED SHOWERS
ARE ALONG THE ITCZ FROM 5N-8N BETWEEN 18W-25W...AND W OF THE
WAVE AXIS FROM 8N-13N BETWEEN 21W-26W.

HIGH AMPLITUDE TROPICAL WAVE IS ALONG 39W/40W S OF 21N DRIFTING
WWD.  THE NRN PART OF THE WAVE IS BEGINNING TO FRACTURE BASED ON
THE POLEWARD MOVEMENT OF MOISTURE SEEN ON SATELLITE AND THE UW
CIMSS TPW ANIMATION. A TROUGH WAS ANALYZED TO REFLECT THIS ALONG
38W/39W FROM 22N-26N. THE GFS MODEL SUGGESTS THAT A SFC LOW MAY
FORM ALONG THE TROUGH AXIS DURING THE NEXT 24 HOURS.  SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS FROM 20N-26N BETWEEN
35W-40W.  FURTHER S... ISOLATED MODERATE CONVECTION IS ALONG THE
ITCZ FROM 2N-10N BETWEEN 34W-40W.

TROPICAL WAVE IS IN THE W CARIBBEAN ALONG 80W/81W S OF 22N
MOVING W 15 KT. THE WAVE IS INTERACTING WITH AN UPPER UPPER LOW
LOCATED W OF THE CAYMAN ISLANDS.  CLUSTERS OF SCATTERED MODERATE
TO STRONG CONVECTION IS OVER THE SW CARIBBEAN...PANAMA...AND N
COLOMBIA FROM 5N-13N BETWEEN 73W-83W.  SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS OVER NICARAGUA AND HONDURAS FROM
12N-16N BETWEEN 82W-87W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N10W 11N20W 9N30W 15N45W 10N60W.
BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES
AND T.D. EIGHT...SCATTERED MODERATE ISOLATED STRONG CONVECTION
IS ALONG THE COAST OF W AFRICA FROM 7N-13N BETWEEN 12W-15W.
SCATTERED MODERATE CONVECTION IS E OF TRINIDAD FROM 9N-11N
BETWEEN 58W-60W.

DISCUSSION...

THE GULF OF MEXICO...
T.D. HUMBERTO IS INLAND OVER LOUISIANA.  SEE SPECIAL FEATURES
FOR MORE DETAILS.  SCATTERED MODERATE CONVECTION IS INLAND OVER
THE YUCATAN PENINSULA FROM 17N-21N BETWEEN 88W-92W.  SCATTERED
MODERATE CONVECTION IS OVER S FLORIDA FROM 25N-28N BETWEEN
81W-83W.  ISOLATED MODERATE CONVECTION IS INLAND OVER N FLORIDA
FROM 30N-31N BETWEEN 81W-88W.  IN THE UPPER LEVELS... FAIRLY
GOOD OUTFLOW IS NOTED OVER HUMBERTO.  AN UPPER UPPER LOW LOCATED
W OF THE CAYMAN ISLANDS NEAR NEAR 21N83W IS PRODUCING CYCLONIC
TURNING OVER THE SE GULF OF MEXICO.  SIGNIFICANT UPPER LEVEL
MOISTURE WITH BROKEN TO OVERCAST HIGH CLOUDS COVERS THE ENTIRE
GULF OF MEXICO.  EXPECT HUMBERTO TO MOVE TO ALABAMA AND EXTEND A
SURFACE TROUGH TO THE NW GULF OF MEXICO WITH CONVECTION ALONG
THE TROUGH WITHIN THE NEXT 24 HOURS.

THE CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE W CARIBBEAN SEA.  SEE ABOVE. LIGHT
TO MODERATE TRADES ARE OVER THE REMAINDER OF THE SEA.  A 1007 MB
LOW IS CENTERED OVER N COLOMBIA NEAR 8N75W.  BESIDES THE
CONVECTION MENTIONED IN THE TROPICAL WAVE SECTION...ISOLATED
MODERATE CONVECTION IS OVER INLAND CUBA BETWEEN 76W-82W.  IN THE
UPPER LEVELS... AN UPPER UPPER LOW IS LOCATED W OF THE CAYMAN
ISLANDS NEAR NEAR 21N83W.  AN UPPER LEVEL HIGH IS CENTERED OVER
N COLOMBIA NEAR 11N74W.  SIGNIFICANT MOISTURE IS W OF 72W.
STRONG SUBSIDENCE IS E OF 72W.  EXPECT CONVECTION OVER THE
WESTERN CARIBBEAN AND CENTRAL AMERICA W OF 80W DURING THE NEXT
24 HOURS MAINLY DUE TO THE TROPICAL WAVE.

THE ATLANTIC OCEAN...
A 1022 MB HIGH IS OVER THE W ATLANTIC NEAR 32N61W.  A WEAK
SURFACE TROUGH IS FURTHER S OVER THE TROPICS ALONG 26N65W
21N62W. ISOLATED MODERATE CONVECTION IS WITHIN 60 NM E OF THE
TROUGH.  A SURFACE RIDGE IS OVER THE E ATLANTIC N OF 25N E OF
30W.  IN THE UPPER LEVELS... A RIDGE IS OVER THE W ATLANTIC N OF
22N W OF 70W.  AN UPPER LEVEL LOW IS OVER THE W ATLANTIC NEAR
26N65W.  A LARGE UPPER LEVEL HIGH IS OVER THE TROPICS NEAR T.D.
EIGHT AT 14N48W.  ANOTHER LARGE UPPER LEVEL HIGH IS OVER THE
EASTERN TROPICAL ATLANTIC NEAR 18N28W.

$$
FORMOSA


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