[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 040007
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON SEP 03 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...

HURRICANE FELIX IS AN EXTREMELY DANGEROUS HURRICANE AND COULD
RESTRENGTHEN BEFORE LANDFALL. FELIX IS CENTERED NEAR 14.5N 80.2W
AT 04/0000 UTC OR ABOUT 205 NM EAST OF CABO GRACIAS A DIOS ON
THE NICARAGUA/HONDURAS BORDER...MOVING W AT 17 KT. THE MINIMUM
CENTRAL PRESSURE ESTIMATED FROM AIR FORCE HURRICANE HUNTER
AIRCRAFT DATA IS 953 MB. MAXIMUM SUSTAINED WIND SPEED IS 115 KT
WITH GUSTS TO 140 KT. THIS MAKES FELIX A CATEGORY FOUR HURRICANE
ON THE SAFFIR-SIMPSON SCALE. SEE LATEST NHC INTERMEDIATE PUBLIC
ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE
FULL FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21
KNHC FOR MORE DETAILS INCLUDING THE LATEST WATCH AND WARNING
INFORMATION. FELIX CONTINUES ON A RATHER QUICK W PATH STEERED
BY A STRONG RIDGE TO ITS N. IR SATELLITE IMAGES DEPICT SOME
STRUCTURAL CHANGES TO THE SHAPE AND SIZE OF THE CONVECTIVE
PATTERN OVER TIME WITH THE EYEWALL NOT QUITE AS SYMMETRIC AS
EARLIER. NUMEROUS STRONG CONVECTION IS FROM 13N-15N BETWEEN
78W-81W.  SCATTERED MODERATE CONVECTION EXTENDS FROM 11N-17N
BETWEEN 77W-84W TO INCLUDE EASTERN MOST NICARAGUA AND
HONDURAS.

A LOW PRESSURE AREA IS OFF THE GEORGIA COASTLINE CENTERED NEAR
31N79W...ESTIMATED TO BE 1013 MB. VISIBLE SATELLITE IMAGERY
SHOWS SOME IMPROVEMENT IN ORGANIZATION WITH LOW-LEVEL TURNING
EASILY APPARENT. AT THE MOMENT...THIS LOW IS STILL SOMEWHAT
FRONTAL IN NATURE WITH A SHIELD OF LOW CLOUDS LINEARLY SHAPED TO
THE E OF THE CIRCULATION. HOWEVER...THERE IS SOME POTENTIAL FOR
SLOW TROPICAL DEVELOPMENT AS IT DRIFTS EASTWARD DURING THE NEXT
COUPLE OF DAYS. DISORGANIZED SHOWERS AND TSTMS ARE WITHIN 180 NM
MOSTLY TO THE E OF THE LOW-LEVEL CENTER.

...TROPICAL WAVES...

LARGE TROPICAL WAVE IS ALONG 27W S OF 22N MOVING W 15 KT. THIS
WAVE IS EMBEDDED WITHIN A STRETCHED GYRE COVERING CLOSE TO A 15
DEG E-W AREA. A FEW SURROUNDING SHIP/BUOY OBSERVATIONS AND A
PARTIAL QSCAT PASS SUGGEST THAT THIS CYCLONIC TURNING IS AT THE
SFC. THE LATEST SATELLITE IMAGERY SHOWS ROTATION CONCENTRATED
ALONG THE WAVE AXIS NEAR 14N...THUS A 1011 MB LOW IS ADDED TO
THE 18Z SYNOPTIC MAP TO REFLECT THIS. EVEN THOUGH THE WAVE
STRUCTURE HAS IMPROVED A BIT...SHOWER ACTIVITY REMAINS VERY
LIMITED LIKELY SUPPRESSED BY THE STABLE LOW TO MID LEVEL AIR
SURROUNDING THIS FEATURE.

TROPICAL WAVE IS ALONG 58W S OF 22N MOVING W 10 KT. SATELLITE
IMAGERY SHOWS A CLASSIC INVERTED V-SHAPE TO THE LOW CLOUD FIELD.
SFC OBSERVATIONS MATCH THE SATELLITE SIGNATURE WITH LOWER
PRESSURES CLOSER TO THE WAVE AXIS AND WINDS TURNING
CYCLONICALLY. SHOWER ACTIVITY REMAINS MINIMAL AND CONFINED TO
THE INTERSECTION OF THE ITCZ FROM 10N-12N BETWEEN
54W-58W...SUPPRESSED BY SINKING AIR PRODUCED BY AN UPPER TROUGH.

TROPICAL WAVE IS OVER CENTRAL AMERICA ALONG 89W MOVING W 10-15
KT. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION HAS
RECENTLY FLARED UP OVER CENTRAL AMERICA FROM EL SALVADOR TO THE
NORTHERN YUCATAN PENINSULA BETWEEN 87W-92W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 15N17W 16N20W 11N30W 11N50W 10N63W.
SCATTERED SHOWERS AND TSTMS COVER A LARGE AREA ROUGHLY FROM
6N-10N E OF 43W ASSOCIATED WITH CROSS EQUATORIAL SWLY FLOW.

DISCUSSION...

GULF OF MEXICO...
A 1021 MB HIGH IS CENTERED S OF LOUISIANA NEAR 28N90W.  A
SURFACE TROUGH IS ALONG THE COAST OF TEXAS ALONG 31N94W 25N97W.
SCATTERED MODERATE CONVECTION IS OVER E TEXAS AND THE NW GULF OF
MEXICO FROM 26N-31N BETWEEN 93W-97W.  A TROPICAL WAVE IS
PRODUCING CONVECTION OVER THE YUCATAN PENINSULA.  SEE ABOVE.
ELSEWHERE... SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
OVER S FLORIDA FROM 25N-28N BETWEEN 80W-83W.  IN THE UPPER
LEVELS... AN UPPER LEVEL HIGH IS OVER THE NORTH CENTRAL GULF OF
MEXICO NEAR 28N88W.  A SMALL UPPER LEVEL LOW IS OVER THE
NORTHERN TIP OF THE YUCATAN PENINSULA NEAR 22N89W.  ANOTHER
SMALL UPPER LEVEL LOW IS OVER S MEXICO NEAR 16N93W.  EXPECT
CONTINUED CONVECTION OVER TEXAS AND THE SW GULF DURING THE NEXT
24 HOURS.  ALSO EXPECT INCREASED CONVECTION OVER THE YUCATAN
PENINSULA DUE TO FELIX DURING THE NEXT 24 HOURS.

CARIBBEAN SEA...
EXTREMELY DANGEROUS HURRICANE FELIX IS EXPECTED TO MAKE LANDFALL
OVER CENTRAL AMERICA IN LESS THAN 24 HOURS.  FELIX IS EXPECTED
TO PRODUCE 5 TO 8 INCHES ACROSS NORTHERN HONDURAS AND
NORTHEASTERN NICARAGUA ...WITH POSSIBLE ISOLATED MAXIMUM AMOUNTS
OF 12 INCHES.  THESE RAINS COULD PRODUCE LIFE-THREATENING FLASH
FLOODS AND MUD SLIDES.  SEVERAL WATCHES AND WARNINGS ARE IN
EFFECT. FOR DETAILS AND REFERENCES SEE SPECIAL FEATURE SECTION
ABOVE.  FURTHER S... A 1008 MB LOW IS CENTERED OVER N COLOMBIA
NEAR 8N75W.  SCATTERED MODERATE TO STRONG CONVECTION IS FROM
7N-12N BETWEEN 72W-77W.  MOSTLY FAIR WEATHER IS OVER THE EASTERN
CARIBBEAN SEA E OF 73W.  IN THE UPPER LEVELS...UPPER LEVEL
OUTFLOW FROM FELIX IS MOSTLY SYMMETRICAL FROM 8N-20N BETWEEN
74W-85W.  MORE UPPER LEVEL RIDGING WITH STRONG SUBSIDENCE IS
OVER THE E CARIBBEAN SEA E OF 70W.

ATLANTIC OCEAN...
A STALLED FRONT IS OVER THE WESTERN ATLANTIC FROM 30N66W TO
32N75W TO A 1013 MB LOW PRES SYSTEM CENTERED OFF THE GEORGIA
COAST NEAR 31N79W.  A SFC TROUGH HANGS SW FROM THE LOW TO THE
STRAITS OF FLORIDA NEAR 25N80W.  SCATTERED MODERATE CONVECTION
IS E OF THE TROUGH FROM 28N-31N BETWEEN 71W-78W.  ANOTHER 1015
MB LOW IS OVER THE CENTRAL ATLANTIC NEAR 29N58W.  A TROUGH
EXTENDS SW FROM THE LOW TO 27N63W.  SCATTERED SHOWERS ARE WITHIN
60 NM OF THE TROUGH.  A 1022 MB HIGH IS OVER THE CENTRAL
ATLANTIC NEAR 27N39W PRODUCING FAIR WEATHER.  IN THE UPPER
LEVELS... RIDGING IS OVER THE W ATLANTIC W OF 60W.  A SMALL
UPPER LEVEL LOW IS CENTERED OVER THE CENTRAL ATLANTIC NEAR
25N53W.  A LARGE UPPER LEVEL HIGH IS OVER THE E ATLANTIC
CENTERED NEAR 23N37W.  ANTICYCLONIC FLOW IS FROM 10N-30N BETWEEN
5W-50W.

$$
FORMOSA





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