[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE SEP 04 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
1715 UTC.

...SPECIAL FEATURES...

FELIX MADE LANDFALL ACROSS THE NE COAST OF NICARAGUA EARLY THIS
MORNING. THE CENTER OF STORM HAS NOW MOVED INLAND ACROSS NRN
NICARAGUA. AT 04/1800 UTC FELIX IS CENTERED NEAR 14.2N 84.5W OR
ABOUT 75 MI WEST OF PUERTO CABEZAS NICARAGUA...MOVING W AT 12
KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 962 MB. MAXIMUM
SUSTAINED WIND SPEED HAS DECREASED TO 85 KT WITH GUSTS TO 100
KT. 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. NOW THAT
FELIX IS INLAND AND INTERACTING WITH THE ROUGH TERRAIN OF
NICARAGUA AND HONDURAS STEADY WEAKENING IS UNDERWAY. THE EYE HAS
FILLED AND CLOUD TOPS ARE WARMING. RAINFALL IS NOW ONE OF THE
BIGGEST CONCERNS. FELIX IS EXPECTED TO PRODUCE 8 TO 12 INCHES OF
RAIN ACROSS NORTHERN NICARAGUA AND EL SALVADOR...WITH 10 TO 15
INCHES OVER MUCH OF HONDURAS. ISOLATED MAXIMUM AMOUNT OF 25
INCHES ARE POSSIBLE IN MOUNTAINOUS AREAS. THESE RAINS WILL
LIKELY PRODUCE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES.
PERSONS IN FLOOD-PRONE AREAS SHOULD TAKE ALL NECESSARY
PRECAUTIONS TO PROTECT LIFE AND PROPERTY.

AN AREA OF LOW PRES...ANALYZED 1010 MB...IS CENTERED NEAR
29N75W. VISIBLE SATELLITE IMAGES SHOW THAT THE CLOUD PATTERN
ASSOCIATED WITH THE LOW IS STRETCHED. A WELL DEFINED TROUGH
HANGS SW FROM THE LOW TO THE STRAITS OF FLORIDA AND EWD FROM THE
LOW TO 30N67W. THIS OVERALL STRUCTURE APPEARS NON-TROPICAL IN
NATURE. HOWEVER...THE CIRCULATION HAS BECOME BETTER APPARENT AND
THIS SYSTEM HAS THE POTENTIAL TO BECOME A TROPICAL OR
SUBTROPICAL CYCLONE OVER THE NEXT COUPLE OF DAYS AS IT MOVES
SLOWLY AND ERRATICALLY. IR IMAGES AND LIGHTNING DATA SUGGEST
THAT SCATTERED SHOWERS AND TSTMS ARE FROM 27N-30N BETWEEN
72W-76W AND WITHIN 45 NM AHEAD OF THE TROUGH.

...TROPICAL WAVES...

LARGE TROPICAL WAVE IS ALONG 30W/31W S OF 22N MOVING W 15 KT.
THIS AXIS IS ROUGHLY PLACED IN THE MIDDLE OF A STRETCHED GYRE
COVERING CLOSE TO A 15 DEG E-W AREA. A FEW SURROUNDING SHIP/BUOY
OBSERVATIONS AND A DIRECT QSCAT OVERPASS HELPED DEFINE THE AXIS
AND SUGGEST THAT THIS CYCLONIC TURNING IS AT THE SFC. EVEN
THOUGH THE WAVE STRUCTURE IS WELL DEFINED...SHOWER ACTIVITY
REMAINS VERY LIMITED LIKELY SUPPRESSED BY THE STABLE LOW TO MID
LEVEL AIR SURROUNDING THIS FEATURE.

TROPICAL WAVE IS ALONG 62W S OF 22N MOVING W 15 KT. THIS WAVE
HAS BECOME LESS DEFINED TODAY AND IT IS LIKELY GOING TO
SPLIT...IF IT HAS NOT ALREADY...AS THE NRN PART LIES IN A
DIFFLUENT LOW LEVEL PATTERN. SHOWER ACTIVITY...OR EVEN ORGANIZED
CLOUDINESS...IS MINIMAL. THE 1012 MB LOW TO THE E NEAR 11N40W
...POSSIBLY SPAWNED FROM THIS WAVE...HAS BEEN ON A SLOW DRIFT
OVER THE PAST COUPLE OF DAYS. THIS LOW HAS GENERALLY CHANGED
LITTLE SINCE YESTERDAY AND IT MAY BECOME SOMEWHAT ABSORBED BY
THE LARGE TROPICAL WAVE TO IT'S E. SCATTERED SHOWERS AND TSTMS
ARE WITHIN 75 NM OF THE LOW.

THE NRN PART OF A TROPICAL WAVE IS OVER PORTIONS OF CENTRAL
AMERICA AND THE BAY OF CAMPECHE ALONG 91W/92W MOVING W 10-15 KT.
THIS ONCE ACTIVE WAVE IS NO LONGER EASILY DISCERNIBLE IN ANY OF
THE AVAILABLE DATA...THEREFORE THE CURRENT POSITION IS BASED ON
FORWARD EXTRAPOLATION. SHOWERS AND TSTMS ARE PRIMARILY ACROSS
THE EPAC WATERS...SEE THE EAST PACIFIC TWD MIATWDEP FOR DETAILS.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 12N16W 15N27W 12N36W 8N51W 9N58W.
SCATTERED SHOWERS AND ISOLATED TSTMS ARE LOCATED WELL S OF THE
ANALYZED AXIS NEAR A CONVERGENT ZONE BETWEEN SLY AND SWLY FLOW
FROM 5N-7N BETWEEN 17W-47W.

DISCUSSION...

GULF OF MEXICO...
AN ELONGATED UPPER HIGH IS STRETCHED ACROSS THE SRN U.S. AND NRN
MEXICO. DIFFLUENT FLOW ALOFT BETWEEN THIS HIGH AND DEEP LAYER
TROUGHING FURTHER E IS PRODUCING SCATTERED SHOWERS AND TSTMS
ACROSS THE N CENTRAL AND NE GULF FROM 28N-29N BETWEEN THE TAMPA
BAY AREA TO THE SRN MISSISSIPPI COAST. LIGHTER LESS ORGANIZED
ACTIVITY IS MOSTLY INLAND OVER TEXAS ALSO ASSOCIATED WITH
DIFFLUENCE ALOFT AND A LINGERING LOW-LEVEL TROUGH. ENHANCED
CONFLUENT UPPER FLOW BETWEEN THE STRETCHED HIGH AND AN UPPER LOW
IN THE BAY OF CAMPECHE IS DRYING OUT THE AIR IN THE MID AND
UPPER LEVELS...PROVIDING MOSTLY FAIR WEATHER ACROSS MUCH OF THE
CENTRAL AND SW GULF. AT THE SFC...A WEAK 1018 MB HIGH IS
CENTERED NEAR 28N92W. THIS IS KEEPING WINDS RATHER LIGHT OUT OF
THE E TO SE ACROSS THE REGION.

CARIBBEAN SEA...
HURRICANE FELIX IS THE MAIN FOCUS THIS MORNING AS IT MOVES
FURTHER INLAND OVER NICARAGUA AND HONDURAS. FOR MORE DETAILS ON
FELIX REFER TO THE SPECIAL FEATURE SECTION ABOVE. THE
INTERACTION BETWEEN AN UPPER LOW IN THE SE CARIB NEAR 13N64W AND
A WEAK TROPICAL WAVE IS PRODUCING SOME CLOUDINESS AND ISOLATED
SHOWERS ACROSS THE WINDWARD ISLANDS. NELY UPPER FLOW BETWEEN THE
UPPER LOW AND A MID-TO UPPER RIDGE TO THE N IS PRODUCING A
FAIR AMOUNT OF DRY STABLE AIR ALOFT...SUPPRESSING DEEP
CLOUDINESS BETWEEN THE WINDWARD ISLANDS AND 70W. A CLUSTER OF
TSTMS HAS DEVELOPED OVER NRN VENEZUELA...LIKELY TIED TO THE
ITCZ.

ATLANTIC OCEAN...
AN AREA OF LOW PRES CENTERED BETWEEN BERMUDA AND THE NE FLORIDA
COAST IS ORGANIZING. FOR MORE DETAILS REFER TO THE SPECIAL
FEATURE SECTION ABOVE. ANOTHER LOW PRES SYSTEM...1014 MB...IS
LOCATED ALONG OUR N BORDER NEAR 31N55W. THIS LOW LIES AT THE
BASE OF A FRONTAL ZONE. ASSOCIATED SCATTERED SHOWERS AND TSTMS
ARE N OF 26N BETWEEN 50W-57W. ELSEWHERE AT THE SFC...A
STATIONARY 1023 MB HIGH IS NEAR 28N36W PROVIDING MODERATE
RIDGING ACROSS THE CENTRAL AND E ATLC. A WEAK 1016 MB HIGH IS
LOCATED FURTHER W NEAR 25N67W. THIS PATTERN HAS ALLOWED TRADES
TO REMAIN LIGHT TO MODERATE ACROSS MOST OF THE AREA...SLIGHTLY
STRONGER NEAR THE LARGE TROPICAL WAVE IN THE E ATLC. ALOFT...A
DOMINATING UPPER HIGH REMAINS PARKED ACROSS THE AREA CENTERED
NEAR 24N33W. ABUNDANT DRY AIR IS EMBEDDED WITHIN THIS RIDGE
PROVIDING FAIR WEATHER FOR MUCH OF THE CENTRAL AND E ATLC.

$$
CANGIALOSI

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