[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 312359
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT WED OCT 31 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 FEATURE...
THE CENTER OF TROPICAL STORM NOEL DRIFTED WESTWARD FOR A
FEW HOURS AROUND MIDDAY...BUT RECENTLY HAS BEEN NEARLY
STATIONARY JUST OFFSHORE OF THE NORTH COAST OF CUBA. NOEL IS
FORECAST TO MOVE TOWARD THE ANDROS ISLAND IN THE BAHAMAS TONIGHT
AND ACROSS THE NW BAHAMAS ON THU BEFORE BECOMING EXTRATROPICAL
IN ABOUT 48 HRS. AT 01/0000 UTC...THE CENTER OF TROPICAL STORM
NOEL WAS LOCATED BY A NOAA HURRICANE HUNTER AIRCRAFT NEAR
LATITUDE 22.9 NORTH...LONGITUDE 78.5 WEST OR ABOUT 140 NM...260
KM...SOUTH-SOUTHWEST OF NASSAU AND ABOUT 200 NM...370 KM...
SOUTH-SOUTHEAST OF MIAMI FLORIDA. ESTIMATED MINIMUM CENTRAL
PRESSURE IS 996 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH
GUSTS TO 55 KT. SEE THE NHC FORECAST/ ADVISORY UNDER AWIPS/WMO
HEADERS MIATCMAT1/ WTNT21 KNHC AND/OR THE PUBLIC ADVISORY UNDER
MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS. DEEP CONVECTION REMAINS
JUST NE OF THE CENTER AFFECTING THE CENTRAL BAHAMAS. THIS
TROPICAL CYCLONE IS EXPECTED TO PRODUCE SIGNIFICANT RAINFALL
ACCUMULATIONS OVER THE BAHAMAS AND ADDITIONAL RAINFALL AMOUNTS
OVER CUBA AND HISPANIOLA. RAINS IN HISPANIOLA AND CUBA ARE
EXPECTED TO CAUSE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES.
OCCASIONALLY HEAVY SHOWERS AND GUSTY WINDS UP TO 35 KT WILL
CONTINUE TO AFFECT SE FLORIDA...INCLUDING THE CITY OF MIAMI. AT
31/2100 UTC...A TROPICAL STORM WATCH WAS ISSUED FROM SE FLORIDA
NORTH OF OCEAN REEF TO JUPITER INLET FLORIDA.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 73W S OF 18N MOVING SLOWLY WWD. THE WAVE
STILL SHOWS UP IN THE UW-CIMSS TPW PRODUCT AND 850 MB SATELLITE
DERIVED VORTICITY. THIS FEATURE IS PROBABLY GENERATING A CLUSTER
OF MODERATE TO STRONG CONVECTION OVER LAKE MARACAIBO IN WESTERN
VENEZUELA. THE WAVE MAY BE ABSORBED BY THE TROPICAL CYCLONE.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 9N13W 5N25W 6N42W 4N58W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 2N-7N
BETWEEN 15W-25W. SIMILAR CONVECTION IS N OF AXIS NEAR 6N44W AND
OVER FRENCH GUIANA. CLUSTERS OF MODERATE TO STRONG CONVECTION
ARE OVER SIERRA LEONE AND LIBERIA.

DISCUSSION...
GULF OF MEXICO...
A DISSIPATING STATIONARY FRONT REMAINS ACROSS FLORIDA JUST N OF
TAMPA BAY AND THE NE PORTION OF THE GULF. SCATTERED SHOWERS AND
ISOLATED TSTMS ARE ASSOCIATED WITH THE FRONTAL BOUNDARY.
ALOFT...A SHORTWAVE TROUGH IS MOVING EWD ACROSS THE N-CENTRAL
GULF WATERS. SOUTHWESTERLY WINDS AHEAD OF THIS TROUGH ARE
ADVANCING TOWARD THE NOEL AND ARE EXPECTED TO INDUCE A NORTHWARD
AND THEN NORTHEASTWARD ACCELERATION OF THIS TROPICAL CYCLONE.
UPPER DRY AIR WITH MODERATE TO STRONG SUBSIDENCE DOMINATES MOST
OF THE AREA. THE TIGHT PRESSURE GRADIENT BETWEEN THE STRONG
SURFACE HIGH OVER THE ATLC OCEAN COMBINED WITH TROPICAL STORM
NOEL IS PRODUCING STRONG NE WINDS OF 20 TO 30 KT ACROSS THE
EASTERN GULF. THIS WEATHER PATTERN WILL PERSIST DURING THE NEXT
DAY OR SO. EVEN THOUGH MOST OF THE DEEP CONVECTION RELATED TO
T.S. NOEL IS NE OF CENTER...LOW LEVEL CLOUDS WITH EMBEDDED
SHOWERS...   ASSOCIATED WITH THE BROAD CIRCULATION OF NOEL...ARE
ROTATING ACROSS THE SE GULF INTO THE NW CARIBBEAN.

CARIBBEAN SEA...
THE EFFECTS OF T.S. NOEL CONTINUE ACROSS THE BASIN. DEEP LOW
LEVEL CONVERGENT FLOW E OF NOEL IS PRODUCING POCKETS OF SHOWERS
WITH EMBEDDED TSTMS OVER THE CENTRAL CARIBBEAN MOVING INTO
JAMAICA...EASTERN CUBA AND HISPANIOLA. THIS ACTIVITY MAY ALSO BE
GETTING SOME SUPPORT BY AN UPPER COL REGION BETWEEN ANTICYCLONES
OVER THE E AND W PORTIONS OF THE BASIN. A SFC TROUGH EXTENDS
FROM NOEL TO THE SW CARIBBEAN NEAR THE COSTA RICA/PANAMA BORDER.
THIS TROUGH IS MOVING IN TANDEM WITH THE TROPICAL CYCLONE. AN
EARLIER ASCAT PASS SHOWED VERY WELL THE WIND SHIFT ASSOCIATED
WITH THIS TROUGH. UPPER NELY WINDS AND DRY AIR DOMINATES THE
EASTERN CARIBBEAN. TRADE WINDS ARE EXPECTED TO REMAIN DISRUPTED
OVER THE WRN CARIBBEAN OVER THE NEXT COUPLE OF DAYS DUE TO THE
TROUGHING S OF T.S. NOEL. LIGHT TO MODERATE TRADES ARE BLOWING
ACROSS THE ERN CARIBBEAN.

ATLANTIC OCEAN...
THE MAIN STORY CONTINUES TO BE TROPICAL STORM NOEL THAT REMAINS
NEARLY STATIONARY BETWEEN CENTRAL CUBA AND ANDROS ISLAND IN THE
BAHAMAS. NOEL IS INTERACTING WITH STRONG HIGH PRES OVER THE ATLC
OCEAN AND A STATIONARY FRONT EXTENDING ALONG 28N/29N OVER THE
WESTERN ATLC. THIS IS PRODUCING STRONG GUSTY WINDS OF 25 TO 35
KT AND LARGE SEAS UP TO 18 FT OVER MUCH OF THE WRN ATLC. A GALE
WARNING IS CURRENTLY IN EFFECT N OF 23N W OF 65W. A MID/UPPER
TROUGH OVER THE N/CENTRAL ATLC SUPPORTS THE FRONT...WHICH SHOULD
START TO DISSIPATE AS THE UPPER LEVEL ENERGY PULLS FATHER AWAY
FROM THE AREA. THE UPPER LEVEL HIGH ASSOCIATED WITH TROPICAL
STORM NOEL EXTENDS OVER THE REMAINDER OF THE W ATLC S OF 31N W
OF 57W PROVIDING GOOD OUTFLOW MOSTLY NE OF NOEL. MID/UPPER LEVEL
MOISTURE AND HIGH CLOUDS COVER MOST OF THE W ATLC. A CUT-OFF
UPPER LOW IS IN THE TROPICAL ATLC NEAR 15N52W PRODUCING ISOLATED
TO SCATTERED SHOWERS FROM 11N-16N BETWEEN 47W-53W. AN E/W UPPER
LEVEL RIDGE EXTENDS FROM OFF AFRICA ALONG 9N/10N TO 40W. A BROAD
UPPER TROUGH COVERS THE E ATLC N OF 20N E OF 24W BUT DOES NOT
APPEAR TO BE GENERATING SIGNIFICANT WEATHER. THE REMAINDER OF
THE E ATLC IS MOSTLY QUIET UNDER THE INFLUENCE OF A SFC RIDGE
WITH TYPICAL PATCHES OF STABLE STRATOCUMULUS CLOUDS. TRADES ARE
MOSTLY MODERATE OVER THE AREA S OF 25N E OF 60W...WITH SLIGHTLY
STRONGER NE WINDS NOTED JUST OFF THE COAST OF W AFRICA BETWEEN
THE CANARY/CAPE VERDE ISLANDS.

$$
GR


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