[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191805
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON SEP 19 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND 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
1715 UTC.

...SPECIAL FEATURES...

TROPICAL STORM RITA IS CENTERED NEAR 23.1N 75.9W...OR 165 MILES
SE OF NASSAU BAHAMAS...AT 19/1800 UTC MOVING WNW AT 12 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 993 MB. MAXIMUM SUSTAINED
WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. SEE LATEST NHC
FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC
AND THE PUBLIC ADVISORY UNDER HEADERS MIATCPAT3/WTNT33 KNHC FOR
MORE DETAILS.  RITA IS QUICKLY TURNING INTO A FORMIDABLE CYCLONE
WITH A CENTRAL DENSE OVERCAST AREA PRESENT ABOVE THE SURFACE
CENTER.  ALL INDICATIONS ARE THAT RITA WILL BE A HURRICANE LATER
TODAY OR TONIGHT AS IT APPROACHES THE ANDROS ISLAND THEN S
FLORIDA OR THE KEYS.  SCATTERED MODERATE WITHIN 75 NM OF THE
CENTER WITH WIDELY SCATTERED BANDS UP TO 240 NM NW OF THE CENTER
AND 330 NM E OF THE CENTER.

HURRICANE PHILIPPE IS CENTERED NEAR 17.4N 56.3W...OR 365 MILES E
OF THE LEEWARD ISLANDS...AT 19/1500 UTC MOVING NNW 6 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 988 MB. MAXIMUM SUSTAINED
WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC
FOR MORE DETAILS. STRONG WLY SHEAR IS PREVENTING ANY
INTENSIFICATION OF PHILIPPE THOUGH THE CYCLONE IS TRYING TO
REORGANIZE A BIT ON SATELLITE PICTURES.  SCATTERED MODERATE
CONVECTION FROM 14N-18.5N BETWEEN 52W-58W.

...TROPICAL WAVES...

E ATLC TROPICAL WAVE IS ALONG 26W S OF 18N MOVING W 10-15 KT
WITH A BROAD 1013 MB LOW ALONG THE WAVE NEAR 11N.  THE BROAD LOW
SEEMS TO BE IN BETWEEN TWO AREAS OF TSTMS.. ONE WITHIN 60 NM OF
LINE 15N23W 11N29W AND THE OTHER WITHIN 60 NM OF 10N25W.  SOME
DRY AIR IS SEEN ON VISIBLE SATELLITE N OF 14N BETWEEN THE CAPE
VERDES AND 39W.

E-CENTRAL ATLC TROPICAL WAVE IS ALONG 39W S OF 25N MOVING W
10-15 KT WITH A 1013 MB ALONG THE WAVE NEAR 13N.  ALTHOUGH THIS
IS A STRONG WAVE WITH WIND GUSTS LIKELY OVER 35 MPH... THE CLOUD
PATTERN IS BECOMING ELONGATED WITH NW SHEAR AFFECTING THE
SYSTEM.  THIS WAVE SEEMS TO HAVE LESS CHANCE OF DEVELOPING THAN
YESTERDAY AS THE SHEAR DISRUPTS THE LOW.  SCATTERED MODERATE
CONVECTION IS FROM 14N-18N BETWEEN 37W-42.5W.

W CARIBBEAN TROPICAL WAVE IS ALONG 78W S OF 20N MOVING W 10 KT.
A SMALL INCREASE IN MOISTURE IS THE EASIEST WAY TO LOCATE THE
WAVE.  LARGE TSTMS ARE ALSO AT THE SOUTHERN END WITH WIDELY
SCATTERED MODERATE CONVECTION S OF 13N BETWEEN 76W-81.5W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 16N17W 12N23W...THEN ALONG 8N27W
15N36W 15N43W 16N53W.  WIDELY SCATTERED MODERATE FROM 11N-14N
BETWEEN 23W-29W.

...DISCUSSION...

GULF OF MEXICO...
ONE MORE BEAUTIFUL DAY FOR THE GULF UNTIL RITA ENTERS THE
FLORIDA STRAITS TOMORROW.  DEEP-LAYERED HIGH PRESSURE IS SITTING
OVER LOUISIANA WITH A LITTLE DRIER AIR FILTERING INTO THE
EXTREME NRN GULF.  HOWEVER THIS WILL BE SHORT-LIVED AS WINDS
TURN ELY IN RESPONSE TO RITA.  A FEW SHOWERS ARE ALSO POSSIBLE
IN THE BAY OF CAMPECHE.  WEATHER WILL BE GOING DOWNHILL FAST
OVER S FLORIDA TONIGHT WITH BANDS OF SHOWERS ALREADY OVER THE
AREA AND THEY SHOULD CONTINUE TO INCREASE OVERNIGHT.

CARIBBEAN...
A LARGE AND NEARLY STATIONARY UPPER LEVEL LOW IS CENTERED NEAR
THE CAYMAN ISLANDS NEAR 20N80W WITH ITS CIRCULATION EXTENDING
FROM THE STRAITS OF FLORIDA S TO THE GULF OF HONDURAS BETWEEN
HAITI AND THE YUCATAN PENINSULA. THIS LOW IS ALSO ASSISTING
CONVECTION WITH A TROPICAL WAVE IN THE SW CARIBBEAN.  A FEW
TSTMS ARE IN THE NW UPPER FLOW IN THE GULF OF HONDURAS.  ANOTHER
LOW IS S OF PUERTO RICO WITH VERY DRY AIR ALOFT KEEPING THINGS
VERY QUIET OVER WATER IN THE E CARIBBEAN.  A FEW TSTMS ARE IN
THE NE LEEWARDS AND SRN WINDWARDS ASSOCIATED WITH SOME
PERIPHERAL MOISTURE FROM PHILIPPE.

ATLANTIC...
AN INVERTED UPPER LEVEL TROUGH...AN EXTENSION OF THE UPPER LOW
NEAR THE CAYMAN ISLANDS...STRETCHES ACROSS W CUBA BETWEEN N
BAHAMAS AND FLORIDA...JUST AHEAD OF T.S. RITA.  THERE IS PLENTY
OF DRY AIR NEAR AND W OF THE THIS TROUGH MOSTLY MOVING AWAY FROM
THE CYCLONE.  UPPER HIGH IS BUILDING JUST E OF RITA NEAR 24N72W
PROVIDING LIGHT ELY SHEAR ON THE SYSTEM.  FARTHER E....SERIES OF
UPPER LOWS ARE ALONG A TROUGH AXIS FROM 31N29W INTO A LOW NEAR
26N41W THEN 25N57W.  A FEW SHOWERS ARE NEAR THE WESTERNMOST
LOW... WITH A FEW TSTMS WITHIN 60 NM OF THE LOW NEAR 26N41W.
UPPER TROUGHING ALSO CONTROLS THE E ATLC.  IN THE DEEP
TROPICS... UPPER RIDGE IS ORIENTED FROM SW TO NE ALONG 10N60W TO
15N47W WITH MODERATE TO STRONG WLY SHEAR AFFECTING PHILIPPE.  NO
SIGNIFICANT CHANGE SHOULD OCCUR WITH A MOSTLY STATIONARY UPPER
PATTERN IN PLACE.  UPPER RIDGE ALSO EXTENDS ALONG 15N TO DAKAR
WITH FAIRLY LIGHT SHEAR NEAR AND S OF THE RIDGE AXIS.

$$
BLAKE




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