[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271127
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN NOV 27 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...SPECIAL FEATURE...

THE CENTER OF TROPICAL STORM DELTA AT 27/0900 UTC IS NEAR 25.6N
32.8W OR ABOUT 945 MILES...1525 KM...WEST-SOUTHWEST OF LA PALMA
IN THE CANARY ISLANDS MOVING NE 21 KT. THE MAXIMUM SUSTAINED
WINDS ARE 35 KT WITH GUSTS TO 45 KT. THE ESTIMATED MINIMUM
CENTRAL PRESSURE IS 993 MB. PLEASE REFER TO THE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC
AND THE LATEST PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS
MIATCPAT3/ WTNT33 KNHC FOR MORE DETAILS.  RECENTLY CIRRUS FROM
NEARBY TSTMS HAVE COVERED THE CENTER OF DELTA... PERHAPS
SUGGESTING THE STORM IS A LITTLE STRONGER.  HOWEVER IT IS
BEGINNING TO TAKE ON A COMMA-LIKE APPEARANCE ON SATELLITE AS ONE
OF THE FIRST SIGNS OF EXTRATROPICAL TRANSITION.    SHEAR IS
FORECAST TO INCREASE SLOWLY IN ADDITION TO GRADUALLY COOLING
WATERS... WHICH SHOULD START THE EXTRATROPICAL PROCESS LATER
TODAY.  STRONG WINDS TO NEAR GALE FORCE APPEAR POSSIBLE IN THE
CANARY ISLANDS STARTING EARLY MON WITH EXTRATROPICAL VERSION OF
DELTA.  SCATTERED MODERATE CONVECTION IS FROM 25.5N-29N BETWEEN
25W-33W.

...ITCZ...

ITCZ IS CENTERED ALONG 9N13W 9N40W 4N51W.    ISOLATED MODERATE
CONVECTION IS FROM 2N-5N BETWEEN 10W-20W AND FROM 8N-10N BETWEEN
W AFRICA AND 20W.  A FEW SHOWERS ARE ALSO WITHIN 90 NM OF
8.5N42W.

...DISCUSSION...

GULF OF MEXICO...
WEAK WARM FRONT PREVIOUSLY ALONG THE LOUISIANA COAST HAS
DISSIPATED.  60-90 NM WIDE BAND OF SHOWERS EXTENDS FROM NEAR
28N87W IN THE NE GULF TO NEAR PENSACOLA FLORIDA.  THIS ACTIVITY
IS OCCURRING AHEAD OF A WEAK SHORTWAVE SHOOTING NEWARD ACROSS NE
TEXAS INTO ARKANSAS.  OTHERWISE THE SUBTROPICAL JET EXTENDS FROM
SE MEXICO NEAR 21N97W NE INTO THE FLORIDA PANHANDLE NEAR
TALLAHASSEE WITH SCATTERED HIGH CLOUDS AND INCREASING MOISTURE
WITHIN 120 NM OF THE JET.  OVERCAST LOW CLOUDS AND ISOLATED
SHOWERS ARE IN THE SRN GULF OF MEXICO S OF 27N E OF 88W
DIMINISHING OVER THE STRAITS OF FLORIDA.  THESE CLOUDS ARE
ASSOCIATED WITH A SURGE IN LOW-LEVEL MOISTURE FROM A  CARIBBEAN
SURFACE TROUGH.  THIS AREA OF CLOUDS IS EXPECTED TO CONTINUE
MOVING NORTHWARD AND COULD ADD TO THE CLOUDINESS OVER SW FLORIDA
TODAY AND SOME SHOWERS OVER CENTRAL FLORIDA NORTHWARD THRU N
FLORIDA INCLUDING THE W COAST OVERNIGHT TONIGHT.  A COLD FRONT
IS EXPECTED TO MOVE INTO THE NW GULF ON MON...THOUGH LIMITED
UPPER DYNAMICS AND MOISTURE SHOULD KEEP THE WESTERN GULF MOSTLY
DRY DURING THE FRONTAL PASSAGE.  A FEW TSTMS WILL LIKELY BREAK
OUT BY TUE IN THE E GULF AS THE FRONT ENCOUNTERS DEEPER
MOISTURE.

CARIBBEAN SEA...
WEAK SURFACE TROUGH EXTENDS FROM E HONDURAS NEAR 15N85W TO THE
YUCATAN CHANNEL NEAR 22N86W MOVING NW.  ISOLATED MODERATE
CONVECTION IS FROM 16N-22N BETWEEN 78W-85W.  RAIN IS EXPECTED
FOR W CUBA LATER TODAY... POSSIBLY SPREADING INTO THE NE TIP OF
YUCATAN THIS AFTERNOON.   FURTHER E...15-20 KT TRADEWINDS ARE
NOTED E OF 78W ALONG WITH ISOLATED SHOWERS FROM 13.5N-16N
BETWEEN 68W-77W.  DRIER AIR IS FILTERING INTO THE NE CARIBBEAN..
WITH DEWPOINTS BELOW 70F OBSERVED AT A FEW STATIONS IN THE
LEEWARD ISLANDS.  A CONTINUATION OF NLY WINDS SHOULD OCCUR
OVER THE E CARIBBEAN WITH DEWPOINTS PERHAPS INTO THE MIDDLE 60S
FILTERING IN BY EARLY WEEK AS A LARGE LOW PRESSURE AREA FORMS
OVER THE CENTRAL ATLC.    IN THE UPPER LEVELS... UPPER RIDGING
DOMINATES THE AREA WITH A HIGH CENTER NEAR JAMAICA.  STRONG
SUBSIDENCE IS PRACTICALLY EVERYWHERE SAVE NEAR THE WEAK SURFACE
TROUGH IN THE NW CARIBBEAN.  SHOWERS MAY BEGIN TO RETURN TO
CENTRAL AMERICA BY MID-WEEK AS DEEP-LAYERED MOISTURE INCREASES.
WEAK LOW-LEVEL TROUGH IS N OF PUERTO RICO ALONG 19N59W TO 21N64W
AND COULD ENHANCE LOW-TOPPED SHOWERS LATER TODAY FOR THE LEEWARD
ISLANDS INTO PUERTO RICO.

ATLANTIC OCEAN...
SCATTERED STRATOCUMULUS CLOUDS DOT ALMOST THE ENTIRE AREA N OF
20N W OF 40W WITH BROKEN HIGH CLOUDS N OF 28N W OF BERMUDA.
OTHER HIGH CLOUDS N OF 26N BETWEEN 50W-60W ARE OCCURRING AHEAD
OF AN UPPER LOW DROPPING INTO THE AREA NEAR 33N57W.  THIS UPPER
LOW SHOULD MOVE SE AND INTERACT WITH A WEAK TROUGH LOCATED NW OF
DELTA IN ADDITION TO A SMALL UPPER LOW NEAR 32N46W... AND FORM
INTO AN EXTRATROPICAL LOW.  COMPUTER MODELS ARE SUGGESTING THAT
AROUND TUE/WED... SOME TRANSITION TO A SUBTROPICAL CYCLONE MIGHT
OCCUR OVER MARGINAL SST'S.  HOWEVER MODELS ARE NOT CONSISTENT ON
WHETHER THE SYSTEM WILL EVENTUALLY ACQUIRE SOME SUBTROPICAL (OR
EVEN TROPICAL) CHARACTERISTICS.  BLOCKING AT HIGH LATITUDES
SEEMS TO FAVOR ANOTHER SUBTROPICAL CYCLONE EFFORT THOUGH.
ELSEWHERE...TROUGH IS SWINGING THRU THE CENTRAL ATLC NEAR 24N45W
TO 17N53W WITH SOME COLD-AIR INSTABILITY NEAR THE TROUGH
PRODUCING ISOLATED TSTMS WITHIN 90 NM OF 23N46W... PLUS ISOLATED
TSTMS N OF 28N BETWEEN 40W-50W.   SHOWERS NEAR 13N38W HAVE
DISSIPATING THOUGH LIFT FROM AN ASSOCIATED LARGE MEAN TROUGH
COVERING THE CENTRAL ATLC FROM ITS EASTERN EXTENT NEAR DELTA
RANGING WESTWARD TO ABOUT 65W COULD ALLOW FOR A COMEBACK LATER
TODAY.  UPPER RIDGING CONTINUES OVER THE E ATLC NEAR THE CAPE
VERDE ISLANDS NNE INTO WESTERN SAHARA.  LARGE AREA OF CIRRUS
DEBRIS CLOUDS IS N OF 22N BETWEEN DELTA AND AFRICA FROM THE
TROPICAL CYCLONE'S TSTMS AND UPPER LIFT FROM THE TROUGH.
OTHERWISE IN THE TROPICAL ATLC STRONG SUBSIDENCE IS ALLOWING
ONLY A FEW CLOUDS S OF 20N W OF 30W.

$$
BLAKE


This weather bulletin was brought to you by:
www.nashvilleweather.net