[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 061721
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SUN NOV 06 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
1645 UTC.

...TROPICAL WAVES...

E-CENTRAL ATLC WAVE ADDED ALONG 35W S OF 11N MOVING W 15 KT.
LONG-TERM SATELLITE LOOPS SUGGEST THE WAVE LEFT AFRICA LATE ON
THE 3RD WITH PERIODIC CONVECTIVE FLARE-UPS.  ALTHOUGH THIS IS A
LOW-AMPLITUDE WAVE...BROAD ROTATION IS NOW SEEN ON VISIBLE
SATELLITE IMAGES IN THE ITCZ ALONG WITH SCATTERED SHOWERS/TSTMS
FROM 4N-9N BETWEEN 30W-40W.  COMPUTER MODELS SUGGEST THERE WILL
BE PLENTY OF TSTMS ASSOCIATED WITH THE WAVE DURING ITS TREK
WESTWARD... ESPECIALLY WHEN IT INTERACTS WITH AN UPPER TROUGH TO
ITS NW IN A DAY OR TWO.

W-CENTRAL ATLC TROPICAL WAVE IS ALONG 54W S OF 13N MOVING W
10-15 KT.  WEATHER FROM THE WAVE IS IMPACTING THE WINDWARD
ISLANDS TODAY WITH WIDELY SCATTERED SHOWERS/TSTMS FROM 8N-13N
BETWEEN 52W-62W.  IT IS POSSIBLE THAT A WEAK MID-LEVEL SPIN
NOTED NEAR 11.5N61.5W IS THE TRUE WAVE AXIS AND RECENT UPPER-AIR
DATA FROM TRINIDAD AND ST MAARTEEN SHOW THAT THE WAVE MAY HAVE
TO BE ADJUSTED AT 1800Z TO BE W OF THE WINDWARD ISLANDS.

CENTRAL CARIBBEAN TROPICAL WAVE IS ALONG 71W S OF 13N MOVING W
15 KT.  THE WAVE HAS BROUGHT UNSETTLED CONDITIONS TO THE ABC
ISLANDS AND NW VENEZUELA.  INCREASING CLOUDS/SHOWERS ARE THE
EASIEST WAY TO TRACK THE WAVE WITH WIDELY SCATTERED SHOWERS S OF
13N BETWEEN 68W-72W.  SOME INCREASE IN TSTMS IS POSSIBLE OVER
THE SW CARIBBEAN NEAR THE COAST OF NICARAGUA WHEN THE WAVE
ENTERS THE AREA LATE TOMORROW.

SW GULF/CENTRAL AMERICAN TROPICAL WAVE IS ALONG 91W S OF 22N
MOVING W 10-15 KT.  BROAD CYCLONIC TURNING IN THE EPAC IS THE
EASIEST WAY TO TRACK THE WAVE.  IN ADDITION...BROKEN LOW CLOUDS
AND ISOLATED SHOWERS ARE IN THE GULF OF MEXICO FROM 89W-93W
BETWEEN 20N-23N.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N12W 6N24W 7N45W 10N53W 9N61W.
SCATTERED MODERATE WITHIN 45 NM OF AXIS BETWEEN 15W-21W.  WIDELY
SCATTERED MODERATE FROM 3N-9N BETWEEN 27W-38W... ALSO ASSOCIATED
WITH A TROPICAL WAVE.  SCATTERED MODERATE CONVECTION IS FROM
7N-11N BETWEEN 56W-60W... SOON TO OVERSPREAD TRINIDAD AND
TOBAGO.

...DISCUSSION...

GULF OF MEXICO...
HIGH PRESSURE HAS SLIDE OFFSHORE OF S CAROLINA... BRINGING ELY
WINDS TO THE E GULF AND SLY WINDS OVER THE REST OF THE REGION.
A COLD FRONT IS OVER S TEXAS BUT IS NOT EXPECTED TO IMPACT THE
AREA WITH ANYTHING OTHER THAN INCREASING CLOUDS.. NOW SEEN IN
BROKEN HIGH CLOUDS N OF 28N BETWEEN THE FLORIDA PANHANDLE AND
S-CENTRAL LOUISIANA.  IN FACT MOST OF THE GULF W OF 89W HAS
SCATTERED TO BROKEN CLOUDINESS IN THE LOW-LEVELS AS MOISTURE
GRADUALLY INCREASES FROM THE DEEP TROPICS.  IN THE UPPER
LEVELS... MID-LEVEL RIDGING EXTENDS FROM THE YUCATAN CHANNEL
NORTHWARD TO THE FLORIDA PANHANDLE WITH A WEAK SUBTROPICAL JET
OVER THE N GULF FROM S TEXAS TO SW GEORGIA.  MOISTURE IN THE S
GULF SHOULD MOVE WESTWARD.. INCREASING SHOWER CHANCES IN NE
MEXICO TOMORROW GRADUALLY SPREADING OVER S TEXAS BY TUE.  THE
NEXT FRONT TO EFFECT THE AREA COULD BE ON FRI BUT IT APPEARS
WEAK AT THIS TIME.

CARIBBEAN...
TWO MID/UPPER HIGHS ARE IN CONTROL OF THE AREA.. ONE IN THE NW
PART NEAR 16N82W AND THE OTHER NEAR PUERTO RICO.  THE
EASTERNMOST HIGH IS A RATHER DRY FEATURE WITH STRONG SUBSIDENCE
INVADING THE CARIBBEAN E OF 75W.. KEEPING ANY SHOWERS RATHER
SHALLOW SAVE NEAR THE ABC ISLANDS AND THE EXTREME S WINDWARD
ISLANDS.  THINGS ARE A BIT DIFFERENT IN THE W CARIBBEAN WITH
MORE DEEP-LEVELED MOISTURE LEADING TO WETTER CONDITIONS.  THE
HEAVIEST STORMS ARE NEAR THE ITCZ S OF 13N W OF 80W... WITH
ISOLATED ACTIVITY FROM 13N-18N BETWEEN 78W-84W.  DRY AIR FROM
THE CENTRAL CARIBBEAN IS EXPECTED TO KEEP MOST OF THE SHOWERS
NEAR CENTRAL AMERICA FOR THE NEXT FEW DAYS... WITH ANOTHER
ENHANCEMENT OF TSTMS IN THE SW CARIBBEAN LIKELY WHEN THE NEXT
WAVE ROLLS THROUGH MID-WEEK.  GRADUALLY INCREASING MOISTURE
SHOULD OCCUR IN THE SE CARIBBEAN ESPECIALLY IN THE WINDWARD
ISLANDS AS A TROPICAL WAVE MOVES INTO COMBINED WITH FAVORABLE
UPPER TROUGHING TO CAUSE SHOWERS/TSTMS OVER THE AREA... WITH
EVEN SOME SHOWERS IN THE LEEWARDS LIKELY BY WED.

ATLANTIC...
WEAK MID/UPPER TROUGH EXTENDS FROM JUST W OF BERMUDA INTO THE SE
BAHAMAS... THE DIVIDING LINE BETWEEN MOST CLEAR SKIES IN THE W
ATLC AND MORE PLENTIFUL DEEP-LAYERED MOISTURE.  SCATTERED TO
BROKEN HIGH CLOUDS ARE E OF THE TROUGH AXIS N OF 21N W OF 62W...
WITH ISOLATED SHOWERS/TSTMS FROM 27N-31N BETWEEN 65W-69W.
SHORTWAVE RIDGING IS FARTHER E... BEFORE THE NEXT SHORTWAVE
TROUGH ALONG 55W N OF 26N.  A FEW TSTMS ARE WITHIN 120 NM OF
27N57W FROM THE TROUGH COMBINED WITH MOISTURE FROM AN OLD
FRONTAL BOUNDARY.  UPPER RIDGING IS S OF THE PREVIOUS TROUGHS..
LIES FROM THE LEEWARD ISLAND TO 30N41W.  A MID/UPPER LOW NEAR
21N44W IS TRAPPED BENEATH THE RIDGE BUT IS SLOWLY SLIPPING
NORTHWARD AS RIDGING IS ERODED FROM THE APPROACHING SHORTWAVE.
A FEW COLD AIR INSTABILITY SHOWERS/TSTMS ARE WITHIN 120 NM OF
THE LOW.  OTHERWISE STRONG SUBSIDENCE COVERS THE TROPICAL ATLC N
OF 11N W OF 45W WITH A FEW SHOWERS FARTHER S IN THE ITCZ.  HIGH
AMPLITUDE RIDGES EXTENDS FROM 8N28W TO 27N32W WITH BROKEN HIGH
CLOUDS OVERSPREADING A LARGE PORTION OF THE E-CENTRAL ATLC FROM
N OF THE CAPE VERDES BETWEEN 25W-45W.  THERE IS PLENTY OF
DIFFLUENCE IN THE E ATLC ITCZ SUPPORTING A FAIR AMOUNT OF TSTMS.
AT THE SURFACE... STRONG HIGH PRESSURE DOMINATES WITH ABOVE
AVERAGE TRADES IN MOST OF THE REGION.

$$
BLAKE

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