[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271710
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT OCT 27 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
1630 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 40W S OF 14N MOVING W 15 KT. A NARROW
BAND OF MOISTURE STRETCHING N-S ALONG THE WAVE AXIS AND AN
ASSOCIATED AREA OF WEAK LOW-LEVEL TURNING IS APPARENT ON
SATELLITE IMAGERY.

TROPICAL WAVE IS ALONG 50W S OF 12N MOVING W 10-15 KT. ANY
MOISTURE ASSOCIATED WITH THIS FEATURE IS BECOMING ABSORBED BY
THE EXTENSIVE DEEP LAYER SWLY FLOW TO THE N OF THE WAVE. THERE
IS NOT MUCH EVIDENCE OF THE TROPICAL PORTION OF THE WAVE AND THE
POSITION IS BASED ON EXTRAPOLATION. THERE IS NO CONVECTION
ASSOCIATED WITH THIS WAVE.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N11W 4N24W 5N35W 5N45W. SCATTERED
MODERATE CONVECTION IS WITHIN 100 NM EITHER SIDE OF THE AXIS
BETWEEN 15W-23W.  SIMILAR CONVECTION IS WITHIN 130 NM N OF
THE AXIS BETWEEN 25W-27W.

DISCUSSION...

GULF OF MEXICO...

A SLOW MOVING WARM FRONT CONTINUES TO MAKE ITS WAY ACROSS THE
FLORIDA PENINSULA. AS OF 15Z...THE FRONT WAS ANALYZED FROM
31N80W SOUTHWEST TO 27N82W WHERE IS BECOMES STATIONARY AND
DISSIPATES NEAR 25N86W. A LARGE CLUSTER OF STRONG SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE FRONT IS IN THE EASTERN GULF
FROM 24N-28N BETWEEN 82W-86W. THE FRONT IS EXPECTED TO WEAKEN
OVERNIGHT. A VERY WEAK SURFACE TROUGH IN THE WESTERN GULF
EXTENDS FROM 27N95W TO 22N92W AND IS MARKED ONLY BY A WIND SHIFT
WITH 20-25 KTS NE AND 10-15 KTS SW OF THE TROUGH. THE MAJORITY
OF THE GULF...WEST OF 87W...IS UNDER STRONG SUBSIDENCE TO THE S
OF A LARGE UPPER TROUGH OVER THE MIDWEST. WINDS AND SEAS WILL
INCREASE OVER MOST OF THE GULF AS A RESULT OF THE TIGHTENING
PRESSURE GRADIENT BETWEEN STRENGTHENING HIGH PRESSURE TO THE
NORTH AND LOW PRESSURE IN THE CARIBBEAN. WINDS ARE EXPECTED TO
REACH GALE FORCE OVER THE FAR SW PORTION OF THE GULF IN THE NEXT
48 HOURS.


CARIBBEAN SEA...

A BROAD AREA OF CONVECTION ASSOCIATED WITH A SURFACE TROUGH IN
THE WESTERN CARIBBEAN EXTENDS FROM THE YUCATAN CHANNEL TO PANAMA
WEST OF 79W. WEAK MID TO UPPER LEVEL CYCLONIC TURNING CAN BE
SEEN IN SATELLITE IMAGERY. SURFACE PRESSURES ARE NOT FALLING AT
THIS TIME AND TROPICAL DEVELOPMENT...IF ANY...WILL BE SLOW TO
OCCUR.

A SECOND AREA OF LOW PRESSURE EXISTS IN THE EASTERN CARIBBEAN
NEAR 15N70W. THE LOW IS SLOWLY MOVING TOWARD THE SW AND IS
ASSOCIATED WITH NUMEROUS SQUALLS WHICH ARE AFFECTING THE ISLANDS
IN THE EASTERN CARIBBEAN...PRIMARILY PUERTO RICO AND THE VIRGIN
ISLANDS. ENVIRONMENTAL CONDITIONS APPEAR SOMEWHAT FAVORABLE FOR
A TROPICAL DEPRESSION TO FORM AS THE SYSTEM MOVES INTO THE
WESTERN CARIBBEAN.

BETWEEN THE TWO LOW PRESSURE AREAS...A NARROW BAND OF DRY AIR IS
MOVING OVER EASTERN CUBA AND SOUTHWEST OF HISPANIOLA AROUND
AN UPPER LOW.


ATLANTIC...

HIGH PRESSURE DOMINATES THE WESTERN ATLANTIC ANCHORED BY A
STRONG 1033 MB SURFACE HIGH IN THE NORTH ATLANTIC. SCATTERED
MODERATE CONVECTION IS EXTENDING INTO THE FAR SOUTH ATLANTIC
WEST OF 62W FROM THE LOW PRESSURE SYSTEM IN THE CARIBBEAN. THE
PRESSURE GRADIENT BETWEEN THIS LOW AND THE HIGH PRESSURE IN THE
W ATLC IS RESULTING IN STRONG EAST WINDS OVER THE BAHAMAS. A
VERY WEAK COLD FRONT DIPPING JUST SOUTH INTO THE AREA BETWEEN
30N48W AND 30N61W IS PUSHING MID TO UPPER LEVEL CLOUDS INTO THE
TROPICAL CENTRAL ATLC. FARTHER EAST...A LARGE DEEP-LAYER
ELONGATED LOW PRES TROUGH LIES OVER THE CENTRAL ATLC. DIFFLUENCE
ALOFT TO THE S AND E OF THE TROUGH IS SPREADING DEBRIS
CLOUDINESS FROM THE E CARIBBEAN ACROSS THE TROPICAL ATLC WITHIN
250 NM OF A LINE THAT STRETCHES NE FROM 15N50W TO 32N36W AND
WELL BEYOND THE REGION INTO THE NORTH ATLC. THE E ATLC IS RATHER
TRANQUIL UNDER THE INFLUENCE OF SFC RIDGING EXTENDING SWD FROM
HIGH PRES N OF THE AZORES AND A WELL DEFINED UPPER ANTICYCLONE
CENTERED NEAR 16N29W.

$$
WADDINGTON




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