[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 270601
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI OCT 27 2006

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
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...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0545 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 36W S OF 13N MOVING W NEAR 10 KT. SOME
CYCLONIC TURNING IS APPARENT IN THE LOW TO MID CLOUD FIELD VIA
SHORTWAVE IR IMAGERY...THOUGH HIGH CLOUDS MOVING AROUND THE
UPPER LOW JUST TO THE N OF THE WAVE ARE MASKING THE SIGNAL A
BIT. SCATTERED MODERATE CONVECTION FROM 2N-8N BETWEEN 32W-40W.

A TROPICAL WAVE ABOUT 390 NM E OF THE WINDWARD ISLANDS IS ALONG
53W S OF 20N MOVING W 10 TO 15 KT. A 1010 MB LOW IS ALONG THE
WAVE NEAR 13N. PATCHES OF SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION NOTED FROM 11N-17N BETWEEN 48W-58W...THOUGH THE
SHOWERS/TSTMS ARE POORLY ORGANIZED AND SIGNIFICANT DEVELOPMENT
OF THIS SYSTEM IS NOT ANTICIPATED AT THIS TIME.

TROPICAL WAVE IS ALONG 69W S OF 19N...0R BETWEEN ERN HISPANIOLA
AND VENEZUELA...MOVING W 10 TO 15 KT. THIS WAVE IS BECOMING
DIFFICULT TO LOCATE WITH JUST A HINT OF CYCLONIC TURNING NOTED S
OF ERN DOMINICAN REPUBLIC AND THE MONA PASSAGE. THE WAVE IS
EMBEDDED IN A DRY ENVIRONMENT JUST SE OF THE STRONG ATLC FRONTAL
BOUNDARY...PRODUCING ONLY ISOLATED SHOWERS.

 ...THE ITCZ...
ITCZ AXIS IS ALONG 10N14W 7N30W 6N45W 10N52W TO NEAR TRINIDAD
NEAR 10N61W. A NARROW BAND OF SCATTERED MODERATE CONVECTION
NOTED FROM 7N-9N BETWEEN 18W-32W. SCATTERED MODERATE ALSO SEEN
FROM 4N-8N BETWEEN 40W-47W.

...DISCUSSION...
THE GULF OF MEXICO...
SURFACE HIGH PRESSURE HAS SLID NE OF THE AREA...NOW NEAR CAPE
FEAR NORTH CAROLINA AT 1024 MB...AS THE NEXT FRONTAL SYSTEM GETS
ITS ACT TOGETHER OVER THE SRN STATES. ASSOCIATED DEEP SLY FLOW
OBSERVED IN THE 15-25 KT RANGE ACROSS THE GULF. NEARLY THE
ENTIRE GULF OF MEXICO IS RAIN-FREE WITH MID TO UPPER RIDGING
EXTENDING NNE FROM THE GULF UP THE EAST COAST. OVERALL UPPER
FLOW IS MOSTLY ZONAL...WITH ABUNDANT DRY AIR ALOFT. TWO
UNSETTLED WEATHER AREAS CONTINUE TO CLIP THE BORDER OF THE
GULF...THE FIRST IS THE CLUSTER OF MODERATE TO STRONG CONVECTION
IN THE YUCATAN CHANNEL AND THE SECOND IS THE CONVECTION HUGGING
THE CENTRAL GULF COAST. THE FORMER IS ASSOCIATED WITH SFC
TROUGHING AT THE TAIL END OF THE STRONG ATLC COLD FRONT. THE
LATTER IS ASSOCIATED WITH THE NEXT FRONTAL SYSTEM THAT WILL
ENTER THE NW PORTION OF THE REGION BY THIS MORNING. THIS FRONT
WILL BRING AN INCREASE IN MOISTURE AHEAD OF IT AND COOLER/DRIER
AIR BEHIND IT. NLY WINDS WILL INCREASE WITH GUSTS TO GALE FORCE
BUILDING STEEP...SHORT PERIOD WIND WAVES AS STRONG SFC RIDGING
BUILDS IN BEHIND THE FRONT.

THE CARIBBEAN SEA...
THE TAIL END OF A STRONG ATLC FRONTAL BOUNDARY EXTENDS THROUGH
THE NW CARIBBEAN AS A TROUGH FROM HISPANIOLA TO THE NE PART OF
THE YUCATAN PENINSULA. A CLUSTER OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ASSOCIATED WITH THIS BOUNDARY NOTED FAR NW
PORTION FROM 19N-23N BETWEEN 84W-87W. AN UPPER LOW IS SEEN IN WV
IMAGERY BETWEEN HONDURAS AND CUBA NEAR 18N83W. A FEW ISOLATED
SHOWERS/TSTMS SEEN ROTATING AROUND THIS UPPER LOW FROM 16N-20N
BETWEEN 80W-85W. THE SW CARIBBEAN DOMINATED BY BROKEN TO
OVERCAST HIGH CLOUDS ROTATING ANTICYCLONICALLY AROUND AN UPPER
HIGH E OF NICARAGUA NEAR 13N79W. THE ERN CARIBBEAN IS MAINLY
DRY...WITH MODERATE DRY AIR ALOFT AND NLY UPPER FLOW BETWEEN THE
UPPER HIGH E OF NICARAGUA AND A BROAD UPPER LOW NEAR TRINIDAD.
THIS FLOW IS ADVECTING SOME MOISTURE S OF HISPANIOLA AND PUERTO
RICO THOUGH...FROM THE LITTLE LEFTOVER CONVECTION FROM THE ATLC
COLD FRONT. MOISTURE WILL LIKELY BE ON THE INCREASE IN THE ERN
CARIB THIS WEEKEND AS A TROPICAL WAVE AND WEAK AREA OF LOW
PRES...CURRENTLY 390 NM E OF THE WINDWARD ISLANDS...MOVES INTO
THE AREA.

THE ATLANTIC OCEAN...
A HIGHLY AMPLIFIED PATTERN IS ESTABLISHED ACROSS THE ATLC. HIGH
PRES RIDGING EXISTS ACROSS THE ERN U.S. AND A PORTION OF THE WRN
ATLC W OF 67W. A LARGE STRONG TROUGH LIES TO THE E OF THE RIDGE.
THE ASSOCIATED COLD FRONT REMAINS WELL DEFINED ALONG 32N48W
24N60W TO THE DOMINICAN REPUBLIC. SCATTERED SHOWERS AND TSTMS
ARE WITHIN 250NM E OF THE FRONT. BEHIND THE FRONT...A DRIER AND
COOLER AIRMASS EXISTS WITH STRATOCUMULUS AND NW FLOW. THE
ASSOCIATED NW SWELL WILL CONTINUE TO SPREAD E THROUGH THE
CARIBBEAN THROUGH THE WEEKEND AND SUBSIDE EARLY NEXT WEEK. A
LARGE STRONG MID/UPPER LEVEL RIDGE IS LOCATED E OF THE TROUGH
CENTERED IN THE SUBTROPICS NEAR 29N31W. THIS RIDGE COVERS THE
REMAINDER OF THE ATLC E OF 45W AND N OF 19N WITH DRY STABLE AIR
ALOFT WIDESPREAD IN THE REGION. SFC HIGH PRES IS ALSO ANALYZED
UNDERNEATH THE MID/UPPER RIDGE WITH A 1022 MB HIGH NEAR 25N39W
AND A 1024 MB HIGH NEAR 32N27W. AN UPPER LOW...WHICH CUT OFF
FROM THE STRONG TROUGH THAT WAS IN THE E ATLC EARLIER THIS
WEEK...IS TRACKING WSW CENTERED NEAR 14N37W. W OF THIS UPPER LOW
THERE IS AN UPPER HIGH NEAR 14N51W. UPPER DIFFLUENCE NEAR THIS
HIGH IS HELPING SUPPORT THE CONVECTION AROUND THE TROPICAL WAVE
ALONG 53W.

$$
WILLIS/CANGIALOSI




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