[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271049
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1045 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 37 S OF 13N MOVING W 10 TO 15 KT. SOME
CYCLONIC TURNING IS APPARENT IN THE LOW TO MID CLOUD
FIELD...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 6N-9N BETWEEN 35W-40W. ISOLATED
SHOWERS/TSTMS NOTED ELSEWHERE WITHIN 150 NM OF THE AXIS.

A TROPICAL WAVE ABOUT 260 NM E OF THE WINDWARD ISLANDS IS ALONG
54W/55W S OF 20N MOVING W 10 TO 15 KT. A 1009 MB LOW IS ALONG
THE WAVE NEAR 13N. MODERATE TO STRONG CONVECTION IS FROM 10N-15N
BETWEEN 52W-59N...THOUGH THE SHOWERS/TSTMS ARE POORLY ORGANIZED
AND SIGNIFICANT DEVELOPMENT OF THIS SYSTEM IS NOT ANTICIPATED.

TROPICAL WAVE IS ALONG 70W S OF 19N...0R BETWEEN ERN HISPANIOLA
AND VENEZUELA...MOVING W 10 TO 15 KT. THIS WAVE IS NOT AS EASY
TO TRACK AS IT ONCE WAS...THOUGH A NARROW ZONE OF CYCLONIC
TURNING NOTED ABOUT THE WAVE AXIS IN SHORTWAVE IR IMAGERY.
SURFACE OBSERVATIONS AT CURACAO ALSO DEPICTED THE WAVE PASSAGE
FAIRLY WELL. THE WAVE REMAINS EMBEDDED IN A DRY ENVIRONMENT JUST
SE OF THE STRONG ATLC FRONTAL BOUNDARY...PRODUCING ONLY ISOLATED
SHOWERS.

 ...THE ITCZ...
ITCZ AXIS IS ALONG 11N15W 7N25W 7N40W 11N52W TO NEAR TRINIDAD
NEAR 10N61W. A NARROW BAND OF SCATTERED MODERATE CONVECTION
NOTED FROM 4N-9N BETWEEN 20W-33W. ISOLATED MODERATE CONVECTION
ALSO SEEN FROM 3N-9N BETWEEN 41W-53W.

...DISCUSSION...
THE GULF OF MEXICO...
DEEP SLY FLOW CONTINUES TO DOMINATE MUCH OF THE GULF OF MEXICO
EARLY THIS MORNING WITH SURFACE HIGH PRESSURE NE OF THE AREA
INTERACTING WITH THE APPROACHING FRONTAL SYSTEM. MANY
BUOYS/SHIPS REPORTING 15-25 KT S/SE FLOW...SOME WITH HIGHER
GUSTS. STATION 42362 REPORTED 41KT AT 0830 UTC BUT THAT
ANEMOMETER IS 120 METERS HIGH. AT 0840 UTC...BUOY 42035 JUST E
OF GALVESTON SHOWED A NW WIND SHIFT INDICATING THE COLD FRONT
HAS ENTERED THE NW GULF. TEXAS AND LOUISIANA MOSAIC RADAR DATA
ALSO SHOWS A FAIRLY IMPRESSIVE LINE OF SHOWERS/TSTMS MOVING INTO
THE NW GULF WITH THE COLD FRONT. THE ONLY OTHER PRECIP SEEN IN
THE GULF ARE A FEW SCATTERED SHOWERS/TSTMS LINGERING NEAR THE
YUCATAN CHANNEL ASSOCIATED WITH THE TAIL END OF OUR OLD COLD
FRONT BOUNDARY...BUT THESE ARE NOT AS SIGNIFICANT AS THEY WERE
OVERNIGHT. THE REMAINDER OF THE GULF IS MOSTLY RAIN FREE WITH
ABUNDANT DRY MID TO UPPER AIR AND ZONAL UPPER FLOW. LOOK FOR THE
FRONT TO CONTINUE PUSHING THROUGH THE GULF THROUGH TOMORROW WITH
ASSOCIATED SHOWERS/TSTMS GENERALLY WITHIN 200NM OF THE FRONT.
INCREASING NLY WINDS OCCASIONALLY GUSTING TO GALE FORCE BEHIND
THE FRONT WILL ALLOW STEEP N WIND WAVES TO GRADUALLY REPLACE THE
EXISTING PREFRONTAL S WIND WAVES. SEE MIAOFFNT4 FOR MORE
DETAILS.

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. ISOLATED SHOWERS/TSTMS NOTED WITHIN 75NM
OF THIS BOUNDARY. AN UPPER LOW IS SEEN IN WV IMAGERY BETWEEN
HONDURAS AND CUBA NEAR 17N83W. 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 12N80W. ISOLATED SHOWERS/TSTMS ALSO NOTED UNDER THIS UPPER
HIGH OFF THE COAST OF CENTRAL AMERICA. 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 260 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 IS SLOWLY BECOME LESS DEFINED...AND IS
ANALYZED ALONG 32N49W 23N60W TO THE DOMINICAN REPUBLIC. ISOLATED
SHOWERS AND TSTMS ARE WITHIN 250NM MAINLY E OF THE FRONT...AND
HAVE DIMINISHED A BIT SINCE LAST NIGHT. 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 30N30W. 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 1023 MB HIGH NEAR 32N27W.
FURTHER SOUTH...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 13N51W. UPPER DIFFLUENCE BETWEEN THIS HIGH AND AN
UPPER LOW NEAR TRINIDAD IS HELPING SUPPORT THE CONVECTION AROUND
THE TROPICAL WAVE ALONG 54W.

$$
WILLIS




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