[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 091754
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT FRI OCT 09 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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
1715 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 31W S OF 15N MOVING W NEAR 22 KT. LOW-
LEVEL SATELLITE DERIVED WINDS AND AN EARLIER SCATTEROMETER PASS
DEPICT CYCLONIC CURVATURE IN THE VICINITY OF THE WAVE AXIS. THIS
LOW-LEVEL LIFTING MECHANISM COUPLED WITH AN UPPER LEVEL RIDGE
ALOFT E OF 40W PROVIDING UPPER LEVEL DIFFLUENCE IS GENERATING
SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 6N-12N
BETWEEN 28W-37W.

TROPICAL WAVE IS ALONG 63W S OF 18N MOVING W NEAR 18 KT. VISIBLE
SATELLITE IMAGERY INDICATES CYCLONIC TURNING IN THE LOW-LEVEL
CLOUD FIELD ACROSS THE SE CARIBBEAN NEAR THE WAVE AXIS. A
MAXIMUM IN DEEP LAYER MOISTURE IS ALSO NOTED ON TOTAL
PRECIPITABLE WATER IMAGERY BETWEEN 58W-66W. ISOLATED MODERATE
CONVECTION AND SCATTERED SHOWERS ARE FROM 9N-14N BETWEEN
59W-65W.

TROPICAL WAVE IS ALONG 83W S OF 16N MOVING W NEAR 18 KT. THE
WAVE LIES IN A BROAD AREA OF DEEP LAYER MOISTURE ACROSS THE SW
CARIBBEAN S OF 17N W OF 76W AS OBSERVED IN THE TOTAL
PRECIPITABLE WATER IMAGERY. LOCATED BENEATH THE ERN PERIPHERY
OF AN UPPER LEVEL LOW LOCATED IN THE E PACIFIC REGION...MOIST
SLY DIFFLUENT FLOW ALOFT IS GENERATING SCATTERED MODERATE TO
STRONG CONVECTION S OF 17N AND W OF A LINE FROM 17N82W TO THE
COAST OF COLOMBIA NEAR 10N76W.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N14W 10N30W 9N33W 5N53W. W OF
THE AREA OF CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG
63W... SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN
200 NM EITHER SIDE OF THE AXIS BETWEEN 33W-46W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED IN THE W
ATLC NEAR 30N74W EXTENDS AN UPPER LEVEL RIDGE ACROSS THE STATE
OF FLORIDA AND ACROSS THE GULF TO 94W. STRONG SUBSIDENCE AND
PLENTY OF DRY AIR IS NOTED ON WATER VAPOR IMAGERY ASSOCIATED
WITH THE UPPER LEVEL HIGH. GENERALLY FAIR WEATHER AND CLEAR
SKIES ARE NOTED ACROSS A MAJORITY OF THE GULF THIS AFTERNOON.
FARTHER WEST...A VIGOROUS UPPER LEVEL TROUGH IS PROGRESSING EWD
ACROSS NW MEXICO AND THE SRN PLAINS. THIS TROUGH SUPPORTS A COLD
FRONT THAT EXTENDS FROM NERN TEXAS SW TOWARDS THE RIO GRANDE
RIVER AND INTO NRN MEXICO NEAR 28N100W. E OF THE FRONTAL
BOUNDARY...MOIST SLY RETURN FLOW DOMINATES ACROSS THE GULF WITH
SCATTERED SHOWERS AND TSTMS BEGINNING TO ENTER THE NW GULF
WATERS FROM THE TEXAS/LOUISIANA BORDER TO NORTH OF BROWNSVILLE
TEXAS. THE COLD FRONT IS FORECAST TO STALL SUNDAY FROM LOUISIANA
TO THE BAY OF CAMPECHE AND DRIFT NORTH BY EARLY NEXT WEEK.

CARIBBEAN SEA...
THE NW CARIBBEAN AND MUCH OF THE GREATER ANTILLES ARE UNDER ELY
UPPER LEVEL FLOW ON THE SRN PERIPHERY OF A BROAD UPPER LEVEL
RIDGE CENTERED IN THE W ATLC. DRY SUBSIDENT AIR IS SUPPORTING
GENERALLY FAIR WEATHER N OF 17N W OF 73W WITH ONLY A FEW
ISOLATED SHOWERS MOVING ACROSS THE YUCATAN CHANNEL. FARTHER S...
AN UPPER LEVEL LOW IS CENTERED IN THE E PACIFIC REGION NEAR
12N90W AND IS PROVIDING THE SW CARIBBEAN WITH MOIST SLY FLOW
ALOFT. INSTABILITY COUPLED WITH THE TROPICAL WAVE ALONG 83W ARE
GENERATING SCATTERED SHOWERS AND TSTMS S OF 17N AND W OF A LINE
FROM 17N82W TO THE COAST OF COLOMBIA NEAR 10N76W. ACROSS THE ERN
CARIBBEAN...THE TROPICAL WAVE ALONG 63W AS WELL AS UPPER LEVEL
RIDGING E OF 73W IS SUPPORTING THE SCATTERED SHOWERS AND
ISOLATED TSTMS E OF 66W AND ACROSS PORTIONS OF THE LESSER
ANTILLES. FRESH TO STRONG TRADE WINDS ARE ACROSS MUCH OF THE
BASIN WITH THE STRONGEST WINDS LOCATED ALONG THE COAST OF
COLOMBIA.

ATLANTIC OCEAN...
OVER THE W ATLC...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS
CENTERED NEAR 30N74W AND EXTENDS UPPER LEVEL RIDGING TO 55W.
MOSTLY DRY AIR AND STRONG SUBSIDENCE IS NOTED ON WATER VAPOR
IMAGERY...HOWEVER THE TAIL END OF A CENTRAL ATLC COLD FRONT
ENTERS THE DISCUSSION AREA NEAR 32N47W AND EXTENDS WSW ALONG
27N60W TO 26N69W. WITH DRY CONDITIONS ALOFT AND A STABLE
ATMOSPHERE IN PLACE OVER THE W ATLC...ONLY ISOLATED SHOWERS
REMAIN WITHIN 30 NM EITHER SIDE OF THE FRONT. SIGNIFICANT
SHOWERS AND CONVECTION ASSOCIATED WITH THE FRONT ARE HOWEVER
LOCATED OVER THE CENTRAL ATLC. AN UPPER LEVEL TROUGH OVER THE
CENTRAL ATLC WITH AXIS ALONG 48W N OF 27N SUPPORTS THE COLD
FRONT WITH SCATTERED SHOWERS AND TSTMS COVERING THE AREA FROM
24N-32N BETWEEN 43W-53W. SOUTH OF THE COLD FRONT...THE REMNANTS
OF HENRI...IS ANALYZED AS A SURFACE TROUGH THAT EXTENDS FROM
NERN PUERTO RICO NEAR 18N66W TO 25N60W. SCATTERED SHOWERS AND
TSTMS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE SURFACE
TROUGH. THE REMAINDER OF THE CENTRAL AND ERN ATLC IS UNDER THE
INFLUENCE OF A SURFACE RIDGE OF HIGH PRESSURE. ANCHORED ON A
1024 MB HIGH BETWEEN THE AZORES AND MADEIRA ISLANDS NEAR
37N17W...THE SURFACE RIDGE EXTENDS SW TO A 1018 MB HIGH NEAR
23N44W.

$$
HUFFMAN



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