[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170552
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN OCT 17 2010

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 08N21W 09N38W 07N41W 07N59W. A
SURFACE TROUGH LOCATES OFFSHORE OF W AFRICA ANALYZED FROM 09N20W
TO 18N17W. LOW-LEVEL CYCLONIC FLOW IS FOCUSED IN THE VICINITY OF
THE TROUGH AXIS AND SUPPORTS SCATTERED MODERATE CONVECTION FROM
03N-12N BETWEEN 18W-24W AND WITHIN 120 NM EITHER SIDE OF THE
TROUGH AXIS N OF 12N. ANOTHER SURFACE TROUGH IS ANALYZED OVER
THE CENTRAL TROPICAL ATLC FROM 07N40W TO 14N38W AND IS EMBEDDED
WITHIN A MONSOONAL GYRE BETWEEN 35W-43W. TOTAL PRECIPITABLE
WATER IMAGERY INDICATES A BROAD AREA OF LOW-LEVEL MOISTURE
POOLING IN THE VICINITY OF THE SURFACE TROUGH GENERATING
ISOLATED MODERATE CONVECTION FROM 06N-13N BETWEEN 33W-40W.
ELSEWHERE SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS
FROM 01N-08N BETWEEN 24W-35W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE AXIS EXTENDS FROM THE NW CARIBBEAN TO THE
ARKLATEX REGION AND ALONG WITH RELATIVELY DRY SOUTHWESTERLY FLOW
ALOFT ACROSS THE GULF...A STABLE ATMOSPHERIC ENVIRONMENT
PERSISTS. THIS UPPER LEVEL PATTERN IS SUPPORTING A 1021 MB HIGH
CENTERED OVER THE NW GULF NEAR 29N92W THAT IS PROVIDING THE
BASIN WITH MOSTLY NE WINDS UP TO 15 KT AND OVERALL CLEAR SKIES
FOR THE OVERNIGHT PERIOD. THE FAIR WEATHER CONDITIONS ARE
FORECAST TO CONTINUE OVER THE NEXT FEW DAYS AS THE SURFACE RIDGE
TRANSLATES EASTWARD ALONG THE GULF COAST LOCATING OVER THE W
ATLC BY EARLY MONDAY. HINTS OF SOUTHERLY RETURN FLOW WILL ONCE
AGAIN APPEAR BY MONDAY OVER THE FAR WESTERN GULF WATERS SE OF
LINGERING LOW PRESSURE OVER THE SOUTHERN PLAINS.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER
HISPANIOLA NEAR 19N72W AND EXTENDS AN UPPER LEVEL RIDGE AXIS
WESTWARD TO THE YUCATAN PENINSULA. WITHIN THE SOUTHWESTERN
PERIPHERY OF THE UPPER HIGH...A DIFFLUENT PATTERN IN THE MIDDLE
TO UPPER LEVELS OF THE ATMOSPHERE IS NOTED ON WATER VAPOR
IMAGERY THAT CONTINUES TO ADVECT MOISTURE OVER PORTIONS OF THE
SW CARIBBEAN AND CENTRAL AMERICA S OF 18N W OF 75W. EASTERLY
TRADES AND NORTHERLY WINDS OVER THE NW CARIBBEAN ARE CONVERGING
OVER THE SW CARIBBEAN WITHIN A LOW-LEVEL CYCLONIC AREA FOCUSED
ALONG A SURFACE TROUGH ANALYZED FROM 14N77W TO A 1012 MB LOW
CENTERED NEAR 09N81W. SCATTERED SHOWERS AND ISOLATED TSTMS
REMAIN DISORGANIZED BUT ARE OCCURRING OVER THE AREA S OF 17N W
OF 75W. GIVEN THE CURRENT ANALYSIS...AND INDICATION FROM MANY OF
THE GLOBAL MODELS...THIS AREA OF LOW PRESSURE OVER THE SW
CARIBBEAN WILL PERSIST AND CONTINUE TO BRING A HIGHER CHANCE OF
PRECIPITATION TO WESTERN PANAMA...COSTA RICA...NICARAGUA...
HONDURAS...AND THE ADJACENT COASTAL WATERS THROUGH MID-WEEK.
ELSEWHERE E OF 75W...DRY NORTHERLY FLOW ALOFT IS PROVIDING FOR
STABLE AND DRY CONDITIONS...HOWEVER AN UPPER LEVEL LOW IS
CENTERED NEAR 16N60W THAT WILL CONTINUE TO PROVIDE A FOCUS FOR
ISOLATED SHOWER ACTIVITY OVER THE NE CARIBBEAN...AND LESSER
ANTILLES THROUGH MUCH OF THE UPCOMING WEEK AHEAD AS THE UPPER
LOW REMAINS NEARLY STATIONARY.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW CENTERED OVER NOVA SCOTIA CANADA EXTENDS AN
UPPER LEVEL TROUGH AXIS ALONG 62W TO 30N60W. THIS SLIGHTLY
NEGATIVELY TILTED TROUGH SUPPORTS A COLD FRONT THAT ENTERS THE
DISCUSSION AREA NEAR 32N55W EXTENDING SW TO 25N65W THEN INTO THE
REMNANT CIRCULATION OF PAULA...A 1012 MB LOW...CENTERED NEAR
23N77W. WHILE NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH
THE FRONT OR REMNANT LOW...SCATTERED SHOWERS ARE WITHIN 120 NM
EITHER SIDE OF THE FRONT AND FROM 21N-23N BETWEEN 75W-77W IN
ASSOCIATION WITH THE REMNANT LOW. STRONG WESTERLY UPPER LEVEL
FLOW IS NOTED BEHIND THE FRONT FEEDING INTO THE BASE OF THE
UPPER LEVEL TROUGH THAT CONTINUES TO SUPPORT STRONG SUBSIDENCE
AND DRY AIR OVER MUCH OF THE SW NORTH ATLC...WHICH IN TURN
SUPPORTS SURFACE RIDGING ANCHORED ON A 1021 MB HIGH CENTERED
OVER THE SE CONUS. FARTHER EAST...A SHARP UPPER LEVEL TROUGH IS
LOCATED ACROSS THE EASTERN ATLC WITH AXIS ALONG 30W THAT DIPS TO
10N. THIS TROUGH SUPPORTS A BROAD AREA OF SURFACE LOW PRESSURE N
OF 25N BETWEEN 25W-40W ANCHORED BY A 1010 MB LOW CENTERED NEAR
33N30W. A SURFACE TROUGH MEANDERS FROM THE LOW ALONG 31N27W
25N35W 22N44W THEN INTO A WEAK 1013 MB LOW CENTERED NEAR 24N50W.
SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 60 NM EITHER
SIDE OF THE SURFACE TROUGH BETWEEN 28W-34W...WHILE POSSIBLE
ISOLATED SHOWERS LINGER WITHIN 90 NM EITHER SIDE OF THE BOUNDARY
BETWEEN 42W-50W. ELSEWHERE OVER THE REMAINDER OF THE EASTERN
ATLC...WEAK SURFACE RIDGING ASSOCIATED WITH A 1015 MB HIGH
CENTERED NEAR 26N22W COVERS THE FAR E ATLC AND SUPPORTS OVERALL
STABLE CONDITIONS N OF 18N SE OF A LINE FROM 32N20W TO 18N40W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
HUFFMAN




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