[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 061129
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN SEP 06 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1000 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 32W S OF 23N MOVING W NEAR 10 KT. A 1012
MB LOW IS EMBEDDED ON THE WAVE AXIS NEAR 19N32W. SATELLITE
IMAGERY AND SATELLITE DERIVED WINDS INDICATE LOW-LEVEL CYCLONIC
FLOW IN THE VICINITY OF THE WAVE AXIS CONCENTRATED AROUND THE
LOW PRESSURE CENTER NEAR 19N. THE WAVE ALSO COINCIDES WITH A
DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER
IMAGERY. SCATTERED MODERATE/STRONG CONVECTION IS FROM 21N-23N
BETWEEN 30W-32W.

TROPICAL WAVE IS ALONG 44W S OF 20N MOVING W NEAR 12 KT. A 1012
MB LOW IS ALONG THE WAVE AXIS NEAR 15N44W. SATELLITE IMAGERY AND
SATELLITE DERIVED WINDS INDICATE LOW-LEVEL CYCLONIC FLOW IN THE
VICINITY OF THE WAVE AXIS CONCENTRATED AROUND THE LOW PRESSURE
CENTER NEAR 15N. THE WAVE COINCIDES WITH A DEEP LAYER MOISTURE
MAXIMUM OBSERVED TOTAL PRECIPITABLE WATER IMAGERY. A DRY SAHARAN
AIR LAYER IS TO THE W OF THE WAVE AXIS WHICH IS LIMITING DEEP
CONVECTION NEAR THE WAVE AXIS.  HOWEVER...SCATTERED SHOWERS ARE
WITHIN 75 NM EITHER SIDE OF THE AXIS FROM 8N-12N AND FROM
16N-19N.

TROPICAL WAVE IS ALONG 62W S OF 16N MOVING W NEAR 12 KT. THE
WAVE REMAINS RELATIVELY LOW-AMPLITUDE WITH NO ASSOCIATED
DEEP CONVECTION DUE TO DRY SAHARAN DUST TO THE E OF THE WAVE
AXIS. THE WAVE COINCIDES WITH A NARROW DEEP LAYER MOISTURE
MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 14N15W 13N25W 17N29W 14N38W
10N46W 6N57W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
FROM 7N-15N BETWEEN 13W-19W. ISOLATED MODERATE CONVECTION IS
FROM 9N-12N BETWEEN 37W-43W.

...DISCUSSION...

GULF OF MEXICO...
THE GULF REMAINS MOIST THIS MORNING WITH ISOLATED SHOWERS ACROSS
MUCH OF THE BASIN. AS OF 0900 UTC...A SURFACE TROUGH IS IN THE
NW GULF HUGGING THE COAST LINE EXTENDING ALONG 30N90W 29N94W
27N97W. ISOLATED SHOWERS/THUNDERSTORMS ARE WITHIN 300 SE OF THE
TROUGH. THIS ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE
BETWEEN AN UPPER RIDGE DOMINATING THE MAJORITY OF THE GULF
CENTERED OVER THE SRN BAY OF CAMPECHE NEAR 19N95W AND AN UPPER
LEVEL TROUGH OVER THE CENTRAL UNITED STATES. A SECOND SURFACE
TROUGH IS IN THE BAY OF CAMPECHE FROM 21N95W TO 16N95W. SURFACE
CONVERGENCE NEAR THE TROUGH IS SUPPORTING SCATTERED SHOWERS AND
THUNDERSTORMS S OF 22N BETWEEN 91W-97W. A SHORTWAVE UPPER LEVEL
TROUGH IS OVER THE ERN GULF WITH AXIS ALONG 30N86W TO 23N81W.
EXPECT SHOWERS/THUNDERSTORMS TO PERSIST FOR THE NEXT 24 HRS.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH OVER THE ERN GULF EXTENDS TO ERN CUBA NEAR
23N81W CONTINUING TO THE NW CARIBBEAN TO NEAR 17N86W. UPPER
LEVEL DIFFLUENCE BETWEEN THIS UPPER TROUGH AND AN UPPER LEVEL
RIDGE OVER THE CENTRAL CARIBBEAN CENTERED NEAR 13N75W IS
SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS OFF THE COAST OF
NICARAGUA AND COSTA RICA FROM 10N-15N BETWEEN 81W-85W. A SURFACE
TROUGH EXTENDS ACROSS THE BAHAMAS AND ACROSS CENTRAL CUBA FROM
22N78W TO 20N79W. SHOWER ACTIVITY ASSOCIATED WITH THE TROUGH IS
CONCENTRATED N OF THE BASIN OVER THE BAHAMAS. A FEW ISOLATED
SHOWERS ARE OVER HISPANIOLA DUE TO SURFACE CONVERGENCE NEAR A
SURFACE TROUGH TO THE N OF THE MONA PASSAGE. MODERATE TO FRESH
TRADE WINDS ARE ACROSS MUCH OF THE BASIN BECOMING STRONG IN THE
E CARIBBEAN. OVER THE NEXT 24 HR...EXPECT THE TROPICAL WAVE
ALONG 62W TO CONTINUE WWD ACROSS THE ERN CARIBBEAN.

ATLANTIC OCEAN...
AS OF 0900 UTC...A SURFACE TROUGH LINES THE FLORIDA E COAST
EXTENDING FROM 27N80W TO 31N79W. SCATTERED SHOWERS/THUNDERSTORMS
ARE WITHIN 120 NM E OF THE TROUGH AXIS. THIS ACTIVITY IS ALSO
ENHANCED BY UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL TROUGH
OVER THE ERN GULF AND AN UPPER LEVEL RIDGE OVER THE CENTRAL ATLC
CENTERED NEAR 32N52W. AN UPPER LEVEL LOW CENTERED NEAR 29N67W
INTRUDES INTO THE SW PORTION OF THE UPPER RIDGE. THIS UPPER
LEVEL LOW SUPPORTS A SURFACE TROUGH EXTENDING FROM JUST N OF THE
MONA PASSAGE NEAR 19N68W TO 29N63W. ISOLATED SHOWERS ARE WITHIN
300 NM E OF THE TROUGH AXIS. ANOTHER SURFACE TROUGH EXTENDS
ACROSS ERN CUBA INTO THE ATLC FROM 22N78W TO NEAR 26N75W.
SURFACE CONVERGENCE NEAR THE TROUGH IS SUPPORTING ISOLATED
SHOWERS/THUNDERSTORMS ACROSS THE BAHAMAS FROM 21N-25N BETWEEN
74W-79W. ELSEWHERE ACROSS THE ATLC...A BROAD SURFACE RIDGE
DOMINATES ANCHORED BY A 1022 MB HIGH NEAR 29N51W...AND A 1025 MB
AZORES HIGH NEAR 37N21W. IN THE UPPER LEVELS...A NARROW UPPER
LEVEL TROUGH IS E OF THE UPPER HIGH NEAR 33N55W. THE UPPER
TROUGH HAS AXIS ALONG 36N25W TO 17N51W. TO THE E OF THE TROUGH
ANOTHER UPPER LEVEL RIDGE IS CENTERED NEAR 20N24W.

$$
WALTON









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